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PROSTHODONTICS
Nadim Z. Baba
Tooth retention through root canal treatment or tooth extraction and implant placement: A prosthodontic perspective Nadim Z. Baba, DMD, MSD1/Charles J. Goodacre, DDS, MSD2/Mathew T. Kattadiyil, DDS, MDS, MS 3 One of the difficult decisions confronting clinicians in daily practice is whether to treat or extract a tooth, particularly those with moderate or advanced disease processes or where trauma has inflicted substantial damage. Studies have shown that the clinician’s decision is based on the length of clinical experience and the complexity of the treatment. The high survival rate of endosseous implants has also had a significant impact on the
way clinicians think about the best treatment for teeth requiring endodontic therapy. Several factors should be considered when making a decision to either treat or extract a tooth. This report provides evidence-based information about the various factors and related treatment outcomes as well as clinical perceptions from a prosthodontic perspective. (Quintessence Int 2014;45:405–416; doi: 10.3290/j.qi.a31544)
Key words: extraction, implant, outcomes, retention, root canal therapy
One of the difficult decisions a clinician is confronted with in daily practice is whether to treat or extract a tooth, particularly those with moderate or advanced disease processes or where trauma has inflicted substantial damage. This complex issue of saving a tooth versus extraction emerged when teeth were retained through root resection.1-3 Several studies1-6 evaluated root resection, with a wide range of failure percentages being reported. Failure rates ranged from 0% after a mean time of 5 years5 to a high of 38% after a mean
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Professor and Director, Hugh Love Center for Research and Education in Technology, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
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Professor, Department of Restorative Dentistry, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
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Professor and Director, Advanced Specialty Education Program in Prosthodontics, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
Correspondence: Dr Nadim Z. Baba, Hugh Love Center for Research and Education in Technology, Loma Linda University, School of Dentistry, 11092 Anderson Street, Loma Linda, CA 92350, USA. Email: [email protected]
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observation time of 10 years.6 The high rate of resection failure in some studies and the emergence of osseointegrated implant therapy presented the clinician with another treatment alternative to root resection.7,8 The high survival rate of endosseous implants has also had a significant impact on the way clinicians think about the best treatment for teeth requiring endodontic therapy. Clinicians are challenged daily with the dilemma of whether a tooth should be endodontically treated or be extracted and replaced by an implant. Di Fiore et al9 conducted a survey amongst dental faculty and students for their treatment preferences, either to retain a tooth by endodontic and restorative treatment, or extraction and implant placement. They concluded that students selected implants as a treatment option more frequently than faculty. However, faculty who had graduated recently selected implants more often than faculty who had graduated earlier. They also found that implants were selected more commonly
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when the complexity of root canal therapy and the complexity of prosthodontic treatment increased. Several factors should be considered when making a decision to either treat or extract a tooth. The purpose of this article is to review these factors from a prosthodontic perspective.
OUTCOMES OF DIFFERENT TREATMENTS Conventional fixed prosthodontics Crowns, inlays, and onlays Single crowns on natural teeth have high success rates, but there is a higher failure rate when the teeth are endodontically treated. In a retrospective clinical exam, Donavan et al10 evaluated 1,314 gold inlays, onlays, and single crowns placed by one practitioner. They found success rates of 90.3% at 10 to 19 years, 94.9% at 20 to 24 years, 98% at 25 to 29 years, 96.9% at 30 to 39 years, and 94.1% at 40 years and more. A cross-sectional study of 688 singleunit metal-ceramic crowns placed in a prosthodontic practice found a 93% success rate between 5 and 10 years. Crowns on endodontically treated teeth had a higher failure rate (5%) than crowns on vital teeth (1%).11 A systematic review of 1,957 computer-aided design/computer-assisted manufacture (CAD/CAM) single-tooth restorations found that CEREC and Celay restorations had a success rate of 91.6%.12 Combination of raw data from multiple clinical studies reported several complications associated with single crowns.13 The three most common complications were the need for endodontic treatment (3%), porcelain veneer fracture (3%), and loss of retention (2%).
Fixed partial dentures (FPDs) FPDs have lower survival rates than single crowns on natural teeth. They also have lower survival rates than both root canal treated teeth and crowns on single implants. Meta-analyses performed on the dental literature presenting clinical data of conventional FPDs showed 94% survival rate after 5 years,14 and 74% survival rate
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after 15 years.15,16 Combination of raw data from multiple clinical studies reported several complications associated with FPDs.13 The three most common complications were caries (18% of the abutments), pulpal necrosis (11% to 17% of the abutments), and loss of retention or debonding (7%). A systematic review14 comparing the outcomes of extraction and an FPD, root canal treatment (RCT) with restoration, and implant-supported single crowns concluded that RCT and restoration as well as implantsupported single crowns resulted in superior long-term survival compared with FPDs attached to natural teeth.
Crowns and pulpal necrosis Some teeth that are prepared for crowns and FPDs experience a need for RCT after restoration. The incidence is generally small but increases over time. The long-term prognosis and the onset of endodontic complications of abutment teeth restored with crowns or FPDs have been extensively evaluated. Several clinical studies17-20 examined the periapical status of abutment and nonabutment teeth over a long period of time. Bergenholtz and Nyman18 evaluated 255 abutment teeth for a mean period of 8.7 years. They found a significantly higher frequency of pulpal necrosis, including periapical lesions, in abutment teeth (15%) when compared to nonabutment teeth (3%). In a 10-year clinical study, Karlsson17 examined 944 abutments of extensive fixed dental prostheses. He reported an incidence of 11% pulpal necrosis. Another 10-year clinical study19 aimed at studying luting cements found the incidence of pulpal necrosis to be around 5.2%. Thirty percent of the 135 abutments that were evaluated had RCT prior to FPD placement. Valderhaug et al20 evaluated the radiographic changes in the periapical status and compared the clinical status of teeth with vital pulp and endodontically treated teeth restored with crowns and FPDs during 25 years. They found that the incidence of pulpal deterioration was 2% at 5 years, 8% at 10 years, 13% at 20 years, and 17% at 25 years.
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Endodontics Success of endodontic therapy Teeth without periapical lesions prior to RCT have higher success rates than those with lesions. Systemic diseases can affect the outcome of RCT. Multiple factors have been identified as influencing the outcome of endodontic therapy. The healing of the periapical lesion and the absence of symptomatic response define endodontic success.21,22 Increased endodontic success has been related to the introduction of modern instruments and equipment (dental microscope, advanced rotary instruments, cone beam computed tomography, improved disinfection medications, etc). A review of several studies was conducted to assess the level of evidence for the outcome (success and failure) of nonsurgical RCT. The authors found that 92% to 98% of teeth without periapical lesions remained disease-free after RCT, whereas 74% to 86% of teeth with apical lesions completely heal after RCT.23,24 In the presence of apical lesions, several studies24-29 including one by Friedman and Mor24 have shown that the success rate of endodontic treatment is about 10% to 20% less than for teeth without periapical lesions. Chugal et al26 found that a tooth with a large periapical lesion prior to RCT will have a greater chance for failure after treatment. A long-term study30 investigating endodontic treatment of teeth with periapical lesions performed by undergraduate dental students showed that only 76% of root canal treated teeth healed. A retrospective cohort study conducted in a private practice to evaluate endodontically treated and retreated teeth found that, within 10 years, only 7% of root canal treated teeth required extraction after treatment and 84% of all endodontically treated teeth were considered successful.31 However, endodontically treated teeth that are asymptomatic and considered clinically successful can still house bacteria within the canal and around the apices.32,33 The presence of systemic disease can affect the prognosis of endodontic treatment. Fouad and Burleson34 found that patients with type 2 diabetes are less likely than nondiabetic patients to have successful RCT when there are preoperative periapical lesions. Segura-Egea et al35 investigated the possible connection between sys-
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temic and periapical disease. They concluded that diabetes could contribute to a high prevalence of periapical lesions. Wang et al36 found that in addition to diabetes, hypertension and coronary artery disease were significant risk factors for tooth extraction after RCT. Several systematic reviews37-40 have been conducted to determine the success rate of endodontic therapy. Kojima et al37 used meta-analysis data from 26 papers to assess the success of root canal treated teeth (nonvital versus vital pulps). They found a cumulative success rate of 82.8% for vital pulps and 78.9% for nonvital pulps. They noted that the best cumulative success rate was obtained when the roots were filled to the apex (vs overextension and underextension). Ng et al38 wanted to study the outcome of primary RCT, and 63 studies met their strict inclusion criteria. The weighted pooled success rates of treatments completed at least 1 year prior to the review ranged from 68% to 85%. The same authors carried out meta-analyses to quantify the influence of the clinical factors on the efficacy of primary RCT.39 Sixty-three studies met their inclusion criteria. They identified four factors that have a significant effect on the outcomes of primary RCT: preoperative absence of periapical radiolucency; root fillings with no voids; root fillings that are within 2 mm of the radiographic apex; and satisfactory coronal restoration. In a more recent study, Ng et al40 investigated tooth survival after RCT. Fourteen studies met their inclusion criteria and the majority of the studies were retrospective (n = 10). They reported an 86% tooth survival (pooled percentages) 2 to 3 years after RCT, 93% tooth survival 4 to 5 years after RCT, and 87% tooth survival 8 to 10 years after RCT. Four factors were determined to be important in improving tooth survival after RCT: crown restoration after RCT; the presence of mesial and distal proximal contact; the treated tooth was not planned as an abutment for a fixed or removable partial denture; and the tooth type.40,41
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Failure of RCT restored with crowns, FPD abutments, or removable partial denture abutments There are multiple studies that indicate root canal treated teeth restored with crowns have better survival than those restored with direct restorations that do not encompass the cusps. Root canal treated teeth that serve as FPD abutments have lower survival rates than those supporting single crowns. A systematic review was conducted to determine if there is any correlation between single crown placement and long-term survival rate of root canal treated teeth as opposed to direct restorations.42 The authors found a 10-year survival rate of 81% for crowned teeth and a 10-year survival rate of 63% for root canal treated with direct restorations (amalgam, composite resins, cements). A study of 220 molars observed teeth restored without crowns for time periods between 6 months and 10 years. The 1-, 2-, and 5-year survival rates were 96%, 88%, and 36%, respectively. The authors determined that teeth with maximum tooth structure had the highest 5-year survival rate of 78%.43 Another study, by Aquilino and Caplan,44 found that root canal treated teeth without crowns were lost at six times the rate of those with crowns, indicating a strong correlation between placement of crowns and survival of endodontically treated teeth. A study of 1,639 root canal treated teeth that were restored with amalgam that did not encompass the cusps determined that maxillary premolars with mesial-occlusal-distal (MOD) amalgams had the highest fracture rate.45 After 3 years, 28% fractured and after 10 years 57% had fractured. After 20 years, the fracture rate rose to 73%. A study was performed that evaluated 116 root canal treated teeth that had failed and required extraction.46 Teeth without crowns were extracted after an average time of 50 months whereas those with crowns were extracted after an average time of 87 months.46 When root canal treated teeth serve as FPD abutments, their survival is reduced.47-52 Sundh and Odman47 reported that 47% of root canal treated were lost after 18 years. Palmqvist and Swartz48 examined the long-term results of single crowns and FPDs in a
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prosthodontic clinic. They found that 24% of nonvital teeth were lost vs 10% for vital teeth. Randow et al49 found that 3% to 21% of nonvital teeth fractured. Randow50 also found increased fractures with root canal treated distal abutments. Leempoel et al51 analyzed the influence of several factors on the lifetime of FPDs. There was a decrease in survival rate of FPDs with nonvital abutments. A retrospective clinical study by Wegner et al52 calculated the survival rate of restored endodontically treated abutments. They found 93% survival of root canal treated teeth serving as FPD abutments versus 51% for RPD abutments. Another study53 found that root canal treated RPD abutments had 1.9times greater failure risk than crowns.
Success of periapical surgery and retreatment A wide range of survival rates have been reported for endodontically treated teeth that have undergone apical surgery. The reported rates have frequently been less than initial endodontic treatment. RCT has been determined to be cost-effective compared to implants and single crowns. Multiple studies24,54-59 determined a wide range of survival rates for endodontically treated teeth after periapical surgery. Friedman and Mor24 conducted a systematic review on the outcome of endodontic therapy and concluded that complete healing of apical periodontitis following periapical surgery ranged from 37% to 85%. They also concluded that comparison between studies should be avoided due to the lack of standardization between treatment protocols and methodologies. In a controlled prospective study, Jannson et al56 found a failure rate of 50% after periapical surgery. They also observed a positive correlation between the size of the periradicular defect and healing. The larger the defect, the more ineffective and uncertain is the healing. Del Fabbro et al60 conducted a systematic review to compare the outcome of surgical versus nonsurgical retreatment. They found only two randomized controlled trials that yielded 82 teeth that had a follow up of 4 years. There was no significant difference in the success rate between the surgical treatment and the endodontic retreatment. After 4 years of follow-up, the outcome for the two procedures was
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similar. Using systematic reviews, Tsesis et al61 studied the success of surgical endodontic treatment performed by a modern technique (surgical microscope, ultrasonic tips to a depth of 3 to 4 mm). In 11 studies, 880 teeth were available for comparison. The pooled percentage of success was 91.6%, and the pooled percentage of failure was 4.7%. Ng et al62 studied the outcome of retreatment of root canal treated teeth. Seventeen studies met their inclusion criteria. The pooled success rate of an endodontic retreatment was 77%. They concluded that significant prognostic factors such as the periapical status, apical extent of the root filling, quality of the coronal restoration, and the size of the lesion can affect the outcome of the retreatment. The cost-effectiveness of RCT versus implant placement was studied63 and the authors concluded that RCT is highly cost-effective as a first line of intervention. Endodontic retreatment is also cost-effective, but surgical retreatment is not. If retreatment fails, implants may play an important role in patient treatment. A more recent study published by Kim and Solomon64 showed that periapical surgery was the most cost-effective among all treatment options for a failed root canal treated molar. Endodontic retreatment with a crown can be the most cost-effective treatment unless adjunctive procedures are required. At such time a single implant-supported crown becomes more cost-effective. Based on current treatment fees, a single implantsupported crown was found to be the least cost-effective treatment option despite its high survival rate.
Implants Dental implants have high survival rates. Multiple systematic reviews have determined that the survival rates of dental implants and root canal treated teeth are similar. Multiple studies65-67 determined high survival rates for single-tooth implants. Survival rates range from 94.4% to 99%, with a mean survival rate of 96.7%. The American Dental Association Council on Scientific Affairs reported a high survival rate for implants in a number of clinical situations.68 They evaluated 10 studies involving 1,453 implants and found survival rates ranging from 94.9% to 99%, with a mean survival rate
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of 96.7%. Lindh et al69 determined the success rate of a single implant to be 97.5% after 6 to 7 years. A more recent study70 investigated the long-term outcomes of titanium implants with roughened, microporous surfaces. Of the 145 original implants placed, only 72 remained for follow-up after 20 years, and 68% of the 72 remaining implants were without technical complications. They concluded that the success rate after 20 years is 75.8% and the survival rate is 89.5%. There have been multiple reviews that compare the survival of root canal treated teeth and dental implants. Torabinejad et al71 conducted a systematic review of outcomes of teeth treated with extraction and no replacement, extraction and FPD, RCT and restoration, or implant-supported single crown: 101 studies were selected for inclusion and studies were from 2 to 6 years in duration and more. They concluded that the success of RCT, FPDs, and implant-supported single crowns could not be effectively compared due to very different definitions of success in the studies. They reported that both implants and RCTs resulted in superior long-term survival, compared to FPDs, and survival of teeth with initial RCT and survival of single implants were comparable. The study also found that when success rate and survival rates are compared, long-term (6+ years) success rates were higher with implants over endodontic therapy (97% vs 84%). The authors further reported that extraction without replacement resulted in inferior psychologic outcomes regarding perception of appearance, emotional effect of tooth loss, and survival of teeth adjacent to posterior edentulous spaces. However, it did not substantially affect satisfaction with slight to moderately shortened dental arches relative to oral comfort, function, tooth migration, temoporomandibular joint dysfunction (TMD), and joint or tooth loading. Holm-Pedersen et al72 conducted a systematic review to compare the longevities of teeth and implants. They identified 49 articles and 6 systematic reviews, and concluded that if periodontally compromised teeth are treated and maintained regularly they will have a long-term success of 92% to 93%. They also concluded that endodontically treated and restored
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teeth yield similar and high success rates. Implants that were evaluated after 10 years did not surpass the longevity of even compromised, but treated, natural teeth. Another systematic review was conducted by Iqbal and Kim,73 looking at the differences in outcome of restored endodontically treated teeth compared to implant-supported restorations. Fifty-five single-tooth implant studies and 13 restored randomized clinical trial studies were included. They found no significant differences in survival between restored endodontically treated teeth and single-tooth implants. They concluded that the decisions must be based on factors other than the treatment outcomes of the procedures.
Discussion of the outcomes of different treatments From the above data related to restored endodontically treated teeth and restored dental implants, no absolute recommendations can be made based solely on outcome data, since there does not appear to be a survival difference between a crowned endodontically treated tooth and a single restored implant. Therefore, the diagnostic decision often needs to be made on the basis of other factors.74 Treatment decisions should be based on satisfying the patient’s desires and on the overall importance of any single tooth to the patient’s comprehensive treatment plan. Each tooth and patient must be individually evaluated to determine which treatment will provide the best result in terms of esthetics, comfort, function, and cost-effectiveness. Practitioners have an obligation to present patients with a balanced perspective regarding alternative treatments, which requires substantial clinical experience with both treatment modalities.
OTHER FACTORS THAT AFFECT THE TREATMENT CHOICE Cost and number of adjunctive procedures Root canal treatment and restoration is usually less costly than an implant and crown. The number of procedures that accompany either treatment can be a determining
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factor in what a patient can afford and therefore becomes part of the decision as to which treatment is provided. The cost of RCT and restoration is generally less than placement of a dental implant and its restoration. However, a number of adjunctive procedures can be required to retain a root canal treated tooth, such as crown-lengthening, apical surgery, core build-up, or post and core. These procedures add to the cost of treatment, increase the complexity, increase the treatment time, and can make the overall cost of treatment greater than that of a dental implant. Similarly, adjunctive procedures may be required with a dental implant, such as bone grafting or connective tissue grafting, or both, to permit implant placement or achieve desirable implant positioning. These procedures add to the cost and treatment time and make the overall cost greater than RCT and restoration.
Esthetic considerations When the bone surrounding a tooth is apical to the interdental papillae and midfacial gingival crest by distances that exceed guidelines established by the dental literature, the extraction of that tooth and placement of a dental implant will usually result in apical relocation of the soft tissue that can create an esthetic liability. The location of the bone apical to the gingiva should be determined as part of the diagnosis and treatment planning. In esthetic locations, retaining a tooth through RCT or even completing adjunctive endodontic procedures such as retreatment or apical surgery may be advantageous in the presence of a thin biotype, unfavorable bone to proximal contact distances, long epithelial attachments, or the presence of an adjacent longstanding dental implant. With a thin periodontal biotype, it is more likely that the interdental papilla will not be present following tooth extraction and implant placement than when a thick biotype is present. It is more likely that a papilla will not fill the interdental space when a thin biotype is present (Fig 1a), especially when the distance from the interproximal bone crest to the proximal contact of the natural tooth being considered for extraction is greater than 4 mm (Fig 1b).75 Even when a thick biotype is pres-
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Fig 1a Thin biotype and increased interproximal bone to proximal contact distance reveals recession of gingival tissue on the site of the lateral incisor. Fig 1b Radiograph of the situation presented in Fig 1a shows the increased interproximal bone to proximal contact distance which contributed to the recession.
a Fig 2a Radiographic images showing increased interproximal bone to proximal contact distance on the left lateral incisor compared to the right lateral incisor.
a Fig 3a Radiograph showing approximately 6 mm distance between the interproximal bone and proximal contact between adjacent implant crowns.
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Fig 2b The right lateral incisor shows ideal gingival esthetics due to favorable interproximal bone to proximal contact distance.
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Fig 3b Lack of interproximal papilla is clearly evident between adjacent implants.
ent around a tooth being considered for extraction, the papilla is unlikely to fill the cervical embrasure space when the distance between the interproximal bone and proximal contact is greater than 5 mm.76 Therefore, it is important to measure the distance between the interproximal bone crest and the proximal contact. When that distance exceeds 4 mm in thin biotype patients and exceeds 5 mm in thick biotype patients, it is more likely
Fig 2c The left lateral incisor reveals some tissue recession on the mesial surface due to the higher interproximal bone to proximal contact distance seen in Fig 2a.
Fig 3c Smile view of definitive restorations on the adjacent implants revealing absence of mesial interdental papilla between the central incisors.
that soft tissue will not fill the cervical embrasures if the tooth is extracted and replaced by an implant (Fig 2). An even more critical situation occurs when two adjacent teeth in the esthetic zone are being considered for extraction. Research indicates that only about 3 mm of mucosa will be present incisal to the healed interproximal bone crest between two adjacent implants placed following the extraction of two adjacent teeth.77 There-
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Fig 4a Pre-extraction radiograph revealing significant bone loss from periodontal disease creating long epithelial attachments. Fig 4b Subsequently placed implant restoration reveals poor esthetic result due to the long epithelial attachment and bone loss prior to extraction.
fore, it is much more likely that an open cervical embrasure will be present between the two implants (Fig 3). Another situation that usually results in the lack of an interdental papilla and also frequently results in an abnormal apical position of the facial mucosa is the presence of a long epithelial attachment around a tooth being considered for extraction. This condition is commonly present when there was significant periodontal pocketing around teeth, and periodontal treatment resulted in reattachment of the gingiva to the tooth. The result is a greater than normal distance between the gingival margin and the underlying bone. Extraction of such teeth will result in greater than normal apical movement of the soft tissue because the bone is located well below the gingival margin (Fig 4). Retaining such a tooth through RCT will allow the mucosa to retain its position around the tooth, and therefore results in preserving gingival esthetics. Another esthetic soft tissue factor that has been observed relates to the presence of an existing dental implant located adjacent to a tooth being considered for extraction. When an implant is present next to a tooth, the interproximal bone typically has an apical slope from the adjacent natural tooth to the implant. The difference between the position of the interproximal bone on the tooth and the position of the bone where it meets the implant can be a few millimeters. This interproximal bone crest is only present because of the periodontal ligament attachment to the natural tooth. Extraction of the tooth will result in substantial
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Figs 5a and 5b Pink porcelain has been applied to the implant crown to mask the soft tissue recession and improve the esthetic outcome.
bone remodeling, even to the level of the bone adjacent to the implant platform. The bone remodeling is associated with concomitant soft tissue recession. Therefore, it may be prudent to retain teeth adjacent to a long-standing dental implant even if endodontic retreatment or apical surgery is required, as extraction will result in substantial recession of the mucosa. In addition to the interdental papilla, the facial gingiva usually undergoes a small amount of recession following extraction of a tooth and implant placement. The amount of facial position change is related to the location of the facial bone crest prior to extraction of a tooth. The distance that the facial bone is located apical to the marginal gingiva averages about 3 mm.78 When a tooth has a low bone crest (bone crest is located more than 3 mm apical to the marginal gingiva), the amount of facial soft tissue recession will be greater. When a high bone crest is present (the bone crest is less than 3 mm apical to the marginal gingiva), there will be little or no soft tissue recession. As a result, it is prudent to measure the distance between the midfacial gingival crest and the underlying bone by anesthetizing the gingiva and using a periodontal probe to measure that distance, a process known as bone sounding. Extraction of teeth with distances greater than 3 mm will result in apical repositioning of the facial mucosa and make the implant crown have a greater incisocervical dimension than the natural tooth to which a match is desirable. The application of pink porcelain in such situations can be a viable option to improve esthetics (Fig 5).
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Fig 6 (left) An implant restoration is a good option for patients who are diagnosed to have a high risk for caries. Fig 7 (right) Clinical situation where an implant restoration is indicated due to the inadequate ferrule effect that suggests a poor prognosis if the fractured tooth were to be restored.
Biologic considerations Some patients with recurring caries and/or periodontal disease can benefit from tooth extraction and implant placement. Implants are often the preferred treatment for patients who have experienced recurrent caries on a regular basis. While most patients can achieve caries control through risk assessment and the introduction of preventive measures, some patients have simply not been successful at incorporating the required changes. As a result, they have experienced the need for restorations followed by re-restoration of the same teeth. At some point such teeth become unrestorable and implants provide a viable treatment for such patients (Fig 6). Similarly, patients who have struggled with recurring periodontal disease and regularly have relapses following treatment can benefit from extraction and replacement with dental implants.
Compromised ability to restore a tooth To provide optimal longevity in root canal treated teeth and minimize the chances for root fracture to occur, there should ideally be 2 mm of cervical tooth structure that can be encompassed by the tooth preparation to form a cervical ferrule. When there is limited tooth structure present incisal or occlusal to the bone, restoration of a root canal treated tooth will result in little or no ferrule being present. Studies have shown that a ferrule is important in helping an endodontically treated tooth resist fracture after restoration. Ferrules of 2.0 mm are considered ideal but often are difficult to obtain on teeth that have been extensively restored, have extensive caries, or have been subjected to substantial trauma leading to
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tooth wear and/or fracture.79,80 Such teeth may be better managed by extraction and implant placement (Fig 7). It has also been determined that the presence of a 2-mm ferrule on all four surfaces of a tooth (facial, lingual, mesial, and distal) provides optimal resistance to tooth fracture, as opposed to having a 2-mm ferrule on only some of the surfaces.80
Systemic factors Certain systemic factors decrease the survival of dental implants and may indicate that it would be more efficacious to retain a natural tooth through RCT. Retaining natural teeth may be beneficial when therapeutic doses of radiation have been administered to the maxilla, since research shows an undesirably high level of implant loss when they have been placed into previously irradiated maxillae.81 While such therapeutic doses of radiation may affect salivary flow and make patients much more susceptible to caries, it may be easier to manage the caries control than manage implant loss. Each such patient will require careful evaluation to determine the best course of treatment. Heavy smoking can contraindicate the use of dental implants.82 Therefore, it may be more prudent to deal with the smoking factors that affect natural teeth and the periodontium rather than place implants. Again, this factor will require individual assessment to determine which treatment is best. Bisphosphonate therapy has resulted in the occurrence of bone osteonecrosis following tooth extraction and other surgically invasive procedures. This documented problem has caused concern related to implant surgery. At the present time, it is not clear from the dental literature whether bisphosphonate therapy
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totally contraindicates dental implant placement.83 Therefore, more research needs to become available before such a definitive conclusion can be made. However, some research84,85 and also clinical experience indicate that patients who have been using oral bisphosphonates may not be contraindicated for implant therapy. However, the use of intravenous bisphosphonates, such as those used for cancer therapy, remains a serious concern and therefore surgical implant placement has typically been avoided in such patients. Until more research emerges, caution should be exercised along with good informed consent. When implants are to be placed in patients who have been taking oral bisphosphonates for multiple years, it is prudent to place only one implant and determine how the patient responds to the treatment rather than to place multiple implants at one time.
Anatomic factors The presence of poor quality bone, proximity to vital structures, and minimal bone present around an existing tooth may limit the use of dental implants and favor retention of a tooth. Very poor quality bone has been associated with higher implant loss rates and may be a factor that would lead to retention of a tooth through RCT rather than extraction and implant placement. This factor would become particularly important should there be a history of implant loss elsewhere in the mouth when the implant was placed into poor quality bone. When vital structures are located in proximity to potential implant sites and there is an increased potential for neurosensory disturbance to occur, it may be best to retain a tooth in that area rather than undergo the risk of abnormal sensation by placing an implant.
Tooth color and tooth thickness Certain teeth have unique color and/or translucency patterns that make it difficult for a crown to match adjacent teeth. This factor can complicate both restoration of a root canal treated tooth and restoration of a dental implant. Matching the color of a ceramic crown to adjacent teeth can be challenging with highly visible teeth that
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have unique internal dentin colorations or substantial amounts of enamel translucency/transparency. Such teeth can be very difficult to color match with ceramic materials. When such teeth are present and they require RCT but do not need a ceramic crown, it may be esthetically advantageous to retain the tooth through RCT, rather than extract it and have an implant crown that does not match the adjacent uniquely colored teeth. Restoring the access opening in such anterior teeth may provide the most esthetic result. A similar situation is encountered when a tooth with very challenging color characteristics requires both RCT and a ceramic crown. It may not be possible to obtain the desired color match with a ceramic crown due to the inability to match the desired color within the ceramic thickness available through reduction of the tooth. Extraction of a tooth and placement of a dental implant allows for a greater thickness of porcelain in the crown, particularly in the cervical aspect of the crown. While the difficulty of the color match still remains, the greater ceramic thickness makes it more likely that the color will be a better approximation to the color of the adjacent natural teeth.
Patient preference Patient preference is an important part of the decisionmaking process. It must be emphasized that effective treatment options be presented to the patient to enable them to make an informed treatment decision based on multiple factors that might be significant to each individual patient. Patient preferences may vary, sometimes influenced by reluctance to accept adjunctive surgical procedures, having natural teeth prepared, the timeline for different treatments, and/or investment in higher fees for treatment. Augusti et al86 reported their findings from a study that assessed patient preferences in the restoration of a single-tooth gap based on the willingness to pay (WTP) index. Most of the population surveyed in this study preferred the implant single crown as a treatment option over a three-unit FPD, revealing a higher WTP index in the esthetic zone.
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CONCLUSION This report provides evidence-based information about the various factors and related treatment outcomes for single-tooth situations as well as some perceptions based on clinical experience. It is intended to assist the clinician in making appropriate treatment decisions for their patients. While utilizing the concepts and considerations discussed here, it cannot be emphasized enough that treatment decisions should always include the varying needs and desires of each informed patient.
REFERENCES 1. Bergenholtz G. Radectomy of multi-rooted teeth. J Am Dent Assoc 1972;85:87–85. 2. Buhler H. Evaluation of root resected teeth. Results after ten years. J Periodontol 1988:59:805–810. 3. Carnavale G, Pontoriero R, di Febo G. Long-term effects of root-resective therapy in furcation-involved molars: A 10-year longitudinal study. J Clin Periodontol 1998;25:209–214. 4. Erpenstein H. A 3-year study of hemisectioned molars. J Clin Periodontol 1983;10:1–10. 5. Hamp SE, Nyman S, Lindhe J. Periodontal treatment of multirooted teeth. Results after 5 years. J Clin Periodontol 1975;2:126–135. 6. Langer B, Stein SD, Wagenberg B. An evaluation of root resection. A ten-year study. J Periodontol 1981;52:719–722. 7. Becker W, Becker B. Replacement of maxillary and mandibular molars with single endosseous implant restorations: A retrospective study. J Prosthet Dent 1995;74:51–55. 8. Becker W, Becker BE, Alsuwyed A, Al-Mubarak S. Long-term evaluation of 282 implants in maxillary and mandibular molar positions: A prospective study. J Periodontol 1999;70:896–901. 9. Di Fiore PM, Tam L, Thai HT, Hittelman E, Norman RG. Retention of teeth versus extraction and implant placement: treatment preferences of dental faculty and dental students. J Dent Educ 2008;72:352–358. 10. Donavan T, Simonsen RJ, Guertin G, Tucker RV. Retrospective clinical evaluation of 1,314 cast gold restorations in service from 1 to 52 years. J Esthet Restor Dent 2004;16:194–204. 11. Walton TR. A 10-year longitudinal study of fixed prosthodontics: clinical characteristics and outcome of single-unit metal-ceramic crowns. Int J Prosthodont 1999;12:519–526. 12. Wittneben JG, Wright RF, Weber HP, Gallucci GO. A systematic review of the clinical performance of CAD/CAM single-tooth restorations. Int J Prosthodont 2009;22:466–471. 13. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complications in fixed prosthodontics. J Prosthet Dent 2003;90:31–41. 14. Salinas TJ, Eckert SE. In patients requiring single-tooth replacement, what are the outcomes of implant as compared to tooth-supported restorations? Int J Oral Maxillofac Implants 2007;22(Suppl):71–95. 15. Creugers NH, Kayser AF, van’t Hof MA. A meta-analysis of durability data on conventional fixed bridges. Community Dent Oral Epidemiol 1994;22:448–452. 16. Scurria MS, Bader JD, Shugars DA. Meta-analysis of fixed partial denture survival: prostheses and abutments. J Prosthet Dent 1998;79:459–464. 17. Karlsson S. A clinical evaluation of fixed bridges, 10 years following insertion. J Oral Rehabil 1986;13:423–432.
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18. Bergenholtz G, Nyman S. Endodontic complications following periodontal and prosthetic treatment of patients with advanced periodontal disease. J Periodontol 1984;55:63–68. 19. Jokstad A, Mjör IA. Ten years’ evaluation of three luting cements. J Dent 1996;24:309–315. 20. Valderhaug J, Jokstad A, Ambjornsen E, Norheim PW. Assessment of periapical and clinical status of crowned teeth over 25 years. J Dent 1997;25:97–105. 21. Strindberg LZ. The dependence of the results of pulp therapy on certain factors. An analytic study based on radiographic and clinical follow-up examinations. Acta Odontol Scand 1956;14(Suppl 21):1–175. 22. Ørstavik D, Kerekes K, Eriksen HM. The periapical index: a scoring system for radiographic assessment of apical periodontitis. Endod Dent Traumatol 1986;2:20–34. 23. Torabinejad M, Kutsenko D, Machnick TK, Ismail A, Newton CW. Levels of evidence for the outcome of nonsurgical endodontic treatment. J Endod 2005;31:637–646. 24. Friedman S, Mor C. The success of endodontic therapy: healing and functionality. J Calif Dent Assoc 2004;32:493–503. 25. Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 1997;30:297–306. 26. Chugal NM, Clive JM, Spångberg LS. A prognostic model for assessment of the outcome of endodontic treatment: effect of biologic and diagnostic variables. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:342–352. 27. Ng YL, Mann V, Gulabivala K. Outcome of secondary root canal treatment: a systematic review of the literature. Int Endod J 2008;41:1026–1046. 28. Sjögren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod 1990;16:498–504. 29. Doyle SL, Hodges JS, Pesun IJ, Law AS, Bowles WR. Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and singletooth implants. J Endod 2006;32:822–827. 30. Siqueria JF Jr, Rôças IN, Riche FN, Provenzano JC. Clinical outcome of the endodontic treatment of the teeth with apical periodontitis using an antimicrobial protocol. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:757–762. 31. Fonzar F, Fonzar A, Buttolo P, Worthington HV, Esposito M. The prognosis of root canal therapy: a 10-year retrospective cohort study on 411 patients with 1175 endodontically treated teeth. Eur J Oral Implantol 2009;2:201–208. 32. Ricucci D, Siqueira JF Jr, Bate AL, Pitt Ford TR. Histologic investigation of root canal-treated teeth with apical periodontitis: a retrospective study from twenty-four patients. J Endod 2009;35:493–502. 33. Tronstad L, Barnett F, Cervone F. Periapical bacteria plaque in teeth refractory to endodontic treatment. Endod Dent Traumatol 1990;6:73–77. 34. Fouad AF, Burleson J. The effect of diabetes mellitus on endodontic treatment outcome: data from an electronic patient record. J Am Dent Assoc 2003;134:43–51. 35. Segura-Egea JJ, Castellanos-Cosano L, Machuca G, et al. Diabetes mellitus, periapical inflammation and endodontic treatment outcome. Med Oral Patol Oral Cir Bucal 2012;17:e356–e361. 36. Wang CH, Chueh LH, Chen SC, Feng YC, Hsiao CK, Chiang CP. Impact of diabetes mellitus, hypertension, and coronary artery disease on tooth extraction after nonsurgical endodontic treatment. J Endod 2001;37:1–5. 37. Kojima K, Inamoto K, Nagamatsu K, et al. Success rate of endodontic treatment of teeth with vital and nonvital pulps. A meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97:95–99. 38. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature - part 1. Effects of study characteristics on probability of success. Int Endod J 2007;40:921–939. 39. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature - part 2. Influence of clinical factors. Int Endod J 2008;40:6–31. 40. Ng YL, Mann V, Gulabivala K. Tooth survival following non-surgical root canal treatment: a systematic review of the literature. Int Endod J 2010;43:171–189.
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41. Heling I, Gorfil C, Slutzky H, Kopolovic K, Zalkind M, Slustzky-Goldberg I. Endodontic failure caused by inadequate restorative procedures; a review and treatment recommendations. J Prosthet Dent 2002;87:674–678. 42. Stavropoulou AF, Koidis PT. A systematic review of single crowns on endodontically treated teeth. J Dent 2007;35:761–767. 43. Nagasiri R, Chitmongkolsuk S. Long-term survival of endodontically treated molars without crown coverage: a retrospective cohort study. J Prosthet Dent 2005;93:164–170. 44. Aquilino SA, Caplan DJ. Relationship between crown placement and the survival of endodontically treated teeth. J Prosthet Dent 2002;87:256–263. 45. Hansen EK, Asmussen E, Christiansen NC. In vivo fractures of endodontically treated posterior teeth restored with amalgam. Endod Dent Traumatol 1990;6:49–55. 46. Vire DE. Failure of endodontically treated teeth: classification and evaluation. J Endod 1991;17:338–342. 47. Sundh B, Odman P. A study of fixed prosthodontics performed at a university clinic 18 years after insertion. Int J Proshtodont 1997;10:513–519. 48. Palmqvist S, Swartz B. Artificial crowns and fixed partial dentures 18 to 23 years after placement. Int J Prosthodont 1993;6:279–285. 49. Randow K, Glantz PO, Zoger B. Technical failures and some related clinical complications in extensive fixed prosthodontics. An epidemiological study of long-term clinical quality. Acta Odontol Scand 1986;44:241–255. 50. Randow K. On the functional deformation of extensive fixed partial dentures. An experimental clinical and epidemiological study. Swed Dent J 1986;34:1–83. 51. Leempoel PJ, Käyser AF, Van Rossum GM, De Haan AF. The survival rate of bridges. A study of 1674 bridges in 40 Dutch general practices. J Oral Rehabil 1995;22:327–330. 52. Wegner PK, Freitag S, Kern M. Survival rate of endodontically treated teeth with posts after prosthetic restoration. J Endod 2006;32:928–931. 53. Balkenhol M, Wöstermann B, Rein C, Ferger P. Survival time of cast post and cores: a 10-year retrospective study. J Dent 2007;35:50–58. 54. Frank Al, Glick DH, Patterson SS, Weine FS. Long-term evaluation of surgically placed amalgam fillings. J Endod 1992;18:391–398. 55. Wesson CM, Gale TM. Molar apicectomy with amalgam root-end filling: results of a prospective study in two district general hospitals. Br Dent J 2003;195:707–714. 56. Jannson L, Sandstedt P, Låftman AC, Skoglund A. Relationship between apical and marginal healing in periradicular surgery. Oral Surg Oral Med Oral Pathol Radiol Endod 1997;83:596–601. 57. Allen RK, Newton CW, Brown Jr CE. A statistical analysis of surgical and nonsurgical endodontic retreatment cases. J Endod 1989;15:261–266. 58. Maddalone M, Gagliani M. Periapical endodontic surgery: a 3-year follow-up study. Int Endod J 2003:36:193–198. 59. Penarrocha M, Marti E, Garcia B, Gay C. Relationship of periapical lesion radiologic size, apical resection, and retrograde filling with the prognosis of periapical surgery. J Oral Maxillofac Surg 2007;65:1526–1529. 60. Del Fabbro M, Taschieri S, Testori T, Francetti L, Weinstein RL. Surgical versus non-surgical endodontic re-treatment for periradicular lesions. Cochrane Database Syst Rev 2007;18(3):CD005511. 61. Tsesis I, Faivishevsky V, Kfir A, Rosen E. Outcome of surgical endodontic treatment performed by a modern technique: a meta-analysis of literature. J Endod 2009;35:1505–1511. 62. Ng YL, Mann V, Gulabivala K. Outcome of secondary root canal treatment: a systematic review of the literature. Int Endod J 2008;41:1026–1046. 63. Pennington MW, Vernazza CR, Shackley P, Armstrong NT, Whitworth JM, Steele JG. Evaluation of the cost-effectiveness of root canal treatment using conventional approaches versus replacement with an implant. Int Endod J 2009;42:874–883. 64. Kim SG, Solomon C. Cost-effectiveness of endodontic molar retreatment compared with fixed partial dentures and single-tooth implant alternatives. J Endod 2011;37:321–325.
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65. Mozzati M, Gallesio G, Del Fabbro M. Long-term (9–12 years) outcomes of titanium implants with oxidized surface: a retrospective investigation on 209 implants. J Oral Implantol 2013 Oct 31 [Epub ahead of print]. 66. Lekholm U, Gunne J, Henry P, et al. Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study. Int J Oral Maxillofac Implants 1999;14:639–645. 67. Creugers NH, Kreulen CM, Snoek PA, de Kanter RJ. A systematic review of single-tooth restorations supported by implants. J Dent 2000;28:209–217. 68. Dental endosseous implants: an update. J Am Dent Assoc 2004;135:92–97. 69. Lindh T, Gunne J, Tillberg A, Molin M. A meta-analysis of implants in partial edentulism. Clin Oral Implants Res 1998;9:80–90. 70. Chappuis V, Buser R, Brägger U, Bornstein MM, Salvi GE, Buser D. Long-term outcomes of dental implants with titanium plasma-sprayed surface: a 20-year prospective case series study in partially edentulous patients. Clin Implant Dent Relat Res 2013;15:780–790 71. Torabinejad M, Anderson P, Bader J, et al. Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed partial dentures, and extraction without replacement: a systematic review. J Prosthet Dent 2007;98:285–311. 72. Holm-Pedersen P, Lang NP, Müller F. What are the longevities of teeth and oral implants? Clin Oral Implants Res 2007;18(Suppl 3):15–19. 73. Iqbal MK, Kim S. For teeth requiring endodontic treatment, what are the differences in outcomes of restored endodontically treated teeth compared to implant-supported restorations. Int J Oral Maxillofac Implants 2007;22(Suppl):96–116. 74. Torabinejad M, Goodacre CJ. Endodontic or dental implant therapy: the factors affecting treatment planning. J Am Dent Assoc 2006;137:973–977. 75. Kan JY, Rungcharassaeng K, Umezu K, Kois JC. Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. J Periodontol 2003;74:557–562. 76. Choquet V, Hermans M, Adriaenssens P, Daelemans P, Tarnow DP, Malevez CJ. Clinical and radiographic evaluation of the papilla level adjacent to singletooth dental implants. A retrospective study in the maxillary anterior region. J Periodontol 2001;72:1364–1371. 77. Tarnow D, Elian N, Fletcher P, et al. Vertical distance from the crest of bone to the height of the interproximal papilla between adjacent implants. J Periodontol 2003;74:1785–1788. 78. Kois JC. The restorative-periodontal interface: biological parameters. Periodontol 2000 1996;11:29–38. 79. Juloski J, Radovic I, Goracci C, Vulicevic ZR, Ferrari M. Ferrule effect: a literature review. J Endod 2012;38:11–19. 80. Tan PL, Aquilino SA, Gratton DG, et al. In vitro fracture resistance of endodontically treated central incisors with varying ferrule heights and configurations. J Prosthet Dent 2005;93:331–336. 81. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complications with implants and implant prostheses. J Prosthet Dent 2003;90:121–132. 82. Moy PK, Medina D, Shetty V, Aghaloo TL. Dental implant failure rates and associated risk factors. Int J Oral Maxillofac Implants 2005;20:569–577. 83. Chadha GK, Ahmadieh A, Kumar S, Sedghizadeh PP. Osseointegration of dental implants and osteonecrosis of the jaw in patients treated with bisphosphonate therapy: a systematic review. J Oral Implantol 2013;39:510–520. 84. Kumar MN, Honne T. Survival of dental implants in bisphosphonate users versus non-users: a systematic review. Eur J Prosthodont Restor Dent 2012;20:159–162. 85. Jeffcoat MK. Safety of oral bisphosphonates: controlled studies on alveolar bone. Int J Oral Maxillofac Implants 2006;21:349–353. 86. Augusti D, Augusti G, Re D. Prosthetic restoration in the single-tooth gap: patient preferences and analysis of the WTP index. Clin Oral Implants Res 2013 Sep 10 doi: 10.1111/clr.12264. [Epub ahead of print]
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PROSTHODONTICS
Nadim Z. Baba
Tooth retention through root canal treatment or tooth extraction and implant placement: A prosthodontic perspective Nadim Z. Baba, DMD, MSD1/Charles J. Goodacre, DDS, MSD2/Mathew T. Kattadiyil, DDS, MDS, MS 3 One of the difficult decisions confronting clinicians in daily practice is whether to treat or extract a tooth, particularly those with moderate or advanced disease processes or where trauma has inflicted substantial damage. Studies have shown that the clinician’s decision is based on the length of clinical experience and the complexity of the treatment. The high survival rate of endosseous implants has also had a significant impact on the
way clinicians think about the best treatment for teeth requiring endodontic therapy. Several factors should be considered when making a decision to either treat or extract a tooth. This report provides evidence-based information about the various factors and related treatment outcomes as well as clinical perceptions from a prosthodontic perspective. (Quintessence Int 2014;45:405–416; doi: 10.3290/j.qi.a31544)
Key words: extraction, implant, outcomes, retention, root canal therapy
One of the difficult decisions a clinician is confronted with in daily practice is whether to treat or extract a tooth, particularly those with moderate or advanced disease processes or where trauma has inflicted substantial damage. This complex issue of saving a tooth versus extraction emerged when teeth were retained through root resection.1-3 Several studies1-6 evaluated root resection, with a wide range of failure percentages being reported. Failure rates ranged from 0% after a mean time of 5 years5 to a high of 38% after a mean
1
Professor and Director, Hugh Love Center for Research and Education in Technology, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
2
Professor, Department of Restorative Dentistry, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
3
Professor and Director, Advanced Specialty Education Program in Prosthodontics, Loma Linda University, School of Dentistry, Loma Linda, California, USA.
Correspondence: Dr Nadim Z. Baba, Hugh Love Center for Research and Education in Technology, Loma Linda University, School of Dentistry, 11092 Anderson Street, Loma Linda, CA 92350, USA. Email: [email protected]
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observation time of 10 years.6 The high rate of resection failure in some studies and the emergence of osseointegrated implant therapy presented the clinician with another treatment alternative to root resection.7,8 The high survival rate of endosseous implants has also had a significant impact on the way clinicians think about the best treatment for teeth requiring endodontic therapy. Clinicians are challenged daily with the dilemma of whether a tooth should be endodontically treated or be extracted and replaced by an implant. Di Fiore et al9 conducted a survey amongst dental faculty and students for their treatment preferences, either to retain a tooth by endodontic and restorative treatment, or extraction and implant placement. They concluded that students selected implants as a treatment option more frequently than faculty. However, faculty who had graduated recently selected implants more often than faculty who had graduated earlier. They also found that implants were selected more commonly
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when the complexity of root canal therapy and the complexity of prosthodontic treatment increased. Several factors should be considered when making a decision to either treat or extract a tooth. The purpose of this article is to review these factors from a prosthodontic perspective.
OUTCOMES OF DIFFERENT TREATMENTS Conventional fixed prosthodontics Crowns, inlays, and onlays Single crowns on natural teeth have high success rates, but there is a higher failure rate when the teeth are endodontically treated. In a retrospective clinical exam, Donavan et al10 evaluated 1,314 gold inlays, onlays, and single crowns placed by one practitioner. They found success rates of 90.3% at 10 to 19 years, 94.9% at 20 to 24 years, 98% at 25 to 29 years, 96.9% at 30 to 39 years, and 94.1% at 40 years and more. A cross-sectional study of 688 singleunit metal-ceramic crowns placed in a prosthodontic practice found a 93% success rate between 5 and 10 years. Crowns on endodontically treated teeth had a higher failure rate (5%) than crowns on vital teeth (1%).11 A systematic review of 1,957 computer-aided design/computer-assisted manufacture (CAD/CAM) single-tooth restorations found that CEREC and Celay restorations had a success rate of 91.6%.12 Combination of raw data from multiple clinical studies reported several complications associated with single crowns.13 The three most common complications were the need for endodontic treatment (3%), porcelain veneer fracture (3%), and loss of retention (2%).
Fixed partial dentures (FPDs) FPDs have lower survival rates than single crowns on natural teeth. They also have lower survival rates than both root canal treated teeth and crowns on single implants. Meta-analyses performed on the dental literature presenting clinical data of conventional FPDs showed 94% survival rate after 5 years,14 and 74% survival rate
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after 15 years.15,16 Combination of raw data from multiple clinical studies reported several complications associated with FPDs.13 The three most common complications were caries (18% of the abutments), pulpal necrosis (11% to 17% of the abutments), and loss of retention or debonding (7%). A systematic review14 comparing the outcomes of extraction and an FPD, root canal treatment (RCT) with restoration, and implant-supported single crowns concluded that RCT and restoration as well as implantsupported single crowns resulted in superior long-term survival compared with FPDs attached to natural teeth.
Crowns and pulpal necrosis Some teeth that are prepared for crowns and FPDs experience a need for RCT after restoration. The incidence is generally small but increases over time. The long-term prognosis and the onset of endodontic complications of abutment teeth restored with crowns or FPDs have been extensively evaluated. Several clinical studies17-20 examined the periapical status of abutment and nonabutment teeth over a long period of time. Bergenholtz and Nyman18 evaluated 255 abutment teeth for a mean period of 8.7 years. They found a significantly higher frequency of pulpal necrosis, including periapical lesions, in abutment teeth (15%) when compared to nonabutment teeth (3%). In a 10-year clinical study, Karlsson17 examined 944 abutments of extensive fixed dental prostheses. He reported an incidence of 11% pulpal necrosis. Another 10-year clinical study19 aimed at studying luting cements found the incidence of pulpal necrosis to be around 5.2%. Thirty percent of the 135 abutments that were evaluated had RCT prior to FPD placement. Valderhaug et al20 evaluated the radiographic changes in the periapical status and compared the clinical status of teeth with vital pulp and endodontically treated teeth restored with crowns and FPDs during 25 years. They found that the incidence of pulpal deterioration was 2% at 5 years, 8% at 10 years, 13% at 20 years, and 17% at 25 years.
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Endodontics Success of endodontic therapy Teeth without periapical lesions prior to RCT have higher success rates than those with lesions. Systemic diseases can affect the outcome of RCT. Multiple factors have been identified as influencing the outcome of endodontic therapy. The healing of the periapical lesion and the absence of symptomatic response define endodontic success.21,22 Increased endodontic success has been related to the introduction of modern instruments and equipment (dental microscope, advanced rotary instruments, cone beam computed tomography, improved disinfection medications, etc). A review of several studies was conducted to assess the level of evidence for the outcome (success and failure) of nonsurgical RCT. The authors found that 92% to 98% of teeth without periapical lesions remained disease-free after RCT, whereas 74% to 86% of teeth with apical lesions completely heal after RCT.23,24 In the presence of apical lesions, several studies24-29 including one by Friedman and Mor24 have shown that the success rate of endodontic treatment is about 10% to 20% less than for teeth without periapical lesions. Chugal et al26 found that a tooth with a large periapical lesion prior to RCT will have a greater chance for failure after treatment. A long-term study30 investigating endodontic treatment of teeth with periapical lesions performed by undergraduate dental students showed that only 76% of root canal treated teeth healed. A retrospective cohort study conducted in a private practice to evaluate endodontically treated and retreated teeth found that, within 10 years, only 7% of root canal treated teeth required extraction after treatment and 84% of all endodontically treated teeth were considered successful.31 However, endodontically treated teeth that are asymptomatic and considered clinically successful can still house bacteria within the canal and around the apices.32,33 The presence of systemic disease can affect the prognosis of endodontic treatment. Fouad and Burleson34 found that patients with type 2 diabetes are less likely than nondiabetic patients to have successful RCT when there are preoperative periapical lesions. Segura-Egea et al35 investigated the possible connection between sys-
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temic and periapical disease. They concluded that diabetes could contribute to a high prevalence of periapical lesions. Wang et al36 found that in addition to diabetes, hypertension and coronary artery disease were significant risk factors for tooth extraction after RCT. Several systematic reviews37-40 have been conducted to determine the success rate of endodontic therapy. Kojima et al37 used meta-analysis data from 26 papers to assess the success of root canal treated teeth (nonvital versus vital pulps). They found a cumulative success rate of 82.8% for vital pulps and 78.9% for nonvital pulps. They noted that the best cumulative success rate was obtained when the roots were filled to the apex (vs overextension and underextension). Ng et al38 wanted to study the outcome of primary RCT, and 63 studies met their strict inclusion criteria. The weighted pooled success rates of treatments completed at least 1 year prior to the review ranged from 68% to 85%. The same authors carried out meta-analyses to quantify the influence of the clinical factors on the efficacy of primary RCT.39 Sixty-three studies met their inclusion criteria. They identified four factors that have a significant effect on the outcomes of primary RCT: preoperative absence of periapical radiolucency; root fillings with no voids; root fillings that are within 2 mm of the radiographic apex; and satisfactory coronal restoration. In a more recent study, Ng et al40 investigated tooth survival after RCT. Fourteen studies met their inclusion criteria and the majority of the studies were retrospective (n = 10). They reported an 86% tooth survival (pooled percentages) 2 to 3 years after RCT, 93% tooth survival 4 to 5 years after RCT, and 87% tooth survival 8 to 10 years after RCT. Four factors were determined to be important in improving tooth survival after RCT: crown restoration after RCT; the presence of mesial and distal proximal contact; the treated tooth was not planned as an abutment for a fixed or removable partial denture; and the tooth type.40,41
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Failure of RCT restored with crowns, FPD abutments, or removable partial denture abutments There are multiple studies that indicate root canal treated teeth restored with crowns have better survival than those restored with direct restorations that do not encompass the cusps. Root canal treated teeth that serve as FPD abutments have lower survival rates than those supporting single crowns. A systematic review was conducted to determine if there is any correlation between single crown placement and long-term survival rate of root canal treated teeth as opposed to direct restorations.42 The authors found a 10-year survival rate of 81% for crowned teeth and a 10-year survival rate of 63% for root canal treated with direct restorations (amalgam, composite resins, cements). A study of 220 molars observed teeth restored without crowns for time periods between 6 months and 10 years. The 1-, 2-, and 5-year survival rates were 96%, 88%, and 36%, respectively. The authors determined that teeth with maximum tooth structure had the highest 5-year survival rate of 78%.43 Another study, by Aquilino and Caplan,44 found that root canal treated teeth without crowns were lost at six times the rate of those with crowns, indicating a strong correlation between placement of crowns and survival of endodontically treated teeth. A study of 1,639 root canal treated teeth that were restored with amalgam that did not encompass the cusps determined that maxillary premolars with mesial-occlusal-distal (MOD) amalgams had the highest fracture rate.45 After 3 years, 28% fractured and after 10 years 57% had fractured. After 20 years, the fracture rate rose to 73%. A study was performed that evaluated 116 root canal treated teeth that had failed and required extraction.46 Teeth without crowns were extracted after an average time of 50 months whereas those with crowns were extracted after an average time of 87 months.46 When root canal treated teeth serve as FPD abutments, their survival is reduced.47-52 Sundh and Odman47 reported that 47% of root canal treated were lost after 18 years. Palmqvist and Swartz48 examined the long-term results of single crowns and FPDs in a
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prosthodontic clinic. They found that 24% of nonvital teeth were lost vs 10% for vital teeth. Randow et al49 found that 3% to 21% of nonvital teeth fractured. Randow50 also found increased fractures with root canal treated distal abutments. Leempoel et al51 analyzed the influence of several factors on the lifetime of FPDs. There was a decrease in survival rate of FPDs with nonvital abutments. A retrospective clinical study by Wegner et al52 calculated the survival rate of restored endodontically treated abutments. They found 93% survival of root canal treated teeth serving as FPD abutments versus 51% for RPD abutments. Another study53 found that root canal treated RPD abutments had 1.9times greater failure risk than crowns.
Success of periapical surgery and retreatment A wide range of survival rates have been reported for endodontically treated teeth that have undergone apical surgery. The reported rates have frequently been less than initial endodontic treatment. RCT has been determined to be cost-effective compared to implants and single crowns. Multiple studies24,54-59 determined a wide range of survival rates for endodontically treated teeth after periapical surgery. Friedman and Mor24 conducted a systematic review on the outcome of endodontic therapy and concluded that complete healing of apical periodontitis following periapical surgery ranged from 37% to 85%. They also concluded that comparison between studies should be avoided due to the lack of standardization between treatment protocols and methodologies. In a controlled prospective study, Jannson et al56 found a failure rate of 50% after periapical surgery. They also observed a positive correlation between the size of the periradicular defect and healing. The larger the defect, the more ineffective and uncertain is the healing. Del Fabbro et al60 conducted a systematic review to compare the outcome of surgical versus nonsurgical retreatment. They found only two randomized controlled trials that yielded 82 teeth that had a follow up of 4 years. There was no significant difference in the success rate between the surgical treatment and the endodontic retreatment. After 4 years of follow-up, the outcome for the two procedures was
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similar. Using systematic reviews, Tsesis et al61 studied the success of surgical endodontic treatment performed by a modern technique (surgical microscope, ultrasonic tips to a depth of 3 to 4 mm). In 11 studies, 880 teeth were available for comparison. The pooled percentage of success was 91.6%, and the pooled percentage of failure was 4.7%. Ng et al62 studied the outcome of retreatment of root canal treated teeth. Seventeen studies met their inclusion criteria. The pooled success rate of an endodontic retreatment was 77%. They concluded that significant prognostic factors such as the periapical status, apical extent of the root filling, quality of the coronal restoration, and the size of the lesion can affect the outcome of the retreatment. The cost-effectiveness of RCT versus implant placement was studied63 and the authors concluded that RCT is highly cost-effective as a first line of intervention. Endodontic retreatment is also cost-effective, but surgical retreatment is not. If retreatment fails, implants may play an important role in patient treatment. A more recent study published by Kim and Solomon64 showed that periapical surgery was the most cost-effective among all treatment options for a failed root canal treated molar. Endodontic retreatment with a crown can be the most cost-effective treatment unless adjunctive procedures are required. At such time a single implant-supported crown becomes more cost-effective. Based on current treatment fees, a single implantsupported crown was found to be the least cost-effective treatment option despite its high survival rate.
Implants Dental implants have high survival rates. Multiple systematic reviews have determined that the survival rates of dental implants and root canal treated teeth are similar. Multiple studies65-67 determined high survival rates for single-tooth implants. Survival rates range from 94.4% to 99%, with a mean survival rate of 96.7%. The American Dental Association Council on Scientific Affairs reported a high survival rate for implants in a number of clinical situations.68 They evaluated 10 studies involving 1,453 implants and found survival rates ranging from 94.9% to 99%, with a mean survival rate
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of 96.7%. Lindh et al69 determined the success rate of a single implant to be 97.5% after 6 to 7 years. A more recent study70 investigated the long-term outcomes of titanium implants with roughened, microporous surfaces. Of the 145 original implants placed, only 72 remained for follow-up after 20 years, and 68% of the 72 remaining implants were without technical complications. They concluded that the success rate after 20 years is 75.8% and the survival rate is 89.5%. There have been multiple reviews that compare the survival of root canal treated teeth and dental implants. Torabinejad et al71 conducted a systematic review of outcomes of teeth treated with extraction and no replacement, extraction and FPD, RCT and restoration, or implant-supported single crown: 101 studies were selected for inclusion and studies were from 2 to 6 years in duration and more. They concluded that the success of RCT, FPDs, and implant-supported single crowns could not be effectively compared due to very different definitions of success in the studies. They reported that both implants and RCTs resulted in superior long-term survival, compared to FPDs, and survival of teeth with initial RCT and survival of single implants were comparable. The study also found that when success rate and survival rates are compared, long-term (6+ years) success rates were higher with implants over endodontic therapy (97% vs 84%). The authors further reported that extraction without replacement resulted in inferior psychologic outcomes regarding perception of appearance, emotional effect of tooth loss, and survival of teeth adjacent to posterior edentulous spaces. However, it did not substantially affect satisfaction with slight to moderately shortened dental arches relative to oral comfort, function, tooth migration, temoporomandibular joint dysfunction (TMD), and joint or tooth loading. Holm-Pedersen et al72 conducted a systematic review to compare the longevities of teeth and implants. They identified 49 articles and 6 systematic reviews, and concluded that if periodontally compromised teeth are treated and maintained regularly they will have a long-term success of 92% to 93%. They also concluded that endodontically treated and restored
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teeth yield similar and high success rates. Implants that were evaluated after 10 years did not surpass the longevity of even compromised, but treated, natural teeth. Another systematic review was conducted by Iqbal and Kim,73 looking at the differences in outcome of restored endodontically treated teeth compared to implant-supported restorations. Fifty-five single-tooth implant studies and 13 restored randomized clinical trial studies were included. They found no significant differences in survival between restored endodontically treated teeth and single-tooth implants. They concluded that the decisions must be based on factors other than the treatment outcomes of the procedures.
Discussion of the outcomes of different treatments From the above data related to restored endodontically treated teeth and restored dental implants, no absolute recommendations can be made based solely on outcome data, since there does not appear to be a survival difference between a crowned endodontically treated tooth and a single restored implant. Therefore, the diagnostic decision often needs to be made on the basis of other factors.74 Treatment decisions should be based on satisfying the patient’s desires and on the overall importance of any single tooth to the patient’s comprehensive treatment plan. Each tooth and patient must be individually evaluated to determine which treatment will provide the best result in terms of esthetics, comfort, function, and cost-effectiveness. Practitioners have an obligation to present patients with a balanced perspective regarding alternative treatments, which requires substantial clinical experience with both treatment modalities.
OTHER FACTORS THAT AFFECT THE TREATMENT CHOICE Cost and number of adjunctive procedures Root canal treatment and restoration is usually less costly than an implant and crown. The number of procedures that accompany either treatment can be a determining
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factor in what a patient can afford and therefore becomes part of the decision as to which treatment is provided. The cost of RCT and restoration is generally less than placement of a dental implant and its restoration. However, a number of adjunctive procedures can be required to retain a root canal treated tooth, such as crown-lengthening, apical surgery, core build-up, or post and core. These procedures add to the cost of treatment, increase the complexity, increase the treatment time, and can make the overall cost of treatment greater than that of a dental implant. Similarly, adjunctive procedures may be required with a dental implant, such as bone grafting or connective tissue grafting, or both, to permit implant placement or achieve desirable implant positioning. These procedures add to the cost and treatment time and make the overall cost greater than RCT and restoration.
Esthetic considerations When the bone surrounding a tooth is apical to the interdental papillae and midfacial gingival crest by distances that exceed guidelines established by the dental literature, the extraction of that tooth and placement of a dental implant will usually result in apical relocation of the soft tissue that can create an esthetic liability. The location of the bone apical to the gingiva should be determined as part of the diagnosis and treatment planning. In esthetic locations, retaining a tooth through RCT or even completing adjunctive endodontic procedures such as retreatment or apical surgery may be advantageous in the presence of a thin biotype, unfavorable bone to proximal contact distances, long epithelial attachments, or the presence of an adjacent longstanding dental implant. With a thin periodontal biotype, it is more likely that the interdental papilla will not be present following tooth extraction and implant placement than when a thick biotype is present. It is more likely that a papilla will not fill the interdental space when a thin biotype is present (Fig 1a), especially when the distance from the interproximal bone crest to the proximal contact of the natural tooth being considered for extraction is greater than 4 mm (Fig 1b).75 Even when a thick biotype is pres-
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Fig 1a Thin biotype and increased interproximal bone to proximal contact distance reveals recession of gingival tissue on the site of the lateral incisor. Fig 1b Radiograph of the situation presented in Fig 1a shows the increased interproximal bone to proximal contact distance which contributed to the recession.
a Fig 2a Radiographic images showing increased interproximal bone to proximal contact distance on the left lateral incisor compared to the right lateral incisor.
a Fig 3a Radiograph showing approximately 6 mm distance between the interproximal bone and proximal contact between adjacent implant crowns.
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Fig 2b The right lateral incisor shows ideal gingival esthetics due to favorable interproximal bone to proximal contact distance.
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Fig 3b Lack of interproximal papilla is clearly evident between adjacent implants.
ent around a tooth being considered for extraction, the papilla is unlikely to fill the cervical embrasure space when the distance between the interproximal bone and proximal contact is greater than 5 mm.76 Therefore, it is important to measure the distance between the interproximal bone crest and the proximal contact. When that distance exceeds 4 mm in thin biotype patients and exceeds 5 mm in thick biotype patients, it is more likely
Fig 2c The left lateral incisor reveals some tissue recession on the mesial surface due to the higher interproximal bone to proximal contact distance seen in Fig 2a.
Fig 3c Smile view of definitive restorations on the adjacent implants revealing absence of mesial interdental papilla between the central incisors.
that soft tissue will not fill the cervical embrasures if the tooth is extracted and replaced by an implant (Fig 2). An even more critical situation occurs when two adjacent teeth in the esthetic zone are being considered for extraction. Research indicates that only about 3 mm of mucosa will be present incisal to the healed interproximal bone crest between two adjacent implants placed following the extraction of two adjacent teeth.77 There-
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b
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Fig 4a Pre-extraction radiograph revealing significant bone loss from periodontal disease creating long epithelial attachments. Fig 4b Subsequently placed implant restoration reveals poor esthetic result due to the long epithelial attachment and bone loss prior to extraction.
fore, it is much more likely that an open cervical embrasure will be present between the two implants (Fig 3). Another situation that usually results in the lack of an interdental papilla and also frequently results in an abnormal apical position of the facial mucosa is the presence of a long epithelial attachment around a tooth being considered for extraction. This condition is commonly present when there was significant periodontal pocketing around teeth, and periodontal treatment resulted in reattachment of the gingiva to the tooth. The result is a greater than normal distance between the gingival margin and the underlying bone. Extraction of such teeth will result in greater than normal apical movement of the soft tissue because the bone is located well below the gingival margin (Fig 4). Retaining such a tooth through RCT will allow the mucosa to retain its position around the tooth, and therefore results in preserving gingival esthetics. Another esthetic soft tissue factor that has been observed relates to the presence of an existing dental implant located adjacent to a tooth being considered for extraction. When an implant is present next to a tooth, the interproximal bone typically has an apical slope from the adjacent natural tooth to the implant. The difference between the position of the interproximal bone on the tooth and the position of the bone where it meets the implant can be a few millimeters. This interproximal bone crest is only present because of the periodontal ligament attachment to the natural tooth. Extraction of the tooth will result in substantial
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Figs 5a and 5b Pink porcelain has been applied to the implant crown to mask the soft tissue recession and improve the esthetic outcome.
bone remodeling, even to the level of the bone adjacent to the implant platform. The bone remodeling is associated with concomitant soft tissue recession. Therefore, it may be prudent to retain teeth adjacent to a long-standing dental implant even if endodontic retreatment or apical surgery is required, as extraction will result in substantial recession of the mucosa. In addition to the interdental papilla, the facial gingiva usually undergoes a small amount of recession following extraction of a tooth and implant placement. The amount of facial position change is related to the location of the facial bone crest prior to extraction of a tooth. The distance that the facial bone is located apical to the marginal gingiva averages about 3 mm.78 When a tooth has a low bone crest (bone crest is located more than 3 mm apical to the marginal gingiva), the amount of facial soft tissue recession will be greater. When a high bone crest is present (the bone crest is less than 3 mm apical to the marginal gingiva), there will be little or no soft tissue recession. As a result, it is prudent to measure the distance between the midfacial gingival crest and the underlying bone by anesthetizing the gingiva and using a periodontal probe to measure that distance, a process known as bone sounding. Extraction of teeth with distances greater than 3 mm will result in apical repositioning of the facial mucosa and make the implant crown have a greater incisocervical dimension than the natural tooth to which a match is desirable. The application of pink porcelain in such situations can be a viable option to improve esthetics (Fig 5).
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Fig 6 (left) An implant restoration is a good option for patients who are diagnosed to have a high risk for caries. Fig 7 (right) Clinical situation where an implant restoration is indicated due to the inadequate ferrule effect that suggests a poor prognosis if the fractured tooth were to be restored.
Biologic considerations Some patients with recurring caries and/or periodontal disease can benefit from tooth extraction and implant placement. Implants are often the preferred treatment for patients who have experienced recurrent caries on a regular basis. While most patients can achieve caries control through risk assessment and the introduction of preventive measures, some patients have simply not been successful at incorporating the required changes. As a result, they have experienced the need for restorations followed by re-restoration of the same teeth. At some point such teeth become unrestorable and implants provide a viable treatment for such patients (Fig 6). Similarly, patients who have struggled with recurring periodontal disease and regularly have relapses following treatment can benefit from extraction and replacement with dental implants.
Compromised ability to restore a tooth To provide optimal longevity in root canal treated teeth and minimize the chances for root fracture to occur, there should ideally be 2 mm of cervical tooth structure that can be encompassed by the tooth preparation to form a cervical ferrule. When there is limited tooth structure present incisal or occlusal to the bone, restoration of a root canal treated tooth will result in little or no ferrule being present. Studies have shown that a ferrule is important in helping an endodontically treated tooth resist fracture after restoration. Ferrules of 2.0 mm are considered ideal but often are difficult to obtain on teeth that have been extensively restored, have extensive caries, or have been subjected to substantial trauma leading to
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tooth wear and/or fracture.79,80 Such teeth may be better managed by extraction and implant placement (Fig 7). It has also been determined that the presence of a 2-mm ferrule on all four surfaces of a tooth (facial, lingual, mesial, and distal) provides optimal resistance to tooth fracture, as opposed to having a 2-mm ferrule on only some of the surfaces.80
Systemic factors Certain systemic factors decrease the survival of dental implants and may indicate that it would be more efficacious to retain a natural tooth through RCT. Retaining natural teeth may be beneficial when therapeutic doses of radiation have been administered to the maxilla, since research shows an undesirably high level of implant loss when they have been placed into previously irradiated maxillae.81 While such therapeutic doses of radiation may affect salivary flow and make patients much more susceptible to caries, it may be easier to manage the caries control than manage implant loss. Each such patient will require careful evaluation to determine the best course of treatment. Heavy smoking can contraindicate the use of dental implants.82 Therefore, it may be more prudent to deal with the smoking factors that affect natural teeth and the periodontium rather than place implants. Again, this factor will require individual assessment to determine which treatment is best. Bisphosphonate therapy has resulted in the occurrence of bone osteonecrosis following tooth extraction and other surgically invasive procedures. This documented problem has caused concern related to implant surgery. At the present time, it is not clear from the dental literature whether bisphosphonate therapy
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totally contraindicates dental implant placement.83 Therefore, more research needs to become available before such a definitive conclusion can be made. However, some research84,85 and also clinical experience indicate that patients who have been using oral bisphosphonates may not be contraindicated for implant therapy. However, the use of intravenous bisphosphonates, such as those used for cancer therapy, remains a serious concern and therefore surgical implant placement has typically been avoided in such patients. Until more research emerges, caution should be exercised along with good informed consent. When implants are to be placed in patients who have been taking oral bisphosphonates for multiple years, it is prudent to place only one implant and determine how the patient responds to the treatment rather than to place multiple implants at one time.
Anatomic factors The presence of poor quality bone, proximity to vital structures, and minimal bone present around an existing tooth may limit the use of dental implants and favor retention of a tooth. Very poor quality bone has been associated with higher implant loss rates and may be a factor that would lead to retention of a tooth through RCT rather than extraction and implant placement. This factor would become particularly important should there be a history of implant loss elsewhere in the mouth when the implant was placed into poor quality bone. When vital structures are located in proximity to potential implant sites and there is an increased potential for neurosensory disturbance to occur, it may be best to retain a tooth in that area rather than undergo the risk of abnormal sensation by placing an implant.
Tooth color and tooth thickness Certain teeth have unique color and/or translucency patterns that make it difficult for a crown to match adjacent teeth. This factor can complicate both restoration of a root canal treated tooth and restoration of a dental implant. Matching the color of a ceramic crown to adjacent teeth can be challenging with highly visible teeth that
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have unique internal dentin colorations or substantial amounts of enamel translucency/transparency. Such teeth can be very difficult to color match with ceramic materials. When such teeth are present and they require RCT but do not need a ceramic crown, it may be esthetically advantageous to retain the tooth through RCT, rather than extract it and have an implant crown that does not match the adjacent uniquely colored teeth. Restoring the access opening in such anterior teeth may provide the most esthetic result. A similar situation is encountered when a tooth with very challenging color characteristics requires both RCT and a ceramic crown. It may not be possible to obtain the desired color match with a ceramic crown due to the inability to match the desired color within the ceramic thickness available through reduction of the tooth. Extraction of a tooth and placement of a dental implant allows for a greater thickness of porcelain in the crown, particularly in the cervical aspect of the crown. While the difficulty of the color match still remains, the greater ceramic thickness makes it more likely that the color will be a better approximation to the color of the adjacent natural teeth.
Patient preference Patient preference is an important part of the decisionmaking process. It must be emphasized that effective treatment options be presented to the patient to enable them to make an informed treatment decision based on multiple factors that might be significant to each individual patient. Patient preferences may vary, sometimes influenced by reluctance to accept adjunctive surgical procedures, having natural teeth prepared, the timeline for different treatments, and/or investment in higher fees for treatment. Augusti et al86 reported their findings from a study that assessed patient preferences in the restoration of a single-tooth gap based on the willingness to pay (WTP) index. Most of the population surveyed in this study preferred the implant single crown as a treatment option over a three-unit FPD, revealing a higher WTP index in the esthetic zone.
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CONCLUSION This report provides evidence-based information about the various factors and related treatment outcomes for single-tooth situations as well as some perceptions based on clinical experience. It is intended to assist the clinician in making appropriate treatment decisions for their patients. While utilizing the concepts and considerations discussed here, it cannot be emphasized enough that treatment decisions should always include the varying needs and desires of each informed patient.
REFERENCES 1. Bergenholtz G. Radectomy of multi-rooted teeth. J Am Dent Assoc 1972;85:87–85. 2. Buhler H. Evaluation of root resected teeth. Results after ten years. J Periodontol 1988:59:805–810. 3. Carnavale G, Pontoriero R, di Febo G. Long-term effects of root-resective therapy in furcation-involved molars: A 10-year longitudinal study. J Clin Periodontol 1998;25:209–214. 4. Erpenstein H. A 3-year study of hemisectioned molars. J Clin Periodontol 1983;10:1–10. 5. Hamp SE, Nyman S, Lindhe J. Periodontal treatment of multirooted teeth. Results after 5 years. J Clin Periodontol 1975;2:126–135. 6. Langer B, Stein SD, Wagenberg B. An evaluation of root resection. A ten-year study. J Periodontol 1981;52:719–722. 7. Becker W, Becker B. Replacement of maxillary and mandibular molars with single endosseous implant restorations: A retrospective study. J Prosthet Dent 1995;74:51–55. 8. Becker W, Becker BE, Alsuwyed A, Al-Mubarak S. Long-term evaluation of 282 implants in maxillary and mandibular molar positions: A prospective study. J Periodontol 1999;70:896–901. 9. Di Fiore PM, Tam L, Thai HT, Hittelman E, Norman RG. Retention of teeth versus extraction and implant placement: treatment preferences of dental faculty and dental students. J Dent Educ 2008;72:352–358. 10. Donavan T, Simonsen RJ, Guertin G, Tucker RV. Retrospective clinical evaluation of 1,314 cast gold restorations in service from 1 to 52 years. J Esthet Restor Dent 2004;16:194–204. 11. Walton TR. A 10-year longitudinal study of fixed prosthodontics: clinical characteristics and outcome of single-unit metal-ceramic crowns. Int J Prosthodont 1999;12:519–526. 12. Wittneben JG, Wright RF, Weber HP, Gallucci GO. A systematic review of the clinical performance of CAD/CAM single-tooth restorations. Int J Prosthodont 2009;22:466–471. 13. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complications in fixed prosthodontics. J Prosthet Dent 2003;90:31–41. 14. Salinas TJ, Eckert SE. In patients requiring single-tooth replacement, what are the outcomes of implant as compared to tooth-supported restorations? Int J Oral Maxillofac Implants 2007;22(Suppl):71–95. 15. Creugers NH, Kayser AF, van’t Hof MA. A meta-analysis of durability data on conventional fixed bridges. Community Dent Oral Epidemiol 1994;22:448–452. 16. Scurria MS, Bader JD, Shugars DA. Meta-analysis of fixed partial denture survival: prostheses and abutments. J Prosthet Dent 1998;79:459–464. 17. Karlsson S. A clinical evaluation of fixed bridges, 10 years following insertion. J Oral Rehabil 1986;13:423–432.
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18. Bergenholtz G, Nyman S. Endodontic complications following periodontal and prosthetic treatment of patients with advanced periodontal disease. J Periodontol 1984;55:63–68. 19. Jokstad A, Mjör IA. Ten years’ evaluation of three luting cements. J Dent 1996;24:309–315. 20. Valderhaug J, Jokstad A, Ambjornsen E, Norheim PW. Assessment of periapical and clinical status of crowned teeth over 25 years. J Dent 1997;25:97–105. 21. Strindberg LZ. The dependence of the results of pulp therapy on certain factors. An analytic study based on radiographic and clinical follow-up examinations. Acta Odontol Scand 1956;14(Suppl 21):1–175. 22. Ørstavik D, Kerekes K, Eriksen HM. The periapical index: a scoring system for radiographic assessment of apical periodontitis. Endod Dent Traumatol 1986;2:20–34. 23. Torabinejad M, Kutsenko D, Machnick TK, Ismail A, Newton CW. Levels of evidence for the outcome of nonsurgical endodontic treatment. J Endod 2005;31:637–646. 24. Friedman S, Mor C. The success of endodontic therapy: healing and functionality. J Calif Dent Assoc 2004;32:493–503. 25. Sjögren U, Figdor D, Persson S, Sundqvist G. Influence of infection at time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis. Int Endod J 1997;30:297–306. 26. Chugal NM, Clive JM, Spångberg LS. A prognostic model for assessment of the outcome of endodontic treatment: effect of biologic and diagnostic variables. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:342–352. 27. Ng YL, Mann V, Gulabivala K. Outcome of secondary root canal treatment: a systematic review of the literature. Int Endod J 2008;41:1026–1046. 28. Sjögren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod 1990;16:498–504. 29. Doyle SL, Hodges JS, Pesun IJ, Law AS, Bowles WR. Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and singletooth implants. J Endod 2006;32:822–827. 30. Siqueria JF Jr, Rôças IN, Riche FN, Provenzano JC. Clinical outcome of the endodontic treatment of the teeth with apical periodontitis using an antimicrobial protocol. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:757–762. 31. Fonzar F, Fonzar A, Buttolo P, Worthington HV, Esposito M. The prognosis of root canal therapy: a 10-year retrospective cohort study on 411 patients with 1175 endodontically treated teeth. Eur J Oral Implantol 2009;2:201–208. 32. Ricucci D, Siqueira JF Jr, Bate AL, Pitt Ford TR. Histologic investigation of root canal-treated teeth with apical periodontitis: a retrospective study from twenty-four patients. J Endod 2009;35:493–502. 33. Tronstad L, Barnett F, Cervone F. Periapical bacteria plaque in teeth refractory to endodontic treatment. Endod Dent Traumatol 1990;6:73–77. 34. Fouad AF, Burleson J. The effect of diabetes mellitus on endodontic treatment outcome: data from an electronic patient record. J Am Dent Assoc 2003;134:43–51. 35. Segura-Egea JJ, Castellanos-Cosano L, Machuca G, et al. Diabetes mellitus, periapical inflammation and endodontic treatment outcome. Med Oral Patol Oral Cir Bucal 2012;17:e356–e361. 36. Wang CH, Chueh LH, Chen SC, Feng YC, Hsiao CK, Chiang CP. Impact of diabetes mellitus, hypertension, and coronary artery disease on tooth extraction after nonsurgical endodontic treatment. J Endod 2001;37:1–5. 37. Kojima K, Inamoto K, Nagamatsu K, et al. Success rate of endodontic treatment of teeth with vital and nonvital pulps. A meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97:95–99. 38. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature - part 1. Effects of study characteristics on probability of success. Int Endod J 2007;40:921–939. 39. Ng YL, Mann V, Rahbaran S, Lewsey J, Gulabivala K. Outcome of primary root canal treatment: systematic review of the literature - part 2. Influence of clinical factors. Int Endod J 2008;40:6–31. 40. Ng YL, Mann V, Gulabivala K. Tooth survival following non-surgical root canal treatment: a systematic review of the literature. Int Endod J 2010;43:171–189.
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41. Heling I, Gorfil C, Slutzky H, Kopolovic K, Zalkind M, Slustzky-Goldberg I. Endodontic failure caused by inadequate restorative procedures; a review and treatment recommendations. J Prosthet Dent 2002;87:674–678. 42. Stavropoulou AF, Koidis PT. A systematic review of single crowns on endodontically treated teeth. J Dent 2007;35:761–767. 43. Nagasiri R, Chitmongkolsuk S. Long-term survival of endodontically treated molars without crown coverage: a retrospective cohort study. J Prosthet Dent 2005;93:164–170. 44. Aquilino SA, Caplan DJ. Relationship between crown placement and the survival of endodontically treated teeth. J Prosthet Dent 2002;87:256–263. 45. Hansen EK, Asmussen E, Christiansen NC. In vivo fractures of endodontically treated posterior teeth restored with amalgam. Endod Dent Traumatol 1990;6:49–55. 46. Vire DE. Failure of endodontically treated teeth: classification and evaluation. J Endod 1991;17:338–342. 47. Sundh B, Odman P. A study of fixed prosthodontics performed at a university clinic 18 years after insertion. Int J Proshtodont 1997;10:513–519. 48. Palmqvist S, Swartz B. Artificial crowns and fixed partial dentures 18 to 23 years after placement. Int J Prosthodont 1993;6:279–285. 49. Randow K, Glantz PO, Zoger B. Technical failures and some related clinical complications in extensive fixed prosthodontics. An epidemiological study of long-term clinical quality. Acta Odontol Scand 1986;44:241–255. 50. Randow K. On the functional deformation of extensive fixed partial dentures. An experimental clinical and epidemiological study. Swed Dent J 1986;34:1–83. 51. Leempoel PJ, Käyser AF, Van Rossum GM, De Haan AF. The survival rate of bridges. A study of 1674 bridges in 40 Dutch general practices. J Oral Rehabil 1995;22:327–330. 52. Wegner PK, Freitag S, Kern M. Survival rate of endodontically treated teeth with posts after prosthetic restoration. J Endod 2006;32:928–931. 53. Balkenhol M, Wöstermann B, Rein C, Ferger P. Survival time of cast post and cores: a 10-year retrospective study. J Dent 2007;35:50–58. 54. Frank Al, Glick DH, Patterson SS, Weine FS. Long-term evaluation of surgically placed amalgam fillings. J Endod 1992;18:391–398. 55. Wesson CM, Gale TM. Molar apicectomy with amalgam root-end filling: results of a prospective study in two district general hospitals. Br Dent J 2003;195:707–714. 56. Jannson L, Sandstedt P, Låftman AC, Skoglund A. Relationship between apical and marginal healing in periradicular surgery. Oral Surg Oral Med Oral Pathol Radiol Endod 1997;83:596–601. 57. Allen RK, Newton CW, Brown Jr CE. A statistical analysis of surgical and nonsurgical endodontic retreatment cases. J Endod 1989;15:261–266. 58. Maddalone M, Gagliani M. Periapical endodontic surgery: a 3-year follow-up study. Int Endod J 2003:36:193–198. 59. Penarrocha M, Marti E, Garcia B, Gay C. Relationship of periapical lesion radiologic size, apical resection, and retrograde filling with the prognosis of periapical surgery. J Oral Maxillofac Surg 2007;65:1526–1529. 60. Del Fabbro M, Taschieri S, Testori T, Francetti L, Weinstein RL. Surgical versus non-surgical endodontic re-treatment for periradicular lesions. Cochrane Database Syst Rev 2007;18(3):CD005511. 61. Tsesis I, Faivishevsky V, Kfir A, Rosen E. Outcome of surgical endodontic treatment performed by a modern technique: a meta-analysis of literature. J Endod 2009;35:1505–1511. 62. Ng YL, Mann V, Gulabivala K. Outcome of secondary root canal treatment: a systematic review of the literature. Int Endod J 2008;41:1026–1046. 63. Pennington MW, Vernazza CR, Shackley P, Armstrong NT, Whitworth JM, Steele JG. Evaluation of the cost-effectiveness of root canal treatment using conventional approaches versus replacement with an implant. Int Endod J 2009;42:874–883. 64. Kim SG, Solomon C. Cost-effectiveness of endodontic molar retreatment compared with fixed partial dentures and single-tooth implant alternatives. J Endod 2011;37:321–325.
416
65. Mozzati M, Gallesio G, Del Fabbro M. Long-term (9–12 years) outcomes of titanium implants with oxidized surface: a retrospective investigation on 209 implants. J Oral Implantol 2013 Oct 31 [Epub ahead of print]. 66. Lekholm U, Gunne J, Henry P, et al. Survival of the Brånemark implant in partially edentulous jaws: a 10-year prospective multicenter study. Int J Oral Maxillofac Implants 1999;14:639–645. 67. Creugers NH, Kreulen CM, Snoek PA, de Kanter RJ. A systematic review of single-tooth restorations supported by implants. J Dent 2000;28:209–217. 68. Dental endosseous implants: an update. J Am Dent Assoc 2004;135:92–97. 69. Lindh T, Gunne J, Tillberg A, Molin M. A meta-analysis of implants in partial edentulism. Clin Oral Implants Res 1998;9:80–90. 70. Chappuis V, Buser R, Brägger U, Bornstein MM, Salvi GE, Buser D. Long-term outcomes of dental implants with titanium plasma-sprayed surface: a 20-year prospective case series study in partially edentulous patients. Clin Implant Dent Relat Res 2013;15:780–790 71. Torabinejad M, Anderson P, Bader J, et al. Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed partial dentures, and extraction without replacement: a systematic review. J Prosthet Dent 2007;98:285–311. 72. Holm-Pedersen P, Lang NP, Müller F. What are the longevities of teeth and oral implants? Clin Oral Implants Res 2007;18(Suppl 3):15–19. 73. Iqbal MK, Kim S. For teeth requiring endodontic treatment, what are the differences in outcomes of restored endodontically treated teeth compared to implant-supported restorations. Int J Oral Maxillofac Implants 2007;22(Suppl):96–116. 74. Torabinejad M, Goodacre CJ. Endodontic or dental implant therapy: the factors affecting treatment planning. J Am Dent Assoc 2006;137:973–977. 75. Kan JY, Rungcharassaeng K, Umezu K, Kois JC. Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. J Periodontol 2003;74:557–562. 76. Choquet V, Hermans M, Adriaenssens P, Daelemans P, Tarnow DP, Malevez CJ. Clinical and radiographic evaluation of the papilla level adjacent to singletooth dental implants. A retrospective study in the maxillary anterior region. J Periodontol 2001;72:1364–1371. 77. Tarnow D, Elian N, Fletcher P, et al. Vertical distance from the crest of bone to the height of the interproximal papilla between adjacent implants. J Periodontol 2003;74:1785–1788. 78. Kois JC. The restorative-periodontal interface: biological parameters. Periodontol 2000 1996;11:29–38. 79. Juloski J, Radovic I, Goracci C, Vulicevic ZR, Ferrari M. Ferrule effect: a literature review. J Endod 2012;38:11–19. 80. Tan PL, Aquilino SA, Gratton DG, et al. In vitro fracture resistance of endodontically treated central incisors with varying ferrule heights and configurations. J Prosthet Dent 2005;93:331–336. 81. Goodacre CJ, Bernal G, Rungcharassaeng K, Kan JY. Clinical complications with implants and implant prostheses. J Prosthet Dent 2003;90:121–132. 82. Moy PK, Medina D, Shetty V, Aghaloo TL. Dental implant failure rates and associated risk factors. Int J Oral Maxillofac Implants 2005;20:569–577. 83. Chadha GK, Ahmadieh A, Kumar S, Sedghizadeh PP. Osseointegration of dental implants and osteonecrosis of the jaw in patients treated with bisphosphonate therapy: a systematic review. J Oral Implantol 2013;39:510–520. 84. Kumar MN, Honne T. Survival of dental implants in bisphosphonate users versus non-users: a systematic review. Eur J Prosthodont Restor Dent 2012;20:159–162. 85. Jeffcoat MK. Safety of oral bisphosphonates: controlled studies on alveolar bone. Int J Oral Maxillofac Implants 2006;21:349–353. 86. Augusti D, Augusti G, Re D. Prosthetic restoration in the single-tooth gap: patient preferences and analysis of the WTP index. Clin Oral Implants Res 2013 Sep 10 doi: 10.1111/clr.12264. [Epub ahead of print]
VOLUME 45 • NUMBER 5 • MAY 2014
