The Clinical Outcomes of Immediate Versus Delayed Restoration Procedures on Immediate Implants: A Comparative Cohort Study for Single-Tooth Replacement Antonio Barone, DDS, PhD, MSc;*† Paolo Toti, BSc, DDS;*† Alessandro Quaranta, DDS, PhD,‡ Giacomo Derchi, DDS;*† Ugo Covani, MD, DDS*†
ABSTRACT Background: Immediate implant placement into fresh extraction sockets is generally considered a reliable procedure that offers several clinical advantages. Purpose: The primary aim of this study was to evaluate and compare the overall clinical outcomes of immediate and delayed restoration procedures for implants placed in fresh extraction sockets by means of a flapless technique and resorbable membrane stabilizing a xenograft. Total costs and operating times were also compared. Materials and Methods: In this prospective cohort study, changes of marginal bone level, facial soft tissue (ΔFST), and width of keratinized gingiva (ΔWKG), in addition to the papilla index, underwent a pairwise comparison; correlations with pristine buccal bone thickness were also investigated. Results: Although similar results were recorded for the two procedures, with a bone loss of −1.0 1 0.5 mm and −0.9 1 0.7 mm, respectively, for immediate and delayed restoration, negative remodeling in the delayed restoration procedure was seen to occur from 4 to 12 months after implant placement. No significant differences were recorded between the two procedures in terms of ΔFST and ΔWKG. A loss of the papillary soft tissues before restoration, followed by a reestablishment after restoration, seemed to be verified for the delayed group, for which the papilla index went from the minimum of 0 at 4 months to a value of 2 at 24 months. Moreover, the immediate restoration procedure seemed to be more promising in terms of healing times and costs. Conclusion: Immediate restoration of implants installed in fresh extraction sockets was at least as effective and safe as delayed restoration. KEY WORDS: alveolar bone resorption, immediate implants, immediately restored implant, soft tissue recession
INTRODUCTION
increasingly common practice. The conventional protocol, which involves the placement of implants in healed ridge sites, is widely accepted as a highly predictable treatment.1,2 Nevertheless, over the years, implant dentistry has tried to further simplify clinical procedures and to shorten the overall treatment time; as a result, the placement of implants into fresh extraction sockets has become a promising area of research. Immediate implant placement reduces surgery and treatment time, morbidity, and, importantly, costs for the patient.3,4 The placement of implants into fresh extraction sockets provides several clinical advantages and has been proven to be a reliable procedure despite the surgical challenges it can pose.3,5 Surgical difficulties that even an
The use of dental implants to replace one or more missing teeth in the anterior maxilla has become an *Department of Surgical, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy; †Tuscan Dental Institute, Versilia General Hospital, Lido di Camaiore, Italy; ‡Department of Odontostomatologic and Specialized Clinical Sciences (DISCO), Marche Polytechnic University, Ancona, Italy Corresponding Author: Dr. Antonio Barone, Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Tuscan Dental Institute, Piazza Diaz 10, 55041 Camaiore, Lucca, Italy; e-mail: [email protected] © 2014 Wiley Periodicals, Inc. DOI 10.1111/cid.12225
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experienced clinician might face include obtaining adequate three-dimensional implant positioning, ensuring primary implant stability, and managing the bone wall remodeling phase subsequent to tooth extraction.6 Several key factors are important for ensuring positive clinical outcomes: namely, surgery should be performed without flap elevation to reduce deleterious facial bone remodeling7–9; the buccal bone plate should be left essentially intact; and the implant should be placed toward the palatal aspect of the socket.10 It has been clearly shown that bone remodeling inevitably occurs after tooth extraction and simultaneous implant placement. Augmentation procedures have been developed for treatment of the peri-implant bone defects that can be observed after the placement of implants into fresh extraction sockets. These procedures may reduce the dimensional changes that spontaneously occur after tooth extraction.11 Single maxillary implants may also be immediately restored with predictable clinical success and high survival rates.12,13 Several authors have suggested that adequate primary implant stability and avoidance of occlusal or eccentric contact during the healing phase could be considered prerequisites for success in this regard. A review of the outcomes of different loading protocols showed no differences in terms of survival rates between immediately and conventionally loaded implants placed in fresh extraction sockets.14 However, there has previously been a lack of information pertaining to reducing soft tissue remodeling and achieving good aesthetics around these implants. Therefore, an aesthetically satisfying result may not be easily achieved following immediate placement and restoration of a dental implant in the anterior maxilla. Furthermore, factors such as the remodeling of bone walls after tooth extraction and the differences in healing of buccal tissue following immediate versus delayed restoration of immediate implants require full consideration and investigation. Another aspect of treatment outcome that is an important consideration is the cost-effectiveness of dental implant therapy, which has been studied for more than 20 years.15,16 The cost-effectiveness of treatment will inevitably have an impact on the decision-making process. The primary aim of the present study was to evaluate and compare the overall clinical outcomes of immediate and conventional restoration procedures for implants placed in fresh extraction sockets. The present
study tested the null hypothesis that there are no differences in clinical outcome between the two procedures against the alternative hypothesis that there is a difference. The short-term implant survival rate was also evaluated. The secondary aim of this study was to compare the total costs and clinical treatment periods between the two above-mentioned procedures. This is a preliminary 2-year report and is part of an ongoing study. MATERIALS AND METHODS This study was designed as a prospective cohort study and included consecutively treated patients. The trial was conducted at Versilia General Hospital (affiliated with the University of Pisa), Camaiore, Italy, between June 2008 and November 2010. All the procedures were performed by two experienced surgeons (UC and AB), who received a week of training before beginning the study. The training covered surgical and follow-up procedures, as well as the handling of any complications. Patients were considered eligible for inclusion in the study if they (1) were at least 18 years of age and able to sign an informed consent form, (2) had a failing cuspid/ bicuspid tooth in the maxillary/mandibular area requiring extraction and immediate dental implant placement with either immediate or delayed restoration, and (3) were willing to have their progress followed for at least 2 years (the present analysis is part of an ongoing study and represents an interim report at 2 years after dental implant insertion). Patients were excluded from the study if any of the following criteria applied: (1) history of systemic diseases that would contraindicate surgical treatment, (2) long-term steroidal and/or aminobisphosphonate therapy, (3) diabetes mellitus, (4) pregnancy or lactation, (5) uncontrolled periodontal disease, (6) more than 10 cigarettes smoked per day (subjects smoking less than 10 cigarettes per day were requested to stop smoking before and after surgery, even though their compliance could not be monitored), (7) absence of teeth adjacent to the ones to be extracted, (8) extraction sites with a partial or complete deficiency of buccal bone plate, (9) acute infection in the failing tooth, or (10) unwillingness to return for the follow-up examination. The study was conducted according to the principles outlined in the Declaration of Helsinki on clinical research involving human subjects, as revised in 2000. All patients received thorough explanations of the study
Immediate and Delayed Restored Dental Implants
and had to complete a written informed consent form prior to being enrolled in the study. Patients who were included in the study were carefully evaluated by examination of clinical aspects and periapical/panoramic radiographs; data such as age, gender, and smoking habits were collected for each patient, as well as both clinical and radiographic indications for tooth extraction and location of the tooth to be extracted. A financial record was compiled for patients where possible, and costs associated with the clinical treatment, including aftercare, were considered. The total costs were calculated following Attard and colleagues.17 Surgery After the consent form had been signed, all patients were subjected to at least one oral hygiene session prior to the extraction procedures in order to provide a more favorable oral environment for wound healing. All patients underwent tooth extraction and clinical measurements at baseline; the amount of available alveolar bone and the presence of an intact buccal bone wall were evaluated. In clinical situations in which an implant could not be inserted immediately, a ridge preservation procedure was performed; these patients were excluded from the study and received an implant 4–5 months later. The implants used for this study were Blossom implants with an Ossean® surface (Intra-Lock International, Boca Raton, FL, USA).18 When an implant could be inserted, the final insertion torque was measured with a calibrated torque wrench (Torque-Lock 2, Intra-Lock International). The surgical wrench was able to perform torque measurements within a range of 20 to 75 Ncm. Implants with an insertion torque of at least 45 Ncm were included in the immediate restoration group and were temporarily restored within 48 hours of implant placement (Figure 1); on the other hand, implants with an insertion torque lower than 45 Ncm were included in the delayed restoration group and were restored 4 months after implant placement (Figure 2). All patients received prophylactic antibiotic therapy (2 g amoxicillin, or 600 mg clindamycin if allergic to penicillins) 1 hour before the extraction procedure and continued to take the antibiotic (1 g amoxicillin or 300 mg clindamycin) postoperatively three times a day for 4 days. All patients rinsed for 1 minute with 0.2% chlorhexidine mouthwash prior to the surgery (and twice a day for the following 3 weeks) and were treated under local anesthesia using lidocaine with adrenaline
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(1:50,000). A flapless approach was chosen, and tooth extractions were carried out with or without elevators as necessary to minimize the trauma; great care was taken to maintain the integrity of the buccal bone wall. Ultrasound bone surgery with appropriate tips was used at the mesial, distal, and lingual/palatal sites to allow easier tooth extraction. After extraction, the socket was carefully curetted, and subsequently, the implant bed was prepared according to the standard procedure (with standard drills, following the palatal bony wall as a guide and making maximum use of the bone apical to the removed tooth). A periodontal probe was used to verify the integrity of the bone walls and to measure the periimplant bone defect after implant osteotomy preparation. The Blossom implants were placed with the implant platform at the marginal level of the palatal/ lingual bone wall (Figures 1 and 2). All the implants were evaluated for their final insertion torque; 45 Ncm was the cutoff value determining whether the implant would be allocated to the immediate restoration or delayed restoration group. The peri-implant bone defect − between the implant surface and bone wall – was augmented with corticocancellous porcine bone particles (OsteoBiol Apatos, Tecnoss, Coazze, Italy). Subsequently, a resorbable membrane (OsteoBiol Evolution, Tecnoss) was used to stabilize the graft, and a crossmattress suture was used to stabilize the blood clot. Secondary soft tissue healing was encouraged with a collagen membrane exposed to the oral cavity. Patients were instructed to continue with prophylactic antibiotic therapy, and 600 mg ibuprofen tablets were prescribed as anti-inflammatories to be taken three times a day as long as required. Sutures were removed after 10 days and oral hygiene instructions were given. The prosthetic procedures were similar for the immediate and delayed restoration groups; impressions were taken, and temporary/resin restorations were prepared within 36 hours using prefabricated abutments (Intra-Lock International). Moreover, the delayed restoration group received a second-stage surgery with a midcrestal incision to allow uncovering of the submerged implants and soft tissue healing. The final impressions were made with individual trays using polyvinylsiloxane material (Flexitime, Heraeus Kulzer, Hanau, Germany), and these were used to prepare the metal-ceramic crowns, which were cemented on individually tailored titanium abutments. Patients were enrolled in an oral hygiene programme with a recall visit every 3 months.
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Figure 1 Immediate restoration. (A) Fresh extraction socket; (B) implant inserted in the extraction socket; (C) occlusal and (D) facial views of restoration; (E) tissue healing at final restoration; (F) buccal view of restored implant after 2 years; (G–I) periapical radiographs (G) immediately after restoration, (H) after 4 months ,and (I) after 2 years.
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index_en.htm), which cites 2013 labor costs in Italy as €27.4 per hour. The time cost for each patient was calculated by multiplying the amount of time per year spent in the clinic by the mean real salary per hour. The total costs were the costs accumulated over the 2 years of the survey. Input Variables
Figure 2 Delayed restoration. (A) View of the extraction socket; (B) implant positioned in the extraction socket; (C) augmentation procedure to treat peri-implant bone defect; (D) secondary soft tissue healing; (E) final restoration after 2 years; (F,G) periapical radiographs (F) immediately after restoration and (G) after 2 years.
For each patient, time spent was recorded, and clinical and financial records were collected. A figure for the mean real salary per hour in Italy was obtained from the European Commission website (http://ec.europa.eu/
Measurements were acquired immediately after implant placement (baseline or time T0), at 4 months after placement (T1), and at 12 and 24 months after placement (with loaded final prosthetic restoration; T2 and T3, respectively). All the measurements were taken by a single examiner, who was not involved in performing the surgical treatment. Variables measured included (1) diameter and length of the dental implants placed, (2) peri-implant marginal bone level (MBL), (3) width of keratinized gingiva (WKG), (4) facial soft tissue (FST) levels, and (5) buccal bone thickness (BT). Peri-implant MBL, evaluated on intraoral radiographs at the mesial and distal sites (mMBLx and dMBLx, respectively, where x = 1,2,3), was defined as the distance between the reference point and the most apical point of the marginal bone level. The reference point was the fixture-abutment interface. Intraoral periapical radiographs were taken (70 kVp, 7 mA) with a digital sensor (Schick Technologies, New York, NY, USA) using a parallel-cone technique. A paralleling device and individualized bite blocks made of polyvinylsiloxane impression material (Flexitime, Heraeus Kulzer) were used for the standardization of the x-ray geometry. Calibration was performed using the known thread-pitch distances of the implants (pitch = 1.0 mm). Known values, such as fixture diameter and length, were used for calibration when the threads were not clearly visible on the radiographs. Measurements were taken to the nearest millimeter using computer software (UTHSCSA Image Tool, Version 3.00, University of Texas Health Science Center, San Antonio, TX, USA). WKG was measured midfacially from the gingival margin to the mucogingival junction of the tooth to be extracted (baseline) or the implant-supported restoration; for delayed restoration (4 months after implant placement), it was also measured from the top of the edentulous crest to the mucogingival junction of the edentulous area.
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FST levels were evaluated by measuring the distance between the soft tissue level at the midfacial gingival level and a reference line from the facial soft tissue level of the adjacent teeth. BT was evaluated at baseline using a surgical caliper, both at the midfacial level of the buccal bone plate and at the most coronal point of the marginal crest. In addition to these five parameters, implant failure (where any mobility of the implant, any infection that required removal, or any implant fracture was considered failure) was evaluated, and implant stability was assessed manually at each measurement time point. Lastly, the cost of the clinical treatment, including the cost of materials (dental implant, abutment, provisional and definitive prostheses) and surgical fees (operating room and clinical staff), was calculated, with the following stages of treatment being taken into account: preoperative consultations and diagnostic tests, firststage surgery, visits during the healing phase, secondstage surgery, and the prosthodontic phase of treatment. Additional clinical costs, including costs of clinical and medical services and costs resulting from time spent by the patient on recall visits (oral hygiene program, with a recall visit every 6 months) and any other visits required, were also calculated. Outcome Variables The outcome variables, obtained by a subtraction (Δ) and evaluated for the present study, could be negative or positive, with a reduction being represented by a negative value. Changes in MBL (ΔMBL) were evaluated for the mesial and distal aspects (mΔMBL and dΔMBL, respectively) by subtracting the T1, T2, and T3 values of the MBL from the respective baseline value (nΔMBLx = nMBL0 − nMBLx, with n as mesial or distal, and x = 1,2,3). Changes in FST were calculated by subtracting the baseline value from the respective values at T1, T2, or T3, according to the formula ΔFSTx = FSTx − FST0 (where x = 1,2,3). Changes in WKG were calculated by subtracting the baseline value from the respective values at T1, T2, or T3, according to the formula ΔWKGx = WKGx − WKG0 (where x = 1,2,3). The status of the interdental papilla was recorded based on the index proposed by Jemt – papilla index, or PI19: 0 = no papilla; 1 = less than half the normal papilla
height is present; 2 = greater than half the normal papilla height is present, but papilla does not extend to the normal contact point; 3 = papilla fills the entire proximal space and is in good harmony; 4 = papilla is hyperplastic. Success rates and cumulative survival rates for implants were calculated according to the criteria suggested by Buser and colleagues, with a recorded radiological peri-implant bone resorption not greater than 1.5 mm during the first year of loading20 or 0.2 mm/year during the following years.21 Clinical treatment period was calculated from time of initial surgery to time of placement of the definitive prosthesis. Total cost (expressed in labor costs per hour) was calculated as costs for the treatment itself plus adjunctive clinical costs. Statistical Analysis Acquired data were entered into a database for automatic analysis (Database Toolbox, MatLab 7.0.1; MathWorks, Natick, MA, USA). Descriptive and statistical analyses were performed using a matrix laboratory tools package (Statistics Toolbox, MatLab 7.0.1). A Shapiro-Wilk test was employed to assess whether data for the immediate restoration and delayed restoration groups were normally distributed; normal distribution was not verified for either of the two groups. For each of the outcome variables, the effects of smoking habits and gender were measured with Friedman’s test; then, pairwise comparisons were performed using the Wilcoxon signed-rank test for matched samples and the Wilcoxon rank-sum test for unmatched data, and p values were obtained. The Spearman correlation (rs) was used to assess the strength of the bivariate associations between BT and changes in MBL and FST. All measurements in the text and tables are given as medians, with interquartile range (IQR; the difference between the 75th and 25th percentiles) following in parentheses. The level of statistical significance was set at .001 for all analyses. RESULTS In the present cohort study, a total of 30 patients were treated with a single-tooth extraction and prosthetic rehabilitation supported by a dental implant: 15 patients were treated via an immediate prosthetic restoration, whereas the remaining 15 were rehabilitated with a
Immediate and Delayed Restored Dental Implants
delayed restoration 4 months after extraction. Table 1 summarizes the demographic data from the two groups. Out of the 30 patients, 14 were females and 12 smokers. Six canines and 24 bicuspids were extracted. At the time of extraction, the measured buccal plate thicknesses were 0.7 1 0.2 mm and 0.6 1 0.2 mm for the immediate and delayed groups, respectively. The variables set out in Table 1 for both groups were measured at baseline (T0) and during follow-up 4 (T1), 12 (T2), and 24 months (T3) after extraction, with corresponding differences from baseline also being measured (Δ1, Δ2, and Δ3 represented differences from T0 to T1, from T0 to T2, and from T0 to T3, respectively), as described in the methods for each outcome variable. Table 1 also shows the median PI values for the two procedures. Figure 3 plots the distribution of dimensional changes for both the hard tissue and soft tissue outlines around the implant restorations (in relation to the status before tooth extraction) for each of the several outcome variables presented. Moreover, the statistically significant differences in the outcome variables (mesial and distal ΔMBL, ΔFST, ΔWKG, and mesial and distal IP) between the two restoration groups and among time points are summarized. Nonparametric ANOVA tests were performed for all outcome variables to investigate the relationships of smoking and gender to the type of prosthetic loading used (immediate or delayed). The results are shown in Table 2; the effects of smoking and gender for were not significant for any of the outcome variables. The analysis of differences in the outcome variables between the two restoration procedures showed significant differences in the mesial and distal PIs at 4 months (mPI1 and dPI1), with values of 2 (0) and 2 (1.5), respectively, for the immediate procedure and 0 (0) for both aspects in the delayed restoration. The p value was 0.5 mm may assure clinicians of the absence of buccal soft tissue loss, at least for delayed restoration. Nevertheless, a few patients in both groups showed a slight buccal recession of the soft tissue, which was recorded as apical displacements at 2 years of 0.5 1 0.7 mm and 0.3 1 0.8 mm, respectively, for the immediate and delayed restorations; the final outcomes of the two procedures were not dissimilar. The review by Lang and colleagues showed that, for implants placed and restored immediately after tooth extraction, the majority of soft tissue changes occurred within the first 3 months, with an apical displacement of the buccal mucosal level ranging from 0.45 1 0.25 mm to 0.51 1 0.38 mm at the end of the first year.6,26 For the immediate restoration procedure, the literature reports a final value of 0.22 mm for the marginal gingival level at 2 years, with no significant changes22; in the case of conventional loading, one study found that buccal soft tissue underwent remodeling (loss of
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0.79 mm) at the time of restoration, following which only slight changes were recorded.2 As has been suggested in previous studies regarding immediate implants placed in fresh extraction sockets, wider papilla shrinkage was seen in delayed restoration than in immediate restoration.6 In the present paper, the differences between the two prosthetic rehabilitations were clear at 4 months; the PIs of the delayed restoration group (mesial and distal aspects = 0) were significantly different to those of the immediate restoration group, which were 2 (0) and 2 (1.5) (mesial and distal, respectively). In the delayed restoration group, the papillae seemed to fill the proximal spaces, as suggested by the significant differences in PIs between T1 and the later time points (T2 and T3). Generally, papilla shrinkage was more extensive in the delayed restoration group at the 4-month follow-up, as has also been described in the literature6; afterward, a change in the papilla height occurred, so that the results of the immediate and delayed groups became comparable at the 12-month observation point. The results of the present study demonstrated significant regrowth of the mesial and distal papillae in both groups, which seemed to show similar behavior despite the marginal bone loss: The final 24-month median PIs, irrespective of the timing of the prosthetic restoration, ranged from 2 to 3, with no significant differences between the two procedures. Moreover, the replacement of a single tooth seemed to lead to an eventual positive dimensional change after tooth extraction as compared with the baseline values (median PI = 1) that were recorded for impaired teeth. This is probably due not only to the influence of the bone level and the residual papilla of the adjacent teeth, but also to the anatomical restoration contour at both the mesial and distal aspects. Results published in the literature seem to confirm that most of the hard and soft tissue changes take place within the first 6 months following immediate implant placement; afterward, the papillae, regardless of the restoration procedure, may undergo a positive remodeling phenomenon leading to a gain in height at the mesial and distal aspects, as attested by analysis both of linear height measurements and of the distribution of PI scores.6 Slightly different results were obtained in the case of immediate postextraction implant placement with immediate provisional restoration and flapless approach when linear measurements were acquired: mean papilla level decreased from 0.38 mm to 0.80 mm at 1 year.26
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Despite a reestablishment of the papillae by the end of the survey, which led to a regaining of the original height, observed in both procedures, an immediate prosthetic restoration may guarantee more predictable results in terms of excellent hard and soft tissue prognosis for all aspects; in the delayed group, soft tissues seemed to go through a loss-and-restoration phenomenon, whereas in the immediate group, the tissue modification appeared without sudden changes. With good patient compliance, treatment time can be successfully minimized through an immediate restoration of a dental implant positioned in a fresh extraction socket.24 The present results, in terms of operating times concerning the clinical treatment (until the final prosthetic restoration), show that the median healing for a delayed restoration, 203 (17) days, is slower than that for an immediate provisionalization, 120 (15) days, and is at a significant level. Several studies reporting long-term costs in partially and totally edentulous patients were performed in order to compare different strategies: for example, conventional fixed prostheses and overdentures or implantsupported fixed prostheses.27–30 Results, in terms of cost, were not comparable with either those present in the above-cited literature or with those for single-tooth replacement, with or without dental implant insertion.31 Comparison between immediate provisionalization and delayed restoration showed the latter as having higher costs than the former (by about 26%), due to both the adjunctive second-stage surgery and the higher number of visits required. The present prospective cohort study was primarily limited by treatment selection: the restoration procedure was neither masked nor randomized. Clinicians, on the basis of the aforementioned clinical criteria, referred patients to an immediate or delayed restoration procedure. Furthermore, an inaccuracy could arise from not having a completely blinded type of measurement for the input variables: the radiological and clinical differences between the immediate and delayed restorations were clear to the researcher. Final confirmation of the present findings and of related suggestions put forward in this paper will require longer periods of observation with an increased number of implants. CONCLUSION The final outcomes of immediate and delayed prosthetic rehabilitation for a single implant installed in a fresh
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extraction socket were very similar, although the two restorative procedures may be employed only following precise clinical indications. No significant differences were recorded between the two procedures with regard to bone resorption, the midfacial gingival margin or the WKG. All modifications in the immediate group appeared slow and gradual, allowing more predictable results with excellent soft tissue prognosis, primarily regarding the mesial and distal aspects. In the delayed group, the loss of papillary soft tissues and the bone resorption were sudden and localized, respectively before and after restoration; then, a reestablishment of the papillary soft tissues seemed to occur. In terms of healing times and costs, immediate restoration seemed to be a more promising procedure than delayed restoration. ACKNOWLEDGMENTS This study was supported by a grant from the Department of Surgery, Medical, Molecular, and Critical Area Pathology, University of Pisa. REFERENCES 1. Gotfredsen K. A 5-year prospective study of single-tooth replacements supported by the Astra Tech implant: a pilot study. Clin Impl Dent Relat Res 2004; 6:1–8. 2. Cordaro L, Torsello F, Roccuzzo M. Clinical outcome of submerged vs non-submerged implants placed in fresh extraction sockets. Clin Oral Implants Res 2009; 20:1307– 1313. 3. Covani U, Chiappe G, Bosco M, Orlando B, Quaranta A, Barone A. A 10-year evaluation of implants placed in fresh extraction sockets: a prospective cohort study. J Periodontol 2012; 83:1226–1234. 4. Wilson TG, Buser D. Timing of anterior implant placement postextraction: immediate versus early placement. Clin Adv Periodontics 2011; 1:61–76. 5. Chen ST, Buser D. Clinical and esthetic outcomes of implants placed in postextraction sites. Int J Oral Maxillofac Implants 2009; 24(Suppl):186–217. 6. Lang NP, Pun L, Lau KY, Li KY, Wong MC. A systematic review on survival and success rates of implants placed immediately into fresh extraction sockets after at least 1 year. Clin Oral Implants Res 2012; 23(Suppl 5):39–66. 7. Fickl S, Zuhr O, Wachtel H, Bolz W, Huerzeler M. Tissue alterations after tooth extraction with and without surgical trauma: a volumetric study in the beagle dog. J Clin Periodontol 2008; 35:356–363.
8. Covani U, Barone A, Cornelini R, Crespi R. Soft tissue healing around implants placed immediately after tooth extraction without incision: a clinical report. Int J Oral Maxillofac Implants 2004; 19:549–553. 9. Covani U, Crespi R, Cornelini R, Barone A. Immediate implants supporting single crown restoration: a 4-year prospective study. J Periodontol 2004; 75:982–988. 10. Covani U, Bortolaia C, Barone A, Sbordone L. Bucco-lingual crestal bone changes after immediate and delayed implant placement. J Periodontol 2004; 75:1605–1612. 11. Barone A, Ricci M, Calvo-Guirado JL, Covani U. Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in beagle dogs. Clin Oral Implants Res 2011; 22:1131–1137. 12. Covani U, Barone A, Cornelini R, Crespi R. Clinical outcome of implants placed immediately after implant removal. J Periodontol 2006; 77:722–727. 13. De Rouck T, Collys K, Cosyn J. Single-tooth replacement in the anterior maxilla by means of immediate implantation and provisionalization: a review. Int J Oral Maxillofac Implants 2008; 23:897–904. 14. den Hartog L, Slater JJ, Vissink A, Meijer HJ, Raghoebar GM. Treatment outcome of immediate, early and conventional single-tooth implants in the aesthetic zone: a systematic review to survival, bone level, soft-tissue, aesthetics and patient satisfaction. J Clin Periodontol 2008; 35:1073–1086. 15. Jacobson J, Maxson B, Mays K, Peebles J, Kowalski C. Cost effectiveness of dental implants: a utility analysis. J Dent Educ 1990; 54:688–689. 16. Jonsson B, Karlsson G. Cost-benefit evaluation of dental implants. Int J Technol Assess Health Care 1990; 6:545–557. 17. Attard NJ, Wei X, Laporte A, Zarb GA, Ungar WJ. A cost minimization analysis of implant treatment in mandibular edentulous patients. Int J Prosthodont 2003; 16:271–276. 18. Freitas AC Jr, Bonfante EA, Giro G, Janal MN, Coelho PG. The effect of implant design on insertion torque and immediate micromotion. Clin Oral Implants Res 2012; 23:113– 118. 19. Jemt T. Regeneration of gingival papillae after singleimplant treatment. Int J Periodontics Restorative Dent 1997; 17:326–333. 20. Buser D, Weber HP, Lang NP. Tissue integration of nonsubmerged implants, 1-year results of a prospective study with 100 ITI hollow-screw and hollow-cylinder implants. Clin Oral Implants Res 1990; 1:33–40. 21. Malchiodi L, Ghensi P, Cucchi A, Corrocher G. A comparative retrospective study of immediately loaded implants in postextraction sites versus healed sites: results after 6 to 7 years in the maxilla. Int J Oral Maxillofac Implants 2011; 26:373–384. 22. Crespi R, Capparè P, Gherlone E, Romanos G. Immediate provisionalization of dental implants placed in fresh
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approach: soft tissue alterations and its relation to gingival biotype. Clin Oral Implants Res 2013; 24:1094–1100. Takanashi Y, Penrod JR, Lund JP, Feine JS. A cost comparison of mandibular two-implant overdenture and conventional denture treatment. Int J Prosthodont 2004; 17:181–186. Attard NJ, Zarb GA, Laporte A. Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients. Int J Prosthodont 2005; 18:117–123. Stoker GT, Wismeijer D, van Waas MAJ. An eight-year follow-up to a randomized clinical trial of aftercare and costanalysis with three types of mandibular implant-retained overdentures. J Dent Res 2007; 86:276–280. Bouchard P, Renouard F, Bourgeois D, Fromentin O, Jeanneret MH, Beresniak A. Cost-effectiveness modeling of dental implant vs bridge. Clin Oral Implants Res 2009; 20:583–587. Bragger U, Krenander P, Lang NP. Economic aspects of single-tooth replacement. Clin Oral Implants Res 2005; 16:335–341.
ABSTRACT Background: Immediate implant placement into fresh extraction sockets is generally considered a reliable procedure that offers several clinical advantages. Purpose: The primary aim of this study was to evaluate and compare the overall clinical outcomes of immediate and delayed restoration procedures for implants placed in fresh extraction sockets by means of a flapless technique and resorbable membrane stabilizing a xenograft. Total costs and operating times were also compared. Materials and Methods: In this prospective cohort study, changes of marginal bone level, facial soft tissue (ΔFST), and width of keratinized gingiva (ΔWKG), in addition to the papilla index, underwent a pairwise comparison; correlations with pristine buccal bone thickness were also investigated. Results: Although similar results were recorded for the two procedures, with a bone loss of −1.0 1 0.5 mm and −0.9 1 0.7 mm, respectively, for immediate and delayed restoration, negative remodeling in the delayed restoration procedure was seen to occur from 4 to 12 months after implant placement. No significant differences were recorded between the two procedures in terms of ΔFST and ΔWKG. A loss of the papillary soft tissues before restoration, followed by a reestablishment after restoration, seemed to be verified for the delayed group, for which the papilla index went from the minimum of 0 at 4 months to a value of 2 at 24 months. Moreover, the immediate restoration procedure seemed to be more promising in terms of healing times and costs. Conclusion: Immediate restoration of implants installed in fresh extraction sockets was at least as effective and safe as delayed restoration. KEY WORDS: alveolar bone resorption, immediate implants, immediately restored implant, soft tissue recession
INTRODUCTION
increasingly common practice. The conventional protocol, which involves the placement of implants in healed ridge sites, is widely accepted as a highly predictable treatment.1,2 Nevertheless, over the years, implant dentistry has tried to further simplify clinical procedures and to shorten the overall treatment time; as a result, the placement of implants into fresh extraction sockets has become a promising area of research. Immediate implant placement reduces surgery and treatment time, morbidity, and, importantly, costs for the patient.3,4 The placement of implants into fresh extraction sockets provides several clinical advantages and has been proven to be a reliable procedure despite the surgical challenges it can pose.3,5 Surgical difficulties that even an
The use of dental implants to replace one or more missing teeth in the anterior maxilla has become an *Department of Surgical, Medical, Molecular, and Critical Area Pathology, University of Pisa, Pisa, Italy; †Tuscan Dental Institute, Versilia General Hospital, Lido di Camaiore, Italy; ‡Department of Odontostomatologic and Specialized Clinical Sciences (DISCO), Marche Polytechnic University, Ancona, Italy Corresponding Author: Dr. Antonio Barone, Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, Tuscan Dental Institute, Piazza Diaz 10, 55041 Camaiore, Lucca, Italy; e-mail: [email protected] © 2014 Wiley Periodicals, Inc. DOI 10.1111/cid.12225
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experienced clinician might face include obtaining adequate three-dimensional implant positioning, ensuring primary implant stability, and managing the bone wall remodeling phase subsequent to tooth extraction.6 Several key factors are important for ensuring positive clinical outcomes: namely, surgery should be performed without flap elevation to reduce deleterious facial bone remodeling7–9; the buccal bone plate should be left essentially intact; and the implant should be placed toward the palatal aspect of the socket.10 It has been clearly shown that bone remodeling inevitably occurs after tooth extraction and simultaneous implant placement. Augmentation procedures have been developed for treatment of the peri-implant bone defects that can be observed after the placement of implants into fresh extraction sockets. These procedures may reduce the dimensional changes that spontaneously occur after tooth extraction.11 Single maxillary implants may also be immediately restored with predictable clinical success and high survival rates.12,13 Several authors have suggested that adequate primary implant stability and avoidance of occlusal or eccentric contact during the healing phase could be considered prerequisites for success in this regard. A review of the outcomes of different loading protocols showed no differences in terms of survival rates between immediately and conventionally loaded implants placed in fresh extraction sockets.14 However, there has previously been a lack of information pertaining to reducing soft tissue remodeling and achieving good aesthetics around these implants. Therefore, an aesthetically satisfying result may not be easily achieved following immediate placement and restoration of a dental implant in the anterior maxilla. Furthermore, factors such as the remodeling of bone walls after tooth extraction and the differences in healing of buccal tissue following immediate versus delayed restoration of immediate implants require full consideration and investigation. Another aspect of treatment outcome that is an important consideration is the cost-effectiveness of dental implant therapy, which has been studied for more than 20 years.15,16 The cost-effectiveness of treatment will inevitably have an impact on the decision-making process. The primary aim of the present study was to evaluate and compare the overall clinical outcomes of immediate and conventional restoration procedures for implants placed in fresh extraction sockets. The present
study tested the null hypothesis that there are no differences in clinical outcome between the two procedures against the alternative hypothesis that there is a difference. The short-term implant survival rate was also evaluated. The secondary aim of this study was to compare the total costs and clinical treatment periods between the two above-mentioned procedures. This is a preliminary 2-year report and is part of an ongoing study. MATERIALS AND METHODS This study was designed as a prospective cohort study and included consecutively treated patients. The trial was conducted at Versilia General Hospital (affiliated with the University of Pisa), Camaiore, Italy, between June 2008 and November 2010. All the procedures were performed by two experienced surgeons (UC and AB), who received a week of training before beginning the study. The training covered surgical and follow-up procedures, as well as the handling of any complications. Patients were considered eligible for inclusion in the study if they (1) were at least 18 years of age and able to sign an informed consent form, (2) had a failing cuspid/ bicuspid tooth in the maxillary/mandibular area requiring extraction and immediate dental implant placement with either immediate or delayed restoration, and (3) were willing to have their progress followed for at least 2 years (the present analysis is part of an ongoing study and represents an interim report at 2 years after dental implant insertion). Patients were excluded from the study if any of the following criteria applied: (1) history of systemic diseases that would contraindicate surgical treatment, (2) long-term steroidal and/or aminobisphosphonate therapy, (3) diabetes mellitus, (4) pregnancy or lactation, (5) uncontrolled periodontal disease, (6) more than 10 cigarettes smoked per day (subjects smoking less than 10 cigarettes per day were requested to stop smoking before and after surgery, even though their compliance could not be monitored), (7) absence of teeth adjacent to the ones to be extracted, (8) extraction sites with a partial or complete deficiency of buccal bone plate, (9) acute infection in the failing tooth, or (10) unwillingness to return for the follow-up examination. The study was conducted according to the principles outlined in the Declaration of Helsinki on clinical research involving human subjects, as revised in 2000. All patients received thorough explanations of the study
Immediate and Delayed Restored Dental Implants
and had to complete a written informed consent form prior to being enrolled in the study. Patients who were included in the study were carefully evaluated by examination of clinical aspects and periapical/panoramic radiographs; data such as age, gender, and smoking habits were collected for each patient, as well as both clinical and radiographic indications for tooth extraction and location of the tooth to be extracted. A financial record was compiled for patients where possible, and costs associated with the clinical treatment, including aftercare, were considered. The total costs were calculated following Attard and colleagues.17 Surgery After the consent form had been signed, all patients were subjected to at least one oral hygiene session prior to the extraction procedures in order to provide a more favorable oral environment for wound healing. All patients underwent tooth extraction and clinical measurements at baseline; the amount of available alveolar bone and the presence of an intact buccal bone wall were evaluated. In clinical situations in which an implant could not be inserted immediately, a ridge preservation procedure was performed; these patients were excluded from the study and received an implant 4–5 months later. The implants used for this study were Blossom implants with an Ossean® surface (Intra-Lock International, Boca Raton, FL, USA).18 When an implant could be inserted, the final insertion torque was measured with a calibrated torque wrench (Torque-Lock 2, Intra-Lock International). The surgical wrench was able to perform torque measurements within a range of 20 to 75 Ncm. Implants with an insertion torque of at least 45 Ncm were included in the immediate restoration group and were temporarily restored within 48 hours of implant placement (Figure 1); on the other hand, implants with an insertion torque lower than 45 Ncm were included in the delayed restoration group and were restored 4 months after implant placement (Figure 2). All patients received prophylactic antibiotic therapy (2 g amoxicillin, or 600 mg clindamycin if allergic to penicillins) 1 hour before the extraction procedure and continued to take the antibiotic (1 g amoxicillin or 300 mg clindamycin) postoperatively three times a day for 4 days. All patients rinsed for 1 minute with 0.2% chlorhexidine mouthwash prior to the surgery (and twice a day for the following 3 weeks) and were treated under local anesthesia using lidocaine with adrenaline
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(1:50,000). A flapless approach was chosen, and tooth extractions were carried out with or without elevators as necessary to minimize the trauma; great care was taken to maintain the integrity of the buccal bone wall. Ultrasound bone surgery with appropriate tips was used at the mesial, distal, and lingual/palatal sites to allow easier tooth extraction. After extraction, the socket was carefully curetted, and subsequently, the implant bed was prepared according to the standard procedure (with standard drills, following the palatal bony wall as a guide and making maximum use of the bone apical to the removed tooth). A periodontal probe was used to verify the integrity of the bone walls and to measure the periimplant bone defect after implant osteotomy preparation. The Blossom implants were placed with the implant platform at the marginal level of the palatal/ lingual bone wall (Figures 1 and 2). All the implants were evaluated for their final insertion torque; 45 Ncm was the cutoff value determining whether the implant would be allocated to the immediate restoration or delayed restoration group. The peri-implant bone defect − between the implant surface and bone wall – was augmented with corticocancellous porcine bone particles (OsteoBiol Apatos, Tecnoss, Coazze, Italy). Subsequently, a resorbable membrane (OsteoBiol Evolution, Tecnoss) was used to stabilize the graft, and a crossmattress suture was used to stabilize the blood clot. Secondary soft tissue healing was encouraged with a collagen membrane exposed to the oral cavity. Patients were instructed to continue with prophylactic antibiotic therapy, and 600 mg ibuprofen tablets were prescribed as anti-inflammatories to be taken three times a day as long as required. Sutures were removed after 10 days and oral hygiene instructions were given. The prosthetic procedures were similar for the immediate and delayed restoration groups; impressions were taken, and temporary/resin restorations were prepared within 36 hours using prefabricated abutments (Intra-Lock International). Moreover, the delayed restoration group received a second-stage surgery with a midcrestal incision to allow uncovering of the submerged implants and soft tissue healing. The final impressions were made with individual trays using polyvinylsiloxane material (Flexitime, Heraeus Kulzer, Hanau, Germany), and these were used to prepare the metal-ceramic crowns, which were cemented on individually tailored titanium abutments. Patients were enrolled in an oral hygiene programme with a recall visit every 3 months.
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Figure 1 Immediate restoration. (A) Fresh extraction socket; (B) implant inserted in the extraction socket; (C) occlusal and (D) facial views of restoration; (E) tissue healing at final restoration; (F) buccal view of restored implant after 2 years; (G–I) periapical radiographs (G) immediately after restoration, (H) after 4 months ,and (I) after 2 years.
Immediate and Delayed Restored Dental Implants
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index_en.htm), which cites 2013 labor costs in Italy as €27.4 per hour. The time cost for each patient was calculated by multiplying the amount of time per year spent in the clinic by the mean real salary per hour. The total costs were the costs accumulated over the 2 years of the survey. Input Variables
Figure 2 Delayed restoration. (A) View of the extraction socket; (B) implant positioned in the extraction socket; (C) augmentation procedure to treat peri-implant bone defect; (D) secondary soft tissue healing; (E) final restoration after 2 years; (F,G) periapical radiographs (F) immediately after restoration and (G) after 2 years.
For each patient, time spent was recorded, and clinical and financial records were collected. A figure for the mean real salary per hour in Italy was obtained from the European Commission website (http://ec.europa.eu/
Measurements were acquired immediately after implant placement (baseline or time T0), at 4 months after placement (T1), and at 12 and 24 months after placement (with loaded final prosthetic restoration; T2 and T3, respectively). All the measurements were taken by a single examiner, who was not involved in performing the surgical treatment. Variables measured included (1) diameter and length of the dental implants placed, (2) peri-implant marginal bone level (MBL), (3) width of keratinized gingiva (WKG), (4) facial soft tissue (FST) levels, and (5) buccal bone thickness (BT). Peri-implant MBL, evaluated on intraoral radiographs at the mesial and distal sites (mMBLx and dMBLx, respectively, where x = 1,2,3), was defined as the distance between the reference point and the most apical point of the marginal bone level. The reference point was the fixture-abutment interface. Intraoral periapical radiographs were taken (70 kVp, 7 mA) with a digital sensor (Schick Technologies, New York, NY, USA) using a parallel-cone technique. A paralleling device and individualized bite blocks made of polyvinylsiloxane impression material (Flexitime, Heraeus Kulzer) were used for the standardization of the x-ray geometry. Calibration was performed using the known thread-pitch distances of the implants (pitch = 1.0 mm). Known values, such as fixture diameter and length, were used for calibration when the threads were not clearly visible on the radiographs. Measurements were taken to the nearest millimeter using computer software (UTHSCSA Image Tool, Version 3.00, University of Texas Health Science Center, San Antonio, TX, USA). WKG was measured midfacially from the gingival margin to the mucogingival junction of the tooth to be extracted (baseline) or the implant-supported restoration; for delayed restoration (4 months after implant placement), it was also measured from the top of the edentulous crest to the mucogingival junction of the edentulous area.
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FST levels were evaluated by measuring the distance between the soft tissue level at the midfacial gingival level and a reference line from the facial soft tissue level of the adjacent teeth. BT was evaluated at baseline using a surgical caliper, both at the midfacial level of the buccal bone plate and at the most coronal point of the marginal crest. In addition to these five parameters, implant failure (where any mobility of the implant, any infection that required removal, or any implant fracture was considered failure) was evaluated, and implant stability was assessed manually at each measurement time point. Lastly, the cost of the clinical treatment, including the cost of materials (dental implant, abutment, provisional and definitive prostheses) and surgical fees (operating room and clinical staff), was calculated, with the following stages of treatment being taken into account: preoperative consultations and diagnostic tests, firststage surgery, visits during the healing phase, secondstage surgery, and the prosthodontic phase of treatment. Additional clinical costs, including costs of clinical and medical services and costs resulting from time spent by the patient on recall visits (oral hygiene program, with a recall visit every 6 months) and any other visits required, were also calculated. Outcome Variables The outcome variables, obtained by a subtraction (Δ) and evaluated for the present study, could be negative or positive, with a reduction being represented by a negative value. Changes in MBL (ΔMBL) were evaluated for the mesial and distal aspects (mΔMBL and dΔMBL, respectively) by subtracting the T1, T2, and T3 values of the MBL from the respective baseline value (nΔMBLx = nMBL0 − nMBLx, with n as mesial or distal, and x = 1,2,3). Changes in FST were calculated by subtracting the baseline value from the respective values at T1, T2, or T3, according to the formula ΔFSTx = FSTx − FST0 (where x = 1,2,3). Changes in WKG were calculated by subtracting the baseline value from the respective values at T1, T2, or T3, according to the formula ΔWKGx = WKGx − WKG0 (where x = 1,2,3). The status of the interdental papilla was recorded based on the index proposed by Jemt – papilla index, or PI19: 0 = no papilla; 1 = less than half the normal papilla
height is present; 2 = greater than half the normal papilla height is present, but papilla does not extend to the normal contact point; 3 = papilla fills the entire proximal space and is in good harmony; 4 = papilla is hyperplastic. Success rates and cumulative survival rates for implants were calculated according to the criteria suggested by Buser and colleagues, with a recorded radiological peri-implant bone resorption not greater than 1.5 mm during the first year of loading20 or 0.2 mm/year during the following years.21 Clinical treatment period was calculated from time of initial surgery to time of placement of the definitive prosthesis. Total cost (expressed in labor costs per hour) was calculated as costs for the treatment itself plus adjunctive clinical costs. Statistical Analysis Acquired data were entered into a database for automatic analysis (Database Toolbox, MatLab 7.0.1; MathWorks, Natick, MA, USA). Descriptive and statistical analyses were performed using a matrix laboratory tools package (Statistics Toolbox, MatLab 7.0.1). A Shapiro-Wilk test was employed to assess whether data for the immediate restoration and delayed restoration groups were normally distributed; normal distribution was not verified for either of the two groups. For each of the outcome variables, the effects of smoking habits and gender were measured with Friedman’s test; then, pairwise comparisons were performed using the Wilcoxon signed-rank test for matched samples and the Wilcoxon rank-sum test for unmatched data, and p values were obtained. The Spearman correlation (rs) was used to assess the strength of the bivariate associations between BT and changes in MBL and FST. All measurements in the text and tables are given as medians, with interquartile range (IQR; the difference between the 75th and 25th percentiles) following in parentheses. The level of statistical significance was set at .001 for all analyses. RESULTS In the present cohort study, a total of 30 patients were treated with a single-tooth extraction and prosthetic rehabilitation supported by a dental implant: 15 patients were treated via an immediate prosthetic restoration, whereas the remaining 15 were rehabilitated with a
Immediate and Delayed Restored Dental Implants
delayed restoration 4 months after extraction. Table 1 summarizes the demographic data from the two groups. Out of the 30 patients, 14 were females and 12 smokers. Six canines and 24 bicuspids were extracted. At the time of extraction, the measured buccal plate thicknesses were 0.7 1 0.2 mm and 0.6 1 0.2 mm for the immediate and delayed groups, respectively. The variables set out in Table 1 for both groups were measured at baseline (T0) and during follow-up 4 (T1), 12 (T2), and 24 months (T3) after extraction, with corresponding differences from baseline also being measured (Δ1, Δ2, and Δ3 represented differences from T0 to T1, from T0 to T2, and from T0 to T3, respectively), as described in the methods for each outcome variable. Table 1 also shows the median PI values for the two procedures. Figure 3 plots the distribution of dimensional changes for both the hard tissue and soft tissue outlines around the implant restorations (in relation to the status before tooth extraction) for each of the several outcome variables presented. Moreover, the statistically significant differences in the outcome variables (mesial and distal ΔMBL, ΔFST, ΔWKG, and mesial and distal IP) between the two restoration groups and among time points are summarized. Nonparametric ANOVA tests were performed for all outcome variables to investigate the relationships of smoking and gender to the type of prosthetic loading used (immediate or delayed). The results are shown in Table 2; the effects of smoking and gender for were not significant for any of the outcome variables. The analysis of differences in the outcome variables between the two restoration procedures showed significant differences in the mesial and distal PIs at 4 months (mPI1 and dPI1), with values of 2 (0) and 2 (1.5), respectively, for the immediate procedure and 0 (0) for both aspects in the delayed restoration. The p value was 0.5 mm may assure clinicians of the absence of buccal soft tissue loss, at least for delayed restoration. Nevertheless, a few patients in both groups showed a slight buccal recession of the soft tissue, which was recorded as apical displacements at 2 years of 0.5 1 0.7 mm and 0.3 1 0.8 mm, respectively, for the immediate and delayed restorations; the final outcomes of the two procedures were not dissimilar. The review by Lang and colleagues showed that, for implants placed and restored immediately after tooth extraction, the majority of soft tissue changes occurred within the first 3 months, with an apical displacement of the buccal mucosal level ranging from 0.45 1 0.25 mm to 0.51 1 0.38 mm at the end of the first year.6,26 For the immediate restoration procedure, the literature reports a final value of 0.22 mm for the marginal gingival level at 2 years, with no significant changes22; in the case of conventional loading, one study found that buccal soft tissue underwent remodeling (loss of
Immediate and Delayed Restored Dental Implants
0.79 mm) at the time of restoration, following which only slight changes were recorded.2 As has been suggested in previous studies regarding immediate implants placed in fresh extraction sockets, wider papilla shrinkage was seen in delayed restoration than in immediate restoration.6 In the present paper, the differences between the two prosthetic rehabilitations were clear at 4 months; the PIs of the delayed restoration group (mesial and distal aspects = 0) were significantly different to those of the immediate restoration group, which were 2 (0) and 2 (1.5) (mesial and distal, respectively). In the delayed restoration group, the papillae seemed to fill the proximal spaces, as suggested by the significant differences in PIs between T1 and the later time points (T2 and T3). Generally, papilla shrinkage was more extensive in the delayed restoration group at the 4-month follow-up, as has also been described in the literature6; afterward, a change in the papilla height occurred, so that the results of the immediate and delayed groups became comparable at the 12-month observation point. The results of the present study demonstrated significant regrowth of the mesial and distal papillae in both groups, which seemed to show similar behavior despite the marginal bone loss: The final 24-month median PIs, irrespective of the timing of the prosthetic restoration, ranged from 2 to 3, with no significant differences between the two procedures. Moreover, the replacement of a single tooth seemed to lead to an eventual positive dimensional change after tooth extraction as compared with the baseline values (median PI = 1) that were recorded for impaired teeth. This is probably due not only to the influence of the bone level and the residual papilla of the adjacent teeth, but also to the anatomical restoration contour at both the mesial and distal aspects. Results published in the literature seem to confirm that most of the hard and soft tissue changes take place within the first 6 months following immediate implant placement; afterward, the papillae, regardless of the restoration procedure, may undergo a positive remodeling phenomenon leading to a gain in height at the mesial and distal aspects, as attested by analysis both of linear height measurements and of the distribution of PI scores.6 Slightly different results were obtained in the case of immediate postextraction implant placement with immediate provisional restoration and flapless approach when linear measurements were acquired: mean papilla level decreased from 0.38 mm to 0.80 mm at 1 year.26
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Despite a reestablishment of the papillae by the end of the survey, which led to a regaining of the original height, observed in both procedures, an immediate prosthetic restoration may guarantee more predictable results in terms of excellent hard and soft tissue prognosis for all aspects; in the delayed group, soft tissues seemed to go through a loss-and-restoration phenomenon, whereas in the immediate group, the tissue modification appeared without sudden changes. With good patient compliance, treatment time can be successfully minimized through an immediate restoration of a dental implant positioned in a fresh extraction socket.24 The present results, in terms of operating times concerning the clinical treatment (until the final prosthetic restoration), show that the median healing for a delayed restoration, 203 (17) days, is slower than that for an immediate provisionalization, 120 (15) days, and is at a significant level. Several studies reporting long-term costs in partially and totally edentulous patients were performed in order to compare different strategies: for example, conventional fixed prostheses and overdentures or implantsupported fixed prostheses.27–30 Results, in terms of cost, were not comparable with either those present in the above-cited literature or with those for single-tooth replacement, with or without dental implant insertion.31 Comparison between immediate provisionalization and delayed restoration showed the latter as having higher costs than the former (by about 26%), due to both the adjunctive second-stage surgery and the higher number of visits required. The present prospective cohort study was primarily limited by treatment selection: the restoration procedure was neither masked nor randomized. Clinicians, on the basis of the aforementioned clinical criteria, referred patients to an immediate or delayed restoration procedure. Furthermore, an inaccuracy could arise from not having a completely blinded type of measurement for the input variables: the radiological and clinical differences between the immediate and delayed restorations were clear to the researcher. Final confirmation of the present findings and of related suggestions put forward in this paper will require longer periods of observation with an increased number of implants. CONCLUSION The final outcomes of immediate and delayed prosthetic rehabilitation for a single implant installed in a fresh
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extraction socket were very similar, although the two restorative procedures may be employed only following precise clinical indications. No significant differences were recorded between the two procedures with regard to bone resorption, the midfacial gingival margin or the WKG. All modifications in the immediate group appeared slow and gradual, allowing more predictable results with excellent soft tissue prognosis, primarily regarding the mesial and distal aspects. In the delayed group, the loss of papillary soft tissues and the bone resorption were sudden and localized, respectively before and after restoration; then, a reestablishment of the papillary soft tissues seemed to occur. In terms of healing times and costs, immediate restoration seemed to be a more promising procedure than delayed restoration. ACKNOWLEDGMENTS This study was supported by a grant from the Department of Surgery, Medical, Molecular, and Critical Area Pathology, University of Pisa. REFERENCES 1. Gotfredsen K. A 5-year prospective study of single-tooth replacements supported by the Astra Tech implant: a pilot study. Clin Impl Dent Relat Res 2004; 6:1–8. 2. Cordaro L, Torsello F, Roccuzzo M. Clinical outcome of submerged vs non-submerged implants placed in fresh extraction sockets. Clin Oral Implants Res 2009; 20:1307– 1313. 3. Covani U, Chiappe G, Bosco M, Orlando B, Quaranta A, Barone A. A 10-year evaluation of implants placed in fresh extraction sockets: a prospective cohort study. J Periodontol 2012; 83:1226–1234. 4. Wilson TG, Buser D. Timing of anterior implant placement postextraction: immediate versus early placement. Clin Adv Periodontics 2011; 1:61–76. 5. Chen ST, Buser D. Clinical and esthetic outcomes of implants placed in postextraction sites. Int J Oral Maxillofac Implants 2009; 24(Suppl):186–217. 6. Lang NP, Pun L, Lau KY, Li KY, Wong MC. A systematic review on survival and success rates of implants placed immediately into fresh extraction sockets after at least 1 year. Clin Oral Implants Res 2012; 23(Suppl 5):39–66. 7. Fickl S, Zuhr O, Wachtel H, Bolz W, Huerzeler M. Tissue alterations after tooth extraction with and without surgical trauma: a volumetric study in the beagle dog. J Clin Periodontol 2008; 35:356–363.
8. Covani U, Barone A, Cornelini R, Crespi R. Soft tissue healing around implants placed immediately after tooth extraction without incision: a clinical report. Int J Oral Maxillofac Implants 2004; 19:549–553. 9. Covani U, Crespi R, Cornelini R, Barone A. Immediate implants supporting single crown restoration: a 4-year prospective study. J Periodontol 2004; 75:982–988. 10. Covani U, Bortolaia C, Barone A, Sbordone L. Bucco-lingual crestal bone changes after immediate and delayed implant placement. J Periodontol 2004; 75:1605–1612. 11. Barone A, Ricci M, Calvo-Guirado JL, Covani U. Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in beagle dogs. Clin Oral Implants Res 2011; 22:1131–1137. 12. Covani U, Barone A, Cornelini R, Crespi R. Clinical outcome of implants placed immediately after implant removal. J Periodontol 2006; 77:722–727. 13. De Rouck T, Collys K, Cosyn J. Single-tooth replacement in the anterior maxilla by means of immediate implantation and provisionalization: a review. Int J Oral Maxillofac Implants 2008; 23:897–904. 14. den Hartog L, Slater JJ, Vissink A, Meijer HJ, Raghoebar GM. Treatment outcome of immediate, early and conventional single-tooth implants in the aesthetic zone: a systematic review to survival, bone level, soft-tissue, aesthetics and patient satisfaction. J Clin Periodontol 2008; 35:1073–1086. 15. Jacobson J, Maxson B, Mays K, Peebles J, Kowalski C. Cost effectiveness of dental implants: a utility analysis. J Dent Educ 1990; 54:688–689. 16. Jonsson B, Karlsson G. Cost-benefit evaluation of dental implants. Int J Technol Assess Health Care 1990; 6:545–557. 17. Attard NJ, Wei X, Laporte A, Zarb GA, Ungar WJ. A cost minimization analysis of implant treatment in mandibular edentulous patients. Int J Prosthodont 2003; 16:271–276. 18. Freitas AC Jr, Bonfante EA, Giro G, Janal MN, Coelho PG. The effect of implant design on insertion torque and immediate micromotion. Clin Oral Implants Res 2012; 23:113– 118. 19. Jemt T. Regeneration of gingival papillae after singleimplant treatment. Int J Periodontics Restorative Dent 1997; 17:326–333. 20. Buser D, Weber HP, Lang NP. Tissue integration of nonsubmerged implants, 1-year results of a prospective study with 100 ITI hollow-screw and hollow-cylinder implants. Clin Oral Implants Res 1990; 1:33–40. 21. Malchiodi L, Ghensi P, Cucchi A, Corrocher G. A comparative retrospective study of immediately loaded implants in postextraction sites versus healed sites: results after 6 to 7 years in the maxilla. Int J Oral Maxillofac Implants 2011; 26:373–384. 22. Crespi R, Capparè P, Gherlone E, Romanos G. Immediate provisionalization of dental implants placed in fresh
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extraction sockets using a flapless technique. Int J Periodontics Restorative Dent 2012; 32:29–37. Rocci A, Rocci M, Scoccia A, Martignoni M, Gottlow J, Sennerby L. Immediate loading of maxillary prostheses using flapless surgery, implant placement in predetermined positions, and prefabricated provisional restorations. Part 2: a retrospective 10-year clinical study. Int J Oral Maxillofac Implants 2012; 27:1199–1204. Del Fabbro M, Ceresoli V, Taschieri S, Ceci C, Testori T. Immediate loading of postextraction implants in the esthetic area: a systematic review of the literature. Clin Implant Dent Relat Res 2013. In press: doi: 10.1111/cid.12074 Maló P, Nobre MD. Flap vs flapless surgical techniques at immediate implant function in predominantly soft bone for rehabilitation of partial edentulism: a prospective cohort study with follow-up of 1 year. Eur J Oral Implantol 2008; 1:293–304. Cabello G, Rioboo M, Fábrega JG. Immediate placement and restoration of implants in the aesthetic zone with a trimodal
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approach: soft tissue alterations and its relation to gingival biotype. Clin Oral Implants Res 2013; 24:1094–1100. Takanashi Y, Penrod JR, Lund JP, Feine JS. A cost comparison of mandibular two-implant overdenture and conventional denture treatment. Int J Prosthodont 2004; 17:181–186. Attard NJ, Zarb GA, Laporte A. Long-term treatment costs associated with implant-supported mandibular prostheses in edentulous patients. Int J Prosthodont 2005; 18:117–123. Stoker GT, Wismeijer D, van Waas MAJ. An eight-year follow-up to a randomized clinical trial of aftercare and costanalysis with three types of mandibular implant-retained overdentures. J Dent Res 2007; 86:276–280. Bouchard P, Renouard F, Bourgeois D, Fromentin O, Jeanneret MH, Beresniak A. Cost-effectiveness modeling of dental implant vs bridge. Clin Oral Implants Res 2009; 20:583–587. Bragger U, Krenander P, Lang NP. Economic aspects of single-tooth replacement. Clin Oral Implants Res 2005; 16:335–341.
