Feng Wang Zhiyong Zhang Alberto Monje Wei Huang Yiqun Wu Guomin Wang
Intermediate long-term clinical performance of dental implants placed in sites with a previous early implant failure: a retrospective analysis
Authors’ affiliations: Feng Wang, Zhiyong Zhang, Wei Huang, Yiqun Wu, Department of Oral Implantology, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China Alberto Monje, Department of Periodontics and Oral Medicine, University of Michigan, School of Dentistry, Ann Arbor, MI, USA Guomin Wang, Center for Cleft Lip and Palate, Department of Oral & Cranio-Maxillofacial Science, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai, China
Key words: cumulative survival rate, early implant failure, reimplantation, replacement,
Corresponding author: Yiqun Wu Department of Oral Implantology, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai 200011, China Tel.: 86 21 63138341 ext. 5299 Fax: 86 21 53073068 e-mail: [email protected] and Guomin Wang Center for Cleft Lip and Palate, Department of Oral & Cranio-Maxillofacial Science, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai 200011, China Tel.: 86 21 23271699 ext. 5149 e-mail: [email protected]
surgery performed prior or at the same of implant placement to obtain proper hard tissues
success rate Abstract Purpose: The aim of this retrospective case–control study was to evaluate the intermediate longterm clinical performance and success rate of dental implants inserted into sites of previous early implant failure. Material and methods: A retrospective evaluation was conducted on 6456 patients with 10,234 implants from January 2004 to December 2011. The patients with early implant failure retreated in previous failed sites were enrolled in the study. The collected data included patient0 s characteristics, implants characteristics (failed and replaced), and if was the case, any additional dimensions. Moreover, peri-implant clinical parameters, marginal bone loss (MBL), and the implant quality scale (IQS) of the replacement implants were recorded after delivering of the final prosthesis and annually thereafter. Results: Ninety-six patients (100 implants) showed initial early failure (failure rate = 0.98%). Sixtysix patients (male: 38; female: 28; mean age: 42.3 18.2 years old) with early implant failure received a total of 67 replacement dental implants. Three patients with three implants dropped out of the study during the mean follow-up of 69.4 27.0 months. The implant length and diameter were varied for seven sites. The number of sites that required additional surgeries increased from 18 to 24 for first and replacement implant insertion, respectively. One of the 67 replacement implants failed before prosthesis delivery, and one implant failure occurred 20 months after prosthesis delivery, which represented a cumulative survival rate of 94.6%. At last follow-up evaluation, the overall mean MBL was 1.7 1.3 mm. Two of 64 implants failed according to IQS criteria, three implants showed satisfactory survival, and one implant showed compromised survival. No pain or tenderness was observed in the rest 58 implants evaluated, showing a success rate (optimum health) of 90.6%. Conclusion: Within the limits of the present study, early implant failure was not an obstacle for implant replacement at the same site after an adequate soft and hard tissues healing period.
Date: Accepted 6 August 2014 To cite this article: Wang F, Zhang Z, Monje A, Huang W, Wu Y, Wang G. Intermediate long-term clinical performance of dental implants placed in sites with a previous early implant failure: a retrospective analysis Clin. Oral Impl. Res. 26, 2015, 1443–1449. doi: 10.1111/clr.12485
Since landmark studies conducted by Br anemark (Br anemark et al. 1977) and Schroeder (Schroeder et al. 1976), the use of osseointegrated implants for oral prosthetic rehabilitation has become a predictable treatment modality (Buser et al. 1991; Pham et al. 1994; Br€agger et al. 1996). Over the years, although high long-term success rates have consistently been reported by many studies, complications leading to loss of the implant still may occur (Br anemark et al. 1977; Adell et al. 1986). Factors that affect implant failure are diverse, including those related to implant macro-/micro-design and composi-
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
tion, biological issues, and surgical technique (Rosenberg et al. 1991; Tonetti & Schmid 1994; Qian et al. 2012). Hence, dental implant failure can be classified as either early or delayed loss, occurring before or after prosthesis delivery, respectively (Alsaadi et al. 2007). Microbiota, host-related factors, implant design, and iatrogenic factors are related to the early failure of dental implants (Berglundh et al. 2002; Montes et al. 2007; Anner et al. 2010). Generally speaking, to elaborate a diagnosis and thus to figure out the prognosis, implant mobility and radiolucency of the bone around the
1443
Wang et al. Dental implants in sites with previous early failure
implant during the healing period are considered evident characteristic of failed osseointegration. In these scenarios, immediate replacement with a wider diameter dental implant has been proposed as an option for replacement of failed dental implants (Evian & Cutler 1995; Glavas & Moses 2003) . Another option would be the replacement after adequate a healing period to ensure implant primary stability. However, regardless the elected treatment modality, these oftentimes represent challenging situations to clinicians because the failed implant site as a rule presents hard tissue defect caused from bone resorption, and additional reconstructive surgery is often required (Mardinger et al. 2008; Manor et al. 2009). For the majority of patients with failed implants, implant replacement is many times the only alternative treatment for a fixed or removable prosthesis. Limited studies have reported the outcome of implants placed in previously failed sites. Some clinical data have demonstrated that the short-term survival rate of dental implants was lower compared with earlier reports for implants placed in pristine bone sites (Grossman & Levin 2007; Machtei et al. 2008), whereas several studies showed a high survival rate for implant replaced in the follow-up period (Kim et al. 2010; Mardinger et al. 2012). Nonetheless, most of the studies included patients with early and late implant failure, peri-implantitis, the main triggering cause for late failure. Moreover, the prognosis for implants replaced after early failed implant removal is still to be determined, inasmuch as there is limited information available regarding the clinical and radiographic outcomes, and success rates for implants placed in sites with an initial early implant failure. Therefore, the purpose of this study was to evaluate the intermediate long-term clinical performance and success rates for dental implants inserted in sites with an initial early implant failure.
the following inclusion criteria: (i) patients with one or more failed implants that were retrieved and were planned to be replaced; (ii) implant failure before prosthesis delivery; (iii) implant(s) inserted in the same site where the failed implant was previously anchored; (iv) surface-modified implants used in the initial and retreatment procedures; and (v) original and replaced fixtures placed by the same operator. Exclusion Criteria
On the contrary, patients were excluded from this study for one or more of the following conditions: (i) systemic status that was likely to affect bone metabolism (unbalanced hormonal condition, previous irradiation in the head and neck region); (ii) non-biological implant failure (i.e. implant fractured); (iii) implant failure after prosthesis delivery; and (iv) active smoker subjects (>10 cigarettes/ day). Screening Process
The patients included in the study were evaluated according to the following parameters using patients’ records: age (upon placement of the first implant) and gender, healthy condition, general illnesses and medication, smoking habits, anatomical position of the implant, characteristics on the failed and replaced implants (implant length, width, and surface treatment). Also, the time intervals between the first implant(s) placement and retrieval and between its retrieval and replacement were recorded. Moreover, if additional augmentation surgery was required during implant insertion (in any time point) was further recorded. This study protocol was approved by the ethics committee of the Ninth People’s Hospital affiliated with Shanghai Jiao Tong University, School of Medicine. Outcome Assessment
The follow-up examination was performed according to a standardized protocol, which included a clinical radiographic evaluation after delivering of the final prosthesis and annually thereafter.
Material and methods Peri-Implant Clinical Parameters Inclusion Criteria
The medical charts of patients who had been treated in the department of Oral Implantology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University, School of Medicine, between January 2004 and December 2011 were reviewed. Patients were selected to participate whether their clinical condition met
1444 |
Clin. Oral Impl. Res. 26, 2015 / 1443–1449
The Modified Plaque Index (mPI) was measured at four points around the implants according to the following scale: 0, no plaque; 1, plaque on probing; 2, visible plaque; and 3, abundant plaque. For each implant, one MPI value was calculated based on the average of the four obtained values (Mombelli & Lang 1994).
The Modified Sulcus Bleeding Index (mSBI) was measured at four surfaces around the implants. The mSBI was scored as follows: 0 = no bleeding when a periodontal probe was passed along the gingival margin adjacent to the implant, 1 = visible, isolated bleeding spots, 2 = blood formed a confluent red line on the margin, and 3 = heavy or profuse bleeding. For each implant, one mSBI value was calculated based on the average of the four obtained values (Mombelli & Lang 1994). MPI and mSBI measurements were recorded using a plastic probe with a standardized probing force of 0.2 N (Click-Probe; KerrHawe SA, Bioggio, Switzerland). Marginal Bone Loss
Peri-implant bone resorption was recorded by comparing standardized long cone periapical radiographs. All of the images were scanned and transferred to a computer with an image analysis program (GE Healthcare Centricity@ v3.0, Milwaukee, WI, USA). Marginal bone loss (MBL) was documented on the radiograph viewer with the aid of four-fold magnification. The radiographic linear distance from the implant shoulder to the first boneto-implant contact was used to calculate the MBL. The location of the MBL in relation to the implant shoulder was assessed at the mesial and the distal aspects at the time of prosthesis delivery and at the last follow-up radiograph. The radiographic assessment was conducted by two assistants. Implant Quality Scale
The Implant Quality Scale (IQS) was used to assess implant0 s condition with the listed criteria in the last follow-up (Misch et al. 2008). 1. Success (optimum health): (i) no pain or tenderness upon use, (ii) no mobility, (iii) 4 mm (less than 1/2 of implant body), (iv) probing depth >7 mm, and (v) may have history of exudate; 4. Failure (clinical or absolute failure, any of the following): (i) pain upon use, (ii) mobility, (iii) radiographic bone loss >1/2 length of implant, (iv) uncontrolled exudate, or v) no longer in mouth.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Wang et al . Dental implants in sites with previous early failure
A statistical analysis was performed using the SAS statistical package (SAS 9.3, SAS Institute Inc., Cary, NC, USA). The data was averaged within the patient with two implant failure to bypass the problem of dependencies between multiple implants within one patient. Cohen’s kappa (j) test was used to measure inter-examiner reliability. Descriptive statistical analyses of peri-implant hygienic parameters and MBL were performed using the mean of the distribution, the standard deviation, and the median. The cumulative survival rate was calculated for the implants. The level of statistical significance was set at P = 0.05.
Results Study Population
An overall of 10,234 implants were placed in 6456 patients between January 2004 and December 2011. Among them, 96 patients (100 implants) showed early failure (failure rate = 0.98%). Six patients (eight implants) went previously under head and neck irradiation therapy after tumor resection and seven patients (eight implants) were active smokers (>10 cigarettes/day) after motivation and smoking cessation education. Implant replacement was not performed in these patients. On the other hand, 84 implants placed in 83 patients met our inclusion criteria. Among these 83 patients, 17 patients refused implant replacement because of additional costs, fear of additional pain, concern for second implant failure and other individual reasons. Overall, 66 patients (male: 38; female: 28) displayed early implant failure and received a total of 67 dental implants. The mean age of the patients at first implantation was 42.3 18.2 years old (21– 68 years). Three patients reported diabetes mellitus, and 12 were smokers (0.8 showing good inter-examiner reliability. Upon analysis of the MBL obtained for mesial and distal periimplant sites, no significant differences were detected between the values for the mesial and distal sites. The overall mean MBL after a mean of 69.4 months was 1.7 1.3 mm (median: 1.5 mm). The maximum radiological bone loss was 4 mm in one implant. Additionally, three implants showed 2–4 mm of radiographic bone loss. Implant Quality Scale
At the last follow-up evaluation, two of the 64 implants assessed, failed according to IQS criteria, three implants showed satisfactory survival, and one implant displayed compromised survival. No pain or tenderness upon function was observed in the other 58 implants, showing a success rate (optimum health) of 90.6%.
Discussion Early implant failure oftentimes occurs with progressive bone resorption and consequent fixation loss before loading (Fransson et al. 2005), and it has been reported to vary between 1.2% and 3% (Testori et al. 2001; Davarpanah et al. 2002; Roos-Jans aker et al. 2006; Huynh-Ba et al. 2008). When assessing early implant failure, it is important to consider multiple factors together because of their interactive effects on the establishment of osseointegration (Pommer et al. 2011; Baqain et al. 2012). The causes and mechanisms
1446 |
Clin. Oral Impl. Res. 26, 2015 / 1443–1449
eliciting early implant failure remain yet to be determined. Different studies have found a variety of statistically significant factors associated with early implant failure, such as age and sex, systemic diseases, smoking, type of edentulism, implant location, quantity and quality of bone, implant length and diameter, and immunological and genetic factors (Kronstr€ om et al. 2001; Van Steenberghe et al. 2002; Noguerol et al. 2006; Alsaadi et al. 2008; Bornstein et al. 2008; Sverzut et al. 2008; Dereka et al. 2012). A very recent study based on a large retrospective case series showed that the causes of early failure were inflammation (47%), premature loading (13%), host response (8%), unknown (3%) and multiple causes (2%). Strikingly, it was found that a strong correlation between the causes of failure and some specific conditions being lack of primary stability, poorer bone quality/density and/or reconstructive procedures the most prevalent (Han et al. 2014). However, there are still remaining unclear crucial risk factors associated with early implant failure. Despite the fact that reimplantation is a common choice in current treatment plans, little information is available in the literature regarding reimplantation after implant failure. The number of studies reporting the outcome of dental implants placed in previously failed sites is limited and the results are controversial. Some have concluded that replaced implants display a lower survival rate compared with implants in pristine sites. In Grossmann and Levin’s study, nine of 31 single replaced implants failed, yielding an overall survival rate of 71%. A third attempt at single-implant replacement was made in two patients succeeding in only 1 (Grossman & Levin 2007). Machtei et al. reported the success rates of reimplantation in 56 patients who had 79 failed implants. Thirteen implants failed, which resulted in an overall survival rate of 83.5%. In their study, some enrolled implants failed several years post-op
due to late peri-implantitis. Accordingly, authors attributed the lower survival rate for implants placed in previously failed sites to site- or patient-specific risk factors (Machtei et al. 2008). Hence, patient-specific factors might have a major effect on the survival of replaced implants. Cluster failures (multiple implant failures in individual patients) have been reported by Horwitz et al. and SchwartzArad et al. (Horwitz et al. 2007; SchwartzArad et al. 2008a,b). However, in the present study, only one patient had 2 early implant failures, and no cluster failures were detected. In contrast, Mardinger et al., a high survival rate of 93% of the implants that replaced those that previously failed was reported. No correlations were found between replaced implant failures and any of the parameters examined. Nevertheless, implant surface modifications and early/delayed implant loss were not reported in the study (Mardinger et al. 2012). A similar high survival rate of replaced implants was also reported by Kim et al. In their study, 60 replaced implants showed 88.3% survival rate for a mean follow-up of 22 months. Interestingly, 48.3% of cases received immediate replacement (Kim et al. 2010). Thereupon, in partial agreement to previous findings, in the present study, a high cumulative survival rate of 94.6% was obtained after a mean follow-up of 69.4 months for dental implants placed in sites with initial early implant failure, yielding a proper clinical outcome. Thus, regardless of implants’ characteristics and the need of additional regenerative surgery, implant replacement at the same site seems to be predictable after an adequate bone healing period. Table 5 summarizes all the studies’ characteristics assessing the effect of previous failed dental implant upon survival for implants placed at the same site. However, it also must be noted that active smokers and patients who underwent head and neck irradiation therapy were excluded of our criteria. This fact might explain the high success rate achieved. Moreover, according to the IQS criteria, success implant is defined as
Intermediate long-term clinical performance of dental implants placed in sites with a previous early implant failure: a retrospective analysis
Authors’ affiliations: Feng Wang, Zhiyong Zhang, Wei Huang, Yiqun Wu, Department of Oral Implantology, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China Alberto Monje, Department of Periodontics and Oral Medicine, University of Michigan, School of Dentistry, Ann Arbor, MI, USA Guomin Wang, Center for Cleft Lip and Palate, Department of Oral & Cranio-Maxillofacial Science, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai, China
Key words: cumulative survival rate, early implant failure, reimplantation, replacement,
Corresponding author: Yiqun Wu Department of Oral Implantology, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai 200011, China Tel.: 86 21 63138341 ext. 5299 Fax: 86 21 53073068 e-mail: [email protected] and Guomin Wang Center for Cleft Lip and Palate, Department of Oral & Cranio-Maxillofacial Science, Ninth People’s Hospital Affiliated with Shanghai Jiao Tong University, School of Medicine, Shanghai 200011, China Tel.: 86 21 23271699 ext. 5149 e-mail: [email protected]
surgery performed prior or at the same of implant placement to obtain proper hard tissues
success rate Abstract Purpose: The aim of this retrospective case–control study was to evaluate the intermediate longterm clinical performance and success rate of dental implants inserted into sites of previous early implant failure. Material and methods: A retrospective evaluation was conducted on 6456 patients with 10,234 implants from January 2004 to December 2011. The patients with early implant failure retreated in previous failed sites were enrolled in the study. The collected data included patient0 s characteristics, implants characteristics (failed and replaced), and if was the case, any additional dimensions. Moreover, peri-implant clinical parameters, marginal bone loss (MBL), and the implant quality scale (IQS) of the replacement implants were recorded after delivering of the final prosthesis and annually thereafter. Results: Ninety-six patients (100 implants) showed initial early failure (failure rate = 0.98%). Sixtysix patients (male: 38; female: 28; mean age: 42.3 18.2 years old) with early implant failure received a total of 67 replacement dental implants. Three patients with three implants dropped out of the study during the mean follow-up of 69.4 27.0 months. The implant length and diameter were varied for seven sites. The number of sites that required additional surgeries increased from 18 to 24 for first and replacement implant insertion, respectively. One of the 67 replacement implants failed before prosthesis delivery, and one implant failure occurred 20 months after prosthesis delivery, which represented a cumulative survival rate of 94.6%. At last follow-up evaluation, the overall mean MBL was 1.7 1.3 mm. Two of 64 implants failed according to IQS criteria, three implants showed satisfactory survival, and one implant showed compromised survival. No pain or tenderness was observed in the rest 58 implants evaluated, showing a success rate (optimum health) of 90.6%. Conclusion: Within the limits of the present study, early implant failure was not an obstacle for implant replacement at the same site after an adequate soft and hard tissues healing period.
Date: Accepted 6 August 2014 To cite this article: Wang F, Zhang Z, Monje A, Huang W, Wu Y, Wang G. Intermediate long-term clinical performance of dental implants placed in sites with a previous early implant failure: a retrospective analysis Clin. Oral Impl. Res. 26, 2015, 1443–1449. doi: 10.1111/clr.12485
Since landmark studies conducted by Br anemark (Br anemark et al. 1977) and Schroeder (Schroeder et al. 1976), the use of osseointegrated implants for oral prosthetic rehabilitation has become a predictable treatment modality (Buser et al. 1991; Pham et al. 1994; Br€agger et al. 1996). Over the years, although high long-term success rates have consistently been reported by many studies, complications leading to loss of the implant still may occur (Br anemark et al. 1977; Adell et al. 1986). Factors that affect implant failure are diverse, including those related to implant macro-/micro-design and composi-
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
tion, biological issues, and surgical technique (Rosenberg et al. 1991; Tonetti & Schmid 1994; Qian et al. 2012). Hence, dental implant failure can be classified as either early or delayed loss, occurring before or after prosthesis delivery, respectively (Alsaadi et al. 2007). Microbiota, host-related factors, implant design, and iatrogenic factors are related to the early failure of dental implants (Berglundh et al. 2002; Montes et al. 2007; Anner et al. 2010). Generally speaking, to elaborate a diagnosis and thus to figure out the prognosis, implant mobility and radiolucency of the bone around the
1443
Wang et al. Dental implants in sites with previous early failure
implant during the healing period are considered evident characteristic of failed osseointegration. In these scenarios, immediate replacement with a wider diameter dental implant has been proposed as an option for replacement of failed dental implants (Evian & Cutler 1995; Glavas & Moses 2003) . Another option would be the replacement after adequate a healing period to ensure implant primary stability. However, regardless the elected treatment modality, these oftentimes represent challenging situations to clinicians because the failed implant site as a rule presents hard tissue defect caused from bone resorption, and additional reconstructive surgery is often required (Mardinger et al. 2008; Manor et al. 2009). For the majority of patients with failed implants, implant replacement is many times the only alternative treatment for a fixed or removable prosthesis. Limited studies have reported the outcome of implants placed in previously failed sites. Some clinical data have demonstrated that the short-term survival rate of dental implants was lower compared with earlier reports for implants placed in pristine bone sites (Grossman & Levin 2007; Machtei et al. 2008), whereas several studies showed a high survival rate for implant replaced in the follow-up period (Kim et al. 2010; Mardinger et al. 2012). Nonetheless, most of the studies included patients with early and late implant failure, peri-implantitis, the main triggering cause for late failure. Moreover, the prognosis for implants replaced after early failed implant removal is still to be determined, inasmuch as there is limited information available regarding the clinical and radiographic outcomes, and success rates for implants placed in sites with an initial early implant failure. Therefore, the purpose of this study was to evaluate the intermediate long-term clinical performance and success rates for dental implants inserted in sites with an initial early implant failure.
the following inclusion criteria: (i) patients with one or more failed implants that were retrieved and were planned to be replaced; (ii) implant failure before prosthesis delivery; (iii) implant(s) inserted in the same site where the failed implant was previously anchored; (iv) surface-modified implants used in the initial and retreatment procedures; and (v) original and replaced fixtures placed by the same operator. Exclusion Criteria
On the contrary, patients were excluded from this study for one or more of the following conditions: (i) systemic status that was likely to affect bone metabolism (unbalanced hormonal condition, previous irradiation in the head and neck region); (ii) non-biological implant failure (i.e. implant fractured); (iii) implant failure after prosthesis delivery; and (iv) active smoker subjects (>10 cigarettes/ day). Screening Process
The patients included in the study were evaluated according to the following parameters using patients’ records: age (upon placement of the first implant) and gender, healthy condition, general illnesses and medication, smoking habits, anatomical position of the implant, characteristics on the failed and replaced implants (implant length, width, and surface treatment). Also, the time intervals between the first implant(s) placement and retrieval and between its retrieval and replacement were recorded. Moreover, if additional augmentation surgery was required during implant insertion (in any time point) was further recorded. This study protocol was approved by the ethics committee of the Ninth People’s Hospital affiliated with Shanghai Jiao Tong University, School of Medicine. Outcome Assessment
The follow-up examination was performed according to a standardized protocol, which included a clinical radiographic evaluation after delivering of the final prosthesis and annually thereafter.
Material and methods Peri-Implant Clinical Parameters Inclusion Criteria
The medical charts of patients who had been treated in the department of Oral Implantology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University, School of Medicine, between January 2004 and December 2011 were reviewed. Patients were selected to participate whether their clinical condition met
1444 |
Clin. Oral Impl. Res. 26, 2015 / 1443–1449
The Modified Plaque Index (mPI) was measured at four points around the implants according to the following scale: 0, no plaque; 1, plaque on probing; 2, visible plaque; and 3, abundant plaque. For each implant, one MPI value was calculated based on the average of the four obtained values (Mombelli & Lang 1994).
The Modified Sulcus Bleeding Index (mSBI) was measured at four surfaces around the implants. The mSBI was scored as follows: 0 = no bleeding when a periodontal probe was passed along the gingival margin adjacent to the implant, 1 = visible, isolated bleeding spots, 2 = blood formed a confluent red line on the margin, and 3 = heavy or profuse bleeding. For each implant, one mSBI value was calculated based on the average of the four obtained values (Mombelli & Lang 1994). MPI and mSBI measurements were recorded using a plastic probe with a standardized probing force of 0.2 N (Click-Probe; KerrHawe SA, Bioggio, Switzerland). Marginal Bone Loss
Peri-implant bone resorption was recorded by comparing standardized long cone periapical radiographs. All of the images were scanned and transferred to a computer with an image analysis program (GE Healthcare Centricity@ v3.0, Milwaukee, WI, USA). Marginal bone loss (MBL) was documented on the radiograph viewer with the aid of four-fold magnification. The radiographic linear distance from the implant shoulder to the first boneto-implant contact was used to calculate the MBL. The location of the MBL in relation to the implant shoulder was assessed at the mesial and the distal aspects at the time of prosthesis delivery and at the last follow-up radiograph. The radiographic assessment was conducted by two assistants. Implant Quality Scale
The Implant Quality Scale (IQS) was used to assess implant0 s condition with the listed criteria in the last follow-up (Misch et al. 2008). 1. Success (optimum health): (i) no pain or tenderness upon use, (ii) no mobility, (iii) 4 mm (less than 1/2 of implant body), (iv) probing depth >7 mm, and (v) may have history of exudate; 4. Failure (clinical or absolute failure, any of the following): (i) pain upon use, (ii) mobility, (iii) radiographic bone loss >1/2 length of implant, (iv) uncontrolled exudate, or v) no longer in mouth.
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Wang et al . Dental implants in sites with previous early failure
A statistical analysis was performed using the SAS statistical package (SAS 9.3, SAS Institute Inc., Cary, NC, USA). The data was averaged within the patient with two implant failure to bypass the problem of dependencies between multiple implants within one patient. Cohen’s kappa (j) test was used to measure inter-examiner reliability. Descriptive statistical analyses of peri-implant hygienic parameters and MBL were performed using the mean of the distribution, the standard deviation, and the median. The cumulative survival rate was calculated for the implants. The level of statistical significance was set at P = 0.05.
Results Study Population
An overall of 10,234 implants were placed in 6456 patients between January 2004 and December 2011. Among them, 96 patients (100 implants) showed early failure (failure rate = 0.98%). Six patients (eight implants) went previously under head and neck irradiation therapy after tumor resection and seven patients (eight implants) were active smokers (>10 cigarettes/day) after motivation and smoking cessation education. Implant replacement was not performed in these patients. On the other hand, 84 implants placed in 83 patients met our inclusion criteria. Among these 83 patients, 17 patients refused implant replacement because of additional costs, fear of additional pain, concern for second implant failure and other individual reasons. Overall, 66 patients (male: 38; female: 28) displayed early implant failure and received a total of 67 dental implants. The mean age of the patients at first implantation was 42.3 18.2 years old (21– 68 years). Three patients reported diabetes mellitus, and 12 were smokers (0.8 showing good inter-examiner reliability. Upon analysis of the MBL obtained for mesial and distal periimplant sites, no significant differences were detected between the values for the mesial and distal sites. The overall mean MBL after a mean of 69.4 months was 1.7 1.3 mm (median: 1.5 mm). The maximum radiological bone loss was 4 mm in one implant. Additionally, three implants showed 2–4 mm of radiographic bone loss. Implant Quality Scale
At the last follow-up evaluation, two of the 64 implants assessed, failed according to IQS criteria, three implants showed satisfactory survival, and one implant displayed compromised survival. No pain or tenderness upon function was observed in the other 58 implants, showing a success rate (optimum health) of 90.6%.
Discussion Early implant failure oftentimes occurs with progressive bone resorption and consequent fixation loss before loading (Fransson et al. 2005), and it has been reported to vary between 1.2% and 3% (Testori et al. 2001; Davarpanah et al. 2002; Roos-Jans aker et al. 2006; Huynh-Ba et al. 2008). When assessing early implant failure, it is important to consider multiple factors together because of their interactive effects on the establishment of osseointegration (Pommer et al. 2011; Baqain et al. 2012). The causes and mechanisms
1446 |
Clin. Oral Impl. Res. 26, 2015 / 1443–1449
eliciting early implant failure remain yet to be determined. Different studies have found a variety of statistically significant factors associated with early implant failure, such as age and sex, systemic diseases, smoking, type of edentulism, implant location, quantity and quality of bone, implant length and diameter, and immunological and genetic factors (Kronstr€ om et al. 2001; Van Steenberghe et al. 2002; Noguerol et al. 2006; Alsaadi et al. 2008; Bornstein et al. 2008; Sverzut et al. 2008; Dereka et al. 2012). A very recent study based on a large retrospective case series showed that the causes of early failure were inflammation (47%), premature loading (13%), host response (8%), unknown (3%) and multiple causes (2%). Strikingly, it was found that a strong correlation between the causes of failure and some specific conditions being lack of primary stability, poorer bone quality/density and/or reconstructive procedures the most prevalent (Han et al. 2014). However, there are still remaining unclear crucial risk factors associated with early implant failure. Despite the fact that reimplantation is a common choice in current treatment plans, little information is available in the literature regarding reimplantation after implant failure. The number of studies reporting the outcome of dental implants placed in previously failed sites is limited and the results are controversial. Some have concluded that replaced implants display a lower survival rate compared with implants in pristine sites. In Grossmann and Levin’s study, nine of 31 single replaced implants failed, yielding an overall survival rate of 71%. A third attempt at single-implant replacement was made in two patients succeeding in only 1 (Grossman & Levin 2007). Machtei et al. reported the success rates of reimplantation in 56 patients who had 79 failed implants. Thirteen implants failed, which resulted in an overall survival rate of 83.5%. In their study, some enrolled implants failed several years post-op
due to late peri-implantitis. Accordingly, authors attributed the lower survival rate for implants placed in previously failed sites to site- or patient-specific risk factors (Machtei et al. 2008). Hence, patient-specific factors might have a major effect on the survival of replaced implants. Cluster failures (multiple implant failures in individual patients) have been reported by Horwitz et al. and SchwartzArad et al. (Horwitz et al. 2007; SchwartzArad et al. 2008a,b). However, in the present study, only one patient had 2 early implant failures, and no cluster failures were detected. In contrast, Mardinger et al., a high survival rate of 93% of the implants that replaced those that previously failed was reported. No correlations were found between replaced implant failures and any of the parameters examined. Nevertheless, implant surface modifications and early/delayed implant loss were not reported in the study (Mardinger et al. 2012). A similar high survival rate of replaced implants was also reported by Kim et al. In their study, 60 replaced implants showed 88.3% survival rate for a mean follow-up of 22 months. Interestingly, 48.3% of cases received immediate replacement (Kim et al. 2010). Thereupon, in partial agreement to previous findings, in the present study, a high cumulative survival rate of 94.6% was obtained after a mean follow-up of 69.4 months for dental implants placed in sites with initial early implant failure, yielding a proper clinical outcome. Thus, regardless of implants’ characteristics and the need of additional regenerative surgery, implant replacement at the same site seems to be predictable after an adequate bone healing period. Table 5 summarizes all the studies’ characteristics assessing the effect of previous failed dental implant upon survival for implants placed at the same site. However, it also must be noted that active smokers and patients who underwent head and neck irradiation therapy were excluded of our criteria. This fact might explain the high success rate achieved. Moreover, according to the IQS criteria, success implant is defined as
