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Survival of various tooth- or implant-supported restorations Viviana Avila-Gnau JADA 2014;145(3):284-286 10.14219/jada.2013.41 The following resources related to this article are available online at jada.ada.org (this information is current as of June 28, 2014): Updated information and services including high-resolution figures, can be found in the online version of this article at: http://jada.ada.org/content/145/3/284
Information about obtaining reprints of this article or about permission to reproduce this article in whole or in part can be found at: http://www.ada.org/990.aspx
Copyright © 2014 American Dental Association. All rights reserved. Reproduction or republication strictly prohibited without prior written permission of the American Dental Association.
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
Critical Summaries
Survival of various tooth- or implantsupported restorations A critical summary of Pjetursson BE, Zwahlen M, Lang NP. Quality of reporting of clinical studies to assess and compare performance of implant-supported restorations. J Clin Periodontol 2012;39(suppl 12):139-159. Viviana Avila-Gnau, DDS
Clinical question. In patients who are partially edentulous, what is the best restorative treatment option? Review methods. The authors performed four searches of MEDLINE, in which they initially focused on randomized controlled trials (RCTs). At least two reviewers independently screened all the titles and abstracts of articles in which investigators compared different types of fixed restorations. After finding no RCTs on the subject, they identified 105 relevant articles included in six systematic reviews. These systematic reviews included prospective and retrospective cohort studies and case studies regarding fixed partial dentures (FPDs) and single crowns, with the following inclusion criteria: a documented mean follow-up time of five years or more, clinical follow-up examinations (versus follow-ups based solely on patient records, questionnaires or interviews) and reported details about the
type of restoration used. The authors rated the quality of the 105 included studies from “mediocre” to “poor” on the basis of STROBE statement standards (“STROBE” stands for STrengthening the Reporting of OBservational studies in Epidemiology), with more recent studies tending to be rated more highly. Main results. The review authors performed meta-analyses of the 105 included studies. They analyzed data by using random-effects Poisson regression models to obtain summary estimates of five- and 10-year survival proportions. They observed the following survival rates after a 10-year follow-up period: implant-supported single crowns, 89.4 percent (95 percent confidence interval [CI], 79.3-95.6 percent); conventional tooth-supported FPDs, 87.7 percent (95 percent CI, 85.689.5 percent); implant-supported FPDs, 86.7 percent (95 percent CI, 81.2-90.7 percent); cantilever FPDs, 80.3 percent (95 percent
284 JADA 145(3) http://jada.ada.org March 2014
CI, 74.8-84.7 percent); combined tooth-implant–supported FPDs, 77.8 percent (95 percent CI, 64.9-86.4 percent); and resin-bonded prostheses, 65.0 percent (95 percent CI, 51.4-76.9 percent). Survival rates for FPDs of different materials and designs varied; to address this, the authors recommended that followup studies address material combinations used routinely in modern dentistry. The incidence of biological complications was similar across all three groups of implant-supported restorations (from 7.0 percent to 9.7 percent at the five-year follow-up), but these results must be interpreted with caution given differing criteria across studies. The authors found no difference between screw-retained and cemented-crown designs. The incidence of implant-supported single crowns with bone loss exceeding 2 millimeters was 6.3 percent at the five-year follow-up. Implantsupported restorations had more technical complications than did
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
tooth-supported restorations (most commonly, ceramic fracture or chipping, abutment or screw loosening, and loss of retention), but these results must be interpreted with caution given largely differing periods in the underlying studies. The review authors used Poisson regression to analyze for possible study-design
effects between retrospective and prospective designs, but they found none. Conclusions. When replacing missing dentition, clinicians first should consider placing FPDs with teeth or implants as abutments and implant-supported single crowns, while considering tooth-implant–
supported FPDs, cantilever on teeth and resin-bonded prostheses only as a secondary option. This systematic review was funded by the European Federation of Periodontology and by unrestricted grants from Astra, Waltham, Mass.; Nobel Biocare, Zurich; and Straumann, Andover, Mass.
COMMENTARY Importance and context. Historically, most dentists base treatment planning decisions on their dental education and clinical experience. When planning a fixed restoration instead of a removable prosthesis, options include FPDs on either abutment teeth or abutment implants, a combination of abutment teeth and implants, implant-supported single crowns, cantilever on teeth and resin-bonded prostheses. Given the number of options for and opinions about how to proceed, examining the evidence—in the form of RCTs, systematic reviews of RCTs, cohort studies and case series—can help in deciding which treatment options to recommend. Strengths and weaknesses of the systematic review. The review authors searched only one database and made no mention of hand-searching, searching of gray literature or contacting experts. Because the authors performed a systematic review of other systematic reviews rather than of primary studies, it is possible that relevant studies were filtered out by the exclusion criteria of the underlying systematic reviews. The authors were thorough in reporting the search strategy, inclusion and exclusion criteria, data extraction and analysis techniques, and results of the review. However, because observational studies are susceptible to bias and confounding errors, it may have been better simply to report the underlying data than to perform a meta-analysis of it at the risk of reaching potentially flawed deductions. Readers should use caution when interpreting a meta-analysis that is based on the findings of observational studies, owing to precise but possibly spurious results. Data presentation and discussion in this review were confusing at times. In various instances, the authors discussed success and failure as annual rates, as well as five-year and 10-year follow-up rates. In some cases, they presented five-year and 10-year rates by using standard Poisson regression, whereas in other cases they used random-effects Poisson regression. They based their final recommendations on the results at the 10-year follow-up despite having provided a warning that some of the 10-year results were based on a
small number of observations relative to the five-year results. The authors presented a wealth of data in this study, but they did not seem to draw clear conclusions for the reader or offer a concise summary of the data. The authors declared that they had no conflicts of interest. Strengths and weaknesses of the evidence. The review authors noted that the included studies did not fulfill present standards—noting, for example, that investigators rarely discussed possible limitations and potential sources of bias—and they rated the 105 studies included in the six systematic reviews as mediocre to poor. Because most of the studies regarding implant-supported FPDs were published within the preceding 10 years, it was necessary to consider a fiveyear follow-up period for them. By contrast, 10-year follow-up studies of tooth-supported FPDs were conducted mostly in the 1980s and 1990s. Readers should be cautious when comparing technical complications of tooth-supported FPDs in data from more than 20 years ago with data regarding implant-supported FPDs and single crowns collected in the past 10 years. Implications for dental practice. When replacing missing dentition, clinicians first should consider FPDs using either teeth or implants as abutments and implant-supported single crowns as treatment options, and leave as secondary alternatives toothimplant–supported FPDs, cantilever on teeth and resin-bonded prostheses. It also should be noted that despite the high survival of FPDs, complications with them are frequent, meaning that dentist and patient should be aware that a considerable amount of chair time may be necessary. Overall, survival for many restorative options is quite good; clinical experience and the patient’s clinical condition should help guide treatment decisions. n doi:10.14219/jada.2013.41 Dr. Avila-Gnau is an assistant professor, Department of Cariology and Comprehensive Care, New York University College of Dentistry, New York City, e-mail [email protected]. She also is an evidence reviewer for the American Dental Association. Address correspondence to Dr. Avila-Gnau.
JADA 145(3) http://jada.ada.org March 2014 285
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
Disclosure. Dr. Avila-Gnau did not report any disclosures. These summaries, published under the auspices of the American Dental Association Center for Evidence-Based Dentistry, are prepared by practitioners trained in critical appraisal of published systematic reviews who work under the mentorship of experts. The summaries are not intended to, and do not, express, imply or summarize standards of care, but rather provide a concise reference for
286 JADA 145(3) http://jada.ada.org March 2014
dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. For more information on the evidence quality rating provided above and additional critical summaries, please visit http://ebd. ada.org.
Survival of various tooth- or implant-supported restorations Viviana Avila-Gnau JADA 2014;145(3):284-286 10.14219/jada.2013.41 The following resources related to this article are available online at jada.ada.org (this information is current as of June 28, 2014): Updated information and services including high-resolution figures, can be found in the online version of this article at: http://jada.ada.org/content/145/3/284
Information about obtaining reprints of this article or about permission to reproduce this article in whole or in part can be found at: http://www.ada.org/990.aspx
Copyright © 2014 American Dental Association. All rights reserved. Reproduction or republication strictly prohibited without prior written permission of the American Dental Association.
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
Critical Summaries
Survival of various tooth- or implantsupported restorations A critical summary of Pjetursson BE, Zwahlen M, Lang NP. Quality of reporting of clinical studies to assess and compare performance of implant-supported restorations. J Clin Periodontol 2012;39(suppl 12):139-159. Viviana Avila-Gnau, DDS
Clinical question. In patients who are partially edentulous, what is the best restorative treatment option? Review methods. The authors performed four searches of MEDLINE, in which they initially focused on randomized controlled trials (RCTs). At least two reviewers independently screened all the titles and abstracts of articles in which investigators compared different types of fixed restorations. After finding no RCTs on the subject, they identified 105 relevant articles included in six systematic reviews. These systematic reviews included prospective and retrospective cohort studies and case studies regarding fixed partial dentures (FPDs) and single crowns, with the following inclusion criteria: a documented mean follow-up time of five years or more, clinical follow-up examinations (versus follow-ups based solely on patient records, questionnaires or interviews) and reported details about the
type of restoration used. The authors rated the quality of the 105 included studies from “mediocre” to “poor” on the basis of STROBE statement standards (“STROBE” stands for STrengthening the Reporting of OBservational studies in Epidemiology), with more recent studies tending to be rated more highly. Main results. The review authors performed meta-analyses of the 105 included studies. They analyzed data by using random-effects Poisson regression models to obtain summary estimates of five- and 10-year survival proportions. They observed the following survival rates after a 10-year follow-up period: implant-supported single crowns, 89.4 percent (95 percent confidence interval [CI], 79.3-95.6 percent); conventional tooth-supported FPDs, 87.7 percent (95 percent CI, 85.689.5 percent); implant-supported FPDs, 86.7 percent (95 percent CI, 81.2-90.7 percent); cantilever FPDs, 80.3 percent (95 percent
284 JADA 145(3) http://jada.ada.org March 2014
CI, 74.8-84.7 percent); combined tooth-implant–supported FPDs, 77.8 percent (95 percent CI, 64.9-86.4 percent); and resin-bonded prostheses, 65.0 percent (95 percent CI, 51.4-76.9 percent). Survival rates for FPDs of different materials and designs varied; to address this, the authors recommended that followup studies address material combinations used routinely in modern dentistry. The incidence of biological complications was similar across all three groups of implant-supported restorations (from 7.0 percent to 9.7 percent at the five-year follow-up), but these results must be interpreted with caution given differing criteria across studies. The authors found no difference between screw-retained and cemented-crown designs. The incidence of implant-supported single crowns with bone loss exceeding 2 millimeters was 6.3 percent at the five-year follow-up. Implantsupported restorations had more technical complications than did
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
tooth-supported restorations (most commonly, ceramic fracture or chipping, abutment or screw loosening, and loss of retention), but these results must be interpreted with caution given largely differing periods in the underlying studies. The review authors used Poisson regression to analyze for possible study-design
effects between retrospective and prospective designs, but they found none. Conclusions. When replacing missing dentition, clinicians first should consider placing FPDs with teeth or implants as abutments and implant-supported single crowns, while considering tooth-implant–
supported FPDs, cantilever on teeth and resin-bonded prostheses only as a secondary option. This systematic review was funded by the European Federation of Periodontology and by unrestricted grants from Astra, Waltham, Mass.; Nobel Biocare, Zurich; and Straumann, Andover, Mass.
COMMENTARY Importance and context. Historically, most dentists base treatment planning decisions on their dental education and clinical experience. When planning a fixed restoration instead of a removable prosthesis, options include FPDs on either abutment teeth or abutment implants, a combination of abutment teeth and implants, implant-supported single crowns, cantilever on teeth and resin-bonded prostheses. Given the number of options for and opinions about how to proceed, examining the evidence—in the form of RCTs, systematic reviews of RCTs, cohort studies and case series—can help in deciding which treatment options to recommend. Strengths and weaknesses of the systematic review. The review authors searched only one database and made no mention of hand-searching, searching of gray literature or contacting experts. Because the authors performed a systematic review of other systematic reviews rather than of primary studies, it is possible that relevant studies were filtered out by the exclusion criteria of the underlying systematic reviews. The authors were thorough in reporting the search strategy, inclusion and exclusion criteria, data extraction and analysis techniques, and results of the review. However, because observational studies are susceptible to bias and confounding errors, it may have been better simply to report the underlying data than to perform a meta-analysis of it at the risk of reaching potentially flawed deductions. Readers should use caution when interpreting a meta-analysis that is based on the findings of observational studies, owing to precise but possibly spurious results. Data presentation and discussion in this review were confusing at times. In various instances, the authors discussed success and failure as annual rates, as well as five-year and 10-year follow-up rates. In some cases, they presented five-year and 10-year rates by using standard Poisson regression, whereas in other cases they used random-effects Poisson regression. They based their final recommendations on the results at the 10-year follow-up despite having provided a warning that some of the 10-year results were based on a
small number of observations relative to the five-year results. The authors presented a wealth of data in this study, but they did not seem to draw clear conclusions for the reader or offer a concise summary of the data. The authors declared that they had no conflicts of interest. Strengths and weaknesses of the evidence. The review authors noted that the included studies did not fulfill present standards—noting, for example, that investigators rarely discussed possible limitations and potential sources of bias—and they rated the 105 studies included in the six systematic reviews as mediocre to poor. Because most of the studies regarding implant-supported FPDs were published within the preceding 10 years, it was necessary to consider a fiveyear follow-up period for them. By contrast, 10-year follow-up studies of tooth-supported FPDs were conducted mostly in the 1980s and 1990s. Readers should be cautious when comparing technical complications of tooth-supported FPDs in data from more than 20 years ago with data regarding implant-supported FPDs and single crowns collected in the past 10 years. Implications for dental practice. When replacing missing dentition, clinicians first should consider FPDs using either teeth or implants as abutments and implant-supported single crowns as treatment options, and leave as secondary alternatives toothimplant–supported FPDs, cantilever on teeth and resin-bonded prostheses. It also should be noted that despite the high survival of FPDs, complications with them are frequent, meaning that dentist and patient should be aware that a considerable amount of chair time may be necessary. Overall, survival for many restorative options is quite good; clinical experience and the patient’s clinical condition should help guide treatment decisions. n doi:10.14219/jada.2013.41 Dr. Avila-Gnau is an assistant professor, Department of Cariology and Comprehensive Care, New York University College of Dentistry, New York City, e-mail [email protected]. She also is an evidence reviewer for the American Dental Association. Address correspondence to Dr. Avila-Gnau.
JADA 145(3) http://jada.ada.org March 2014 285
Downloaded from jada.ada.org on June 28, 2014
ORIGINAL CONTRIBUTIONS
Disclosure. Dr. Avila-Gnau did not report any disclosures. These summaries, published under the auspices of the American Dental Association Center for Evidence-Based Dentistry, are prepared by practitioners trained in critical appraisal of published systematic reviews who work under the mentorship of experts. The summaries are not intended to, and do not, express, imply or summarize standards of care, but rather provide a concise reference for
286 JADA 145(3) http://jada.ada.org March 2014
dentists to aid in understanding and applying evidence from the referenced systematic review in making clinically sound decisions as guided by their clinical judgment and by patient needs. For more information on the evidence quality rating provided above and additional critical summaries, please visit http://ebd. ada.org.
