Background: The peri‐implant diseases, namely peri‐implant mucositis and peri‐implantitis, have been extensively studied. However, little is known about the true magnitude of the problem, owing mainly to the lack of consistent and definite diagnostic criteria used to describe the condition. The objective of the present review is to systematically estimate the overall frequency of peri‐implant diseases in general and high‐risk patients.Methods: The systematic review is prepared according to the Meta‐analysis of Observational Studies in Epidemiology statement. Studies were searched in four electronic databases, complemented by manual searching. The quality of the studies was assessed according to Strengthening the Reporting of Observational Studies in Epidemiology, and the data were analyzed using statistical software.Results: Of 504 studies identified, nine studies with 1,497 participants and 6,283 implants were included. The summary estimates for the frequency of peri‐implant mucositis were 63.4% of participants and 30.7% of implants, and those of peri‐implantitis were 18.8% of participants and 9.6% of implants. A higher frequency of occurrence of peri‐implant diseases was recorded for smokers, with a summary estimate of 36.3%. Supportive periodontal therapy seemed to reduce the rate of occurrence of peri‐implant diseases.Conclusions: Peri‐implant diseases are not uncommon following implant therapy. Long‐term maintenance care for high‐risk groups is essential to reduce the risk of peri‐implantitis. Informed consent for patients receiving implant treatment must include the need for such maintenance therapy.

Background: Platform switching for maintaining peri‐implant bone levels has gained popularity among implant manufacturers over the last few years. However, the assumption that the inward shifting of the implant‐abutment junction may preserve crestal bone was primarily based on serendipitous finding rather than scientific evidence. The objectives of the present study were to systematically review radiographic marginal bone‐level changes and the survival of platform‐switched implants compared to conventional platform‐matched implants.Methods: A literature search of electronic databases (MEDLINE, EMBASE, The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials, the U.K. National Research Register, the Australian New Zealand Clinical Trials Registry, the Database of Abstracts of Reviews of Effectiveness, and Conference Proceedings Citation Index) was performed up to March 15, 2010. Hand searches included several dental journals, and authors were contacted for missing information. Controlled trials that compared marginal bone‐level changes around platform‐switched dental implants with those restored with platform‐matched prostheses were selected. The review and meta‐analysis were done according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses statement. Data were analyzed using two meta‐analytic statistical packages. Mean differences (MDs) were calculated for analyzing continuous data, and risk ratios (RRs) were used for dichotomous data with 95% confidence intervals (CIs).Results: Ten studies with 1,239 implants were included. The marginal bone loss around platform‐switched implants was significantly less than around platform‐matched implants (MD: −0.37; 95% CI: −0.55 to −0.20; P <0.0001). No statistically significant difference was detected for implant failures between the two groups (RR: 0.93; 95% CI: 0.34 to 2.95; P = 0.89). Subgroup analyses showed that an implant‐abutment diameter difference ≥0.4 was associated with a more favorable bone response.Conclusions: The review and meta‐analysis show that platform switching may preserve interimplant bone height and soft tissue levels. The degree of marginal bone resorption is inversely related to the extent of the implant‐abutment mismatch. Further long‐term, well‐conducted, randomized controlled studies are needed to confirm the validity of this concept.