What is the effect of soft tissue thickness on crestal bone loss around dental implants? A systematic review.

ObjectivesThe aim of this systematic review was to determine whether soft tissue biotype at implant placement has an influence on crestal bone loss (CBL) at 1year after implant loading. Material and methodsFollowing electronic search in three databases (MEDLINE via OVID, EMBASE and The Cochrane Database) and hand search up to April 2015, two reviewers screened independently and in duplicate the references to identify randomized controlled trials, controlled clinical trials (CCTs) and prospective case series eligible for systematic review and meta-analysis. Cochrane Collaboration's tool was used for assessing risk of bias. ResultsFrom 2944 citations, six studies (6 CCTs) met the inclusion criteria. Four of six individual studies that compared thin vs. thick biotype showed significantly higher CBL in thin biotype. Meta-analysis could only be performed with two studies and the differences did not reach significant level. None of the included studies was of low risk of bias. ConclusionsAt present, there is insufficient evidence to answer the question on the differences in clinical outcome in terms of CBL between implants placed in sites with initial soft tissue thickness <2mm and those with 2mm. Further, well-designed controlled clinical studies are needed to analyze the effect of soft tissue thickness on the clinical outcomes of dental implants.