Surgical procedures for soft tissue augmentation at implant sites. A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Different procedures were proposed to augment soft tissue around dental implants. OBJECTIVE: Aims of this Systematic Review (SR) were to evaluate (a) clinical benefit of soft tissue augmentation at implant sites (b) which is the best surgical procedure to augment soft tissue. MATERIALS AND METHODS: Manual/electronic searches were performed to identify randomized controlled trials (RCTs). Change in keratinized tissue thickness (STT) and height (KT) were primary outcomes. Random effects meta-analyses were performed where suitable and expressed as weighted mean differences (MD) with their associated 95% confidence intervals (CI). RESULTS: Fourteen RCTs accounting for 475 patients and 538 implants were included. Only five studies were judged at low risk of bias. In the single studies, soft augmentation lead to higher STT and KT compared to no augmentation. Considering primary outcomes, connective tissue graft (CTG) was more effective than xenogeneic collagen matrix (XCM) to improve STT (MD: -0.30 mm; 95% CI -0.43; -0.17; P < .00001) in the meta-analysis for different techniques for augmentation. CONCLUSIONS: Even if further studies at low risk of bias are needed, soft tissue augmentation techniques improved quantity and quality of peri-implant soft tissue. Among the augmentation procedures, CTG was associated to higher STT change compared to XCM.