Two independent reviewers conducted an electronic literature search in PubMed, Web of Science, EMBASE and Cochrane databases as well as a manual search to identify eligible clinical studies up to January 2020. Randomized controlled trials (RCTs) and non-randomized controlled studies (NRSs) comparing IIP with CTG and without CTG over a mean follow-up of at least 12 months were included for a qualitative analysis. Meta-analyses were performed on data provided by RCTs.
Out of 1814 records, 5 RCTs and 3 NRSs reported on 409 (IIP + CTG: 246, IIP: 163) immediately installed implants with a mean follow-up ranging from 12 to 108 months. Only 1 RCT showed low risk of bias. Meta-analysis revealed a significant difference in terms of vertical mid-facial soft tissue change between IIP + CTG and IIP pointing to 0.41 mm (95% CI [0.21; 0.61], p < .001) in favour of soft tissue grafting. This outcome was clinically relevant since the risk for ≥1 mm asymmetry in mid-facial vertical soft tissue level was 12 times (RR 12.10, 95% CI [2.57; 56.91], p = .002) lower following IIP + CTG. Soft tissue grafting also resulted in a trend towards less bleeding on probing (MD 17%, 95% CI [-35%; 1%], p = .06). Meta-analyses did not reveal significant differences in terms of pink aesthetic score, marginal bone level change and probing depth. Results were inconclusive for horizontal mid-facial soft tissue change and papilla height change. Based on GRADE guidelines, a moderate recommendation for the use of a CTG following IIP can be made.
CTG contributes to mid-facial soft tissue stability following IIP. Therefore, CTG should be considered when elevated risk for mid-facial recession is expected in the aesthetic zone (thin gingival biotype, <0.5 mm buccal bone thickness).