Abstract: We included 48 RCTs in the review. Of these, we assessed one as at low risk of bias, 12 as at high risk of bias and 35 as at unclear risk of bias. The results indicated a greater reduction in gingival recession for subepithelial connective tissue grafts (SCTG) + coronally advanced flap (CAF) compared to guided tissue regeneration with resorbable membranes (GTR rm) + CAF (MD -0.37 mm; 95% CI -0.60 to -0.13, P = 0.002; 3 studies; 98 participants; low-quality evidence). There was insufficient evidence of a difference in gingival recession reduction between acellular dermal matrix grafts (ADMG) + CAF and SCTG + CAF or between enamel matrix protein (EMP) + CAF and SCTG + CAF. Regarding clinical attachment level changes, GTR rm + CAF promoted additional gains compared to SCTG + CAF (MD 0.35; 95% CI 0.06 to 0.63, P = 0.02; 3 studies; 98 participants; low-quality evidence) but there was insufficient evidence of a difference between ADMG + CAF and SCTG + CAF or between EMP + CAF and SCTG + CAF. Greater gains in the keratinized tissue were found for SCTG + CAF when compared to EMP + CAF (MD -1.06 mm; 95% CI -1.36 to -0.76, P < 0.00001; 2 studies; 62 participants; low-quality evidence), and SCTG + CAF when compared to GTR rm + CAF (MD -1.77 mm; 95% CI -2.66 to -0.89, P < 0.0001; 3 studies; 98 participants; very low-quality evidence). There was insufficient evidence of a difference in keratinized tissue gain between ADMG + CAF and SCTG + CAF. Few data exist on aesthetic condition change related to patients' opinion and patients' preference for a specific procedure. Subepithelial connective tissue grafts, coronally advanced flap alone or associated with other biomaterial and guided tissue regeneration may be used as root coverage procedures for treating localised or multiple recession-type defects. The available evidence base indicates that in cases where both root coverage and gain in the width of keratinized tissue are expected, the use of subepithelial connective tissue grafts shows a slight improvement in outcome. There is also some weak evidence suggesting that acellular dermal matrix grafts appear as the soft tissue substitute that may provide the most similar outcomes to those achieved by subepithelial connective tissue grafts. RCTs are necessary to identify possible factors associated with the prognosis of each RCPPS procedure. The potential impact of bias on these outcomes is unclear.

Plain-language summary: Authors from Cochrane Oral Health carried out this review and the evidence is up to date to 15 January 2018. A total of 48 randomised controlled trials on 1227 adults were included with five studies evaluating multiple recession-type defects and the rest single gingival recessions. Most trials followed participants for 6 months to 12 months. The review looked at different interventions: free gingival grafts (FGG), coronally advanced flap (CAF) alone or associated to acellular dermal matrix grafts (ADMG), enamel matrix protein (EMP), guided tissue regeneration with resorbable membranes (GTR rm), guided tissue regeneration with non-resorbable membranes (GTR nrm), GTR rm associated with bone substitutes, platelet-rich plasma or fibrin (PRP or PRF), growth factors (rhPDGF-BB) associated to bone substitutes (b-TCP), subepithelial connective tissue grafts (SCTG) or xenogeneic collagen matrix (XCM). We did not find any trials evaluating laterally positioned flaps (LPF). The results of this review have shown that most root coverage periodontal plastic surgery procedures led to gains in reduction of gingival recession. However, we are uncertain about which intervention is the most effective as all studies were judged to be at unclear or high risk of bias. Preferably, subepithelial connective tissue grafts, coronally advanced flap alone or associated with another graft or biomaterial and guided tissue regeneration can be used as root coverage procedures for treating recession-type defects. Limited data exist on how these interventions affect the appearance of the teeth. Adverse effects reported in the studies included discomfort and pain, but these were mainly related to the site where the tissue graft was taken, and occurred mainly within the first week after surgery with no influence on root coverage outcomes. Further research is needed on the results to be achieved from each root coverage periodontal plastic procedure. We judged the quality of the evidence to be low or very low mainly due to problems with the design of the studies.