Comparative Efficacy of Different Flapless Ridge Preservation Techniques: A Systematic Review and Meta-Analysis
Although the efficacy of ridge preservation is well documented, there is a lack of robust evidence regarding the influence of different surgical techniques. Flapless approaches are thought to be better at preserving soft tissue architecture and have been suggested for mild to moderate defects. This review investigates the efficacy of different flapless techniques for ridge preservation in mild to moderate defects with <50% buccal bone loss. PubMed, EMBASE, and Cochrane Library databases were searched to obtain relevant articles published in English from 1974 to December 2019. The primary outcome was horizontal and vertical hard tissue dimensional changes. Soft tissue changes were evaluated as a secondary outcome. The Bio-Col technique, subperiosteal tunnel technique, and hard tissue with autogenous soft tissue graft/collagen matrix technique were identified. Eight studies were included, and quantitative analyses were performed for 4 studies for the primary outcome variables. The meta-analysis revealed significant reductions for horizontal changes (weighted mean difference [WMD] = 2.56 mm, 95% CI [2.18, 2.95]), vertical mid-buccal (WMD = 1.47 mm, 95% CI [1.04, 1.90]), and vertical mid-lingual (WMD = 1.28 mm, 95% CI [0.68, 1.87]) in favor of flapless ridge preservation techniques. Subgroup analysis based on technique suggests minimal hard tissue differences. The efficacy of flapless ridge preservation techniques on soft tissue changes was inconclusive. In conclusion, flapless ridge preservation techniques are effective for mild to moderate defects. The technique or material used to close the extraction socket does not seem to significantly affect hard tissue changes, while the effect on soft tissue changes warrants further investigation.

Flowchart of the study selection process.

Flapless surgical procedures for alveolar ridge preservation. Bio-Col technique (a–c), hard tissue with autogenous soft tissue graft (d–f), and subperiosteal technique (g–i). (a) Atraumatic tooth extraction. (b) The socket was filled with deproteinized bovine bone mineral. (c) A collagen sponge was inserted and secured with an internal cross mattress. (d) After atraumatic extraction. (e) Deproteinized bovine bone mineral embedded in a 10% collagen matrix was used to fill the extraction socket. (f) Free gingival graft from the palate was sutured in place. (g) A periotome was used to create a circumferential subperiosteal tunnel, and the socket was filled with freeze-dried bone allograft. The site was covered with a dense polytetrafluoroethylene membrane. (h) 5-mo follow-up. (i) 2-mo post-implant placement

Meta-analysis comparing 2 flapless ridge preservation techniques with spontaneous healing. (a) Horizontal dimensional changes. (b) Vertical dimensional changes (buccal). (c) Vertical dimensional changes (lingual).
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