Clinical efficacy of two vertical soft tissue augmentation techniques for peri-implant crestal bone level stability: A randomized clinical trial

Objectives: This study aimed to compare the efficacy of two techniques-acellular dermal matrix (ADM) grafting and tenting technique (TT)-for soft tissue height (STH) augmentation simultaneous to implant placement to minimize peri-implant crestal bone level (CBL) changes. Methods: Forty patients with a healed single mandibular posterior edentulous site with a thin soft tissue phenotype were enrolled. Twenty patients received simultaneously to implant placement ADM grafting, while the others received submerged healing abutment (TT). Clinical peri-implant soft tissue height and radiographic CBL changes were measured at restoration delivery and 1-year follow-up. Results: Both techniques effectively increased soft tissue thickness, resulting in a final average STH of 3.4 +/- 0.5 mm after augmentation. On average, soft tissue increased by 1.6 +/- 0.5 mm in group ADM and by 1.8 +/- 0.4 mm in group TT after augmentation. In Group ADM, mesial CBL decreased from 0.4 +/- 0.3 mm to 0.1 +/- 0.2 mm, and distal CBL decreased from 0.5 +/- 0.3 mm to 0.2 +/- 0.3 mm over 1 year. In Group TT, mesial CBL remained stable at 0.3 +/- 0.2 mm, while distal CBL reduced slightly from 0.5 +/- 0.5 mm to 0.3 +/- 0.2 mm. Both groups showed minimal changes in CBL, indicating great stability (pmesial = 0.003, p(distal )= 0.004). TT was particularly effective in preventing mesial bone loss (p(mesial) = 0.019). The mesial CBL changes significantly differed between groups (p = 0.019), and not significantly at distal sites (p = 0.944). Neither treatment exhibited significant bone remodeling below the implant shoulder. Conclusion: This study suggests that both techniques were successful in STH augmentation, and they may effectively reduce peri-implant crestal bone level changes, with TT being slightly superior. TT was more prone to post-surgical complications. This RCT was not registered before participant recruitment and randomization.