Hard and soft tissue contour changes following simultaneous guided bone regeneration at single peri-implant dehiscence defects using either resorbable or non-resorbable membranes: a 6-month secondary analysis of a randomized controlled trial.

OBJECTIVES: To compare radiographic and profilometric outcomes 6 months after simultaneous lateral guided bone regeneration (GBR) at single peri-implant dehiscence defects in the anterior region using either resorbable or non-resorbable membranes. MATERIALS AND METHODS: In 27 patients with a single tooth gap in the anterior region (second premolar to second premolar in the maxilla) a dental implant was placed. Following implant placement GBR was performed at the buccal aspect using randomly either a resorbable collagen membrane (RES) or a non-resorbable titanium-reinforced ePTFE membrane (N-RES). Radiographic (cone-beam computed tomography; CBCT) measurements were performed to assess the buccal bone thickness immediately after the implant placement with simultaneous GBR (baseline) and 6 months later. Buccal soft tissue thickness was assessed by superimposing surface scans taken at baseline and again 6 months later. RESULTS: A total of 25 datasets could be assessed for the bone dimensions (n = 12, RES; n = 13, N-RES) and 14 datasets for profilometric changes (n = 7, RES; n = 7, N-RES). Group RES showed a significant mean reduction in buccal bone between baseline and 6 months of 0.8 +/- 0.4 mm (p = 0.004). The respective mean reduction for group N-RES amounted to 0.1 +/- 0.4 mm (p = 0.581). When comparing the buccal bone changes between both group over time, group RES exhibited greater reduction in comparison to group N-RES (intergroup p = 0.017). Profilometric analyses showed a non-significant trend towards soft tissue gain in group RES 0.6 +/- 0.7 mm (p = 0.125). Conversely, N-RES group revealed stability, with a mean change of 0.0 +/- 0.3 mm (p = 1.000). CONCLUSIONS: GBR using non-resorbable membranes seems to provide greater dimensional stability of augmented bone at 6 months re-entry and before implant loading compared to resorbable membranes. The lack of differences in the profilometric outcomes and contour changes may be explained by a partial compensation through an increase in soft tissue thickness with resorbable membranes. CLINICAL RELEVANCE: GBR using non-resorbable membranes may offer greater dimensional stability of augmented bone compared to resorbable membranes. However, these potential benefits may be offset by a compensatory increase in soft tissue thickness when using resorbable membranes.