A Multicenter Randomized Controlled Clinical Trial Using a New Resorbable Non-Cross-linked Collagen Membrane for Guided Bone Regeneration at Dehisced Single Implant Sites: Interim Results of a Bone Augmentation Procedure

Objective: To compare clinical performance of a new resorbable non-cross-linked collagen membrane, creos xenoprotect (CXP), with a reference membrane (BG) for guided bone regeneration at dehisced implant sites. Materials and methods: This randomized controlled clinical trial enrolled patients with expected dehiscence defects following implant placement to restore single teeth in the maxillary and mandibular esthetic zone and premolar area. Implants were placed using a two-stage surgical protocol with delayed loading. Bone augmentation material placed at the implant surface was immobilized with CXP or BG membrane. Soft tissue health was followed during the healing period, and the defect size was measured at reentry and 6 months after implant placement. Results: Of the 49 included patients, 24 were treated with CXP and 25 with BG. Patient characteristics did not differ between the two arms. In the CXP arm, the defect height at implant insertion was (meanSD) 5.1 +/- 2.1 mm (n=24) and reduced at reentry by 81% to 1.0 +/- 1.3 mm (n = 23). In the BG arm, the defect height at implant insertion was 4.9 +/- 1.9 mm (n=25) and reduced at reentry by 62% to 1.7 +/- 2.1 mm (n=24). Assuming a margin of non-inferiority of 1 mm, CXP was non-inferior to BG. Membrane exposure rate was highest at week 3 in both arms, reaching 16.7% for BG and 8.7% for CXP. Conclusions: The new resorbable non-cross-linked collagen membrane facilitates bone gain to support implant placement in expected dehiscence defects. The observed trend toward higher mean bone gain and lower exposure rate with CXP compared to BG should be further investigated.