Dimensional Changes After Different Alveolar Ridge Preservation Techniques for Posterior Region: A Randomised Controlled Clinical Trial

Aim: Alveolar ridge preservation (ARP) after tooth extraction aims to maintain ridge dimensions for future implant placement. However, limited evidence is available for posterior sites. We evaluated the dimensional changes in posterior extraction sockets using four approaches: modified free gingival graft (MFGG); MFGG with xenograft (MFGG + XG); guided bone regeneration with titanium membrane and xenograft (TM + XG); and unassisted socket healing (USH). Materials and Methods: Patients requiring posterior tooth extraction were randomly assigned to one of four groups (n = 22/group). Cone-beam computed tomography (CBCT) was performed immediately after operation and at 6 months to assess vertical and horizontal alveolar ridge changes and implant-related outcomes. Results: Significant dimensional changes occurred in all groups (p < 0.05). The TM + XG and MFGG + XG groups showed better preservation of vertical ridge dimensions than the USH and MFGG groups (p < 0.05). Horizontal reductions were significant in all groups (p < 0.05). USH presented the highest sinus floor elevation rate (67% of maxillary cases) and the most frequent use of short implants (< 8.5 mm; 71%). Postoperative pain was significantly greater in the MFGG groups compared to the USH group (p < 0.05). Conclusion: Bone grafting with MFGG or a titanium membrane enhanced ridge preservation and reduced the need for additional surgery compared to USH. Trial Registration: ClinicalTrials.gov identifier: NCT06081296.