Comparison of bone augmentation techniques in the mandibular posterior region: A randomized clinical trial protocol

This randomized, statistician-blinded, parallel-group clinical trial will compare the effectiveness of three bone-augmentation techniques applied to the posterior mandible using the cortical shell approach. Eighty-seven participants will be randomly allocated into three groups (autogenous, xenogeneic, or allogeneic cortical shells), each combined with a 1:1 mixture of autogenous bone chips and biomaterial. Participants may contribute one or two eligible posterior mandibular sites; however, the unit of analysis for the primary outcome will be the participant, using a participant-level summary (mean value when two sites are treated). The study is registered at ClinicalTrials.gov (Identifier: NCT06661447). Recruitment has not yet begun. The single primary endpoint is horizontal bone gain (mm) at 6 months, evaluated by cone-beam computed tomography (CBCT). Additional CBCT assessments at 3 and 12 months will be analyzed as secondary longitudinal outcomes. Volumetric and morphometric analyses will be performed through a standardized digital workflow integrating intraoral scanning, CBCT segmentation, and surface registration. Secondary outcomes will include bone density, surgical duration, and postoperative inflammation. Based on a previous CBCT-based randomized clinical trial with a related horizontal ridge-augmentation methodology, assuming a pooled standard deviation of approximately 1.12 mm and a clinically relevant between-group difference of 1.0 mm, 26 evaluable participants per group are required to achieve approximately 81.5% power for each prespecified primary comparison using a conservative two-sided α of 0.025 for sample-size planning. To allow for an anticipated 10% attrition rate, 29 participants will be recruited per group, resulting in a total planned sample of 87 participants. The primary analysis will use an ANCOVA model adjusted for baseline ridge width. This study aims to generate controlled, quantitative evidence on the volumetric and clinical performance of different cortical graft materials for posterior mandibular reconstruction.Trial registrationClinicalTrials.gov Identifier: NCT06661447. The registry record will be updated before recruitment begins.