This study will compare three methods to rebuild lost bone in the back part of the lower jaw (posterior mandible) before dental implant placement. Seventy-eight adults will be randomly assigned to receive one of three "cortical shell" techniques using either the patient's own bone (autogenous) or prefabricated bone plates from animal (xenogeneic) or human donors (allogeneic). In all groups, the space inside the shell will be filled with a mixture of small bone chips and bone substitute material. The main outcome is the increase in jawbone width measured on 3D cone-beam CT scans at 6 months after surgery. Additional scans and clinical assessments up to 12 months will evaluate healing, bone stability, and postoperative recovery.

Inclusion Criteria:

Posterior mandibular edentulism requiring horizontal ridge augmentation (Cawood & Howell Classes IV-VI).

One or two eligible posterior mandibular sites suitable for cortical shell augmentation.

Adequate residual bone height to allow safe fixation above the mandibular canal.

Good general health (ASA I or II). Plaque index < 20% and absence of active periodontal infection. Ability and willingness to attend scheduled follow-up visits (up to 12 months). Written informed consent provided prior to any study-related procedure.

Exclusion Criteria:

Uncontrolled systemic diseases affecting bone healing (e.g., uncontrolled diabetes mellitus, immunosuppressive disorders).

Current heavy smoking (>5 cigarettes/day). Pregnancy or lactation. Current use of medications known to affect bone metabolism or healing (e.g., bisphosphonates, long-term corticosteroids, anticoagulants).

Active periodontal disease or untreated oral infection. History of chemotherapy or radiotherapy to the head and neck region.

Yes, De-identified participant data and analysis code will be available upon reasonable request to the corresponding author after publication, following UEES data-sharing policies.

De-identified individual participant data (IPD) and supporting documents will be available beginning 6 months after publication of the main results and will remain accessible for 5 years thereafter through the institutional repository of Universidad de Especialidades Espíritu Santo (UEES).

Qualified researchers may request access to the anonymized dataset, protocol, statistical analysis plan, informed consent form, and analytic code by contacting the corresponding author at alanataf@uees.edu.ec. Requests will be reviewed by the study team and the UEES Ethics Committee to ensure compliance with ethical and privacy regulations. Approved users will receive controlled access to the data for non-commercial research purposes only.

This is an open-label surgical trial. Due to the nature of the interventions, participants, surgeons, and investigators cannot be blinded. The statistician responsible for the primary analysis will remain blinded to group allocation until completion of the primary analysis.