Abstract
BACKGROUND: Insufficient bone volume is one of the major problems encountered in the rehabilitation of the edentulous posterior maxilla with an implant-supported prosthesis. Melatonin gel appears to have positive effects on improving dental implant osseointegration and bone defect repair. This study aimed to assess the efficacy of combining melatonin gel with a xenograft in promoting bone regeneration during maxillary sinus augmentation. METHODS: A total of 16 patients with average residual alveolar bone height less than 4 mm indicated for maxillary sinus augmentation participated in this randomized controlled clinical trial. Patients were randomized into two groups: an intervention group (n = 8), which was treated with melatonin gel combined with a xenograft, and a control group (n = 8), which was treated with a xenograft alone. Cone beam computed tomography was carried out 8 months after surgery to assess the bone height gained, and histological evaluations were performed before implant installation to assess bone quality. All patients underwent clinical evaluations to assess healing progress and record any pain, swelling, or complications. RESULTS: Radiographically, both groups demonstrated a considerable increase in vertical bone height eight months post-operatively; however, the control group exhibited a statistically greater increase (13.22±2.45). Histologically, the intervention group showed superior bone regeneration (44.5±5.8), with a significantly greater percentage of mature bone and overall improved bone quality than the control group. CONCLUSION: Melatonin may play a beneficial role in enhancing bone quality during maxillary sinus augmentation without increasing the risk of complications. These findings suggest its potential as a safe and effective adjunct in maxillary sinus augmentation procedures. TRIAL REGISTRATION: ClinicalTrials.gov, NCT06736821. Registered on December 8, 2024. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12903-026-08201-0.