Abstract
BACKGROUND: Atrophy of the alveolar ridge in the posterior maxilla often requires sinus floor elevation prior to implant placement. Photobiomodulation using low-level laser therapy (LLLT) has been suggested as a supportive approach for bone healing, although data based on histological evaluation are still limited. METHODS: This study presents histological and radiological secondary outcomes of a randomized clinical trial on bone regeneration after lateral window sinus augmentation. Twenty patients were allocated according to grafting material (allogeneic or xenogeneic) and the use of adjunctive LLLT. After 6 months, bone core biopsies were obtained at the time of implant placement and processed for histological analysis. Radiological bone gain was assessed using CBCT. RESULTS: Bone gain was achieved in all groups, allowing implant placement in every case. Mean bone gain reached 7.53 ± 3.32 mm in LLLT-treated sites and 7.02 ± 2.00 mm in controls, with no statistically significant differences. Histological analysis confirmed trabecular bone formation across all groups. Mild inflammatory cell infiltrates were observed more frequently in LLLT-treated sites (p = 0.029), although this finding was not associated with impaired tissue organization or compromised healing. CONCLUSIONS: Both allogeneic and xenogeneic grafts showed good biocompatibility and supported effective bone regeneration after sinus augmentation. The addition of photobiomodulation did not demonstrate statistically significant clinical or radiological benefits within this exploratory cohort, but it may be associated with subtle differences in tissue remodeling.