Effects of isotretinoin on bone dynamics in the craniomaxillofacial region: a systematic review of preclinical evidence.

Purpose: This systematic review provides a critical evaluation, synthesis of the existing literature on isotretinoin's effects on craniomaxillofacial bone.

Methods: Following the PRISMA guidelines and registered in PROSPERO, the review was conducted in August 2024 across various databases. Eligible in vivo studies were analysed for their assessment of isotretinoin's effects on craniomaxillofacial bone. Risk of bias was performed according to the Systematic Review Centre for Laboratory Animal Experimentation's RoB tool for animal studies.

Results: Out of 3670 studies, eight were eligible. Four studies revealed increased hyalinised areas in specific dental root regions amongst isotretinoin-treated groups, alongside significant differences in osteoblast and osteoclast counts, capillary formation, and new bone growth, indicating isotretinoin's impact on bone tissue. Two studies reported no significant disparities in trabecular bone structure but observed variations in collagen formation, root resorption, and bone resorption frequency. Studies on isotretinoin's effects on bone repair reveal contrasting outcomes: higher doses (7.5 mg/kg/day) enhanced bone formation in calvaria defects, whilst lower doses (1 mg/kg/day) slowed bone healing in a rabbit rhinoplasty model, showing reduced healing rates compared to controls.

Conclusions: The reviewed studies indicate that isotretinoin has dose-dependent effects on bone remodelling. Higher doses enhance bone formation and alveolar repair but increase root resorption and alter bone morphology, whilst lower doses slow bone healing. Some studies report no significant changes in bone volume or displacement but note improved gingival healing. These findings emphasise the need for further research to guide clinical decisions on isotretinoin's long-term impact on craniomaxillofacial bone health.