Introduction: Osteogenesis Imperfecta (OI) is a genetic disease that affects type I collagen metabolism in quantity or quality. Signs and symptoms of the disease vary from mild to severe, allowing for classification of the disease according to its severity and its clinical features in types I, II, III and IV. Clinical features of OI are: Multiple fractures and deformities in long bones, growth deficiency, ligament laxity, hearing loss, and oral and maxillofacial alterations. Over 80% of OI patients present class III skeletal alteration.

Case report: 17-year-old under evaluation for orthognathic surgery diagnosed with type IA OI. Undergoing endovenous bisphosphonate treatment for osteoporosis and history of multiple fractures in long bones. After evaluation and suspension of bisphosphonate therapy, the Orthognathic surgery, consisting in an advance through Le Fort I osteotomy and retrogression through sagittal bilateral ramus osteotomy, was performed. Longer bone consolidation and osseointegration periods were taken into account. In this case, conventional internal osteosynthesis systems were used. Post operative orthodontic treatment was maintained for 15 months.

Result: Clinical and radiological controls 12–24–36 months after surgery were used to evaluate the stability of the results. No complications associated with the surgery arose. The skeletal and occlusal results remain stable 3 years after surgery.

Conclusion: The collaboration of the Orthodontist, Maxillofacial Surgeon and treating physician allows to establish risk based on the severity of the OI in order to minimize risks in the immediate and mediate post op. The consent form was reviewed and analyzed by the patient and her parents.

Conflict of interest: None declared.