PURPOSE, METHODS: This study (50 patients; Ø 25 years) compared surgically assisted rapid maxillary expansion (SARME) with (+/-PP) to SARME without pterygomaxillary (-PP) disjunction due to dentoskeletal effects in 3D CT preoperatively and Ø 11 weeks post-expansion.
Results: In t test, SARME-PP declined in transverse width from anterior to posterior but more symmetrically than SARME+PP. It produced more segmental inclination and vestibular bone resorption in the premolars. SARME+PP also declined in transverse width from anterior to posterior but more asymmetrically with an extreme convergence to the molars. It produced more segmental inclination and vestibular bone resorption (second molar) in the molars and a palatal bone plate thickness increase in the second premolar. With variance analysis, a further differentiation between the two independent groups due to secondary variables was made: SARME+PP produced the biggest decline in transverse width (patients <20 years) and the biggest segmental outward inclination from anterior to posterior in patients with bone-borne devices. SARME-PP in patients <20 years and SARME+PP in patients >20 years both produced the biggest lateral pterygoid bending.
Conclusion: Pterygomaxillary disjunction should be based on patient age and individual requirements, i.e., in patients <20 years (SARME-PP) and >20 years (SARME+PP).