EVALUATION OF DIFFERENT OSTEOTOMUES IN SURGICALLY ASSISTED RAPID PALATAL EXPANSION: A FINITE ELEMENT ANALYSIS STUDY

Abstract

Background: The management of transverse maxillary deficiency may require adjunct surgical osteotomies such as the surgically assisted rapid palatal expansion (SARPE) in patients with skeletally mature craniofacial morphology. Aims: evaluate a mid-palatal sagittal osteotomy as a minimally invasive surgery in reducing stress and allowing adequate expansion. Methods: Finite element (FE) modeling was applied to five expansion setups: 1. Control model with no surgical cuts; 2. Bone-anchored expander with mid-palatal osteotomy; 3. Setup 2 + osteotomy at the level of the anterior nasal spine ; 4. Setup 3 + lateral supra-apical cuts (5mm above apices of maxillary canine to second molar); 5. SARPE cuts: setup 3 + Lefort 1 osteotomy with pterygomaxillary disjunction. Von mises stresses and displacement were measured through FE analysis. Results: Stress at the mid-palatal area was highest in the control (32006.54 ± 2984.55 MPa) then in setup 2 (16331.88 ± 2207.93 MPa), in which the lowest stress was recorded. Stresses palatal to the molars and buccal to the incisors were statistically significantly different between the control and experimental setups, the highest in setup 5 (3091.89 ± 991.22 MPa buccal to incisors; 3091.89 ± 991.22 MPa palatal to molars). Expansion increased significantly incrementally from setups 1 to 5, except between setups 3 and 4 (p>0.005). The amount of expansion obtained was mostly affected by cortical bone thickness in setup 5. Conclusion: The minimally invasive mid-palatal cut was the most efficient at reducing stress near the mid-palatal suture. Clinical research parallel to a time-dependent FE analysis is needed.