偏颌患者(牙合)平面横向倾斜度和Spee曲线改变对颞下颌关节的生物力学分析OA

Objective To investigate the influence of transverse occlusal plane leveling and Spee curve flattening on stress distribution in the temporomandibular joint(TMJ)condyles in patients with mandibular laterognathism,providing a biomechanical basis for clinical treatment strategies.Methods Based on Cone-beam CT(Cone Beam Computed Tomography,CBCT)data from a patient with mandibular laterognathism,three-dimensional finite ele-ment models of the mandible,teeth,and temporomandibular joints were established.Four working conditions were set:Condition 0(original laterognathic state),Condition 1(increasing cusp height on the deviated side),Condition 2(decreasing cusp height on the non-deviated side),and Condition 3(Spee curve flattening).The distribution of von Mises stress,maximum principal stress,and minimum principal stress in bilateral condyles under intercuspation loading was analyzed.Results The baseline model(Condition 0)showed significantly high-er stress in the condyle on the non-deviated side compared to the deviated side.Although Conditions 1 and 2 al-tered the stress values,they did not change the stress concentration pattern.Condition 3(Spee curve flatten-ing),while moderately increasing stress on the non-deviated side,significantly reduced stress on the deviated side and resulted in a more dispersed stress distribution on both sides,effectively alleviating localized stress con-centration.Conclusion Compared with simple transverse correction of the occlusal plane,flattening the Spee curve can more effectively optimize stress distribution in the TMJ of patients with mandibular laterognathism,im-proving the biomechanical environment.This suggests that vertical control,especially the management of an ex-cessively steep Spee curve,should be emphasized in the treatment of mandibular laterognathism.