Analysis Of Root-Cortical Bone Fusion In Molar Distalization

To assess clear aligner efficiency in distalizing molars in Class II malocclusion patients across different vertical skeletal patterns, examining 3D crown/root movements, the relationship between distal crown movement and horizontal width, and factors affecting distalization efficiency. 270 molars/premolars from Class II patients were grouped by mandibular plane angle (∠FH-MP): low-angle (≤22°), average-angle (22–28°), and high-angle (>28°). Crown/root spatial changes were measured at treatment stages. Gender, age, and initial molar inclination effects on distalization efficiency were analyzed. 1.No significant differences in aligner efficiency (X/Y/Z-axes) were found among vertical skeletal patterns. 2.First molar Z-axis movement and X-axis width change followed: Xd = 0.508 - 1.296Zd. No significant linear relationship was observed for second molars. Second premolar root and second molar crown Z-axis movement differed by gender; other teeth showed no differences. Age did not affect X/Y/Z-axis efficiency. 3.Second molar mesial inclination correlated positively with first molar root Z-axis movement efficiency. 1.Vertical skeletal pattern and age do not influence clear aligner distalization efficiency. 2.First molar distalization increases intermolar width. 3.Distalization involves tipping movements, with efficiency linked to initial tooth inclination.