A new perspective on the relationship between anchorage and palatal morphology: Three-dimensional digital model analysis.

Abstract

The tooth movements were generally analyzed in two dimensions on cephalometric radiographs. Nowaday, 3D digital model analysis, which does not have any harmful effects on patients, can be used to evaluate the palatal morphology and coronal tooth movements in a very comfortable and easy way. To investigate the effect of palatal morphology on anchorage reinforcement during intraoral molar distalization with pendulum appliance using 3D model analysis. The material consisted of before (T0) and after (T1) dental plaster models of Class II malocclusion patients (17 females, 3 males) treated with pendulum appliance for molar distalization and Nance appliance for anchorage. T0 and T1 digital models were superimposed using the palatal area as a reference via three points and surface-matching software, and the changes in teeth movement were calculated for left and right central incisors, first premolars, and first and second molars. Palatal morphology was evaluated at T0 on digital models as palatal inclination, palatal depth angles, and anterior hard palate area. Wilcoxon test was used to evaluate the treatment results and Spearman's correlation analysis was performed to evaluate the relationship between palatal morphology and dental movement. The upper limit for the level of significance was taken as 0.05. Mesial movement of first premolars and distal movement of first and second molars were found to be statistically significant (P < 0.001). A weak negative correlation was found between the palatal inclination and the movement of first premolars (P < 0.045 and P < 0.003). Palatal depth angles and anterior hard palate area had no correlation with dental movements. Presented results supported that the mesial movement of premolar teeth decreased as the inclination of the palate increased.