Identifying cortical plate inclination as a parameter to re-assess transverse discrepancies in untreated adults with different vertical facial heights-A retrospective CBCT study.

Abstract

To determine the inclination angles of buccal, palatal cortical plates and assess its harmony with existing molar buccolingual inclination in adults with different vertical facial heights. The aim of this study was to identify the role of cortical plate inclination as a diagnostic tool for determining alveolar support in adults with transverse discrepancies. One-hundred and fifty seven CBCTs (50-Hypo-divergent, 51-Normo-divergent and 56-Hyper-divergent growth patterns) of untreated adults were utilized. Cross-sectional slices with respect to the maxillary first molar were taken as orientation landmarks in defined reference planes. Inclination angles for the first molar, buccal and palatal cortical plate were determined with respect to the palatal plane. ANOVA and Post Hoc Tukey's HSD test were carried out to determine significant differences between groups. Molar inclination was significantly greater in hyper-divergent groups compared to normo-divergent and hypo-divergent groups (P<.05). Greater variation between molar inclination and cortical plate inclination (buccal and palatal) was seen in hyper-divergent groups (P<.05). Hypo-divergent and normo-divergent groups showed almost similar molar and cortical plate inclinations; however, there was a significant difference between the buccal and palatal cortical plates (P<.05). Cortical plate inclination is in agreement with molar inclination in hypo- and normo-divergent groups when compared to hyper-divergent groups. In adults with decreased/normal facial heights, greater balance and harmony is observed between the dental and alveolar substructures in the posterior region. In adults with increased facial heights, a greater amount of dentoalveolar compensation is seen with respect to the molar and its surrounding bone support.