Correlation of Tongue Dimensions and Posture with Lower Central Incisor Inclination and Alveolar Bone Thickness in Skeletal Class I and II Malocclusion: A CBCT Study

Background: In this study, Cone-Beam Computed Tomography (CBCT) was used to assess the dimension and posture of the tongue, as well as Alveolar Bone Thickness (ABT) and labiolingual inclination of mandibular central incisors in order to look for any correlations. Methods: A total of 200 CBCT images of skeletal Class I and II individuals were studied. Each group of malocclusion was divided into three subgroups: low-angle, normal-angle, and high-angle. Buccal and lingual alveolar bone thickness (BT & LT), and the Inclination of Mandibular Plane Angle (IMPA) were measured and compared by using T-test. The spearman rank correlations test analyzed the correlations between dental variables and tongue measurements (p<0.05). Results: Significant weak correlations were identified between dental variables and tongue measurements. In Cl I malocclusion, IMPA and Tongue Length (TGL) were found to be significantly correlated with a correlation value of 0.324 (p=0.001). In Cl II malocclusion, there was a significant correlation between BT3 and TGH. About BT3, there was a significant correlation with D4’ and a negative correlation with D5’. Further comparison among vertical subgroups revealed the same results. Conclusion: Class I patients with superior tongue posture may have thicker lingual alveolar bone around mandibular incisors and Class II patients showed that thicker labial alveolar bone of lower incisor and thinner alveolar bone at the lingual side may be associated with a superior position of the posterior portion of the tongue.