Ultrasonographic evaluation of the circumoral musculature in skeletal class I and skeletal class ii division 1 malocclusion subjects: A comparative study

Background and Objectives: There should a balance between the forces of the tongue from within the dental arches and compensating action of the lips and cheek musculature. Alterations in function of the facial muscle can establish changes in facial skeleton and in the development of malocclusion. The role of lips in determining the facial morphology and the tooth position has intrigued dental researchers for decades. Thus this prospective study was carried out to ultrasonographically measure the lip thickness in class II division 1 malocclusion cases and compare with class I subjects. Methodology: Patients reporting to the Department of Orthodontics, for fixed orthodontic treatment between 18-25 years were screened for inclusion and exclusion criteria and 30 subjects (15 class 1 occlusion and 15 class 2 div I malocclusion) were included in the study. Ultrasonographic measurements were made for upper and lower lip in relaxed and contracted states; which were divided into three regions i.e. right, middle and left in both the groups and the resultant data was subjected to analysis. Results: Thickness of oral musculature of different sites of the lower lip were increased in skeletal class II division 1group as compared to skeletal class I group in the contracted state and in relaxed state. A more predisposition towards females was observed in skeletal class II division 1group.