Assessment of Palatal Plane and Occlusal Plane for Determining Anteroposterior Jaw Relation

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Sagittal jaw relationship is an important parameter for orthodontic treatment planning. Angular and linear measurements both have been proposed and used in orthodontic cephalometrics to assess the sagittal jaw relationships. However, angular measurement has been questioned over the years for its reliability as a result of changes in facial height, jaw inclination and the variable positions of Nasion. So, the objective of our study was to assess the linear anteroposterior jaw relation in a sample of Nepali population using occlusal (Wits appraisal) and palatal planes as reference lines. A descriptive cross-sectional study was conducted using the lateral cephalogram of 101 individuals visiting the Department of Orthodontics, Kantipur Dental College, Kathmandu, Nepal. Individuals with Class I skeletal relation were selected using convenience sampling method. Radiographs were standardised and traced. Occlusal and palatal planes were drawn that were bisected by the perpendicular lines from Point A and Point B. The linear distances between the intersections were measured to determine sagittal jaw relations. In Nepali individuals with normal ANB angle (3.05°±2.511°), the sagittal jaw relation with reference to occlusal (Wits appraisal) and palatal planes were found to be 0.203±3.343mm and 3.574±4.074mm respectively. Various methods has been proposed and used to assess the sagittal jaw relation and each method has its own strength and limitations. So, it is well advised to use additional cephalometric analysis whenever possible before arriving at any diagnosis and treatment plans.