Electronic Thesis and Dissertation Repository


Master of Clinical Science




Dr. Antonios Mamandras


An accurate anteroposterior measurement of jaw relationships is essential in orthodontic diagnosis and treatment planning. The purpose of this longitudinal study was to establish a new cephalometric Wits appraisal using a bisector of the mandibular plane angle, named the Frankfort Mandibular Plane Angle Bisector (FMAB). The FMAB was used to assess the sagittal jaw relationship in a sample of Class I individuals, and compare this measurement to the ANB angle and the Wits appraisal using the Maxillomandibular Bisector (MMB).

The data were collected from pre-treatment (T0), immediate post-treatment (T1) and two year post-retention (T2) lateral cephalograms of 61 male and 60 female Class I subjects. Non-extraction, fixed orthodontic appliance treatment in the permanent dentition was carried out for these patients. Cephalometric data were compared to 19 male and 19 female Class I subjects who had no orthodontic treatment and served as controls.

The FMAB was determined to be a reproducible reference plane which undergoes change in response to growth and treatment, consistent with the changes seen in the ANB angle. A good correlation (r>0.86) was found between the MMB and FMAB Wits appraisal measurements in both the control and treatment groups for all time periods, indicating that the use of either of these measures may be indicated in cephalometric analysis.

Key Words: Wits Appraisal, Frankfort Mandibular Plane Bisector, Anteroposterior Skeletal Discrepancy