Establishing Norms for Beta Angle and Wits Appraisal for Various Skeletal Malocclusions

Assessing sagittal relationship is a challenging issue in orthodontics. The present study was undertaken to establish norms for Beta angle and Wits appraisal and also to establish a correlation between them in skeletal class I, class II and class III group of patients visiting Government Dental College And Research Institute, Bangalore. A comparison between males and females was also made. 150 subjects were classified as Class I, Class II and Class III on the basis of ANB angle. Their cephalograms were retraced by the examiner and Beta angle and Witts values were calculated. Pearson's test was used to find the correlation of angles among all the three malocclusion groups. The results of the present study showed that the Beta angle had a value of 31.80° ± 3.57°, 26.06° ± 3.29° and 39.88° ± 3.68° in the Class I, Class II and Class III groups respectively. The Wits appraisal had a value of -1.49mm ± 1.19mm, 4.74mm ± 3.11mm and -5.57mm ± 2.23mm in the Class I, Class II and Class III groups respectively. No significant difference in the norms for males and females was found. Beta angle showed a negative linear correlation with ANB angle with Pearson's correlation coefficient (r) values of -0.17, -0.38 and -0.54 for Class I, Class II and Class III groups respectively. Beta angle also showed a negative linear correlation with Wits appraisal, with Pearson's correlation coefficient (r) values of -0.61, -0.34 and -0.48 for Class I, Class II and Class III groups respectively. ANB angle showed a positive linear correlation with Wits appraisal with Pearson's correlation coefficient (r) values of 0.27, 0.52 and 0.38 for Class I, Class II and Class III groups respectively. The readings obtained from the present study can be utilized, without qualms, to delineate between the various sagittal skeletal relationships.