1 Assistant Professor, Department of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences

2 Associate Professor, Department of Orthodontics and Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences

3 Dentist



Aim: Some cphalometric angles change during growth and in accordance with facial height and other 'facial landmarks which make it less reliable for orthodontic diagnosis. The purpose of this study was to find out relationship between Beta Angle and the anterior-posterior position of jaws.
Materials and Method: Sixty lateral cephalograms of 16 boys and 44 girls with class I, H or HI malocclusions were evaluated in our study. we traced all of the cephalograms to measure Beta angle and compare these values between different types of malocclusions. Data were annalized by means of T-student statistical test.
Results: Beta angle was 28.5° - 37.5° for class 1, less than 28.5° for class II and more than 37.5° for class III. There was no correlation between t3 angle and facial height.
Conclusion: Beta angle is independent from facial height. Beta Angle has an acceptable specificity and sensitivity for determining the anterior posterior position of Jaws (IJO 2006; 1: 184-7).