A correlation between a new angle (S-Gn-Go angle)‎ with the facial height

الملخص EN

Background : Y-axis has been used by many authors as a growth parameter while horizontal growth of mandible is outlined by moving forward along the Go-Gn line.

The purposes of this study were to introduce a new angle that determine the vertical growth direction and establish its relation with the facial heights in different skeletal classes.

Materials and methods : The sample consisted of 146 digital true lateral cephalometric radiographs collected from the files of the patients attending the Orthodontic clinic in the College of Dentistry, University of Baghdad.

According to the ANB angle, the sample was classified into : CL I (17 males and 21 females), CL II (30 males and 40 females) and CL III (20 males and 18 females).

2 linear and 3 angular skeletal variables were measured using AutoCAD computer program 2007.

Descriptive statistics applied for all the measurements for both genders and total sample in each class.

Independent samples t-test was used to compare the measurements between both genders, while ANOVA test was used to compare the measurements among the skeletal classes, and Pearson correlation coefficient was applied to find the relation between the new angle and other variables.

Results : The mean values of S-Gn-Go angle were established and found to be higher in Class I then Class II and III ; also they were higher in males than females.

This angle showed direct significant correlation with posterior facial height in all of the skeletal classes.

Conclusions : Y-axis and S-Gn-Go angle is very important angles in determination the direction of mandibular growth.