Dental maturation in subjects with extreme vertical facial types.

The purpose of this research was to investigate whether there is a difference in dental maturation between skeletal open bite and skeletal deep bite subjects of the same chronological age. The material consisted of 40 lateral headfilms and 40 panoramic radiographs of 20 male and 20 female white subjects, with a mean chronological age of 9 years and 2 months (range: 7 years 6 months to 10 years 11 months). These subjects were selected on the basis of lower anterior face height as a percentage of total face height and on the amount of open or deep-bite from a total sample of 400 subjects. The persons exhibiting the most extreme values at both ends of the distribution were selected to create two groups with 20 subjects in each (10 males and 10 females). Thus, the groups represented subjects with either a large lower anterior face height associated with an open bite or a small lower anterior face height associated with a deep bite. A double blind determination of dental maturation, expressed by dental age, for each subject was performed on the panoramic radiographs using the system of Demirjian et al. (1973). A covariance analysis was used to eliminate variability introduced by the large age range of the sample. The skeletal open bite and deep bite groups presented mean dental ages of 120.48 and 114.00 months, respectively. Statistical analysis demonstrated that this difference was statistically significant at P < 0.05. Therefore, it seems that skeletal open bite subjects presented a slight tendency to have an advanced dental maturation, expressed by dental age, as compared with skeletal deep bite subjects.