Estimating and comparing the duration of adolescent growth peak in skeletal class I and III subjects using cervical vertebral maturation method.

Background: Estimating skeletal maturation and growth potential is essential for developing adolescents' best orthodontic treatment plan. The purpose of this study was to compare the duration of adolescent growth peak in subjects of skeletal classes I and III using the cervical vertebral maturation (CVM) method.

Methods: This retrospective cross-sectional study included 116 Iranian subjects (skeletal class I = 68, skeletal class III = 48) aged 8-16 years old and without previous orthodontic treatments. Using Steiner and Wits analyses, two independent examiners traced pre-treatment lateral cephalograms to determine the subjects' skeletal relationship. The skeletal maturation was then assessed using Baccetti's CVM method. The onset and duration of adolescent growth peak (interval of CS3-CS4) were compared between two skeletal classes and two genders using independent samples t test.

Results: In skeletal class I and III subjects, the adolescent peak had a mean duration of 1.62 (± 1.33) and 2.00 (± 1.27) years, respectively. The average difference of 0.38 years (4.6 months) between the two groups was statistically significant (p < 0.001). Furthermore, the onset age of adolescent growth peak was 11.91 (± 1.32) and 12.08 (± 1.31) years old in class I and III subjects, respectively. This age difference was not statistically significant (p = 0.630). Males' adolescent growth peak occurred 1.44 years later (p < 0.001) and lasted 0.20 years less (p < 0.001).

Conclusions: The adolescent growth peak started at a similar age in class I and III subjects, but the latter experienced the peak for 4.6 months longer. Moreover, females had an earlier and more extended adolescent growth peak.