Longitudinal cephalometric study of mandibular growth in Qazvin children with normal occlusion

Background: During growth and development, mandible may have a protrusive or retrusive rotation in relation to cranial base which may cause different types of malocclusion. On the basis of cephalocaudal growth pattern, mandibular growth potential is higher than the other craniofacial counterparts and hence, the evaluation of its normal pattern is critical. Objective: To assess the mandibular growth in 9-11-year Iranian children with normal occlusion in Qazvin. Methods: This was a longitudinal descriptive study on mandibular growth of sixty (20 ineach age) with normal occlusion in Qazvin city. The cases were selected by means of stratified random sampling and were followed for an average of 607.5 days. Mandibular structures and SN plan were traced from two cephalograms superimposed by Athanasious method. Nine landmarks and four measurements were identified and further calculations on their mean, SD and mean differences were made. Statistical analyses including T-test, ANOVA and MANOVA were used to evaluate gender and age differences within and between groups. Findings: In all samples mandible rotated forward, changes of gonial angle was negligible and maximum horizontal and vertical changes occurred in condylion, and articular. Conclusion: In 9- to 11-year old children the growth increments were statistically significant during the two-year period. The only difference between genders was in growth of articular and condylion.