ABSTRACT
Objective:To observed the longitudinal changes of the facial growth in vertical dimension in the Chinese adolescents with normal occlusion from 13 to 15 years old.Methods:The subjects were from Beijing area and consisted of 9 males and 14 females aged 12.5-13.5 years with Class I skeletal and dental pattern and without previous orthodontic treatment. Serial 2-year- annual cephalometric radiographs were taken and digitalized. Descriptive statistics for the absolute and incremental changes of the skeletal cephalometric measurements were conducted.Results:Significant gender differences in the changes of facial growth in vertical dimension from 13 to 15 years old were observed. Most of the skeletal measurements in males showed greater value than those in females. The number of the measurements which showed gender difference increased with age. The annual incremental changes of TAFH, TPFH, LAFH, U6-PP in males and those of TPFH and RH in females from 13 to 14 years old were greater than those from 14 to 15 years, However, the average increment of L6-MP in males and that of UI-PP, LI-MP, U6-PP and OB in females from 13 to 14 years old were smaller than those from 14 to 15 years old. There was no significant gender difference in TAFH/TPFH from 13 to 15 years of age. Gender difference from 14 to 15 years old was found in the growth of dental-alveolar height. The main dento-alveolar height changes happened in lower incisors and lower molars in males and in the region of upper molars and upper incisor in females.Conclusion:The skeletal facial growth in vertical dimension from 13 to 14 year old falls into the accelerating period. After 14 years old, the growth velocity is slowed down. There are significant gender differences in the skeletal changes of facial growth in vertical dimension from 13 to 15 years old. From 14 to 15 years old, the gender differences are mainly found in the growth of the dento-alveolar height.
ABSTRACT
Objective: To evaluate the clinical application of MBT straight wire. Methods: 41 cases, 11 males and 30 famales aged 12-42 years old, with malocclusion were treated by MBT straight wire appliance in orthodontic clinics, follow-up was carried out. Results: Satisfactory effects were obtained in 11 completely treated cases, preliminary improvement of occlusion was observed in the other 30 cases being still in the treatment. Conclusion: MBT straight wire appliances may be used in the treatment of various malocclusion, but special consideration should be taken according to the type of occlusion in each case.