ABSTRACT
Objective@# To compare the morphology of the crown roots of upper and lower canines in patients with skeletal Class Ⅰ, Ⅱ, and Ⅲ malocclusions by CBCT and to provide guidance for the clinical treatment of orthodontics. @*Methods@#Randomly selected patients with permanent occlusal malocclusion who had undergone CBCT and X-ray skull lateral radiographs were Classified according to the ANB angle size: group Ⅰ, group Ⅱ, and group Ⅲ. Three-dimensional reconstruction was used to obtain the median sagittal section images of the right upper and lower canines. The crown root angle, crown root deflection distance, and lip tangent angle at the center of the clinical crown were used as indicators for measurement and analysis with the use of AutoCAD software.@*Results @#The difference in the crown-root skew distance between different sagittal face types, including upper canines (F=3.335, P=0.042), lower canines (F=3.745, P=0.029) crown root angles and upper canines (F=3.312, P=0.043), and lower canines (F=3.641, P= 0.032), was statistically significant (P < 0.05). The crown root angle of the maxillary canine in group Ⅰ was larger than that in group Ⅱ, and the deflection distance of the crown root was negative and the absolute value was lager in group Ⅰ than in group Ⅱ (P < 0.05). The deflection distance was positive and greater in group Ⅲ than in groups Ⅰ and Ⅱ (P < 0.05). There was no significant difference in the maxillary canine crown-labial tangent angle between the different sagittal facial misalignment groups (P > 0.05).@*Conclusion@#Differences in the morphology of canines were found among subjects with skeletal Class Ⅰ, Ⅱ, and Ⅲ malocclusions. The root of the upper canine in Class Ⅰ malocclusions was relatively closer to the labial side of the crown than that in Class Ⅱ malocclusions. The root of the lower canine in Class Ⅲ malocclusions was the closest to the lingual side of the crown among the three Classes.
ABSTRACT
The purpose of this study was to obtain the lingual morphology(angulation, inclination, horizontal and vertical contour) and lingual arch form of Korean adult with normal occlusion in order to provide the basic datas for lingual brackets and ideal lingual archwire. Dental models of thirty person with normal occlusion(Male: 16, Female: 14) were selected for this study. Crown angulation, inclination, horizontal and vertical contour of lingual surfaces from Lt. 1st molar to Rt 1st molar of both upper and lower arch were measured. Lingual archform was studied from copied papers of dental models attached Fujita lingual bracket. The results of this study were summarized as follows: 1. The average angulation and inclination of lingual surfaces of all tooth types for Korean adults with normal occlusion were obtained. 2. The average horizontal and vertical contour of lingual surfaces of all tooth types were obtained. 3. There were similar figures in horizontal and vertical contour of lingual surfaces between upper and lower molars, upper and lower premolars, upper and lower canines, upper central and lateral incisors and lower central and lateral incisors respectively. It was possible that the use of those contour of bracket bases in common. 4. The average of lingual archform was provided, which was arch-shaped from canine to canine, linear along the premolars and molars with small offset bend between them, and where canines and premolars met, it was bent in a crank-shape. 5. There was no difference between lingual archform of male and that of female, although lingual archform of female was smaller than that of male in lower arch.