An Evaluation Of Maxillofacial Asymmetries In Angle â… , Angle â…¡ And Angle â…¢ Patients Using Cone-beam Computed Tomography

Objective: The aim of this study was to evaluate malocclusion effect on skeletal,alveolar, dental asymmetries using cone-beam computed tomography (CBCT)combined with DOLPHIN IMAGING software. Method: Fifteen selected patients forvarious malocclusions were scanned by CBCT. The original images werereconstructed and repositioned by DOLPHIN IMAGING software. Sella, Nasion, andBasion were choosen as landmarks to create the3D reference planes, which were usedto measure linear distances from27specific landmarks about maxillofacial bone,alveolar bone, tooth. The asymmetry indice (AI) developed by Katsumata wasintroduced to evaluate those skeletal, alveolar, dental asymmetries. All statisticalanalyses were performed using SPSS17.0(P <0.05was considered statisticallysignificant). Results:1. The AIs of the maxillofacial bone (the maxillary complexand the mandible) of ClassⅠ, ClassⅡand ClassⅢ were approximately increasedfrom upper to lower gradually, especially the ramus area were the largest. Comparingto the maxillofacial bone, the AIs in alveolar bone’s and tooth’s were a little larger.2.There were significant AI differences in gonion point between ClassⅢ and ClassⅠ(P<0.05); the AI of ClassⅢ was larger than that of ClassⅠand ClassⅡby comparingmeans.3. The AI differences were statistically significant in the central of the alveolarmargin of the lower first molar, the mesiobuccal cusp of the lower first molar and thecenter of the pulp cavity at the crown of the upper first molar between ClassⅡandClassⅡsubdivision malocclusions (P<0.05), and the result was the same to ClassⅢand ClassⅢ subdivision malocclusions. Conclusion:1. Although there may be noevident clinical symptoms, the subtle skeletal, alveolar, dental asymmetries can befound by CBCT. And most people have different degree of maxillofacial asymmetry.2. The degree of the maxillofacial asymmetry increased from upper to lower gradually.Compare with ClassⅠand Class Ⅱ, the degrees of the mandible asymmetry of classⅢ were more severe.3. The differences between ClassⅡand ClassⅡsubdivision, ClassⅢ and ClassⅢ subdivision mainly showed in the lower first molar, and thatrevealled the main differences were in the dental parameters.