Cephalometric Analysis On Vertical Features Of Craniofacial Structure In Adult Class Ⅱ～1 And Class Ⅲ Malocclusion

〔Objective〕For provide a theoretical basis to clinic diagnosis and treatment, this cephalometric study was carried out to investigate the vertical features of craniofacial structure in adult classⅡ1 and classⅢmalocclusion, and to discuss morphology differences among the different mandibular plane angle groups.〔Material and Methods〕The patients who met the inclusion criteria were selected. ClassⅡ1 malocclusion comprised of 46 male cases (12 high angle, 14 middle angle, 20 low angle) and 54 female cases (16 high angle, 24 middle angle, 14 low angle). ClassⅢmalocclusion comprised of 44 male cases (15 high angle, 14 middle angle, 15 low angle) and 46 female cases (12 high angle,18 middle angle, 16 low angle). Lateral cephalograms were taken for the patients, then marking points were fixed and measured. The measurement datum obtained were analyzed statistically with SPSS11.5.〔Results〕1,The vertical features of classⅡ1 could be drawn from the statistical results: (1)The∠BaSN is smaller in the low-angle group than that in the high-angle and middle-angle group. The length of BaS in the high-angle group is shorter than that in the middle-angle and low-angle group. Skullbase is counterclockwise circumrotatory in low-angle group while clockwise circumrotatory in high-angle group. (2)With the increase of mandibular plane angle, growth of mandible is greater in vertical direction than in horizontal direction, and the palatal plane of low-angle group rotates counterclockwise. (3)The percentage of upper facial height in anterior facial height increases in high-angle group, while posterior facial height decreases obviously in it. Anterior facial height decreases significantly. The percentage of upper facial height in anterior height shows no significant difference among the three groups. (4)With the decrease of mandibular plane angle, the alveoli dentales height of upper and lower anterior teeth decreases. The alveoli dentales height of upper and lower molar shows no significant difference. The inclination of occlusal plane displays significant difference among three groups, the occlusal plane of high-angle group rotates clockwise while that of low-angle group rotates counterclockwise. 2,The vertical features of classⅢcould be drawn from the statistical results: (1) The∠BaSN is smaller in the low-angle group than that in the high-angle and middle-angle group. The length of BaS in the middle-angle group is shorter than that in high-angle the and low-angle group. (2)With the decrease of mandibular plane angle, the mandible rotates counterclockwise. The palatal plane of low-angle group rotates counterclockwise. (3)The upper facial height shows no significant difference among the three groups. Lower facial height increases and posterior height decreases in high-angle group. The percentage of upper facial height in anterior height at low-angle group increases while that of lower facial height in anterior height decreases. The alveoli dentales height of upper and lower anterior teeth in low-angle group decreases. The alveoli dentales height of upper and lower molar shows no significant difference among the three groups. The inclination of occlusal plane rotates counterclockwise.〔Conclusion〕The pathogenesis of classⅡ1 and classⅢis complicated, which includes three dimensional mismatch of craniofacial structure and dental arch. There are different performance among different classes, different mandibular plane angle groups. We should take specific measures to different type of malocclusion.