Changes Of The Craniofacialand Soft Profile In Patients With Skeletal Class Ⅱ High-angle Malocclusion After Orthodonitic Treatment

Objective: To evaluate changes of craniofacial hard tissue and soft tissueprofile of skeletal classⅡ high-angle malocclusion after tooth-extractiontreatment.Methods: Twenty adult cases with skeletal class Ⅱh igh-anglemalocclusion who met the criteria were included into this study. Thecephalometric X-ray films pre-and post-treatment were measured andforty-four linear and angular measurements were analyzed by SPSSversion16.0.Paired t test and Pearson correlation analysis were used.Results: After the treatment,①∠SNA decreased0.43°(P＞0.05),∠SNB increased0.65°(P＞0.05);∠ANB1.08°, the difference wasstatistically significant (P＜0.05);②∠SN-MP decreased0.22°, thedifference was not statistically significant (P＞0.05);③Upper and lowerlip protrusions were decreased by3.13mm and2.94mm, respectively；Maxillary and mandibular incisor tips were retracted by7.94mm and3.25mm, respectively; the distance of upper labrale and lower labrale toRicketts esthetic plane was reduced3.12mm and2.84mm, respectively; ∠U1-SN,∠U1-NA decreased14.86°,11.13°, respectively;∠FMIAincreased5.67°; G-Sn-Pos, Z angle and Naso-labial angle increased2.39°,3.72°and8.11°, respectively; These parameters after treatments showedsignificant differences, compared with that before treatments(P＜0.05);④The G-Sn-Pos was positively correlated with△Pos-Y(r=0.411, P＜0.05),and was negatively correlated with△FMIA (r=-0.402, P＜0.05);△UI-SN (r=-0.414, P＜0.05)、△UL-Y (r=-0.421, P＜0.05) and△LL-Y(r=-0.435, P＜0.05) was negatively correlated with Z angle; TheNaso-labial angle was negatively correlated with△UI-Y (r=-0.542, P＜0.05)、△UL-Y (r=-0.388, P＜0.05)、△UI-SN (r=-0.516, P＜0.05) and△FMIA(r=-0.400, P＜0.05).Conclusion: Soft tissue profile was improved after four premolarsextraction in skeletal classⅡhigh-angle malocclusion adult patients. Therelationship of sagittal jaw became coordinated after the anterior toothretraction and the vertical height showed no significant changes. Thechanges of soft tissue profile were moderately correlated with changes ofanterior tooth retraction and the postion of both lips.