Detection On Change Of Dentognathic Tissue And Limitation For Discrepancy Upper And Lower Jaw In Adult Skeletal ? Class Malocclusion With Extractic Camouflage Fixed Treatment

Objective:?1?To compare changes of soft and hard tissue,long axis of incisor teeth after extractic camouflage fixed treatment for adults skeletal?malocclusion;?2?Study on the correlation between the long axis of the lower anterior teeth changes,soft and hard tissues changes,and the long axis of the upper incisor changes after orthodontic camouflage fixed treatment of adult skeletal?malocclusion;?3?To explore the limitation of discrepancy between upper and lower jaw in adult skeletal?malocclusion treated with extractic camouflage fixed treatment.Methods:?1?24 adult skeletal?malocclusion patients who had been extracted f our premolars before treatment and treated successfully with camouflage fixed techniqu e were involved.They included Male 2,Female 22,and mean age before treatment w as?22.8±4.4?years old;?2?Cephalometric films were taken before and after extractic camouflage fixed treatment and 15 cephalometric parameters were chosen on cephalo metric software.Parametres included SNA,SNB,ANB,FMA,SN-MP,U1-NA,U1-NA distance,U1-SN,U1-L1,L1-NB,L1-NB distance,L1-MP,Ls-E line distance,Li-E li ne distance and Z angle were compared before and after treatment,each parametre bef ore and after treatment was compared with the normal value of normal occlusion;?3?The correlation between the variation of the long axis??L1-NB distance?of lower an terior teeth and the variation of other 14 cephalometric parameters was analyzed;?4?Correlation between pre-treatment ANB angle and other fourteen parameters before and after treatment were analyzed.Regression equation for pairs with clinical significance were setted up.Results:?1?Cephalometric parameters of ANB,FMA,L1-NB,L1-MP were no significant difference before and after treatment?p>0.05?,and the other parameters were statistically significant before and after treatment.Values of SNA,SNB,U1-NA,U1-NA distance,U1-SN,L1-NB distance,Ls-E line distance and Li-E line distance were lower and values of SN-MP,U1-L1,Z angle were larger after treatment.But the change of SNA,SNB,SN-MP before and after treatment were very small and had no clinical significance;?2?The SNB,ANB,SN-MP,L1-NB distance,L1-MP,U1-L1,Ls-E line distance,Li-E line distance and Z angle of 24 adult skeletal?malocclusion patients were statistically significant compared with the normal value of normal occlusion?p<0.05?.Values of SNB,ANB,SN-MP,U1-NA,U1-NA distance U1-SN,L1-MP,U1-L1,Ls-E line distance after treatment were statistically significant compared with the normal value of normal occlusion?p<0.05?;?3?There was moderate positive correlation between?L1-NB distance and?U1-NA,?U1-NA distance,?U1-SN,?Ls-E distance,?Li-E distance.The distance of?L1-NB was strong positive correlation with?L1-NB and?L1-MP.There was a moderate negative correlation between the?L1-NB distance and the?Z angle and a very strong negative correlation with the?U1-L1 angle.?4?The pre-treatment ANB angle was significantly correlated with the L1-NB distance before and after treatment,the correlation coefficient was0.681 and 0.624.The regression equation of the pre-treatment ANB angle?Y₁?with the pre-treatment L1-NB distance?X₁?was established as Y₁=0.208X₁+4.84,the regression equation of the pre-treatment ANB angle?Y₂?with the post-treatment L1-NB distance?X₂?was established as Y₂=0.432X₂+3.83.Conclusion:?1?Parameters on upper and lower lip soft tissue and the long axis of the lower incisor were all improved compared with those before treatment,the long axis of the upper incisor was slightly retroclined than normal,There wasn't significant improvement on hard tissues after treatment;?2?When the ANB angle is equal or more than 8.6°before treatment,patients should be actively advised to choose orthognathic surgery treatment,otherwise the lower incisor may be over proclined after pure orthodontic treatment or effect was not satisfying to most of people.