Evaluate The Dental Changes Of Adult Skeletal Class Ⅱ Malocclusion After Treatment By Par Index

Objective:To study the correlation between the change of PAR (Peer Assessment Rating)Index of different severity of adult skeletal Class Ⅱ malocclusion and the changes of disharmony of maxillary and mandibular, the changes of axis of upper central incisors and lower central incisors, research good camouflage by the limitations of the disharmony of maxillary and mandibular, and the changes of axis of upper central incisors and lower central incisors.Methods:Thirty-eight adult skeletal Class Ⅱ malocclusion camouflage cases were chosen as study sample. The sample consists of 6 males,32females. The follow-up lateral head films and study casts were taken at least 2 years after orthodontic treatment. The cephalograms were measured by computerized program and the study casts measured by caliper. The before and after orthodontic treatment were respectively and X thrum shadow measurement model.Results:(1) All patients post-treatment were obtained good occlusal relationship, including 14 cases obtained great improvement, accounting for 36.8% of the total number of cases,24 cases got improvement, accounting for 63,2% of the total number of cases;(2) The total cases, post-treatment weighted PAR scores is decrease, post-treatment U1-SN and pre-treatment ANB there exists linear correlation (p <0.05), while the post-treatment U1-SN change, the post-treatment weighted PAR score change rate, the post-treatment U1-L1 change, post-treatment U1-L1, post-treatment U1-NA change there were no linear correlation between the pre-treatment ANB (p>0.05), the post-treatment weighted PAR scroes change with the post-treatment U1-SN change there is no linear correlation too (p>0.05).Conclusion:(1) As long as choosing the right cases, adult skeletal Class Ⅱ malocclusion deformity can obtain satisfactory effects by camouflage;(2) The greater pre-treatment ANB patients had, the worse of pre-treatment oc-clusion;(3) For adult patient with skeletal Class Ⅱ malocclusion, when the pre-treatment ANB angle is greater than 11°, suggested that the pre-treatment occlusion is very disorders possible.In this condition, if choose the camouflage,it would not get a satisfactory outcomes after treatment, the patients should be advised to considering the orthognathic surgery;(4) PAR Index is a good evaluation to evaluate the occlusion commonly used in the world, but it also has many insufficiencies, need to design better.