| The adjustment of occluding relation is the key point at the end stage of orthodontic treatment, no matter how to design treatment plan , some cases still don't have a good occluding relation. For instance, Angle classⅡ2 patients canines and molars are always neutral relationship in one side at the later stage of adjustment,the other side are distal molar relationship. Angle classⅢpatients canines and molars are neutral relationship in one side at the later stage of adjustment,the other side are mesial molar relationship, or both sides are mesial molar relationship. But when doctors make treatment prescriptions ,who always would rather lay particular emphasis on x-ray cephalometric analysis than analyzing of model. Especially what a influence of post-treatment will be make by the proportion between the upper and lower dental arch, teeth quantity.The Investigations of proportion between the breadth of dentals crown; upper and lower teeth quantity, mostly concentrate into contradistinction of Bolton index , upper and lower teeth quantity in different patho-occlusion groups at the prior treatment. The research (一)to study the post-treatment occluding relation to approach the relationship between the post-treatment's not ideal occlusion and upper and lower teeth quantity's proportion. To know well teeths'size ratio, which can prompt doctor, patients and their parents that there is infallibility that can result in unideal occluding relation, can help doctor to institute correct treatment plans to avoid dispute between doctor and patients.Exterior and interior scholars Invest differents between pro-treatment and post-treatment always concentrate in cephalometric analysis,seldom seen model analysis. There is not a report about model analyzing for the target of post-treatment'occluding relation. In the research(二)(三), whose author measure the pro and post treatment models of functionality angle classⅢand Angle classⅡ1 patho-occlusion with extracting teeth , analyze the ideal occluding relation team and the unideal team's patients'arch length, breadth, curve of occlusion, pars palatalis height's change , and make a summary of which influence the adjustment of occluding relation.The purpose of this investigate: to understand the dependability of Angle classⅡ1,Angle classⅡ2,Angle classⅢpatho-occlusion post-treatment's occluding relation and tooth quantity ratio. To measure the pro and post treatment models of functionality Angle classⅢand Angle classⅡ1 patho-occlusion with extracting teeth, analyze the ideal occluding relation team and the unideal team's patients'arch length, breadth, curve of occlusion, pars palatalis height's change.Empirical method: research(一) choosing 153 complete Angle classⅡ, Angle classⅢpatho-occlusion patients'models, dividing into ideal team and unideal team by PAR index, measure every model's all teeth's Bolton index, according to normal value can get a ratio of two teams samples'teeth quantity's unsuitable, to do statistics analyze. Research(二) choosing 78 Angle classⅢpatho-occlusion patients'models who are extracted both sides upper the second premolar and lower first premolar. Research(三) choosing 34 Angle classⅡ1 patho-occlusion patients'models who are extracted both sides upper first premolar and the lower second premolar and PAR over bite index at least above 2. Dividing into ideal team and unideal team by PAR index to model analyze, measure every patient's pro and post treatment's model's arch length, breadth, curve of occlusion, pars palatalis height's change.Results: after treatment ,the ideal occluding relation team Bolton index all teeth ratio does not match is 47.27%, but the unideal occluding relation team Bolton index all teeth ratio does not match is 71.43%; through classified post-treatment unideal occluding relation team models we can get a result: The tooth quantity does not adjust the ratio From large to small in turn is Angle classⅡ2>Angle classⅢ>Angle classⅡ1, respectively is 85%, 68.8%, 66.7%. The occluding relation not ideal group all teeth quantity does not adjust is higher than the ideal occluding relation group obviously, P=0.003, Angle classⅡ2 of all teeth quantities do not adjust the formation rate to be highest. Angle classⅢpatho-occlusion After treatment, the occluding relation normal group the segmentum anterius, the segmentum posterius of upper jaw dental arch length increase. The lower jaw segmentum anterius reduces obviously P<0.05. The change of occluding relation unusual group is not obvious P>0.05. In occluding relation unusual in Latter tooth section group, Lower jaw width increases obviously P<0.05. Other each item and the curve of occlusion, the palate height change during two groups have not difference. Angle classⅡ1 malocclusion deformity , dental arch length segmentum anterius of the lower jaw occluding relation normal group reduces not obviously, The unusual group reduces obviously P<0.05; in normal group dental arch length center-section reduces obviously P<0.05,The unusual group upper jaw reduces not obviously P > 0.05 ; in normal group dental arch length segmentum posterius increase P<0.05,The unusual group lower jaw increases not obviously .in normal group lower jaw dental arch center-section width increases obviously P<0.05, The unusual group lower jaw increases not obviously .after treatment , the curve of occlusion normal group reduces extremely obviously P=0.000,The unusual group reduces not obviously . The palate height reduces in both groups , but is not remarkable.Conclusion: upper and lower tooth quantity proportion directly influence post-treatment the canine, the double canine,molars to adjust occluding relation, and Angle classⅡ2 Bolton ratio's not adjusting rate is highest. Also after the treatment, it is easiest to present one side occluding relation ideal ,but another one side is not. To Angle classⅢpatho-occlusion patients, it is key point to promote upper jaw to grow, to restrain the lower jaw, to patients those have missed the growth development period, a certain extent compensation movement of upper and low teeth is essential.Evolving upper front teeth's to lip side, the adducent extent of lower front teeth, and avoiding the buccal-version malposition impaction of lower molars is the key point of post treatment ideal occluding relation. Angle classⅡ1 patho-occlusion after treatment, the occluding relation is not ideal owing to lower front teeth's adduction excessively; the increase of lower jaw center-section. Segmentum posterius are not sufficient; the smoothing of curve of occlusion is not thoroughly.
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