| Objectives: To analyze the soft tissue profile characteristic in the early permanent dentition with Class II,III malocclusion, furthermore, to choose several soft tissue variables as the indexes for assessing esthetics of facial profile and reveal the relationship between hard and soft tissue. Methods: 150 children were enrolled into the study. Of these children, 50(25 male, 25 female, with average age of 12.28)were normal occlusion selected from 3850 primary and middle school students with the early permanent dentition in ShiJiaZhuang; 50(25 male, 25 female, with average age of 12.37) were Class II malocclusion; 50(25 male, 25 famale, with average age of 12.10)were Class III malocclusion. All these children were examined cephalometrially with the lip at rest. 22 soft tissue variables and 9 hard tissue variable were selected and the cephalometric data of three groups were analyzed statistically by using SPSS11. 5 software.Results: 1. Compared with the normal occlusion group, All measurement except 3 soft tissue variables and 2 hard tissue variables was statistically significant with t-test in the Class II malocclusion group (p<0.05). The indexes which may represent the prime facial profile characteristic of Class II malocclusion were selected through discriminant analysis. They were B'Li-FH,NsLs-FH,LiNsPg',Li-E and CmSnLs, which constituting the discriminant formula: Y=3.744+0.170X1 -0.177X2 +0.469X3 -0.261X4+0.048X5. When Y>0, the sample was classified into normal occlusion group; When Y<0, was classified into Class II malocclusion group. The contribution of these five indexes to discriminant analysis decreased successively and the discriminant efficiency was 95%. Pearson correlation analyses showed there was correlation between the hard tissue variables and the facial balance indexes. The r values of B'Li-FH to ANB and U1-NA were –0.706 and –0.403; those of NsLs-FH to SNA and L1-NB were 0.569 and 0.283; those of LiNsPg' to FMIA and SNB were –0.417 and –0.423; those of Li-E to ANB and FMIA were 0.527 and –0.416; those of CmSnLs to U1-SN,U1-NA,IMPA and FMIA were-0.426,–0.453,–0.452 and 0.464(p<0.05).2.Statistically significance was shown with t-test analysis between the normal occlusion group and the Class III malocclusion group except 9 soft tissue and 1 hard tissue variables (p<0.05). Variables which were essential to the facial profile were used as the facial esthetics indexes through discriminant analysis. They were LsNsLi, CmSnLs, NsLi-FH, Ls-E and li-E, which constituting the discriminant formula: Y=4.434+0.375X1+0.055X2-0.102X3+0.298X4-0.219X5. If Y>0,the sample was classified into normal occlusion group; if not, was classified into Class III malocclusion group. The discriminant efficiency was 93%. Pearson correlation analyses of hard tissue variables to 5 facial profile indexes was carried out. Close relationship was found between hard tissue and soft tissue profile. The r values of LsNsLi to ANB was 0.830; those of CmSnLs to U1-NA and ANB were –0.57 and 0.558; those of NsLi-FH to SNB, FMIA, U1-NA and L1-NB were 0.607,0.480,0.358 and 0.214; those of Li-E to ANB and IMPA were 0.647 and 0.562; those of Li-E to ANB and L1-NB were –0.306 and 0.256(p<0.05).Conclusions: 1.Different malocclusion caused different change of soft tissue profile.2.Through discriminant analysis, B'Li-FH, NsLs-FH, LiNsPg', Li-E and CmSnLs were selected as five indexes which may represent the abnormality of facial profile of Class II malocclusion. 3.In Class III malocclusion, LsNsLi, CmSnLs, NsLi-FH, Ls-E and Li-E were selected as five indexes to assess esthetics of facial profile. 4.The discriminant formulae which were constituted by these five indexes was useful to diagnose the abnormality of Class II ,III malocclusion profile and assess the treatment effect respectively .5.The hard tissue variables were relavant to the facial profile indexes, indicating the soft tissue profile will be harmonious by the treatment of inharmonious hard tissue. ... |
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