| Class Ⅱ Division 1 malocclusion is generally described as having a distal relationship of mandibular teeth relative to the maxillary teeth of more than one-half the width of the cusp,labially inclined maxillary incisors and increased overjet and overbite.According to Zou Bingshuang,three were 52% of patients with skeletal Class Ⅱ malocclusion and vertical discrepancy from 50% to 60% in adult Class Ⅱ Division 1 malocclusion.[1] Previous studies found that vertical growth patterns made significant differences to soft tissue facial profile on Class Ⅱ Division 1 malocclusion and the differences were mainly concentrated in the soft tissue profile at the lower anterior face.Some studies demonstrated that the soft tissue structures at the lower anterior face were vital to facial soft tissue profile at the lower anterior face.This study which is a restrospective study,based on computer aided measurement technology,analysed the cephalometric lateral headfilm of untreated patients.The objective of the study is to know the differences of facial soft tissue profile and soft tissue structures at the lower anterior face.And to further attempt to make clear the correlations between them.Study one: Study on the differences of facial soft tissue profile at the lower anterior face in skeletal Class Ⅱ Division 1 patients with different vertical skeletal patternsObjective: To evaluate and compare the soft tissue profile at the lower anterior face of skeletal Class Ⅱ Division 1 subjects with various vertical patterns.Methods: The sample consisted of 180 untreated adults with skeletal Class Ⅱ Division 1 malocclusion and 60 adults in normal occlusion group.All of the Class Ⅱ Division 1 patients were divided into 3 groups based on vertical skeletal pattern(SN-MP angle): low angle group,normal angle group and high angle group.In each group,there were 60 subjects(30 men,30 women).The 11 soft tissue measurements at the lower anterior face were done and analyzed by SPSS 13.0 software.Results:(1)Compared with the normal occlusion group,there were some same variation trends among three different vertical patterns: Ls-E,Li-E,Ls A’-FH,Ls-N’-Pg’and Li-N’-Pg’ increased significantly(P<0.05);A’-E and Z angle decreased significantly(P<0.05).On the other hand,Si-E and Pg’Si-FH in high angle group and average angle group decreased significantly(P<0.05).In low angle group,Si-E and Pg’Si-FH increased significantly(P<0.05).(2)For Ls-E,high angle group showed significantly greater values than the other two groups(P<0.05);For the Si-E,high angle and average angle group showed significantly smaller values than the low angle group(P<0.05);For Ls-N’-Pg’and Li-N’-Pg’,high angle group had greater value than the other groups(P<0.05);While the mandibular plane angle increased,Pg’Si-FH decreased significantly(P<0.05).Conclusions: Compared with the normal occlusion group,we found that the convexity of upper lip and lower lip,the facial profile convexity were greater in Class Ⅱ Division 1;For the morphology of chin in high angle group was less developed.On the contrary,the low angle group had a better chin morphology.Three were some regular changes in most facial profile variables while the mandibular plane angle increased: the facial profile convexity and the upper-and low-lip convexity increased significantly;the morphology of chin developed worsely.Study two: Study differences of facial soft tissue structures at the lower anterior face in skeletal Class Ⅱ Division 1 patients with different vertical skeletal patternsObjective: To evaluate and compare the structures of soft tissue at the lower anterior face of skeletal Class Ⅱ Division 1 subjects with various vertical patterns.Methods: The sample consisted of 180 untreated adults with skeletal Class Ⅱ Division 1 malocclusion and 60 adults in normal occlusion group.All of the patients were divided into 3 groups based on vertical skeletal pattern(SN-MP angle): low angle group,normal angle group and high angle group.In each group,there were 60 subjects(30 men,30 women).The soft tissue measurements at the lower anterior face were done and analyzed by SPSS 13.0 software.Results: Compared with the normal occlusion group,for the basic upper lip thickness in the low angle men group had greater values(P<0.05);In the high angle men and women groups,the upper lip length showed greater value than the normal occlusion group(P<0.05);The lower lip thickness showed greater values than the normal group in the men different vertical patterns groups(P<0.05);In high angle men and women group,and average angle in women,the basic lower lip thickness were greater than the normal occlusion group(P<0.05);The lower lip length was smaller than the normal occlusion group in low and average angle group of men and women(P<0.05).For the structures of chin,the soft tissue thickness of menton in men and women,the normal occlusion group showed smaller values than the three different vertical groups(P<0.05).Among different vertical patterns groups,for upper lip length and lower lip length in men and women groups,high angle group showed significantly greater values than the other two groups(P<0.05).For basic lower lip thickness,high angle men group had greater values than the other men groups(P<0.05),and low angle women group showed smaller values than the other women groups(P<0.05).For the soft tissue thickness of chin,high angle women group showed smaller values than the other women groups(P<0.05),and no significant differences were found among the three men groups(P<0.05).Conclusions: Among three different vertical patterns in Class Ⅱ Division 1,we found that the upper lip length,the lower lip length,the basic lower lip thickness and the soft tissue thickness of gnathion had significantly differences.There were some regular changes while the mandibular plane angle increased: the upper lip and lower lip length,and the basic lower lip thickness increased significantly in women and men;the soft tissue thickness of gnathion decreased significantly.Study three: Study of the correlation between the differences of soft tissue profile in skeletal Class Ⅱ Division 1 patients with different vertical skeletal patterns and the differences of soft tissue structuresObjective: The purpose of this study was to analyze the correlation between the differences of soft tissue profile in skeletal Class Ⅱ Division 1 with three vertical patterns and the differences of soft tissue structures.Methods: The Pearson correlation analysis was used to determine the indexes affecting soft tissue profile by SPSS 13.0 software.Results: We found that there was not a correlation between the length of the upper and lower lip and the different soft tissue profile indexes among three vertical patterns.Ls-E and Ls-N’-Pg’ were positively correlated with the basic lower lip thickness and were negatively correlated with the soft tissue thickness of gnathion.On the contrary,Si-E,Pg’Si-FH and Z angle were negatively correlated with the basic lower lip thickness and were positively correlated with the soft tissue thickness of gnathion.Conclusions: In skeletal Class Ⅱ Division 1 patients,from low angle to high angle,the upper lip and the facial profile convexity were increasing and morphology of chin was getting worsely developed.The one of the mechanisms was on the soft structures,which was the problems of the basic lower lip thickness and the soft tissue thickness of gnathion. |
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