| Objective: In this study,three-dimensional reconstruction of image data of cone beam computed tomrahhy(CBCT)before treatment for Angle III malocclusion patients of class II malocclusion was performed.The lip inclination,type of root position,and tooth of the incisors were studied.The angle between the sulcus and the height and thickness of the alveolar bone were measured and analyzed.The angles of inclination,root position,and root angle of the different vertical bone types in the Angle Class II Division 1 malocclusion of adults were also investigated.Whether there is a certain correlation between the alveolar bone height and thickness,etc.,for the diagnosis of adult class II Division 1 malocclusion,the development of an orthodontic plan,the choice of treatment options,the risk assessment of orthodontic treatment,and the achievement of expected results.To ensure the stability of the results of the correction to provide a certain reference and guidance.Method: From the database of orthodontists in Tianjin Medical University,60 patients with Angle Class II Division 1 malocclusion admitted to our hospital who were admitted to our hospital from June 2010 to March 2017 were selected.The average age of patients was 25.40± 5.14 years old.CBCT images were used to generate cranial lateral radiographs.Subjects were divided into high angle group,mean angle group,and low angle group according to the FMA angle and FHI index measured by the lateral radiograph.There were 20 cases in each group.Invivo 5 software was used to reconstruct the image data.Afterwards,the type of anterior teeth and the alveolar bone of the anterior teeth were measured in a three-dimensional coordinate system.The data analysis of the measurement results was performed using SPSS 22.0 statistical software for one-way analysis of variance and analysis of adult II.Class 1 classifies the incisors of different vertical facial types and the alveolar bone in incisor regions.Result:1.Cutting lip inclination: Maxillary incisor lip inclination: The differences in the inclination of the maxillary central incisor teeth between the ?U1-SN,?U1-NA,U1-NA(mm),and U1-NPog groups were statistically significant(P<0.01).?U1-SN,?U1-NA,U1-NA(mm)are the minimum for the high angle group,the average angle group is centered,and the low angle group is the largest.The difference between the mean values of the ?U1-SN high angle group and the low angle group is 4.55°,?U1.The difference between the mean value of the high angle group and the low angle group of the NA is 5.09°,and the difference between the mean angles of the U1-NA(mm)high angle group and the low angle group is 3.31 mm.U1-NPog was the lowest in the low-angle group,the middle in the mean angle group,and the highest in the high-angle group,and the difference between the low-angle group and the high-angle group was 4.71 mm.,Mandibular incisor lip inclination: There were significant differences among the three groups of high-average and low-group in the measurement of ? L1-MP,?L1-NB,L1-NB(mm),and L1-NPog in the central incisors(P<0.01).The difference between the mean value of the high angle group and the low angle group of the ?L1-MP is 10.3°,and the difference between the mean value of the high angle group and the low angle group of the ?L1-NB is The difference between the 3.55°,L1-NB(mm)high angle group and the low angle group mean is 3.48 mm.The difference between the mean value of the L1-NPog high angle group and the low angle group was 4.91 mm.2.Root position type: Maxillary:(1)The type of incisor root was mainly lablabial.The type I of the root lip of the maxillary central incisor was the main type.The proportion of the subtype I in the low-angle central incisor was the highest,accounting for 95%.2)The type of lip subtype II in the lateral incisor was the main type,and the percentage of the three groups had no significant difference;(3)In the overall sample,the proportion of the middle class was smaller than that of the labial side,and the percentage of middle incisors was smaller.The number of teeth was more than that of lateral incisors,and the proportion of low angle group was higher than that of the mean angle group and high angle group.(4)The proportion of hemiplegia in the sample was smaller,the percentage of lateral incisors was higher than that of middle incisors,and the percentage of low angle and mean angle groups was greater than that of high angle group.Mandible:(1)In the total sample percentage,the percentage of the incisor root position was the highest,followed by the middle type,and the least in the lingual type.In the high-average group and the low-group group,90%,92.5%,and 80% of the labial palpebral lobes were present,and the 3 groups of the side incisors accounted for 90%,90%,and 92.5%,respectively.The percentages of the high-angle group and the mean angle group were higher than the low-angle group.Compared with the high angle group,the three groups had the highest percentage of the lateral incisors in the incisor and low angle group,which were 95% and 92.5% respectively;(2)The three groups of incisor roots and subgroup I were The main types,including high angle group,mean angle group and low angle group accounted for no significant difference;in the side incisor,the type of lip subtype II was the main type,the percentage of the three groups was close,there was no significant difference;(3)the central incisor The median percentage of the intermediate type was 11.6% higher than that of the side incisor,and there was no significant difference in the percentages of the high angle group,the mean angle group,and the low angle group.The percentage of middle-angled high-angle group was higher than that of the mean-angle group and low-angle group.(4)The proportion of the lingual type in the whole sample was the smallest,and this type was not found in this sample.3.The angle between the long axis of the root and the long axis of the alveolar bone: Maxillary: In the high angle group,the angle of the root of the incisor was larger than that of the mean angle group and the low angle group.The difference was statistically significant(P<0.05),but there was no significant difference between the high angle group and the low angle group.There was no statistically significant difference in the angles of the roots of the high-angle group,the mean angle group,and the low-angle group of the lateral incisors.Mandible: The angle of the root in the high angle group was higher than that in the low angle group and the mean angle group,and the difference was statistically significant(p<0.05).However,there was no significant difference between the mean angle group and the low angle group.4.Alveolar bone height: Maxillary incisors: The three groups of incisors were in the labial alveolar crest,the lingual alveolar crest-CEJ,the labial alveolar crest-PP,the lingual alveolar crest-PP,and the apical-PP There was a statistical difference(p<0.05);the alveolar crest-CEJ,lingual alveolar crest-CEJ were the smallest in the high angle group,the median angle group was the middle,and the low angle group was the largest,the difference between the three groups was statistically significant(p<0.05);lip alveolar ridge-PP,lingual alveolar ridge-PP,apical-PP in the low-angle group was the smallest,the mean angle group was centered,and the high-angle group was the largest,the difference between the three groups was statistically significant(p<0.05);p<0.05).The distance from the alveolar ridges of the lateral incisors to the margins of the glaze cementum,the distance from the lingual alveolar ridges to the glaze cementum,and the distance from the alveolar crests to the sacral plane were all in the high-low group There was a statistically significant difference(p<0.05).The maxillary alveolar dome-CEJ and the lingual alveolar dome-CEJ were the smallest in the high-angle group,the middle-angle group was the lowest,and the low-angle group was the largest.The difference between the three groups was statistically significant.(p<0.05);The distance from the alveolar ridge dome to the temporal plane was the highest in the high angle group,the median angle group was in the middle,and the low angle group was the smallest,the difference was statistically significant(p<0.05).Mandible: In the high-low group and the high-low group,the alveolar bone height of the mandibular incisors was measured on the three items of the alveolar crest-CEJ,the lingual alveolar dome-CEJ,and the labial alveolar crest-PP.Differences in statistics (p<0.05),the height of the alveolar crest-CEJ,and the lingual alveolar crest-CEJ were the lowest in the high angle group,the lowest in the mean angle group,and the highest in the low angle group.Significance(p<0.05);lip alveolar dome-PP was the lowest in the low-angle group,medium-angle group was centered,and the high-angle group was the largest,and the difference between the three groups was statistically significant(p<0.05).5.5.Alveolar bone thickness: Maxillary: The middle incisor was in the high-low group and the maxillary alveolar ridge,3 mm from the maxillary alveolar dome,the labial root apex,3 mm from the lingual alveolar ridge,and the distance from the lingual alveolar ridge.The thickness of the alveolar bone at the total thickness of 6mm was statistically different,and the lowest angle in the high angle group was the highest in the middle angle group and the lowest angle group was the highest.The difference between the three groups was statistically significant(p<0.01);In the group,the maxillary alveolar dome,3 mm from the maxillary alveolar dome,the labial root apex,the lingual alveolar dome,3 mm from the lingual alveolar ridge,6 mm from the lingual alveolar ridge,and the lingual lateral root The alveolar bone thickness at the apex was the lowest in the highangle group,the middle-angle group was the highest,and the low-angle group was the largest.The difference between the three groups was statistically significant(p<0.01).Mandible:middle incisors in the high-low three groups,the lateral alveolar dome,6 mm from the alveolar dome,the lingual alveolar dome,3 mm from the lingual alveolar ridge,and the distance from the alveolar dome The alveolar bone thickness at 6mm was statistically different,with the lowest in the high angle group,the highest in the mean angle group,and the highest in the low angle group(p<0.01);the lateral incisors were in the high and low three groups.Alveolar crest,3 mm from the labial alveolar crest,6 mm from the labial alveolar crest,3 mm from the lingual alveolar crest,and the lowest alveolar bone thickness at the lingual apex The median and low angle groups were the largest,and the difference between the three groups was statistically significant(p<0.05).Conclusion: 1.There is a correlation between the degree of dental incline,the position of the root of the tooth,the angle of the root,the height and thickness of the alveolar bone,and the vertical facial profile of the class II malocclusion.2.Different vertical facial types of adult class II malocclusion mandibular maxillofacial incisors with high degree of lip inclination in the high angle group had the lowest degree of lip inclination,the average angle group was centered,and the low angle group had large lip inclination.3.The type of root incisor with class II malocclusion is mainly the labial type.The subtype I of the upper-middle incisor lip is the main type,the low-angle group is the most,and the upper incisor lip subtype II is the main type.Types;The lower incisor lip subtype I is the main type,the lower incisor lip subtype II is the main type,and there is no obvious correlation with the vertical bone type z.4.The maxillary incisor root angle was the highest in the high angle group,the mean angle group was the middle,and the low angle group was the smallest.The maxillary central incisor has a greater root angle than the lateral incisors.The angles of the roots of the mandibular lateral incisors and the central incisors were similar.The angles of the roots in the high angle group were the largest,those in the mean angle group were medium,and those in the low angle group were the smallest.5.The thickness of alveolar bone in Angle Class II 1 incisors in adults was the thinnest in the high-angle group,the middle-angle group was the middle,and the low-angle group was the thickest.6.The height of alveolar bone in Class II 1 class incisional teeth of adults was highest,that of high angle group was the highest,that of mean angle group was middle,and that of low angle group was the lowest. |
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