| Objective1.The measurements of the alveolar bone height and thickness of mandibular anterior teeth which include the central incisors and lateral incisors in adults skeletal classⅢ with high angle before the orthodontic treatment and after the pre-surgical orthodontic decompensation are to analyse the differences of the alveolar bone between the left and right teeth,the central and lateral,moreover,the more important is to analyse whether the alveolar bone condition change after the pre-surgical orthodontic decompensation.In order to provide the preferences about the orthodontic treatments for the orthodontists.2.Measure the alveolar bone height and thickness of mandibular anterior teeth which include the central incisors and lateral incisors in adults skeletal class Ⅲ with high angle after the post-surgical one year later by CBCT,then analyse whether the alveolar bone condition change the post-surgical one year later.Then we can know the ability of the alveolar bone after the orthognathic surgical.3.The measurements of the root lengths of mandibular anterior teeth which include the central incisor and lateral incisor in adults skeletal class Ⅲ with high angle before the orthodontic treatment and after the pre-surgical orthodontic decompensation and one later after the orthognathic surgical are to analyse the differences of the root lengths between the left and right teeth,the central and lateral,moreover,the more important is to analysis whether the root lengths changed after the pre-surgical orthodontic decompensation and one year later.In order to provide the preferences about the orthodontic treatment for the orthodontists.MethodsThe sample was consisted of 20 patients in adults with skeletal Class Ⅲmalocclusion with high angle according to the inclusion criteria,who were treated in the First Affiliated Hospital of Zhengzhou University from September 2018 to January 2020(11 men,9 women,average age:19 years,the youngest is 18).They were taken CBCT before treatment(T0)and after the orthodontic decompensation(T1)and after the orthognathic surgery one year later.The eXamVison soft ware was used to measure the related data.1.Measured the alveolar bone thickness and height of the left and right of the central and lateral incisors in the stage of T0/T1.Statistical tests were performed using SPSS 21.0 software package.Differences between the measured variables were tested by t-test and paired-t test.2.Measured the alveolar bone thickness and height of the left and right of the central and lateral incisors in the stage of T2.Statistical tests were performed using SPSS 21.0 software package.Differences between the measured variables were.tested by t-test and paired-t test.3.Measured the root lengths of the left and right of the central and lateral incisors in the stage of T0/T1/T3.Statistical tests were performed using SPSS 21.0 software package.Differences between the measured variables were tested by t-test and paired-t test.Results1.There was no statistical difference in the height or thickness of the alveolar bone between the left and right central or lateral incisors in T0 or T1;The height comparison:The comparison of the measured height of all the teeth between the T0 stage and T1 stage was statistically significant(P<0.05),and the measured height value became larger,indicating that the alveolar bones were all vertically absorbed,and after the decompensation,it occurred different degrees of dehiscence or aggravated the original degree of the alveolar bone dehiscence.The thickness comparison:the thickness of the labial of the central incisor before orthodontics was less than that of the lingual side,and the difference was statistically significant(P<0.05);the thickness of the labial and lingual side changed after the decompensation;The thickness of the labial region around the apical region increased,while the thickness of the lingual side decreased,and the difference was statistically significant(P<0.05);the total thickness of the central incisor apical region before orthodontics was compared with the total thickness of the lateral incisor was different(P<0.05),and the total thickness of the central incisor was less than that of the lateral incisor;compared with the T0 stage,the total thickness of the alveolar bone in the apical area of the lateral incisor was reduced in the T1 stage,and the difference was statistically significant(P<0.05).2.There was no statistically significant difference in the height and thickness of the alveolar bone between the left and right side of the central and lateral incisors in the T2 stage;compared with the corresponding height in the T1 stage:the labial and lingual height difference of the lateral incisors in the T2 stage was not statistically significant(P>0.05),indicating that there was no significant change in the height of alveolar bone in stage T1;compared with the thickness of the corresponding alveolar bone in stage T1,there was no statistically significant difference in the labia-lingual thickness and total thickness of the apical alveolar bone of the central incisors in stage T2(P>0.05),indicating there was no significant change in the alveolar bone thickness of the apex of the lateral incisor at stage T2.3.Compared with T0 stage,the root length of the central and lateral incisors changed with different degrees,and the difference was statistically significant(P<0.05);compared with T1 stage,the T2 root lengths of the central and lateral incisors still changed with different degrees.But the difference in the change of T0-T1 was statistically significant(P<0.05),but there was no statistically significant difference in the change of the root lengths between the central and the lateral incisors(P>0.05).Compared with T0-T1,the change of T2-T1 was less.Conclusion1.There is no significant difference between the left and right in the thickness and height of the skeletal class Ⅲ with high angle malocclusion in adults before orthodontic treatment;after decompensation,the thickness of the alveolar bone on the apical labial side increases,and the thickness of the lingual alveolar bone decreases.And the total thickness is reduced.2.It is no significant difference in alveolar bone height and alveolar bone thickness in the apical area of the central and lateral incisor one year later after surgery of the adult patients of skeletal Class Ⅲ with high-angle malocclusion.The recurrence of mandibular anterior teeth is not obvious after 1 year,and the stability of alveolar bone and lower anterior teeth is good.3.The root length of the lower middle and lateral incisors in adults with the skeletal class Ⅲ with high angle malocclusion can reduce after the orthodontic decompensation before the orthognathic surgery,but there was no significant difference in the amount of root absorption between the central incisor and the lateral incisor.While it still decreases about the root length of the lower incisors during the period of 1 year after the operation. |
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