Effect Observation Of Surgery Combined With Orthodontic Traction Of Maxillary Central Incisor With Dentigerous Cyst In The Mixed Dentition

ObjectiveSurgery combined with orthodontic traction was performed to treat the impacted and undeveloped maxillary central incisors with dentigerous cysts in the mixed dentition.The normal homonymous tooth on the opposite side of the same jaw was used as a control.The changes of the root,alveolar bone and pulp vitality of the impacted teeth were compared before and after the treatment.The effect and significance of the treatment were analyzed in order to provide a reference for the treatment of impacted teeth with dentigerous cyst in the mixed dentition.MethodsA total of 20 patients with unilateral impacted maxillary central incisors with dentigerous cysts admitted to the first affiliated hospital of zhengzhou university from August 2015 to August 2018 were selected.All of them underwent surgical exposure combined with closed orthodontic traction.The cone-beam CT(CBCT)was taken to measure the root length,root canal wall thickness,alveolar bone level and thickness before and after the treatment,at the same time pulp vitality was checked,which were compared with the contralateral counterpart tooth(control group).And the differences of root development,alveolar bone development and pulp activity between impacted teeth and control teeth before and after treatment were compared.ResultsThe treatment time of this group was 14 to 33 months,with an average of 23.6 months.At the end of the treatment,the cyst cavities in the jaws disappeared and were filled with new bone.The impacted teeth were brought into dental arches.1.Root length:The root length of the impacted maxillary central incisor before the treatment was(8.76±1.16)mm and that of the control tooth was(10.95±1.03)mm,between which the difference was statistically significant(P<0.05).The root length of the impacted maxillary central incisor after the treatment was(11.41±0.94)mm and that of the control tooth was(13.06±0.72)mm,between which the difference still was statistically significant(P<0.05),but it was significantly increased compared with that before the treatment and the difference was statistically significant(P<0.05).After the treatment,the change of root length in the treatment group was(2.65±0.95)mm and that in the control group was(2.11±0.99)mm,which was statistically difference(P<0.05).2.Thickness of root canal wall:The thickness of the root canal wall of the impacted maxillary central incisor before the treatment was(1.67±0.26)mm and that of the control tooth was(1.71 ±0.25)mm,between which the difference was no significant(P>0.05).The thickness of the root canal wall of the impacted maxillary central incisor was(1.87±0.20)mm after the treatment and the thickness of that of the control tooth was(1.89±0.19)mm,between which the difference was still no significant(P>0.05),but the wall of the root canal was thicker than that before the treatment and the difference was statistically significant(P<0.05).After the treatment,the change of root canal wall thickness in the treatment group was(0.19±0.11)mm and that in the control group was(0.18±0.10)mm,which was no significant difference(P>0.05).3.Alveolar bone:After the treatment,the levels of the labial and palatal alveolar bone in the treatment group were(2.50±0.41)mm and(1.27±0.23)mm,and that of the control group were(1.38±0.28)mm and(1.23±0.21)mm.The thickness of the labial and palatal alveolar bone in the treatment group were(0.56±0.19)mm and(1.49±0.28)mm,and that in the control group were(0.79±0.24)mm and(1.58±0.24)mm.There were statistically significant difference only in the level and thickness of the alveolar bone on the labial side(P<0.05).4.Pulp vitality:The dental pulp vitality of the treatment group and the control group was compared after the treatment,and there was no significant difference(P>0.05).Conclusion1.The patients with impacted maxillary central incisor with dentigerous cyst in the mixed dentition were treated with surgical operation and orthodontic traction under the condition of selecting suitable indications.As a result,the root could continue to grow to more than 2/3 of the root length with the root canal wall of the impacted teeth developing normally,and the pulp vitality was normal,which reached the clinical preservation standard and can be the reference for clinical diagnosis and treatment.2.Surgical operation combined with orthodontic traction as the treatment of impacted maxillary central incisors with dengtigerous cysts in the mixed dentition could lead to a mild loss of alveolar bone on the labial side.