| Objective:Cone Beam Computed Tomography(Cone Beam Computed Tomography,CBCT)was used to observer the number? form? location? the direction of growth and the clinical classification of the maxillary anterior ambushed supernumerary teeth,and the shape of the nasopalatine nerve canal.Analyzing and assessing the relationship between the maxillary anterior ambushed supernumerary teeth and the nasopalatine nerve canal,then guide to remove the supernumerary teeth by surgical approach.Reduce the injury of the nasopalatine nerve intraoperative.Following-up them whose nasopalatine nerve was injured intraoperative and observed the recovery of the function of the nasopalatine nerve.Method:The patients of the maxillary anterior ambushed supernumerary teeth were collected form Ningxia Medical University Hospital from April in 2015 to August in 2016.Application of CBCT to analyze the characteristics of the maxillary anterior ambushed supernumerary teeth and the relationship with the nasopalatine nerve canal.Then remove the supernumerary teeth by surgical approach.Result:1.This study of 85 patients,56 of them were male,29 were female.The sex ration was 1.93:1.Their ages ranged from 5 to 18 years old.7~9 years old were at the most,accounting for 45.88%.2.This study had 85 patients and 117 supernumerary teeth,there were 54 patients with single supernumerary,accounting for 63.53%;30 patients with two supernumerary,accounting for 35.29%;1 patient with three supernumerary,accounting for1.18%.3.The form of 117 supernumerary teeth,cone 73,accounting for 62.39%;nodular 31,accounting for 26.50%;lateral incisor form 13,accounting for 11.11%.4.Clinical classification of 117 supernumerary teeth,36 of which were part of the bone ambushed(type ?),accounting for 30.77%;62 were all bone lie low type(type ?),accounting for 53.00%;19 were all bone ambushed high type(type ?),accounting for 16.23%.5.The location in dental arch of 117 supernumerary teeth,palatal ambushed 85,accounting for 72.65%;labial palatal ambushed 22,accounting for 18.80%;labial ambushed 7,accounting for 5.98%;dental arch ambushed 3,accounting for 2.56%.6.The direction of growth of the supernumerary teeth,inverted impacted 61,accounting for 52.14%;25 normal impacted,accounting for 21.37%;24 labial palatal horizontal impacted,accounting for 20.51%;7 near and far horizontal impacted,accounting for 5.98%.7.The region in the maxillary anterior of 117 supernumerary teeth,69 at the location of 11-21,accounting for 58.97%;21 at the location of 11-12,accounting for 17.95%;16 at the location of 21-22,accounting for 13.68%;6 at the location of 22-23,accounting for 5.13%;5 at the location of 12-13,accounting for 4.27%.8.This study of 85 patients,the shape of the nasopalatine nerve canal in median sagittal slice could be divided into five types by CBCT.Type ? 28,the diameter of the nasopalatine nerve canal from oral cavity to nasal cavity is cut down,accounting for 32.94%.Type ? 7,the diameter the nasopalatine nerve canal from oral cavity to nasal cavity is increscent,accounting for 8.24%.Type ? 18,the diameter of the nasopalatine nerve canal from oral cavity to nasal cavity is irregular,accounting for 21.18%.Type ? 20,the diameter of the nasopalatine nerve canal from oral cavity to nasal cavity is regular and uniform,accounting for 23.53%.Type ? 12,the diameter of the nasopalatine nerve canal from oral cavity to nasal cavity is thin and uniform,accounting for 14.12%.9.The axial morphology of the nasopalatine nerve canal could be divided into three types by CBCT.Incisive foramen: none bony crest 65,accounting for 76.47%;bony crest18,accounting for 21.18%%;bony interval 2,accounting for 2.35%.The axial morphology of the middle foramen of the nasopalatine nerve canal: none bony crest 36,accounting for 42.35%;bony crest 37,accounting for 43.53%;bony interval 12,accounting for 14.12%.Stensen's foramen: none bony crest 30,accounting for 35.29%;bony crest 18,accounting for 21.18%;bony interval 37,accounting for 43.53%.10.This study of 85 patients,there were 28 patients and 42 supernumerary teeth touch the nasopalatine nerve canal by CBCT,22 patients' nasopalatine nerve canal were injured and 6 patients' nasopalatine nerve were cut off intraoperative.The function of the nasopalatine nerve was all normally before surgical operation.One day after surgical operation,there were 25 patients had different degrees of the function of the nasopalatine nerve.11.The surgical approach of this study: 19 chose the labial,55 chose the palatal,11 chose the labial and palatal.There was no patient of whose nasopalatine nerve was injured by labial surgical approach,16 were injured by palatal surgical approach,6 were injured by labial and palatal surgical approach.There was 4 nasopalatine nerve was cut off by palatal surgical approach,2 nasopalatine nerve was cut off by labial and palatal surgical approach.The function of whose nasopalatine nerve was injured intraoperative and recovered after 6 months followed-up.12.Correlation analysis:the clinical classification of the maxillary anterior ambushed supernumerary teeth and the supernumerary teeth's location of dental arch were highly correlated,and had no relationship with the direction of growth of the supernumerary teeth.The type of the nasopalatine nerve canal in median sagittal slice and the clinical classification of the maxillary anterior ambushed supernumerary teeth,the supernumerary teeth's location of dental arch,the direction of growth of the supernumerary teeth were highly correlated.Conclusion:1.The application of CBCT precisely before operation to site the position between the maxillary anterior ambushed supernumerary teeth and the nasopalatine nerve canal can provide reliably basis for the operation.And reduce the injury of the nasopalatine nerve effectively.2.The function of the nasopalatine nerve with whose nasopalatine nerve was injured and cut off intraoperative recovered after 6 months followed-up in this study.3.The clinical classification of the maxillary anterior ambushed supernumerary teeth and the supernumerary teeth's location in dental arch are highly correlated,and have no relationship with the direction of growth of the supernumerary teeth.The type of the nasopalatine nerve canal in median sagittal slice and the clinical classification of the maxillary anterior ambushed supernumerary teeth,the supernumerary teeth's location in dental arch,the direction of growth of the supernumerary teeth are highly correlated. |
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