| Objective: For 54 impacted and embedded anterior teeth of teenagers, we hoped to provide accurate basis of clinical diagnosis and treatment design by CBCT three-dimensional positioning analysis.Methods:By means of CBCT of CS 3D Imaging three dimensional image reconstruction and measurement analysis software were applied. 41 cases of adolescents with 54 impacted teeth was reconstructed the 3D data through the vertical cutting, curve cutting, inclined cutting to display omnibearing and stereoscopic sitution of impacted teeth, which presenting precise three-dimensional positioning analysis of impacted teeth. Based on the impacted teeth position(horizontal and vertical direction, the inverted resistivity crown, tooth long axis angle, height), root condition(ambush)( apical position, root length, root resorption and tooth root bending number), the relationship to adjacent teeth and bone tissue(contact with adjacent teeth and dental ankylosis) etc. the situation of three dimensional measurement analysis, provide diagnostic basis for orthodontic traction treatment. The impacted teeth, which can be treated through orthodontic traction, were expended gap of impacted site, surgical exposure, orthodontic traction and finally made them into aligning and leveling.Results:1.With the assistance of CBCT, 54 anterior impacted teeth in 41 cases, 39 of them were labial and buccal impacted, the 15 of them were tongue and palatal impacted. Through the measurement and analysis: vertical impaction is the most of crown vertical, the level and the inversely impaction, which 32 vertical impacted teeth were accounted for 59.3% of the total; axis tilt angle most within 30 degrees, which 16-30 degrees is the 23 accounted for 42.6% of the total; ambush height of impacted teeth was located to the root 1/2 of adjacent teeth with 36 accounted for 66.7% of the total; apex position of impacted teeth was mostly partial to within the 10 mm of normal position with number of 38 accounted for 70.4% of the total; apical root resorption of impacted teeth was mainly from 0 to 1/3 root tip absorption with the number of 47 accounted for 87% of total; root bending of the impacted tooth was 2 bending of S type root, the number of 3 accounted for 5.6% of the total; the contact with adjacent teeth of the impacted tooth was from 0, the number is 41 and 75.9% of the total; The impacted teeth which were tooth osseous adhesion were rarely seen and in this study found only 1 of the total 1.9%.2.Supported by CBCT, 54 impacted teeth of 41 cases, surgical fenestration traction 45 teeth which contained of horizontal impacted 13 teeth, vertical impacted 30 teeth, and the inversely impacted 2 teeth; surgical removal 9 teeth which contained of horizontal impacted 3 teeth, vertical impaction 2 teeth, inversely impacted 4 teeth.Conclusion:Conclusions conme from 3D CS software measurement of this clinical experimental data through analycing CBCT images of 54 impacted tooth of 41 cases:1.The success rate is higher to tract the vertical impacted tooth. It is nessary to be cautious traction if it is difficulty of the above eight and no serious tooth problems, can be cautious traction.2.To the horizontal impacted tooth it will be difficult to tract with the difficulty level of the project increased gradually increased,such as the difficulty level conbinging any arbitrary should be cautious to give traction.3. Traction should be prudent if there is any one of following conditions such as the long axis of the teeth more than 30 degrees, crown located below the adjacent teeth root of inverted resistivity students buried the impacted teeth. |
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