RESUMEN
Objective To analyze the skeletal characteristics of temporomandibular joint in patients with unilateral posterior scis-sors bite by using the cone-beam computed tomography(CBCT) .Methods Thirty-five patients of Angle class Ⅰ were scanned by CBCT (19 cases with unilateral scissors bite as the experimental group and 16 cases without scissors bite as the control group ) The CT images were reconstructed into 3D computer models by using the Dental Volume Reformat Function of the Ondemand 3D pack-age .9 anatomical landmarks were located and all data of 11 measured value were statistically analyzed .Results There were statisti-cal differences in the skeletal characteristics of temporomandibular joint in the scissors-bite side of the experimental group compared with those in the non-scissors-bite side (P0 .05) .There were statistical significances in the skeletal characteris-tics of temporomandibular joint of the controlled group compared with those in the scissors-bite side of the experimental group ,and the same with those in the non-scissors-bite side (P<0 .01) .Conclusion The CBCT is an effective tool to analyze the skeletal char-acteristics of temporomandibular joint characteristics .There were differences in the morphology of the condyle and the glenoid fossa of patients with unilateral posterior scissors bite .
RESUMEN
OBJECTIVE: The purpose of this study was to compare the difference in three dimensional tooth movement using three different wire sizes (0.018 x 0.025-in, 0.016 x 0.022-in, 0.016-in) on a NiTi scissors-bite corrector. METHODS: Computed tomography (CT) images of the experimental model before and after tooth movement were taken and reconstructed into three dimensional models for superimposition. The direction and the amount of tooth movement were measured and analyzed statistically. RESULTS: The lingual and intrusive movements of the crown of the maxillary second molar were increased as the size of the NiTi wire increased. The roots of the maxillary second molars moved buccally except for the 0.016-in group. The intrusive movement of the roots of the maxillary second molars was increased as the size of the NiTi wire increased. Due to the use of orthodontic mini-implants, anchorage loss was under 0.2 mm on average. CONCLUSIONS: The 0.018 x 0.025-in NiTi wire was most effective in lingual and intrusive movement of the maxillary second molar which was in scissors-bite position. Indirect skeletal anchorage with a single orthodontic mini-implant was rigid enough to prevent anchorage loss.
Asunto(s)
Coronas , Modelos Teóricos , Diente Molar , Diente , Técnicas de Movimiento DentalRESUMEN
In this paper,a maxillary molar retractor was introduced.It could control the direction of orthodontic force and provide a quick and easy solution for reposition of the tooth and correction of scissors-bite.