ABSTRACT
Objective:To assess the guidance of 3D reconstruction in the surgical and orthodontic management of maxillary palatal impacted canines with cone-beam computed tomography (CBCT).Methods:22 adolescent patients with 26 impacted maxillary conines were examined by CBCT.CBCT 3D reconstruction was used to observe the impaction of the canines.Measurements were taken to evaluate spatial relationship between the canine and adjacent structures and resorption of neighboring incisor roots.Results:CBCT was effective to localize the impacted canines.All of the maxillary palatal impacted canines inclinated mesially,angles of impacted ca-nines to occlusal plane were 61.1°±18.1°,there were 8,5,3 and 10 impacted canines found in classⅠ,Ⅱ,Ⅲ and Ⅳ mesial mal-position respectively.3 adjacent lateral incisors and 2 central incisors were extracted because of severely root resorption.Normal occlu-sion was achieved for 26 impacted canines by the traction of the canines into dental arch and reaching the occlusal plane.Conclusion:CBCT can spatially show the palatal impaction of maxillary canines and the relationship to adjacent tooth,can guide the treatment plan and traction direction,therefore increase therapeutic effect.
ABSTRACT
Objective:To explore the torque effect of controlling root auxiliary arch on the straight wire appliance on maxillary anterior teeth.Methods:22 patients with class Ⅱ1 extraction treatment,treated with straightwire appliance,at the detailing treatment stage were treated with controlling root auxiliary arch over the erect or introverted maxillary incisors for positive torque.The main arch wire of 0.46 mm ×0.64 mm stainless steel edge wire was used in 14 cases,the main arch wire of 0.46 mm stainless steel round wire was used in 8 cases.Cephalometric results before and after maxillary incisor torque were analyzed by t test.Results:After maxillary incisor torque in the 22 cases 1-SN and UIa-NA value increased(P ＜0.01),positive torque was achieved by controlling root auxiliary arch on the upper incisors;the round wire maxillary incisor torque worked faster than the edge wire(P ＜0.05).Conclusion:At the detailing stage of treatment straight wire appliance on front teeth,controlling root auxiliary arch is simple and effective in the treatment of exces-sive erect or lingual inclination of maxillary incisor.