Department of Orthodontics, Alma Mater Studiorum University of Bologna, Bologna, Italy.
Am J Orthod Dentofacial Orthop. 2011 Mar;139(3):316-23. doi: 10.1016/j.ajodo.2009.03.051.
In this research project, we aimed to compare the effectiveness of single (1 deciduous canine) and double (deciduous canine and first molar) extractions in subjects with retained maxillary permanent canines positioned palatally or centrally in the alveolar crest, at risk for root resorption of adjacent permanent teeth.
Subjects at risk for canine impaction or resorptive situations were randomly assigned to 1 of 2 treatment modalities: single extraction (17 patients, 28 canines) or double extraction (20 patients, 37 canines). Thirty-one patients with 53 canines judged to be not at risk constituted the untreated control group. Panoramic radiographs were taken at the initial observation and after 18 months on average. Between-group statistical comparisons were carried out on the changes in canine inclination and sector location (measured on panoramic radiographs) and on the percentages of successful permanent canine eruptions.
The double-extraction group showed significant improvements in the success rate and the intrabony position of the permanent canine, in terms of uprighting the canine's long axis with a crown movement in a distal direction.
Concomitant deciduous canine and first molar extractions proved to be more effective as a preventive approach to promote eruption of retained maxillary permanent canines positioned palatally or centrally.
在这项研究项目中，我们旨在比较单（1 颗乳尖牙）和双（乳尖牙和第一磨牙）拔牙在患有上颌恒尖牙埋伏或位于牙槽嵴中央、有邻牙牙根吸收风险的患者中的效果。
有恒尖牙埋伏或吸收风险的患者被随机分为 2 种治疗方式之一：单拔牙（17 例患者，28 颗尖牙）或双拔牙（20 例患者，37 颗尖牙）。31 例被认为没有风险的患者（53 颗尖牙）构成未治疗对照组。在初始观察和平均 18 个月后拍摄全景片。对犬牙倾斜和扇形位置（全景片测量）的变化以及恒犬牙成功萌出的百分比进行组间统计比较。
双拔牙组在恒犬牙的成功率和骨内位置方面有显著改善，表现为犬牙长轴的直立和冠部向远中移动。
同时拔除乳尖牙和第一磨牙作为一种预防措施，可更有效地促进埋伏于上颌牙槽嵴中央或近中位置的恒尖牙萌出。
