Hsu Yu Lin, Chang Chris H, Roberts W Eugene
Director, Andersen Dental Clinic, HsinChu, Taiwan.
Director, Beethoven Orthodontic Center, HsinChu, Taiwan.
Am J Orthod Dentofacial Orthop. 2016 Dec;150(6):1039-1050. doi: 10.1016/j.ajodo.2015.10.036.
A 12-year-old girl presented with a Class II Division 1 malocclusion, complicated by a complete transposition of the maxillary left canine into the position normally occupied by the left lateral incisor. Dental and medical histories were noncontributory. Brackets were bonded on all maxillary teeth, from first molar to first molar, except for the left lateral incisor. Because the lateral incisor was not engaged on the archwire, the tooth was free to physiologically move out of the path of canine root movement. To prepare the site for canine retraction, a coil spring was used to open space between the left central incisor and the first premolar. A 2 × 12-mm stainless steel miniscrew was placed in the infrazygomatic crest, labial to the mesiodistal cusp of the maxillary left first molar. A 0.019 × 0.025-in titanium-molybdenum alloy T-loop, anchored by the miniscrew, was used to retract the canine root over the labial surface of the root of the distally positioned lateral incisor. In 24 months, this difficult malocclusion, with a Discrepancy Index score of 18, was treated to a Cast-Radiograph Evaluation score of 26.
一名12岁女孩表现为安氏II类1分类错牙合畸形，并发上颌左侧尖牙完全移位至正常左侧侧切牙的位置。牙科和病史均无特殊情况。除左侧侧切牙外，在上颌所有牙齿（从第一磨牙到第一磨牙）上粘结了托槽。由于侧切牙未与弓丝接触，该牙齿可自由地生理性移出尖牙根移动路径。为准备尖牙后移的部位，使用螺旋弹簧在左侧中切牙和第一前磨牙之间开辟间隙。在上颌左侧第一磨牙近远中牙尖唇侧的颧下嵴处植入一枚2×12毫米的不锈钢微螺钉。用一枚由该微螺钉固定的0.019×0.025英寸的钛钼合金T形曲，将尖牙牙根向远中移位的侧切牙根唇面牵拉。在24个月内，将这一难度较大、差异指数评分为18的错牙合畸形，治疗至模型-头颅侧位片评价评分为26。
