Ho Cheng-Ting, Lo Lun-Jou, Liou Eric J W, Huang Chiung Shing
Department of Orthodontics and Craniofacial Dentistry, Chang Gung Memorial Hospital, No. 199, Dunhua N. Rd., Songshan District, Taipei City 105, Taiwan (R.O.C.).
Chang Gung Med J. 2008 Jul-Aug;31(4):346-57.
Lengthening the maxillary dental arch as a treatment approach for patients with maxillary deficiency and dental crowding is seldom reported. The purpose of this study was to assess dental and skeletal changes in the maxilla in the correction of maxillary deficiency associated with a retruded maxillary arch using a surgically assisted rapid maxillary anterior-posterior expansion appliance.
Predistraction and postraction lateral cephalometric and periapical radiographs and maxillary dental casts of six young adolescents (four boys, two girls, mean age 11 years, 2 months) were examined. These patients received a maxillary anterior segmental osteotomy and distraction osteogenesis with an anteroposteriorly oriented Hyrax expansion appliance based on the biological principles of bone distraction.
The retruded dental arch and dental crowding were successfully corrected. Significant forward movement of the point anterior nasal spine, point A, central incisors and first premolars was noted. The maxillary dental arch depth increased an average of 4.2 mm while the arch width remained unchanged. In total, 11.5 mm of dental space was created in the maxillary arch which was sufficient to resolve dental crowding. New bone formation along the distraction site was observed three months after distraction.
The use of maxillary anterior segmental osteotomy combined with a Hyrax expansion distraction appliance was effective in arch lengthening and creation of dental space. An overcorrection in this interdental distraction osteogenesis could be a good treatment option for children with maxillary deficiency combined with crowded maxillary dentition.
延长上颌牙弓作为治疗上颌骨发育不足和牙列拥挤患者的一种治疗方法鲜有报道。本研究的目的是评估使用外科辅助快速上颌前后向扩弓矫治器矫治与上颌后缩弓相关的上颌骨发育不足时上颌骨的牙齿和骨骼变化。
对6名青少年（4名男孩，2名女孩，平均年龄11岁2个月）牵引前和牵引后的头颅侧位片、根尖片以及上颌牙模型进行检查。这些患者基于骨牵引的生物学原理，接受了上颌前部节段性截骨术，并使用前后向定向的Hyrax扩弓矫治器进行牵引成骨。
上颌后缩弓和牙列拥挤得到成功矫治。观察到鼻前棘点、A点、中切牙和第一前磨牙明显向前移动。上颌牙弓深度平均增加4.2mm，而牙弓宽度保持不变。上颌牙弓总共增加了11.5mm的牙间隙，足以解决牙列拥挤问题。牵引三个月后，在牵引部位观察到新骨形成。
上颌前部节段性截骨术联合Hyrax扩弓牵引矫治器在牙弓延长和创造牙间隙方面是有效的。这种牙间牵引成骨中的过度矫正可能是治疗上颌骨发育不足合并上颌牙列拥挤儿童的一种良好治疗选择。
