Department of Orthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC, USA.
Am J Orthod Dentofacial Orthop. 2012 Jul;142(1):25-31. doi: 10.1016/j.ajodo.2012.01.017.
Conventional treatment for young Class III patients involves extraoral devices designed to either protract the maxilla or restrain mandibular growth. The use of skeletal anchorage offers a promising alternative to obtain orthopedic results with fewer dental compensations. Our aim was to evaluate 3-dimensional changes in the mandibles and the glenoid fossae of Class III patients treated with bone-anchored maxillary protraction.
Twenty-five consecutive skeletal Class III patients between the ages of 9 and 13 years (mean age, 11.10 ± 1.1 year) were treated with Class III intermaxillary elastics and bilateral miniplates (2 in the infrazygomatic crests of the maxilla and 2 in the anterior mandible). The patients had cone-beam computed tomography images taken before initial loading and at the end of active treatment. Three-dimensional models were generated from these images, registered on the anterior cranial base, and analyzed by using color maps.
Posterior displacement of the mandible at the end of treatment was observed in all subjects (posterior ramus: mean, 2.74 ± 1.36 mm; condyles: mean, 2.07 ± 1.16 mm; chin: mean, -0.13 ± 2.89 mm). Remodeling of the glenoid fossa at the anterior eminence (mean, 1.38 ± 1.03 mm) and bone resorption at the posterior wall (mean, -1.34 ± 0.6 mm) were observed in most patients.
This new treatment approach offers a promising alternative to restrain mandibular growth for Class III patients with a component of mandibular prognathism or to compensate for maxillary deficiency in patients with hypoplasia of the midface. Future studies with long-term follow-up and comparisons with facemask and chincup therapies are needed to better understand the treatment effects.
传统的治疗年轻的 III 类患者涉及的口腔外设备旨在要么延长上颌骨或抑制下颌骨生长。骨骼锚固的使用提供了一个有前途的替代方法，以获得较少的牙齿补偿的矫形效果。我们的目的是评估使用骨锚定上颌骨前牵引治疗 III 类患者的下颌骨和颞下颌关节窝的三维变化。
25 例连续的骨骼 III 类患者，年龄在 9 至 13 岁之间（平均年龄，11.10 ± 1.1 岁），用 III 类颌间弹性装置和双侧微型板治疗（上颌骨的眶下嵴 2 个，下颌骨前 2 个）。在初始加载和主动治疗结束时，对患者进行锥形束计算机断层扫描（CBCT）成像。从这些图像生成三维模型，在颅前基底注册，并通过使用彩色图谱进行分析。
所有患者在治疗结束时都观察到下颌骨的后向移位（后支：平均 2.74 ± 1.36 毫米；髁突：平均 2.07 ± 1.16 毫米；颏：平均-0.13 ± 2.89 毫米）。在大多数患者中观察到颞下颌关节窝前嵴的重塑（平均 1.38 ± 1.03 毫米）和后壁的骨吸收（平均-1.34 ± 0.6 毫米）。
这种新的治疗方法为下颌骨前突或中面部发育不全的患者提供了一种有前途的替代方法，用于抑制 III 类患者的下颌骨生长或补偿上颌骨不足。需要进行长期随访的未来研究和与面具和颏兜治疗的比较，以更好地了解治疗效果。
