Department of Orthodontics, Ajou University, School of Medicine, Suwon, Korea.
Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):423-32. doi: 10.1016/j.ajodo.2009.08.036.
This report introduces an innovative treatment approach of selecting atypical and unconventional teeth for orthodontic extraction without compromising the quality of treatment outcomes by using temporary skeletal anchorage devices in patients with bimaxillary protrusion. Both patients introduced in this report had solid Class I molar relationships with bimaxillary anterior protrusion without facial or dental midline asymmetry. Their chief concerns were significant facial convexity, which conventionally requires the extraction of all 4 first premolars. However, 3 second premolars and 1 first premolar were removed in the first patient, and 2 second premolars and 2 first premolars were removed in the second patient. All second premolars extracted had previously had root canal treatment and large prosthodontic restorations, which resulted in a compromised short lifespan of the teeth relative to the natural dentition. To manage these cases of asymmetric extraction space in a symmetric dental and skeletal environment, 2 mini-implants were placed in the posterior maxillary interradicular spaces, 1 on each side. Despite the unusual asymmetric extraction of teeth, superimposition of the pretreatment and posttreatment cephalometric tracings shows excellent treatment outcomes of facial convexity reduction by asymetric maximum retraction of the anterior teeth with no change in the molar relationships.
本报告介绍了一种创新的治疗方法,即在不拔除四颗第一前磨牙的情况下,通过使用临时骨锚固装置,选择非典型和非常规的牙齿进行正畸拔牙,以治疗双颌前突患者。本报告介绍的两名患者均具有稳固的 Class I 磨牙关系,双颌前突且无面型或牙中线不对称。他们的主要诉求是显著的面型前凸,这通常需要拔除所有四颗第一前磨牙。然而,第一位患者拔除了 3 颗第二前磨牙和 1 颗第一前磨牙,第二位患者拔除了 2 颗第二前磨牙和 2 颗第一前磨牙。所有拔除的第二前磨牙均已进行根管治疗和大型修复体修复,相对于天然牙列,其牙齿的预期寿命较短。为了在对称的牙颌环境中管理这些非对称拔牙间隙的病例,在每侧上颌后牙区的牙间间隙中各放置了 2 个微型种植体。尽管存在不寻常的非对称拔牙,但治疗前和治疗后面颅侧位片的重叠显示,通过不对称的最大前牙后移,显著减少了面型前凸,而磨牙关系没有改变。