Atypical orthodontic extraction pattern managed by differential en-masse retraction against a temporary skeletal anchorage device in the treatment of bimaxillary protrusion

作者：Chung Kyu Rhim; Choo HyeRan; Lee Jin Hwa; Kim Seong Hun^*

来源：American Journal of Orthodontics and Dentofacial Orthopedics, 2011, 140(3): 423-432.

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. (Am J Orthod Dentofacial Orthop 2011; 140: 423-32)

• 出版日期2011-9