Orthodontic traction of impacted canines: Concepts and clinical application

ABSTRACT Orthodontic traction of impacted canines stands as a major challenge for Orthodontics. It is a relatively frequent clinical complaint which management, more often than not, requires a multidisciplinary approach. Surgical exposure of the impacted canine, and the complex orthodontic mechanics applied to align the tooth back into the arch, may frequently lead to complications involving supporting tissues, not to mention the long treatment time and high costs imposed to patients. In face of that, it is worth highlighting the relevance of early diagnosis as to intervene efficiently and as soon as possible. This paper presents a review of the main concepts involving prevalence, etiology and classification of impacted canines, and describes the different clinical management options that would help solve the problem. It illustrates the topic by presenting a treatment delivered to a 13 year 7 months old male patient, suffering from a Class II, division 2, left subdivision, malocclusion, associated to a deep bite and a prolonged retention of a primary upper canine caused by the impaction of the permanent tooth. Corrective orthodontic therapy was associated to a rapid maxillary expansion and to the use of a high pull headgear. Impacted canine was submitted to orthodontic traction and correctly positioned back into the arch. This approach proved to be efficient in meeting both functional and aesthetic goals.

摘要：阻生尖牙（impacted canines）的正畸牵引（orthodontic traction）是正畸学领域的一大难题。该病症临床相对常见，其诊疗往往需要多学科协作模式（multidisciplinary approach）。通过外科手术暴露阻生尖牙，并采用复杂的正畸力学装置将牙齿牵引至牙弓内的治疗方案，常可能引发支持组织（supporting tissues）相关并发症，更不必说治疗周期漫长、患者需承担高额诊疗费用。有鉴于此，尽早开展诊断以实现及时高效干预的重要性不言而喻。本文综述了阻生尖牙的患病率、病因学及分类等核心概念，并介绍了可用于解决该问题的各类临床诊疗方案。此外，本文以1例13岁7个月的男性患者为例展开说明：该患者罹患安氏Ⅱ类2分类左侧亚类错颌畸形（Class II, division 2, left subdivision malocclusion），伴随深覆合（deep bite），且因恒牙阻生导致上颌乳尖牙（primary upper canine）滞留过久。治疗采用正畸矫治联合上颌快速扩弓（rapid maxillary expansion）与高位牵引头帽（high pull headgear）的方案，对该阻生尖牙实施正畸牵引后，将其成功复位至牙弓内。该治疗方案在实现功能与美观双重目标方面均展现出良好疗效。