Orthodontic treatment with passive eruption and mesialization of semi-impacted mandibular third molar in an adult with multiple dental losses

ABSTRACT Objective: This article describes the orthodontic treatment performed on an adult patient with multiple dental losses. Case report: A female patient, 20 years and 4 months old, presented with the following conditions: absence of teeth #26, #35, #36 and #46; semi-impacted tooth #48; inclined molars adjacent to an edentulous space; canines and premolars in a Class II relationship; a convex profile; biprotrusion; and forced lip sealing. Results: Space in the region of tooth #26 was closed, as well the space of tooth #46; tooth #48 erupted and followed mesial movement passively; space of the region of tooth #35 was maintained for the placement of a dental implant; uprighting of tooth #37 was obtained. Aesthetic and functional goals of the treatment were achieved. Results remained stable 10 years after the end of the treatment. Conclusion: The modified helical loop could be effectively used in orthodontic mechanics to close edentulous spaces. Passive semi-impacted mandibular third molar eruption and mesialization can occur in adults when proper space is provided.

摘要
目的：本文报道1例多颗牙缺失成年患者的正畸治疗（orthodontic treatment）过程。
病例报告：患者为20岁4个月的女性，临床表现如下：26、35、36、46号牙缺失；48号牙半阻生；缺牙间隙（edentulous space）相邻的磨牙倾斜；尖牙与前磨牙呈II类咬合关系；侧貌呈凸面型；双颌前突；唇闭合费力。
治疗结果：关闭了26号牙及46号牙区域的缺牙间隙；48号牙萌出并发生被动近中移动；保留35号牙区域的间隙以植入牙科种植体（dental implant）；完成37号牙的直立矫治。本次治疗达成了美学与功能目标，治疗结束10年后疗效保持稳定。
结论：改良螺旋环（modified helical loop）可有效应用于正畸力学系统以关闭缺牙间隙。成年患者在获得适宜间隙的前提下，可实现下颌第三磨牙的被动半阻生萌出及近中移位。