不同正畸移动方式对牙龈“黑三角”的影响

Effects of different orthodontic movements on gingival "black triangle"

目的不同正畸移动方式矫治后对"黑三角"产生的影响。方法选取70例牙周健康青年患者,均通过直丝弓固定矫正,绘制矫治前后图,记录840颗上下颌前牙,并按正畸移动方式分为4类,比较治疗前后相应的牙龈乳头指数的变化,并针对发生黑三角的牙位进行分析。结果黑三角发生率分别为唇舌倾斜(1.28%),唇展压低(3.45%),整体内收(8.00%),内收压低(4.29%)。重叠扭转牙位在4种移动方式下黑三角发生率大增,分别为3.85%、10.87%、18.39%、9.52%。结论唇舌倾斜发生黑三角的概率最低,整体内收黑三角风险最高,其次是唇展压低移位。重叠扭转牙会显著增加发生黑三角的风险。

Objective To determine the effects of different orthodontic movements on the ＂black triangle＂. Methods Seventy young adult patients with healthy periodontal tissues were treated with straight wire appliance, and the diagram was plotted before and after the orthodontic treatment. A total of 840 maxillary and mandibular anterior teeth were recorded and divided into four categories according to the orthodontic movements. The changes of the corresponding gingival papillary index before and after treatment were compared, and the tooth position of the ＂black triangle＂ was analyzed. Results The incidences of the ＂black triangle＂ were oblique lips and tongue （1.28%）, lowered lips opening （3.45%）, overall adduetion （8.00%）, lowered adduction （4.29%）, respectively. The incidences of the ＂black triangle＂ significantly increased under the four movements of the tooth position with overlapping torsion, which were 3.85%, 10.87%, 18.39% and 9.52%, respectively. Conclusion The incidence of oblique lips and tongue-induced ＂black triangle＂ is the lowest, and the overall adduction is the highest risk for ＂black triangle＂, followed by the movement of lowered lips opening. The overlapping torsion of teeth may significantly increase the risk for the occurrence of ＂black triangle＂.