改良舌弓治疗下颌第一磨牙异位萌出的临床应用

Clinical application of the modified lingual arch in treating the ectopic eruption of the permanent mandibular first molar

目的探讨改良舌弓治疗下颌第一恒磨牙异位萌出的临床效果。方法选择于2018年1月至2021年6月于东莞健力口腔医院正畸科就诊的15例下颌第一恒磨牙异位萌出的患儿,年龄7~8岁,其中5例双侧、10例单侧,以第二乳磨牙作为直接支抗,通过传统的下颌舌弓焊接远端牵引钩,在异位萌出的恒磨牙牙合面粘接舌侧扣联合链状橡皮圈牵引异位萌出恒磨牙向远中,以达到其正常的生理位置。使用SPSS 20.0统计软件分别对治疗前后作为直接支抗牙的第二乳磨牙与异位的第一恒磨牙的倾斜角度与冠近远中高度进行统计学分析,采用配对t检验进行对比,以P<0.05为差异有统计学意义。结果第二乳磨牙治疗前的倾斜角度为64°±3°,治疗后为63°±4°,差异无统计学意义(t=1.399,P=0.178)。同样,第二乳磨牙治疗前的近远中冠高比(85%±4%)与治疗后(84%±4%)相比,差异无统计学意义(t=0.608,P=0.550)。异位的下颌第一恒磨牙治疗前的倾斜角度为52°±6°,治疗后为69°±4°,差异有统计学意义(t=-10.423,P<0.001)。异位的下颌第一恒磨牙治疗后的近远中冠高比(90%±3%)高于治疗前(80%±5%),差异有统计学意义(t=-8.231,P<0.001)。结论改良舌弓临床操作简便,提供的支抗良好、充分,能有效治疗下颌第一恒磨牙异位萌出。

Objective To evaluate the efficacy of the modified lingual arch in treating the ectopic eruption of the permanent mandibular first molar.Methods The subjects consisted of 15 children who visited the department of orthodontics of Jianli Stomatological Hospital of Dongguan between January 2018 and June 2021,aged 7 to 8 with ectopic eruption of the first mandibular permanent molar,5 of which were bilateral and 10 of which were unilateral.By welding the distal extension hook via lingual arch and bonding the lingual button on the first permanent molar,the first permanent molar was moved distally to the normal position using chain rubber band.The inclination angle and the ratio of mesio crown height to distal before and after treatment were analyzed respectively with software(SPSS 20.0)with the second deciduous molar as direct anchorage and the ectopic first mandibular permanent molar.The paired t⁃test was used for comparison,and the significant level was set at 0.05.Results The inclination angle of the second primary molars were 64°±3°before treatment and 63°±4°after treatment respectively,where there was no significant difference(t=1.399,P=0.178).Similarly,there was no significantly difference comparing the ratio of the mesio crown height to distal of the second primary molars before treatment 85%±4%,the ratio after treatment 84%±4%(t=0.608,P=0.550).Significant difference(t=-10.423,P<0.001)was found in the inclination angle of the ectopic mandibular first permanent molars before treatment 52°±6°and after treatment 69°±4°.The ratio of the mesio crown height to distal of the ectopic mandibular first permanent molars after treatment was 90%±3%,which was significantly higher than that before treatment(80%±5%;t=-8.231,P<0.001).