模型测量评价NiTi方丝反扎扩弓的临床效果

The expansion effects of reversed tieing NiTi arch wire assessed by model measurements

目的 利用模型测量扩弓前、后牙弓宽度和上颌第一磨牙冠颊倾度及扭转度的变化,评价NiTi方丝反扎扩弓的临床效果。方法 采用1 6例(9例女性,7例男性,平均年龄1 7.2岁)单侧/双侧后牙反牙合病例,均戴用0 .0 2 2系统直丝弓矫治器经过初步排齐,在上颌牙列将0 .0 1 8×0 .0 2 5英寸NiTi方丝反向结扎入槽扩弓。扩弓前后取石膏模型,在模型上测量上颌尖牙牙尖间距、第一、二双尖牙颊尖间距,第一磨牙近中颊尖间距,第一磨牙冠颊倾度及扭转度。应用配对t检验评价扩弓前、后的显著性变化。结果 NiTi方丝反扎后上颌尖牙牙尖间距、第一、二双尖牙颊尖间距及第一磨牙近中颊尖间距分别增加了3.0±1 .1mm、3.5±1 .4mm、2 .9±0 .9mm、4 .8±1 .8mm ,第一磨牙冠颊倾1 0 .7±4 .6°,远中颊向扭转5 .6±3.7°,具有显著性差异。所有病例反牙合均解除并稍过矫正,平均疗程6周。结论 NiTi方丝反扎扩弓是一种简单有效的快速解除后牙牙性反牙合的方法。

Objective To evaluate the expansion effects produced by reversed tieing 0.018× 0.025 inch NiTi arch wire.Methods The subjects consisted of 16 patients (9 females and 7 males, mean age of 17.2 years) presenting with unilateral/bilateral posterior crossbite. Treatment effects were assessed by model measurements.Results All posterior crossbites were corrected in 3～10 weeks (mean treatment time 6 weeks). As a result of expansion, maxillary intercanine, interfirst and second premolar, and interfirst molar arch widths increased 3.0± 1.1mm? 3.5± 1.4mm? 2.9± 0.9mm? 4.8± 1.8mm respectively. The maxillary first molar showed a buccal crown tipping of 10.7± 4.6°, and a distobuccal rotation of 5.6± 3.7°.Conclusion It was found that the method of reversed tieing NiTi arch wire was effective in correcting posterior crossbite in a short time, and should not be used for overcorrection in case of severe crown buccal tipping.