摘要
目的:研究第一前磨牙拔除后对第三磨牙位置变化的影响,探讨影响第三磨牙萌出的客观因素。方法:选择56例上下颌第三磨牙均存在的患者进行方丝弓正畸治疗,按照第一前磨牙拔除与否分为拔牙组(30例)和非拔牙组(26例),利用术前术后曲面断层片对患者上下颌第三磨牙萌出间隙、第三磨牙与牙合平面的距离以及下颌长度进行测量分析。结果:拔牙组术前术后各指标变化均有统计学意义,但是非拔牙组中下颌萌出间隙变化不具有统计学意义。拔牙组与非拔牙组术前术后变化量进行组间比较,上颌萌出间隙(U-ES)拔牙组比非拔牙组平均增大1.35 mm(P<0.05),下颌萌出间隙L-ES(R)和L-ES(X i)分别增大了2.72 mm(P<0.05)和3.16 mm(P<0.01),下颌第三磨牙与牙合平面的距离减小0.31 mm(P<0.05),下颌骨长度增加1.68 mm(P<0.05);上颌第三磨牙与牙合平面的距离变化在两组间没有统计学差异(P>0.05)。结论:正畸治疗中拔除第一前磨牙可增大上下颌第三磨牙萌出间隙,有利于第三磨牙的萌出。
Objective： To study the changes of upper and lower third molar position in patients treated with first premolars extractions. Methods： Fifty -fix adolescents were chosen and divided into first premolar extraction and nonextraction groups, with 30 and 26 patients respectively. The pretreatment and posttreatment panoramic radiographs were taken. The indexes of third molar eruption space, distance from third molar to occlusal plane and the length of mandible were measured and analyzed. Results： All the measurement indexes had statistically significant differences between pretreatment and postreatment in first premolar extraction group （P 〈 0.05 ）. The lower eruption space had no statistically significant difference in nonextrction group （ P 〉 0. 05）. Compared first premolar extraction group with nonextrction group, the lower eruotion space increased 1.35 mm （ P 〈 0.05 ） , the lower eruption spaces L - ES （R） and L - ES （ Xi ） increased 2. 72mm （ P 〈 0.05 ） and 3.16mm （ P 〈 0.01 ） respectively, the distance from lower third molar to occlusal plane decreased 0.31 mm （ P 〈0.05 ）, the length of mandible increased 1.68mm （ P 〈 0.05 ）. The distance from upper third molar to occlusual plane had no statistically difference. Conclusion： First premolar extraction in orthodontics could increase the eruption space of third molar. It could promote the eruption of third molar.
出处
《口腔医学研究》
CAS
CSCD
2006年第4期430-432,共3页
Journal of Oral Science Research
