根管预备对下颌切牙颈部牙体硬组织厚度的影响

The effect of root canal preparation on the cervical thickness of hard tissue of mandibular incisors

目的:分析根管预备对下颌切牙颈部牙体硬组织厚度的影响,结合临床讨论这种影响的特点和临床意义。方法:选择无解剖结构破坏的离体下颌切牙40颗,用标准法[1]进行根管预备成形,测量并计算在根管预备各阶段,牙颈部横断面唇舌向及近远中向最大径上的牙体硬组织厚度及厚度变化。结果:在下颌切牙颈部横剖面上,根管预备前,唇舌向牙体硬组织厚度是近远中向的1.6倍。40#号扩锉完成后,唇舌向牙体硬组织厚度减少了16.5%,近远中向牙体硬组织厚度减少了18.7%。20#,25#扩锉过程中牙体硬组织厚度在两个方向上的减小都最显著。结论:标准法根管预备过程中,下颌切牙颈部根管壁牙体硬组织量减少明显。根管治疗过程中保护根管壁硬组织,对根管治疗后患牙的修复具有重要的临床意义。

Objeetive： To study the effect of root cancal preparation on the cervical thickness of hard tissue of mandibular incisors, analyze the character and the clinical significance of the effect. Methods： 40 mandibular exvivo incisors without anatomical structure destruction were included. The cervical thickness of hard tissue of mandibular incisors was measured in the all stages of root canal preparation. Results： On the cervical portion of mandibular incisors. The average thickness of hard tissue in Labial-Lingual direction was 1.6 times as much as that in Mesial-Distal direction before root cancal preparation. After 40^# root cancal preparation, the decrement of thickness of hard tissue in Labial-lingial direction was 16.5% and that in Mesial-Distal direction was 18.7%. The decrement of thickness of hard tissue was the most in the stage of 20^# and 25^# root cancal proparation. Conclusions： The decrease of cervical thickness of the hard tissue of mandibular incisors is significant in the root cancal preparation. It is very important to protect the hard tissue from serious destruction in RCT, which is valuable in restoration.