牙骨质对根管壁通透性的影响

The effects of cementum on the permeability of the root canal wall

目的本研究探讨牙骨质对根管壁通透性的影响。方法前牙、前磨牙、磨牙各140颗,分别随机分为6组,分别为A1,A2,B1,B2,C1,C2,每组70颗。A1、B1、C1组用手持锄形刮治器彻底刮除距根尖4~10 mm处的牙骨质,暴露牙本质。A2、B2、C2组牙根表面牙骨质不做处理,保持牙骨质完整。所有离体牙根尖4 mm区域涂布指甲油封闭根尖孔,2%亚甲蓝浸没牙根至10 mm处,每隔24 h随机从6组中选取10颗牙齿,沿牙长轴纵向劈开,观察亚甲蓝渗入牙本质小管情况,连续观察7 d。结果 A1、B1、C1组在第1天即可见到亚甲蓝渗入牙本质内,渗透距离只局限在根管壁外1/3及中间部分。到第3天即可见亚甲蓝渗入根管壁的内1/3部分,至第4天几乎每组均可见亚甲蓝全部渗入根管内。前牙刮除牙骨质组(A1组)与不刮除牙骨质组(A2组)、前磨牙刮除牙骨质组(B1组)与不刮除牙骨质组(B2组)、磨牙刮除牙骨质组(C1组)与不刮除牙骨质组(C2组)分别在第1、2、3、4、5、6、7天进行比较,差异均有统计学意义(P<0.05),说明,刮除牙骨质以后,根管壁的通透性显著增加。结论牙骨质刮除后,根管壁的通透性增加,可发生从牙周向牙髓方向发生渗漏。

Objective To investigate the effects of cementum on the permeability of root canal wall. Methods The140 anterior teeth,140 premolars,140 molars were randomly divided into 2 groups,respectively,which were group A1,A2,B1,B2,C1,C2,with 70 teeth in each group. The cementum located 4 ～ 10 mm from root apex was removed by hand-held hoe to expose the dentin in group A1,group B1 and group C1. However the cementum of teeth in group A2,B2 and C2 was not treated to keep the cementum integrity. All in vitro teeth root apex 4 mm area was evenly coated with two layers of nail polish.Then these teeth root apex 10 mm area was immersed into 2% methylene blue solution in eppendorf tube,and 10 teeth were selected from each group at an interval of 24 hours,and the teeth were cleavaged along the long axis of the tooth to observe the methylene blue infiltration status into the dentinal tubules for continuous 7 days. Results In group A1,B1,C1,methylene blue penetration into dentine could be observed at the first day,and the penetration distance limited outer 1/3 layer and middle 1/3 layer of dentin of the root canal. However methylene blue penetration could be found in inner 1/3 layer of dentin at the third day,moreover,which could be observed at the forth day in allthe groups. There was significant difference at 1 d,2 d,3 d,4 d,5 d,6 d,7 d between group A1 and group A2,between group B1 and group B2 and between group C1 and group C2（ P〈 0. 05）.Conclusion The permeability of the root canal wall is increased significantly after cementum being destroyed,and leakage oriented from peridontal tissue to pulp can be observed.