【作者】 张健； 葛久禹；

【Author】 ZHANG Jian,GE jiu-yu.(School of Stomatology,Nanjing University,Nanjing 210008,China)

【机构】 南京大学医学院口腔医学院；

【摘要】 目的:研究氢氧化钙对牙本质抗折强度的影响比较。方法:选择32颗猪尖牙,分别在釉牙本质界处去除牙冠,去除部分牙根尖,制备成长30mm长的统一样本,样本根管内去除牙髓后分别用生理盐水冲洗,将所有的样本随机分为4组,每组样本为8个。第一组为对照组,根管内不做任何处理,置于37℃生理盐水域中3个月;第二组样本根管内用氢氧化钙糊剂充填暂封后置于37℃生理盐水域中1个月;第三组样本根管内用氢氧化钙糊剂充填暂封后置于37℃生理盐水域中3个月;第四组样本根管内用Vitapex糊剂充填暂封后置于37℃生理盐水域中3个月。通过垂直加压探头以2 mm/min的速度对各组样本在牙釉牙本质界下15mm处加压,检测导致牙根折裂时所需的最小压力,通过计算得到牙本质的三点弯曲强度。所得数据采用方差分析,显著性水准为0.05。结果:各组样本折裂时的三点弯曲强度分别为:第1组(154.99-i-11.30) MPa,第2组(157.38-i-11.50)MPa,第3组(128.17-i-8.20) MPa,第4组(150.45-i-9.40)MPa。第1、2组间样本折裂时的三点弯曲强度差异无统计学意义(P>0.05);第3组与第1、2组相比,样本折裂时的三点弯曲强度差异有统计学意义(P<0.05);第4组与第1组相比,样本折裂时的三点弯曲强度差异无统计学意义(P>0.05)。结论:长时间的氢氧化钙糊剂使牙本质三点弯曲强度下降,降低了牙本质的抗折性;短时间氢氧化钙糊剂对牙本质的三点弯曲强度没有明显改变;Viatapex糊剂长时间对根管牙本质的三点弯曲强度改变不明显。更多还原

【Abstract】 OBJECTIVE:To compare the dentine’s fracture resistance in root canals after filling with calcium hydroxide.METHODS:32 freshly extracted pigs’ canines were collected and randomly divided into 4 groups with 8 specimen in each group.Each specimen was excluded the root crown in the dentoenamel junction,and the some apex of root of tooth,prepare unity sample with the length of 30 mm,each sample’s root canal removal the dental pulp with the irrigation of the normal saline.The first group was the control group,each sample without any treatment to put 37℃normal saline for 3 month;the second group’s samples filled the calcium hydroxide paste to put 37C normal saline for 1 month;the third group’s samples filled the calcium hydroxide paste to put 37℃normal saline for 3 month;the fourth group’s samples filled the Vitapex paste to put 37℃normal saline for 3 month.The three point flexural strength of the tested teeth was determined by applying a vertical splitting load through a specially shaped steel rod at a crosshead speed of 2 mm / min.The data were analyzed by ANOVA.The significance level was 0.05.RESULTS:The average three point flexural strength of the 5 groups were:First group(154.99-i-11.30) MPa, Second group(157.38-i-11.50) MPa,Third group(128.17-i-8.20) MPa,Fourth group(150.45-i-9.40) MPa。There was no significant difference between the group 1 and group 2(P>0.05);The three point flexural strength of group 3 was much lower than that of group 1 and group 2(P<0.05);No significant difference was found between group 4 and group 1(P>0.05).CONCLUSION:Long-term calcium hydroxide paste as a root canal dressing may decrease the dentine’s three point flexural strength and increase risk of root fracture;Short-term calcium hydroxide paste as a root canal dressing can’t obviously change the dentine’s three point flexural strength;Long-term Vitapex paste as a root canal dressing would not obviously change the dentine’s three point flexural strength.更多还原