氢氧化钙根管消毒后根尖周环境中Ca^(2+)浓度和pH值测定

Determination of pH and calcium concentration with apical foramen environment after root canal dressing using calcium hydroxide

目的观察不同剂型氢氧化钙根管消毒后对根尖周环境中Ca2+浓度和pH值的影响。方法选择已拔除的新鲜单根管离体牙60颗,随机分为6组,根管预备后,A、B、C组根管内分别封入30%、40%、50%的氢氧化钙水糊剂,D组根管内封入Ca(OH)2粉末,E组根管内封入Ga(OH)2牙胶尖,F组空置对照。全部牙齿分别置于蒸馏水中,于1、2、3、4、5周测定蒸馏水中Ca2+浓度和pH值。结果各实验组Ca2+浓度随时间的延长呈上升趋势;糊剂组Ca2+浓度和pH值变化明显高于其他组(P<0.05),不同浓度组间差异无统计学意义(P>0.05);各实验组pH值变化在2～3周达峰值,之后下降。结论氢氧化钙糊剂对根尖周环境中Ca2+浓度和pH的影响较氢氧化钙粉末和氢氧化钙牙胶尖明显;氢氧化钙根管消毒的理想封药时间在2～3周。

Objective To observe the change of pH and calcium concentration with apical foramen environment after root canal dressing using different level of calcium hydroxide.Methods Sixty extracted single-rooted teeth were randomly divided into six groups on the basis of root shaping.Calcium hydroxide was placed inside the canals,namely 30%（A）,40%（B）,50%（C） calcium hydroxide paste,calcium hydroxide powder（D）,calcium hydroxide gutta-percha point（E） and blank group（F）.The teeth were stored in distilled water,pH and calcium concentration were determined at the 1st,2nd,3rd,4th and 5th week.Results Along with prolonged time,calcium concentration increased.Differences in the pH and calcium concentration with paste group were highly significant（P0.05）.There was no significant difference among three paste groups（P0.05）.The change of pH in the experimental groups reached peak at the 2nd and 3rd week,afterwards descended slowly.Conclusion Significant differences of pH and calcium concentration with apical foramen environment were recorded among paste,powder and gutta-percha point groups,paste groups showed the greater striking change than other two groups.The ideal time of calcium hydroxide sealing inside the root canals is in 2-3 weeks.