Latham Jason, Fong Hanson, Jewett Anahid, Johnson James D, Paranjpe Avina
Department of Endodontics, University of Washington, Seattle, Washington.
Department of Material Science and Engineering, University of Washington, Seattle, Washington.
J Endod. 2016 Aug;42(8):1218-25. doi: 10.1016/j.joen.2016.05.004. Epub 2016 Jun 29.
The lack of mechanical debridement and reduced concentrations suggested for chemical debridement to maintain stem cell viability call into question the disinfection efficacy of current regenerative protocols. Current protocols vary in the concentration and type of antibiotic medicaments used. The aim of this study was to determine if simulated immature teeth infected with Enterococcus faecalis can be completely disinfected by following current standardized regenerative protocols and to evaluate the probable effects of residual bacteria on stem cell toxicity.
Sixty-eight caries-free maxillary incisors were used. S1 sampling protocols were validated in both negative and positive control groups via culture, scanning electron microscopy, and confocal laser scanning microscopy. All teeth, except the negative controls, were inoculated with E. faecalis. The teeth were divided into the following groups: group 1, triple antibiotic paste (ciprofloxacin:metronidazole:minocycline) at concentrations of 10, 1, and 0.1 mg/mL; group 2, double antibiotic paste (ciprofloxacin:metronidazole) at concentrations of 10, 1, and 0.1 mg/mL; group 3: Ultracal XS calcium hydroxide (Ultradent, St Louis, MO); and controls, negative and positive controls. Current regenerative protocols recommended by the American Association of Endodontists were followed. S2 sampling was performed after 4 weeks and tested for bacterial presence via culturing, scanning electron microscopy, and confocal laser scanning microscopic analysis.
The data showed that calcium hydroxide and the current recommended antibiotic concentrations are not capable of completely eliminating bacteria from simulated necrotic immature permanent teeth.
Overall, this study focuses on the need to re-evaluate the balance between stem cell toxicity and bacterial elimination in order to determine the appropriate concentrations and medicaments for successful regenerative endodontic procedures.
缺乏机械清创以及为维持干细胞活力而建议降低化学清创的浓度，这使得当前再生方案的消毒效果受到质疑。当前的方案在所用抗生素药物的浓度和类型上各不相同。本研究的目的是确定按照当前标准化再生方案，感染粪肠球菌的模拟未成熟牙齿能否被完全消毒，并评估残留细菌对干细胞毒性的可能影响。
使用68颗无龋的上颌切牙。通过培养、扫描电子显微镜和共聚焦激光扫描显微镜在阴性和阳性对照组中验证S1采样方案。除阴性对照外，所有牙齿均接种粪肠球菌。牙齿被分为以下几组：第1组，三联抗生素糊剂（环丙沙星：甲硝唑：米诺环素），浓度分别为10、1和0.1mg/mL；第2组，双联抗生素糊剂（环丙沙星：甲硝唑），浓度分别为10、1和0.1mg/mL；第3组：UltraCal XS氢氧化钙（Ultradent，圣路易斯，密苏里州）；以及对照组，阴性和阳性对照组。遵循美国牙髓病学家协会推荐的当前再生方案。4周后进行S2采样，并通过培养、扫描电子显微镜和共聚焦激光扫描显微镜分析检测细菌的存在情况。
数据表明，氢氧化钙和当前推荐的抗生素浓度无法完全清除模拟坏死未成熟恒牙中的细菌。
总体而言，本研究强调需要重新评估干细胞毒性与细菌清除之间的平衡，以确定成功进行再生牙髓治疗的合适浓度和药物。
