根管封闭剂对牙周膜细胞生物相容性的影响

目的：研究氧化锌丁香油类（zinc oxide and eugenol based sealers，ZOE）、环氧树脂类（epoxy resin sealers，ERS）、硅酮基类(silicone based sealers，SBS)根管封闭剂对牙周膜细胞(human periodontal ligmant cells, hPDLCs)的增殖和矿化潜能的影响。方法：选用3颗不同人牙齿来源的hPDLCs进行重复实验，采用酶消化法+组织块培养法进行hPDLCs体外原代培养，按照培养基的不同成分分组：（1）ZOE固化 24 h 浸提液培养基组；（2）ZOE固化 1周浸提液培养基组；（3）ZOE固化 2周浸提液培养基组；（4）ERS固化 24 h 浸提液培养基组；（5）ERS固化 1周浸提液培养基组；（6）ERS固化 2周浸提液培养基组；（7）SBS固化 24 h 浸提液培养基组；（8）SBS固化 1周浸提液培养基组；（9）SBS固化 2周 浸提液培养基组；（10）不含浸提液培养基组（对照组）。采用倒置显微镜观察hPDLCs细胞形态的变化，3-(4，5-二甲基噻唑 2) 2，5-二苯基四氮唑溴盐（methyl-thiazol-diphenyltetrazolium，MTT）法测定细胞增殖能力，试剂盒法测定碱性磷酸酶（alkaline phosphatase，ALP）活性。选取固化2周的各组材料制备矿化诱导浸提液，不含浸提液的矿化培养基为阳性对照组,采用茜素红染色法及氯化十六烷基吡啶半定量法分析矿化物形成情况。结果：比较相对增殖率( relative growth rate，RGR)，ZOE固化2周内均具有中度或严重细胞毒性（RGR为13.6%~39.9%）；ERS固化24 h具有轻微细胞毒性（RGR为63.6%~76.4%），固化1周后轻微或无细胞毒性(RGR为87.6%~95.3%)；SBS固化后无明显细胞毒性(RGR为91.8%~106.7%)。比较ALP活性,SBS不同固化时间组间差异无统计学意义（F=3.397，P=0.053），且均高于ZOE和ERS组。半定量法检测数据显示，ZOE：D562 nm= 0.180±0.050,ERS：D562 nm= 2.968±0.201,SBS：D562 nm=3.623±0.039,对照组：D562 nm=3.477±0.102，即ZOE

Effect of root canal sealers on biocompatibility of human periodontal ligament cells

Objective:To compare the effects of three root canal sealers with respect to time on biocom-patibility of human periodontal ligament cells (hPDLCs).The sealers included zinc oxide and eugenol based sealers (ZOE),epoxy resin sealers (ERS)and silicone based sealers (SBS).Methods:hPDLCs were primarily cultured,with the method combining of tissue explant and enzymatic digestion.The cells were then exposed to different extract fluids:(1)ZOE extracted for 24 h group ;(2)ZOE extracted for 1 week group;(3)ZOE extracted for 2 weeks group;(4)ERS extracted after 24 h group;(5)ERS extracted after 1 week group;(6)ERS extracted after 2 weeks group;(7)SBS extracted after 24 h group;(8)SBS extracted after 1 week group;(9)SBS extracted after 2 weeks group;(10)Dulbecco modified Eagle’s me-dium/F12(DMEM/F12)as negative control group.Cell morphology was observed under an inverted mi-croscope.Cell proliferation was measured by methyl-thiazol-diphenyltetrazolium (MTT)assay.ALP assay kit was used for measuring alkaline phosphatase (ALP)activity.Sealers of 2 weeks’setting time were then immersed in an osteogenic medium for examination of mineral nodules and calcium deposits.Re-sults:Considering the relative growth rate (RGR),ZOE was severely to moderately cytotoxic (RGR:13.6% -39.9%),while ERS was slightly or not cytotoxic (RGR:87.6% -95.3%).Only SBS did not show any cytotoxicity after setting (RGR:91.8% -106.7%).The setting time influenced the cytotoxic-ity of ERS which decreased after 1 week.Considering the ALP activity,there was no difference between SBS group and control group(F =3.397,P =0.053).According to the results of calcium deposits, ZOE:D562 nm =0.180 ±0.050,ERS:D562 nm =2.968 ±0.201,SBS:D562 nm =3.623 ±0.039,Control:D562 nm =3.477 ±0.102,the ranking of ALP activity and calcium deposits was as follows:ZOE