Department of Endodontics, Medical College of Georgia, Augusta, GA, USA.
J Endod. 2011 May;37(5):673-7. doi: 10.1016/j.joen.2011.01.003. Epub 2011 Mar 3.
This study investigated the setting time and micohardness of a premixed calcium phosphate silicate-based sealer (EndoSequence BC Sealer; Brasseler USA, Savannah, GA) in the presence of different moisture contents (0-9 wt%). The moisture content that produced the most optimal setting properties was used to prepare set EndoSequence BC Sealer for cytotoxicity comparison with an epoxy resin-based sealer (AH Plus; Dentsply Caulk, Milford, DE).
Standardized disks were created with BC Sealer, AH Plus, Pulp Canal Sealer EWT (positive control) (SybronEndo, Orange CA), and Teflon (Small Parts Inc., Miami Lakes, FL; negative control). Disks were placed in Transwell Inserts, providing indirect contact with MC3T3-E1 cells. Succinate dehydrogenase activity of the cells was evaluated over a 6-week period using MTT ((3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cytotoxicity profiles of BC Sealer and AH Plus were fitted with polynomial regression models. The time for 50% of the cells to survive (T(0.5)) was analyzed using the Wald statistic with a two-tailed significance level of 0.05.
BC Sealer required at least 168 hours to reach the final setting using the Gilmore needle method, and its microhardeness significantly declined when water was included in the sealer (P = .004). All set sealers exhibited severe cytotoxicity at 24 hours. The cytotoxicity of AH Plus gradually decreased and became noncytotoxic, whereas BC Sealer remained moderately cytotoxic over the 6-week period. A significant difference (P < .001) was detected between T(0.5) of BC Sealer (5.10 weeks; 95% confidence interval [CI], 4.69-5.42, standard error [SE] = 0.09) and T(0.5) of AH Plus (0.86 weeks; 95% CI, 0.68-1.05; SE = 0.18).
Further studies are required to evaluate the correlation between the length of setting time of BC Sealer and its degree of cytotoxicity.
本研究调查了一种混合钙磷酸盐硅酸盐基密封剂(EndoSequence BC 密封剂;Brasseler USA,佐治亚州萨凡纳)在不同含水量(0-9wt%)下的凝固时间和显微硬度。使用产生最佳凝固性能的含水量来制备凝固的 EndoSequence BC 密封剂,以与基于环氧树脂的密封剂(AH Plus;Dentsply Caulk,特拉华州米尔福德)进行细胞毒性比较。
用 BC 密封剂、AH Plus、牙髓腔密封剂 EWT(阳性对照)(SybronEndo,加利福尼亚州橙市)和特氟隆(Small Parts Inc.,佛罗里达州迈阿密湖;阴性对照)制成标准圆盘。将圆盘置于 Transwell 插入物中,与 MC3T3-E1 细胞间接接触。使用 MTT((3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴盐)测定法在 6 周的时间内评估细胞的琥珀酸脱氢酶活性。使用 Wald 统计量和双侧显著性水平 0.05 分析 BC 密封剂和 AH Plus 的细胞毒性曲线拟合的多项式回归模型。使用 50%的细胞存活时间(T(0.5))进行分析。
使用吉尔摩针方法,BC 密封剂至少需要 168 小时才能达到最终凝固,当密封剂中包含水时,其显微硬度显著下降(P =.004)。所有凝固的密封剂在 24 小时时均表现出严重的细胞毒性。AH Plus 的细胞毒性逐渐降低,变得无细胞毒性,而 BC 密封剂在 6 周的时间内仍保持中度细胞毒性。BC 密封剂的 T(0.5)(5.10 周;95%置信区间[CI],4.69-5.42,标准误差[SE] = 0.09)和 AH Plus 的 T(0.5)(0.86 周;95% CI,0.68-1.05;SE = 0.18)之间存在显著差异(P <.001)。
需要进一步研究来评估 BC 密封剂凝固时间的长短与其细胞毒性程度之间的相关性。