Setting Properties and Cytotoxicity Evaluation of a Premixed Bioceramic Root Canal Sealer

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• 作者：Bethany A. Loushine ; DMD^&lowast ; ; Thomas E. Bryan ; BS^&lowast ; ; Stephen W. Looney ; PhD^&dagger ; ; ^&Dagger ; ; Brian M. Gillen ; DDS^&lowast ; ; Robert J. Loushine ; DDS^&lowast ; ; R. Norman Weller ; MS ; DMD^&lowast ; ; David H. Pashley ; DMD ; PhD^§ ; ; Franklin R. Tay ; BDSc (Hons) ; PhD^&lowast ; ; ^{ftay@mcg.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Biocompatibility ; microhardness ; MTT ; premixed calcium silicate-based sealer ; setting time
• 刊名：Journal of Endodontics
• 出版年：2011
• 出版时间：May 2011
• 年：2011
• 卷：37
• 期：5
• 页码：673-677
• 全文大小：252 K

文摘

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).

Methods

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 (m>T_0.5m>) was analyzed using the Wald statistic with a two-tailed significance level of 0.05.

Results

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 (m>Pm> = .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 (m>Pm> < .001) was detected between m>T_0.5m> of BC Sealer (5.10 weeks; 95% confidence interval [CI], 4.69–5.42, standard error [SE] = 0.09) and m>T_0.5m> of AH Plus (0.86 weeks; 95% CI, 0.68–1.05; SE = 0.18).

Conclusions

Further studies are required to evaluate the correlation between the length of setting time of BC Sealer and its degree of cytotoxicity.