The cytotoxic effect of cysteamine and its combinations with various endodontic intracanal medications on fibroblast cells: in vitro study

Abstract

Background This study was established to assess cysteamine’s cytotoxic effect alone and in combination with various intracanal medications on fibroblast cells, because the biocompatibility of intracanal medication is considered one of the main factors that affect the selection of specific medication for usage near vital periodontal tissues. Methods All tested medications were prepared in a solution form. Cysteamine preparation was prepared at 200 mg/ml concentration in distilled water. The chlorhexidine–cysteamine combination was prepared by dissolving 10 mg/ml of cysteamine in chlorhexidine. Calcium hydroxide–cysteamine combination was prepared by dissolving 10 mg/mL of cysteamine in a saturated solution of calcium hydroxide (CaOH). Triple antibiotic paste (TAP)–cysteamine combination was prepared by dissolving 10 mg/mL of cysteamine in triple antibiotic paste (TAP). BHK cells were seeded in well-microtiter plates. The testing materials were filtrated using a 0.22 μm syringe filter. BHK-21 cells precultured well plates were treated with descending 12-fold serially diluted medications at 37 °C for 24 h. Residual living cells were treated with 25 μl of MTT dye. MTT was discarded, and then, dimethyl sulfoxide was added as 50 μl/well. The absorbance was conducted at 570 nm. The mean optical density and 50% cell growth inhibition (IC50) were calculated. Cell viability data showed parametric distribution, so they were analyzed using one-way ANOVA followed by Tukey’s post hoc test for intergroup comparisons and repeated measures ANOVA followed by Bonferroni’s post hoc test for intragroup comparisons. The significance level was set at p ≤ 0.05. Results Viability % and IC50 results showed that triple antibiotic paste (TAP)–cysteamine combination had the lowest cytotoxicity level compared to other intracanal combinations followed by cysteamine and the highest cytotoxicity was with chlorhexidine–cysteamine combination. Conclusions Triple antibiotic paste (TAP)–cysteamine combination was the safest drug compared to other drug combinations with cysteamine, so it needs more research to detect its acceptance with stem cells and its effect on defense mechanisms during healing.