ABSTRACT
Aims: To determine the cytokine expression by human gingival fibroblasts in response to different calcium hydroxide (Ca(OH)2) dilutions and test the effectiveness of these dilutions in root canal dentin infected with Enterococcus faecalis (E. faecalis). Methods: UltraCal XS Ca(OH)2 dilutions were prepared (60, 10, and 1 mg\mL) and co?cultured with gingival fibroblasts for 24 and 48 hours. Untreated cells were used as controls. Expressions of interleukin (IL?1?), tumour necrosis factor alpha (TNF??), transforming growth factor beta (TGF??), and IL?10 were analysed with real?time polymerase chain reaction (PCR). Root canals of extracted human teeth were inoculated with E. faecalis. After 21 days, canals were medicated with Ca(OH)2 dilutions for 7 days. Samples were taken to determine bacterial reduction using quantitative PCR. Analysis of variance, Tukey post?test, and Wilcoxon matched pair test were used for statistics. Results: IL?1? and TNF?? expressions of all Ca(OH)2 dilutions were higher at 24 and 48 hours compared to the control. Similarly, all Ca(OH)2 dilutions induced TGF?? expression at 24 hours compared to the control and continued to be higher in 60 mg/mL groups at 48 hours. In contrast, IL?10 was constitutively expressed by untreated cells in the control group and was down?regulated significantly by all Ca(OH)2 dilutions at 24 and 48 hours. All dilutions demonstrated a significant E. faecalis reduction (P < 0.001) with no significant difference between dilution groups (P > 0.05). Conclusions: All Ca(OH)2 dilutions had a differential inflammatory effect on fibroblasts and had a down?regulation effect to IL?10. All dilutions tested were effective against E. faecalis, with 60 mg/mL having the highest bacterial reduction