Cytokine expression and anti-microbial effectiveness of different calcium hydroxide dilutions: An In Vitro study

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).

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-1β), tumour necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), 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.

IL-1β and TNF-α 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-β 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).

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.