Cytotoxicity of set polymer nanocomposite resin root-end filling materials

AIM

To evaluate the cytotoxicity of two forms of the novel root-end filling materials, polymer nanocomposite (PNC) resins [C-18 Amine montmorillonate (MMT) and VODAC MMT] both containing Chlorhexidine Diacetate Salt Hydrate 2%, and to compare it to that of two widely accepted commercially available materials, ProRoot® MTA and Geristore®.

METHODOLOGY

Elutes of experimental materials extracted after 24 h, 1, 2 and 3 weeks were interacted with the mouse fibroblasts L-929 using a colorimetric cell viability assay (MTS) based on mitochondrial dehydrogenases activity. Using 100% and 50% concentrations of the extracted elutes of the experimental materials the effect of different concentrations of elutes on the cells was analysed. In the positive control group Hygrogold® was added to the cell culture to arrest cells bioactivity. In the negative control group, fresh Dulbecco's Eagle's minimum essential medium supplemented with 10% foetal bovine serum was used to enhance cell bioactivity. Differences in mean bioactivity values were assessed using a t-test and one-way anova (P<0.05).

RESULTS

No significant difference was found in cytotoxicity between ProRoot® MTA, Geristore® and PNC resin C-18 Amine MMT on 24 h, 1, 2 and 3 weeks samples. Sample elutes of PNC resin VODAC MMT, however, revealed cytotoxic activity during most of these experiments.

CONCLUSION

Cytotoxicity of the elutes of PNC resin C-18 Amine MMT was not significantly different from that of ProRoot® and Geristore®. PNC resin VODAC MMT, revealed significantly more cytotoxicity compared to the other tested materials.

Growth inhibition of Streptococcus anginosus (milleri) by three calcium hydroxide sealers and one zinc oxide-eugenol sealer

The inhibition of growth of Streptococcus anginosus (milleri) by three calcium hydroxide sealers--calciobiotic root canal sealer (Hygienic Corporation, Akron, OH), Sealapex (Kerr Division, Sybron Corporation, Romulus, MI), and Apexit (Vivadent, USA, Amherst, NY)--was compared with a zinc oxide-eugenol sealer: Roth (Roth International, Chicago, IL). Sixteen brain heart infusion agar plates were inoculated with S. anginosus. Each plate was divided into five separate areas. In each area, a 0.1 ml droplet of a given sealer was placed such that each plate had five areas with the same sealer. There were four plates (for each of the four sealers) for a total of 20 observation areas to evaluate each sealer. The plates were incubated at 37 degrees C in a 5% CO2 atmosphere. After varying periods of incubation, the zones of inhibition of bacterial growth were observed and measured. Roth sealer had a statistically significant larger mean zone of inhibition than the calcium hydroxide sealers. However, all of the sealers exhibited clinically relevant antimicrobial activity. It is likely that the eugenol in the Roth sealer is responsible for its greater antimicrobial activity.