Sevbitov A.V., Kuznetsova M.Y., Bogdanova E.A., Kozhokar A.S., Bratus A.E.

I.M. Sechenov First Moscow State Medical University, Russia

The research on antiseptic effectiveness of irrigants for root canals

Numerous researches which had been held showed that treating root canals with tools decreased the quantity of bacteria. However it is impossible to clear up all the anatomical structures (such as isthmus, delta, lateral canal) and up to one third of the root canal surface is impossible to be cleaned up at all. So, in order to reduce the risk of complications the chemical disinfection is used. Irrigative solutions, which are used for disinfection, provide removal of decayed pulp tissue, bacteria and its toxins, smear layer (formed during preparation) and dentinal cuttings.

The aim of the research is to study the antiseptic effectiveness of irrigants for root canals through finding out the minimum of inhibitory concentration.

Tools and methods. In order to determine the antiseptic effectiveness, bacteria (Staphylococeusaureus, Micrococusluteus, Escherichia coli, Enterococcus faecium, Enterococcus fecalis, yeast-like fungi Candida albicans) which represent residential microflora of mouth cavity were studied in vitro. Then the irrigative agents were incubated on the growth medium: NaOCL solution 3,25%, Parcan, Hypoclen, Chlorhexidine 2%, Guaiafen, Camphophene, Endo Gj№3 with/without dilution 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, 1:128, 1:200. The incubation lasted for 3 days under the temperature of 37⁰C. The results of the antibacterial effect of irrigants have been checked for at least 3 times.

The results of the research. Such results were obtained during the research for the influence of irrigants on the culture medium with Staphylococcusaureus: Hypoclean is still effective at a concentration of 1:128, Guaiafen, Camphorphene and Chlorhexidine 2% have the minimal inhibitory concentration of 1:16, NaOCl 3.25% and Endo Gi №3 have the minimal inhibitory concentration of 1:2, and Parcan is not detrimental for S.aureus even if it is slightly diluted.

The research for the influence of irrigants on the culture medium with Micrococus luteus showed that Hypoclean resulted into being the most effective solution, its minimal inhibitory concentration was 1:400. The minimal inhibitory concentration for Chlorhexidine 2% was 1:200, Guaiafen was the next in a row for reduction of antimicrobial activity with the minimal inhibitory concentration of 1:64. Parcan, NaOCl 3.25% and Endo Gi №3 had the same level of efficiency with the minimal inhibitory concentration of 1:16. Camphorphene turned out to be the less effective for this kind of microorganism, its minimal inhibitory concentration was 1:8.

We obtained results during the research on the culture medium with Escherta coli: the minimal inhibitory concentration of NaOCl 3.25%, Camphorphene and Endo Gi №3 reduced significantly to the level of 1:8. Hypoclean and Chlorhexidine 2% were effective at the most considerable dilution. Guaiafen was the most effective against E.coli, its minimal inhibitory concentration was 1:128.

There was also a study of the effectiveness of selected irrigation solutions against Enterococcus faecium and Enterococcus fecalis in vitro. This research has shown that these microorganisms irrigation solutions are about the same. Hypoclean still has the highest antiseptic activity, its minimal inhibitory concentration is 1:128. Parcan, NaOCl 3.25%, the solution of Guaiafen and Chlorhexidine are a bit less effective and kill only 20% of microorganisms when diluted as 1:16, and Camphorphene and Endo Gi №3 as 1:8.

The next step in our research was the study of the effects of the chosen irrigants on Candida albicans. NaOCl 3.25% kills the fungi; its minimal inhibitory concentration is 1:32, a bit less than that of the majority of the other medications (the minimal inhibitory concentration of Parcan, Hypoclean, Chlorhexidine, Guaiafen, Camphorphene is 1:64). The antifungal efficiency of Endo Gi №3 is a bit less: diluted as 1:8, the medication only killed 20% of the microorganisms.

All the test medications caused the blood hemolysis. After the irrigant solution Hypoclean with the highest antiseptic activity gets into blood, hemoglobulin fully dissolves, red blood cells shrink and precipitate in the form of light brown sediment. The most sparing medication for blood proved to be Chlorhexidine. After it was added to blood, hemolysis took place, but the blood consistency did not change, thus this sample is the least cytotoxic.

Conclusion. Consequently, the revealed highest minimal inhibitory concentration of Hypoclean and Chlorhexidine 2% allows us to assume that, not diluted, these medications will kill a greater variety of microorganisms as well as act better in obliterated root canals compared to their analogs.