Intra-tubular desinfection of bovine teeth contamined with calcium hydroxide pastes associated with different vehicles

Biomechanical preparation followed by irrigation in endodontic treatment of infected root canals has been shown, however, some micro-organisms still survive. The most frequently founded bacterial specie in endodontic treatment fail is Enterococcus faecalis. To combat it, different intra-canal medications are used, mainly the calcium hydroxide pastes and other substances have been associated to calcium hydroxide to leverage it antimicrobial effect. Thus, its relevant to compare in vitro the antimicrobial ability of calcium hydroxide with different vehicles and additives, against Enterococcus faecalis, through microbiological culture and confocal laser scanning microscopy (CLSM). For this, standard dentine tubes were sterilized and then infected with the bacteria for 5 days and were divided in five test-groups, submitted to medication for 15 days with calcium hydroxide paste in distilled water (G1), in propylene glycol (G2), besides clacium hydroxide in propylene glycol with ethanol extract of propolis (G3), chlorexidine (G4) and CPMC (G5). After the medication period, the bacterial collection of the dentine´s fragments was done with Largos drill in a sterilized device, to count micro-organisms still viable in colony forming units. The CLSM evaluated the viable (green) and dead (red) bacteria inside the dentinal tubules with the aid of the Live and Dead® dye. There was dentinal intra-tubular antimicrobial action against Enterococcus faecalis for all the tested calcium hydroxide pastes. From this work was possible to observe a better antimicrobial activity against Enterococcus faecalis by the calcium hydroxide paste in propylene glycol and CPMC in superficial and deep areas of the dentine. (AU)