Migration of a Streptococcus sanguis strain through the root dentinal tubules.

The persistent presence of bacteria in the root canal system often leads to the failure of treatment. The aim of this study was to study the in vitro penetration of root dentinal tubules by bacteria. Bovine dentin was inoculated with a strain of Streptococcus sanguis, NCTC 7863; samples were taken at 10, 20, and 28 days, and bacterial penetration of the tubules was demonstrated using two techniques, scanning electron microscopy and light microscopy after Brown and Brenn staining. The results showed that S. sanguis can penetrate deep inside the tubules (792 microns). The maturity of the dentin blocks seems to be a major factor in tubule penetration.