Microbes in Endodontic Infections

In 1967, Antony van Leewenhoek, became the first person to describe bacteria from root canals using one of single-lens microscopes.

The true significance of bacteria in endodontic disease was shown in the classic study by Kakehashi et al in 1965. They found that no pathologic changes occurred in the exposed pulps or periradicular tissues in germ-free rats. In conventional animals, however, pulp exposures led to pulpal necrosis and periradicular lesion formation. In contrast, the germ-free rats healed with dentinal bridging regardless of the severity of the pulpal exposure. Thus, the presence or absence of microbial flora was the major determinant for the destruction or healing of exposed rodent pulps.