Bacterial penetration of human dentin in vitro.

The ability of bacteria to penetrate acid-etched and unetched human dentin was examined in vitro using a split chamber. Results indicate that bacteria can grow through or be filtered by pressure through acid-etched dentin. Unetched dentin, while permitting fluid filtration, restricts bacterial penetration. Penetration of dentin tubules by bacteria reduces the rate of fluid filtration across dentin.