Bacterial Invasion of Non-vital Dentin

¹ University of Otago Dental School, Dunedin, New Zealand

An experiment was designed to test the ability of bacteria to invade odontoblastic processes of non-vital dentin when it was exposed to the mouth. Crowns of freshly extracted premolars from which the occlusal enamel and pulps had been removed were worn in the mouth for varying periods. Subsequent examination of Gram-stained sections revealed that, in the brief period of 3 weeks, bacteria had invaded odontoblastic processes and reached the pulp chamber.

The conclusion was reached, therefore, that if odontoblastic processes succumb following death of the pulp or peripheral injury and are exposed to the mouth, they are liable to invasion by bacteria present. This conclusion is discussed in relation to (1) the presence of bacteria in advance of decalcification under a carious lesion; (2) infection of pulps of teeth which die following a blow; and (3) odontoblastic processes injured by operative procedures and subsequently exposed to bacteria.