Experimental pulpitis in immunized monkeys

Bovine serum albumin (BSA) was topically applied to exposed dentin to assess whether inflammatory reactions can be induced in the pulp of monkeys immunized against BSA. Four cynomolgus monkeys received repeated injections of BSA emulsified with Freund's incomplete adjuvant. Pulp challenge was performed by applying BSA in freshly cut dentin cavities prepared on the buccal surface in 34 teeth. In 29 control teeth ovalbumin (OVA) was applied. Control applications of BSA were also performed in 15 teeth prepared in three nonimmunized monkeys. Forty-eight hours after the initiation of the pulp challenge the monkeys were sacrificed and the pulp tissue examined in the light microscope. Topical application of BSA to freshly exosed dentin in immunized monkeys resulted in severe inflammatory lesions in the pulp, characterized by bleeding and extravascular infiltration of large numbers of leukocytes. Extensive tissue damage was an important feature in several pulps. Identical applications of OVA in control teeth and BSA applications in nonimmunized monkeys produced no such reactions. The results indicate that interactions between antigens and antibodies can occur within the dentin-pulp area and following the formation of immune-complexes, severe injury to the pulp can be induced.