Microbiologic and pathologic aspects of endodontics.

Oral microorganisms, either directly or indirectly, produce the majority of cases of pulpal and periapical disease. Because microorganisms play such an important role in the pathogenesis of pulpal and periapical disease, a fundamental understanding of the disease process is important. Culture studies have identified infections of endodontic origin as being polymicrobial and predominantly anaerobic. Although several species of bacteria have been associated with infections of endodontic origin, there is no absolute correlation with signs and symptoms. The use of immunologic studies in addition to traditional microbiologic studies provides a better understanding of the mechanisms involved in the pathogenesis of pulpal and periapical disease.