Bacteriology & Applied Microbiology

Bacteriology of dental infections

The most common dental diseases, periodontal disease and dental caries, are chronic infections caused by bacteria of normal oral flora. When these bacteria increase in number and irritation exceeds the host defence threshold, disease arises. The human oral flora comprises more than 300 different bacteria. During the last decade approximately 10 species, mainly Gram-negative anaerobes, have been noted as putative pathogens in periodontal disease. The Gram-positive and facultatively anaerobic mutans streptococci are aetiologically the most important bacteria in dental caries. Chronic dental infections have been the focus of renewed interest because of recent advances in oral microbiology as well as in medicine. Oral bacteria may spread into the blood stream through ulcerated epithelium in diseased periodontal pockets and cause transient bacteraemias, which are regarded as increased risk, especially for immunocompromised patients or persons with endoprotheses. In these patients, routine antibiotic prophylaxis is recommended for invasive dental care procedures.