The oral cavity encompasses a diverse set of ecological niches for microbial populations. For example, yeasts are commonly found on the dorsal tongue surface, as well as other soft tissue surfaces within the oral cavity. Although oral carriage is often asymptomatic in healthy individuals, perturbations in host defenses and other factors such as the usage of broad-spectrum antibiotics may favor the proliferation of these opportunistic pathogens and localized oral mucosal infections.

While oral soft tissues undergo continual epithelial turnover, tooth surfaces are incapable of shedding and provide a unique environment for the buildup of dental plaque. Plaque exists as a biofilm, and its role in dental caries and periodontal disease has been well established. Infections associated with oral microbes, however, are not limited to the oral cavity. The location of plaque on tooth surfaces also presents the potential for microbial access to the periodontal vasculature and systemic circulation, upon disruption of the dentogingival junction. The latter may be caused by daily activities such as tooth brushing, as well as operative dental procedures which involve manipulation of the periodontal tissues. Such oral origins for bacteremia have been associated with end-organ infections. The oral cavity also serves as a major portal of entry for the respiratory tract, and the harboring of oral respiratory pathogens is a prime etiological factor for aspiration pneumonia.

The goal of this special edition is broad and will be to provide a comprehensive collection of research articles documenting recent findings in relation to oral microbiology- from the molecular level to clinical practice, and oral infections-from local to systemic.