Oral infections can be odontogenic or nonodontogenic in origin. Odontogenic infections are most prevalent and include dental caries, periodontal disease, and suppurative deep space infections. Nonodontogenic infections include sialadenitis and parotitis, vesiculobullous gingivostomatitis, aphthous ulcers, oropharyngeal candidiasis, and severe oral mucositis in the immunocompromised host. Clinical presentations can be variable. An understanding of the underlying anatomic structures, the oral microflora, and associated medical conditions of the host is critical to guide appropriate diagnosis and management. In this paper, preventative strategies to reduce dental plaque formation and promote oral health are emphasized.