In general, a nonpathologic resident bacterium gains entry when the host's defenses are breached, rather than when a nontypical microorganism is introduced. The predominant species associated with dental abscess include Bacteroides, Fusobacterium, Actinomyces, Peptococcus, Peptostreptococcus, and Porphyromonas, as well as Prevotella oralis, Prevotella melaninogenica, and Streptococcus viridans. Beta-lactamase producing organisms occur in approximately one third of dental abscesses. Although lactobacilli are not primary causes, they are progressive agents of caries because of their great acid-producing capacity.
The term "dentoalveolar abscess" comprises three distinct processes, as follows:
A periapical abscess that originates in the dental pulp and is usually secondary to dental caries is the most common dental abscess in children. Dental caries erode the protective layers of the tooth (ie, enamel, dentin) and allow bacteria to invade the pulp, producing a pulpitis. Pulpitis can progress to necrosis, with bacterial invasion of the alveolar bone, causing an abscess.
A periodontal abscess involves the supporting structures of the teeth (periodontal ligaments, alveolar bone). This is the most common dental abscess in adults, but may occur in children with impaction of a foreign body in the gingiva.
"Pericoronitis" describes the infection of the gum flap (operculum) that overlies a partially erupted or impacted third molar.
Odontogenic infections are polymicrobial, with an average of 4-6 different causative bacteria. The dominant isolates are strictly anaerobic gram-negative rods and gram-positive cocci, in addition to facultative and microaerophilic streptococci. Anaerobic bacteria outnumber aerobes 2-3:1. In general, strictly anaerobic gram-negative rods are more pathogenic than facultative or strictly anaerobic gram-positive cocci.
For more on the etiology of dental disease, read here.
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Cite this: Jeff Burgess. Fast Five Quiz: What Do You Know About Dental Health? - Medscape - Oct 16, 2017.