Dental Infections



A dental infection is an acute or chronic inflammatory response of the dental pulp (pulpitis) tissue caused by the invasion of bacteria secondary to caries or trauma. Pulpal infection can lead to necrosis of the pulp tissue and cause an abscess (localized collection of pus) to form.

  • Reversible pulpitis is a condition when pulpitis can be reversed such as the placement of a filling in a tooth.
  • Irreversible pulpitis is a condition that cannot be reversed and rather leads to necrosis of the nerve and eventual abscess deposition.


Periapical abscesses account for 47% of all dental-related attendances at pediatric emergency rooms in the United States.

Risk Factors

  • Poor diet (high in sugar)
  • Poor hygiene (visible plaque on teeth)
  • Dental caries
  • Low socioeconomic status
  • Lack of dental home due to access to care


  • Most dental infections are a result of the advancement of dental caries from the enamel, into the dentin, and finally, into the pulp tissue of the tooth.
    • Advancement occurs due to the production of acid by a group of bacteria that metabolize sugar from diet.
    • As more acid is created, the pH of the oral cavity is lowered, which further enhances the cycle.
    • Demineralization of the tooth layers occurs. As the caries process progresses, the bacteria then invade the pulp where an inflammatory response is initiated.
    • Necrosis of the pulp tissue occurs and forms an abscess at the apex of the root, resulting in bone destruction.
  • Depending on host factors, infection may remain localized and drain through a sinus tract or may spread into the marrow, perforate the cortical plate, and invade surrounding tissues and facial planes.
  • Typically, once full necrosis of the nerve has occurred, the pain subsides, and abscess formation is present.
    • This situation is particularly dangerous because the abscess can remain localized at the apex of the tooth or proceed between muscles, arteries, and veins into fascial spaces and cause significant and potentially life-threatening problems.
    • However, most are self-limiting and establish intraoral localized drainage.

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