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Periapical tissue infections

author icon By Dr. George Ghidrai

Pulp infections that are not properly treated will spread in the periapical tissue, causing an acute or chronic infection.

Apical periodontitis (also termed periapical periodontitis) is an acute or chronic inflammatory lesion around the apex of a tooth root, which is caused by bacterial invasion of the pulp of the tooth.

  1. Acute apical periodontitis

    Periapical periodontitis may develop into a periapical abscess (also known as dental abscess), where a collection of pus forms at the end of the root, the consequence of spread of infection from the tooth pulp (which is often already dead).

    acute apical periodontitis : dental abscess

    dental abscess

    Signs and symptoms

    Symptoms from a dental abscess may range from light discomfort in the localized area to severe pain. Putting pressure or warmth on the tooth may induce extreme pain. The area may be sensitive to touch and it is normally swollen.

    An acute abscess may be painless but still have a swelling present on the gum.


    Successful treatment of a dental abscess centres on the reduction and elimination of the offending organisms. This can include treatment with antibiotics and/or drainage.

    If the tooth can be restored, root canal therapy can be performed. If not, tooth must be extracted, followed by curettage of all apical infected soft tissue.

    more about tooth abscess

  2. Chronic apical periodontitis

    Chronic apical lesions develop over time around the apex of a tooth's root. They are caused by pulp infections (and/or necrosis) that release toxins at the apex of the tooth leading to periapical inflammation.

    Chronic infections are normally asymptomatic (they do not cause any pain), but a secondary infection can cause pain. Two of the most common chronic lesions are the periapical cyst (or dental cyst) and the apical granuloma (also termed radicular granuloma).

    On radiographs, they appear as radiolucency areas (dark areas) of various sizes around the apex of teeth's root.

    chronic apical periodontitis : dental cyst and apical granuloma


    The treatment approach can range from a conservative treatment (endodontic therapy) to extraction of the tooth.

    1. Root canal therapy

      Peripheral lesions including radicular cysts or apical granulomas are eliminated by body once the causative agents are removed. Majority of the lesions can undergo resolutions following root canal treatment and thus do not require surgical intervention.

      In this case, the endodontic treatment may take more time (4 to 8 weeks) depending on how long it will take for the tooth to heal.

    2. Apical resection

      The apical resection (or apicoectomy) is a surgical procedure through which both the top of the tooth root and the surrounding infected tissues are removed.

      The apical resection is indicated only after failure of non-surgical endodontic treatment and/or retreatment and when tooth stability inside the bone is still good.

      apicoectomy procedure apicoectomy procedure apicoectomy procedure

      apicoectomy procedure

    3. Extraction

      When coronal damage is advanced or tooth stability lacks because of bone loss around the tooth's root, the best option is the extraction of the tooth followed by curettage of all apical infected tissues.

Last review and update: November 2020

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