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Pulpitis is the inflammation of dental pulp tissue. It may be caused by a dental caries that penetrate through the enamel and dentin to reach the pulp, but can also be due to other insults. Pulpitis can be divided into two distinct groups: reversible pulpitis and irreversible pulpitis

Dental pulp infections

author icon By Dr. George Ghidrai

Pulpitis is the inflammation of dental pulp tissue. The clinical examination and imaging methods (dental X-rays) will enable the practitioner to determine the diagnosis.

Pulpitis may be caused by dental caries that penetrate through the enamel and dentin to reach the pulp, but can also be due to other insults (such as thermal insults from repeated dental procedures, repetitive trauma etc.)

Pulpitis can be divided into two distinct groups:

  1. Reversible pulpitis

    Reversible (or transitory) pulpitis is the condition where the pulp is (only) inflamed because it is actively responding to an irritant.

    Most often, the irritants are bacteria from a carious lesion that has not reached the pulp (image below). Other types of irritants can be very hot agents (for example from repeated dental procedures), harmful chemical agents etc.

    reversible pulpitis

    Signs and symptoms

    Symptoms include transient pain or sensitivity resulting from various stimuli: hot, cold, sweet, water and touch.

    Inside the pulp, the inflammation is not as pronounced as with irreversible pulpitis, and less damage to the pulp tissues (if any) has occurred.


    Because the pulp is not infected and is still vital, once the irritant is eliminated, usually by removal of decay and the placement of a restoration, the pulp will normally return to its healthy state.

    This means that root canal therapy is not necessary. However, it is advisable to place pulp-capping agents (for example calcium hydroxide) on the floor of the prepared cavity to stimulate pulp tissue healing.

  2. Irreversible pulpitis

    Irreversible pulpitis is a condition where the pulp is irreversibly damaged. Most often, the decay that has reached the pulp of the tooth introduces bacteria into the pulp (image below).

    irreversible pulpitis

    The pulp tissue is still alive, but the introduction of bacteria into the pulp will not allow the pulp to heal and it will ultimately result in necrosis, or death, of the pulp tissue.

    Signs and symptoms

    Symptoms associated with irreversible pulpitis may include aching pain, prolonged sensitivity to cold and/or heat, and sometimes to sweets, lingering pain after removal of a stimulus, spontaneous pain, or referred pain.

    Clinical signs may include reduced response when the vitality of the tooth is tested and painful response to thermal stimuli.


    The pulp of a tooth with irreversible pulpitis may not be left alone to heal. Because the pulp is infected and irreversibly damaged, a root canal therapy (whereby the pulp is totally removed and replaced by a root canal filling) is required.

    An alternative is the extraction of the tooth. This may be required if there is insufficient coronal tissue remaining for restoration once the root canal therapy has been completed.


Pulp infections that are not properly treated will spread through the apical foramen from the pulp to the periapical tissue, which is located around the apex of the tooth's root.

The inflammation of the periapical tissue that is caused by bacterial invasion from the dental pulp is called apical periodontitis.

Last review and update: November 2020

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