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What Causes the Pulp Of the Tooth to Become Infected?

Posted on August 26, 2021

Did you ever wake up on a Sunday morning with a throbbing pain in your mouth? When this occurs we cannot wait to get to our dental office. What is causing the pain? How can I get rid of it? What can I do right now as I wait to get an appointment? In most cases the organic part of the tooth, the pulp has become inflamed and possibly infected.

What is the Pulp?

Pulp is gelatinous, organic material composed of connective tissue, nerves, artery, and vein. It is found in the center of the tooth in a hollow cavity called the pulp chamber. The pulp is surrounded immediately by dentin, which comprises the largest part of the tooth. Enamel, the hardest substance in the body, is the thin outer covering of the tooth, protecting the dentin and the pulp. The pulp produces new dentin and provides sensation to the tooth, hot, cold, sweet, and pressure, and thus protection of this part of our tooth is crucial. Finally, it is the “heart” of the tooth, providing blood to the tooth.

If something such as caries (deep cavity), a fracture, deep crack, trauma (from a fall or blow), periodontal disease, or bruxism (grinding one’s teeth) broaches the sanctity of the pulp chamber two thing will occur:

  1. Inflammation which may be reversible
  2. Infection which necessitates the choice between Root Canal Therapy and Extraction

Reversible Pulpitis (inflammation only)


  1. Pain especially throbbing pain in sync with the heartbeat
  2. Sensitivity to sweet, hot, and cold
  3. Pain on tapping, pressure
  4. Inflammation

The pulp has been overstimulated by a cavity, broken filling, chip, malocclusion, or bruxism. The dentist can easily, non-invasively correct the problem with a bonded filling, occlusal adjustment, or night guard. The symptoms correct themselves in 2-3 days. The pulp chamber has not been violated.

Irreversible Pulpitis (inflammation plus infection)


  1. Same as reversible, plus the following as this is a more severe condition
  2. Fever, chills
  3. Swelling in cheek or on top of the tooth in the gum
  4. Unpleasant taste
  5. Bad breath
  6. Difficulty eating, swallowing
  7. Swollen glands
  8. Painful rash
  9. Trismus (difficulty in opening your mouth)

The pulp chamber has been invaded, bacteria are now causing infection along with inflammation. This condition requires immediate attention. The pulp is dying; this condition is called Pulp Necrosis. Necrosis of the pulp leads to gas and pus formation. This in turn produces swelling and pain (the classic toothache).  The dental specialist (endodontist) must decide between doing Root Canal Therapy and thus saving the tooth or having the tooth extracted. Many times antibiotics and analgesic medications will be used in conjunction with dental treatment.

If NOT treated, complex medical conditions can result:

  • Irreversible pulpitis can lead to a dental abscess
  • A dental abscess can lead to cellulitis (a bacterial infection that affects the inner layers of the skin)
  • Cellulitis can lead to osteomyelitis (a bacterial infection of the bone)
  • Sinusitis
  • Meningitis
  • Brain abscess
  • Ludwig’s angina
  • Pericarditis

How do we diagnose Pulpitis?

  1. Listening to our patient’s symptoms
  2. Clinical exam
    1. Hot/Cold Test (dead pulps cannot feel cold, yet cold make tooth pain feel better, while heat exacerbates the pain)
    2. Tapping test
    3. Electric pulp test
    4. Checking for swelling in surrounding tissues
  3. Radiographic changes (can be seen on Xrays)

When to be Treated

  • First signs of pain, sensitivity, or swelling.
  • Any type of inflammation
  • Sooner rather than later

Prevention of Pulpitis

  1. Twice a year checkup at your dentist for exams, x rays, and cleanings
  2. If notice a problem, come in immediately (a stitch in time saves nine)
  3. Brush 2x daily for two minutes each time with a small, soft brush
  4. Floss once a day, every day before bedtime
  5. Avoid sugar
  6. Wear a nightguard or occlusal guard if you are grinding or playing contact sports

Schedule an Appointment Today

Midtown Endodontist NYC, headed by the acclaimed Dr. Steven Lipner, is here to treat your toothache In the most gentle, conservative, and efficient manner. If you have dental pain we make it go away. Do not hesitate to call; we are here for you. Contact us today at (347) 708-8795.

About Dr. Chiyoon Ahn

Throughout his academic and professional career, Dr. Chiyoon Ahn has excelled in teaching as well as the practical application of his knowledge. He has also found time to participate in numerous community service ventures over the years, including musical therapy for geriatric patients and providing support services for low-income communities.

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