There are many reasons you may feel pain in your tooth. When the pain is due to infection of the tooth pulp and canal, you will need to see an endodontist for root canal therapy.

In order for your dentist to determine whether your pain is from an infected root canal, the dentist will need to perform a variety of tests, beginning with asking you details about your pain. What are you feeling? When did the pain begin? Is there something that may have caused it?

The dentist will also inquire after your general medical and dental history. Information regarding any preexisting conditions, current medications and allergies are all important in determining your diagnosis.

After documenting your medical and dental information, your dentist will perform a clinical examination. He or she will begin by checking for any swelling around your face and neck. The dentist will also examine inside your mouth to check the general condition of the gums, tongue, inner cheeks and roof of your mouth. They will make note of oral hygiene, any previous dental work, the condition of your teeth and look for any swellings.

The dentist may also take radiographs to see if there are any other conditions that may be causing the pain, such as cavities, as well as determining the number and shape of roots of the teeth.

Once the clinical examination is complete, the dentist will select appropriate specialized tests to discover the source of your pain. These tests may include the following:

Sinus Tract and Sinogram

The dentist can examine your sinus tract by taking a sinogram, which is an x-ray examination of the sinus tract. The x-ray is taken after the dentist inserts a product called gutta percha into the opening of the sinus tract. This is not painful and will be done quickly. This allows the dentist to view the condition of the sinus tract, which may be a source to tooth pain.

Palpation

The dentist will be able to check the sensitivity of the gums around the tooth by palpating, or gently massaging the gums over the roots of the tooth or teeth suspected of causing your pain. They will also palpate control teeth, or those that are not suspected of causing pain, as a comparison. The dentist is looking to see which areas cause pain as well as for any swellings.

Percussion

In the percussion test, the dentist is looking to replicate your pain on biting down. They will apply pressure the occlusal, or chewing, surface of the teeth, first with their finger and then with the handle end of an instrument. If you feel no difference on the occlusal surface, the dentist will try again on the buccal, or outer, surface, and then the lingual, or inner, surface of the teeth. This test helps determine the number of teeth where pain is felt.

Mobility

The dentist may then check the mobility, or movement, of the teeth.

This test is performed with two dental mirrors by placing the handle ends on the inner and outer surfaces of the tooth, and gently pressing to see if there is any movement. This will not be an indication of pulpal infection, but will rather indicate if there is an issue with the health of the surrounding bone and gums.

Periodontal Examination

To further examine the health of the gums, the dentist may check the attachment of the gums and surrounding bone to your teeth. They will insert an instrument called a periodontal probe into this space to check the depth. This depth is called the gingival pocket. The deeper this pocket, the more detachment there is between your gums and teeth. The dentist will check this depth at three points in the inner and three points in the outer surfaces of each tooth, noting the depth in your chart. Depending on the type of bone loss, the dentist may be able to determine if it is of a periodontal nature, or if it affects the pulp which is an endodontic issue.

Vitality Tests

If the dentist suspects that the source of the pain is endodontic in nature, they will then perform some tests to determine the vitality of the sensory nerves in the pulp.

The first is a thermal test, which checks for a response to either hot or cold. The dentist will be checking to see if you feel a sensation to the temperature change and for how long it is felt after the stimulus is removed. To do this test, the dentist will need to isolate the tooth with a rubber dam. The dentist will also check surrounding teeth as a comparison.

Another vitality test is called an electric test. To perform this test, the tooth is first isolated with a rubber dam and then dried. With this test an electric current is passed through the tooth in order to test for a response by the nerve fibers in the pulp. This test is performed twice to test for accuracy. This test is also performed on a control tooth to compare the results.

Your dentist may do a test called a laser Doppler flowmetry test. This is a non-invasive method that determines the flow of blood in the pulp. A diode projects an infrared light beam into the tissue to be tested, scattering the light through the pulpal tissue. Depending on whether or not the light frequency shifts the dentist will determine if there is blood flow or if the tissue is static.

The final vitality test the dentist may use is a pulse oximetry test. While not commonly used in a clinical setting, this test is very useful for teeth that have suffered traumatic injury. This test measures the level of oxygen in the blood as well as the pulse rate. Similar to the previous test, this test uses two wavelengths of light, one red and the other infrared, through the area in question. The pulse rate and oxygen level is then read with a sensor that is placed on the other side of the tooth.

Other Tests

Another test that the dentist may perform includes the bite test, where the dentist will apply some pressure to the tips of the tooth with a special instrument. You will be asked to apply a biting pressure while the instrument is in place. Depending on whether or not you feel pain, the dentist can determine if there are any cracks or fractures in the tooth.

Another test is the cavity test where a small hole is drilled into the tooth surface and depending on what you feel; the dentist can determine the health of the nerve tissue in the pulp.

The dentist may also use staining or trans-illumination to check for the presence of cracks or crown fractures, which may cause pain.

The final test that the dentist may use in determining your diagnosis is selective anaesthesia. This is used when it is difficult to isolate the cause of your pain. The dentist will selectively anaesthetize small areas at a time until the pain is eliminated. This will be done one arch at a time until the source of discomfort is found.

Through the use of clinical and radiographic examination and these specialized tests, the dentist will be able to discover if the source of your pain is endodontic in nature and will then be able to create an appropriate treatment plan for you.