Often times, diagnosis of a root canal problem is relatively straightforward and we can know with certainty that a root canal is recommended to save a tooth. However, there are times when just figuring out the problem can be the trickiest part of treatment. There can be other oral conditions that may mimic a root canal toothache or there can be complicating factors associated with a tooth that may affect the overall prognosis of the tooth. We will perform tests as needed to help with diagnosis and discuss any concerns prior to rendering treatment. Tests may include: tapping on the teeth, palpating the teeth or gum tissue, using cold (or hot) on the teeth, using an electric pulp tester (EPT), bite testing on the teeth. X-Rays are also important aids to help visualize any problems with the teeth or changes in the surrounding jaw bone.
Below is a general classification of the stages of root canal health but not all teeth follow these guidelines. Diagnosis difficulty can occur because every tooth and patient is different and sometimes pain symptoms do not present in a typical manner.
There should be no tapping pain or pain to touch/push on the tooth. The tooth should feel a cold response, but it should not really be painful and it should only last a few seconds before returning to normal. The tooth should also feel an electrical stimulus (slight sting or tingling) with the EPT tester.
As a cavity starts to get deeper into a tooth, or sometimes when there is exposed dentin or gum recession, the tooth can develop sensitivity to temperature (especially cold) or sometimes sweet or acidic foods/liquids. Teeth can also become temporarily sensitive after fillings are placed. If the cold sensitivity is sharp but goes away quickly (within several seconds) it means that there may be some slight inflammation starting within the pulp but the pulp tissue may still have the ability to heal on its own at this point. The cells that line the pulp space and grow dentin (tooth structure) can be triggered into growing new layers of dentin in the area of irritation. This is the tooth’s way of insulating the pulp from the irritation. In most cases if a deep cavity is restored, or sensitivity toothpaste is used to seal the exposed root, the sensitivity may resolve on its own. This happens more predictably in teeth with larger pulp spaces which have better blood supplies to the pulp tissue. As we age, the pulp space in the teeth tends to calcify or shrink over time, so this natural healing response may not work as well in adults compared to children or teenagers. If the sensitivity in a tooth starts to worsen, then it may be a sign that a root canal is needed.
If inflammation or irritation to the nerve gets more severe then what the pulp can tolerate and heal from on its own, then root canal treatment may be required to remove the inflamed pulp tissue. Signs of irreversible (no longer healable) inflammation may include: cold pain that lingers for longer than normal or makes the tooth ache continuously, spontaneous aching/throbbing (especially at night), tapping or biting pain on the tooth (due to inflammation now spreading out of the tooth into the surrounding bone). Once the inflammation has spread to the jaw bone, there may also be changes on an X-ray that can help localize the problem. As the pulp inflammation continues to worsens, the blood supply in the pulp becomes compromised and the tissue can then start to die. Root canal treatment is required to remove the inflamed pulp tissue from the tooth and prevent infection from occurring. Once the blood supply to the inside of the tooth is lost, then bacteria can infect the canal space.
A necrotic pulp means that some or all of the pulp tissue is “dead” due to the loss of blood supply to the tissue. Once pulp death occurs, the blood supply is no longer providing a protective immune response to the space inside the tooth. If there any bacteria present due to a cavity, crack in the tooth, or leaking filling/crown, then bacteria can then live freely within the root canal space and cause infection to spread to the supporting jaw bone.
Signs of pulp necrosis may include: lack of any cold response (especially when there had been previous cold pain), swelling or draining infection around a tooth, tapping or biting pain, further changes on an X-ray showing bone degradation around the tip of the root(s). Root canals are also used to treat and retain infected teeth. After disinfecting the hollow canal spaces inside the roots and sealing them with the root canal filling material, the body can typically heal the area of infection in the bone around the root tip and new bone will grow back over time. In larger or more chronic infections, it may be difficult for the bone to completely heal on its own and in a minority of cases, further surgical treatment may be required to treat the tip of the root and remove the infection. (see Apical Surgery section for more details).
Sometimes teeth develop fractures that cause pulpal inflammation and then require root canal treatment. Back teeth, especially the bottom molars, are prone to developing fractures. In general, the shallower the fracture the better the prognosis. If the fracture line does not extend below the gum line of the tooth, a crown can be placed to contain the fracture and the prognosis is usually pretty good for at least several more years. Long-term prognosis (10+ years) can be unpredictable because even though crowns greatly reduce the risk of the fracture growing, the crack can occasionally worsen over time under the repeated stress of chewing. This is especially true if a person grinds their teeth, chews ice, or does anything else to beat the teeth up more than usual. If a fracture is extending slightly onto the root surface, the prognosis is more unpredictable but occasionally attempting the root canal and crown may be indicated depending on individual circumstances. If the fracture is already extending significantly down the root surface or along the entire root, prognosis is poor and extraction typically the best option. If a fracture is seen or suspected, we will evaluate the extent of the fracture and talk to you about prognosis and options before deciding the best course of treatment to meet your goals.
There are several types of resorption that can affect teeth and root canal intervention may or may not be required depending on the type and location of the resorption. Resorption is not decay, but it is a pathological process that causes degradation of the tooth structure. Resorption can occur on the external root surface, or along the walls of the root canal space inside the tooth. Resorption can be a tricky condition to deal with, so if encountered, we will evaluate the extent and location of the resorption and discuss all options and prognosis before making a treatment decision.