How to diagnose tooth vitality for teeth with deep decay
Diagnosing vitality of teeth
First, get the X-rays you need.
X-rays
Ideally, you would get a periapical X-ray of the tooth and also get some bite wings. That way you can see the root of the tooth in question, but you can also see the rest of the teeth around the mouth.
Patient history
Second thing is getting the patient history.
When you look at that deep cavity, are there symptoms? Ask the patient:
- Have you had any pain with this tooth?
- If so, what triggers the symptoms- is it sensitive to hot or cold?
- Does biting pressure trigger it?
- Is there any spontaneous pain that can wake you up at night and you feel it hurting?
- Have you taken any medications for it? If so, what have you taken?
- Have you taken anything today that might affect how the tooth responds to testing it?
- Have you had any recent colds or sinus congestion?
- Has there been any recent dental work? If there has been a recent filling, then it’s important to know when the dental work was done to the symptomatic tooth. But if you’re just looking at the x-ray and see a deep cavity, this may not be a factor.
- Have there been any signs of swelling that would help give us an indication of how the decay is affecting the nerve of the tooth?
It’s nice to test the teeth using various modalities to gather more information. Use percussion tests, thermal cold tests, tooth slooth to check for cracks if needed, periodontal probe if signs of a periodontal abscess. Look for wearfacets on the teeth or ask about a
history of bruxism. There also electronic pulp testing units that can be used. Sometimes a hurts percha can be placed in a fistula and an xray taken to trace the origen.
We need to gather data and then use a flow chart to aid diagnosis and treatment planning.
If there’s no decay and no other symptoms besides a sharp quick pain to biting pressure, it may just be a crack. But if someone says that the cold is triggering pain, then there could be some recession and sensitivity on the exposed root of the tooth. There also could be some deep decay that sensitive to cold. And spontaneous pain is often something more serious affecting the nerve in the tooth.
If the tooth hurts all by itself, it may be a necrotic pulp or a tooth with irreversible pulpitis. It could also be pain from things like grinding your teeth or in your sleep. Or a sinus infection could make upper molars ache.
After gathering reported symptoms and triggers from the patient, it’s time to test the teeth.
Testing the teeth
Percussion testing
You’ll want to see if the tooth responds normally or if it’s sensitive.
If it’s sensitive, it could indicate that a root canal is needed or could be related to bruxism.
Or could be close to another tooth that’s also sore. It’s good to put the results together in context with the other information.
If the percussion sensitive tooth is a little mobile, there could be loss of bone around the tooth because of an abscess and some swelling.
Or there could be a traumatic occlusion making the tooth sensitive and mobile.Generally, if the tooth doesn’t have a cavity or even a filling, but is sensitive and mobile- there could be an occlusion or periodontal factor.
It’s a good idea to check the percussion response and then record the results of several teeth in the notes to compare them all. Document results for the teeth adjacent as well as the tooth in question.
To do a percussion test, tap the back end of the handle of the mirror on several teeth and percussion normal should be no symptoms for the patient. If the patient feels sensitive or it feels different than the others- it’s a percussion positive test result.
Cold Test
Next do a cold test. Spray endo ice cold spray on a piece of cotton, and then place it on the tooth for several seconds until the patient responds.
If there’s no response, it could mean that the nerve is necrotic and has died, but it doesn’t mean that automatically, some teeth just aren’t that sensitive.
If the tooth was percussion sensitive and had no cold response, it could be a necrotic tooth, especially if the other teeth felt cold and had signs of vitality.
If the tooth is able to feel the cold, generally there’s some vitality in the tooth. And if the cold resolves itself quickly, that’s a normal response.
But if that cold lingers for five, 10 seconds or more, it could be a sign of irreversible pulpitis.
Diagnosis of the nerve and indications for root canal treatment
First, start with the diagnosis and the results of testing the teeth. Compare the results to a flowchart. Realize some answers may be inconsistent, but work through the steps to make the diagnosis. Determine your diagnosis and document it.
If the pulp is normal, it likely has a normal response to cold, possible mild discomfort that recovers quickly.
If the nerve has reversible pulpitis, there may be pain to the cold initially, but then it goes away pretty quickly.
Sometimes there is a crack in a tooth cusp that needs a crown but not necessarily a root canal. If the tooth has no decay and is vital as shown by a normal cold and normal percussion test, but maybe when you bite something hard it’s sensitive, then you could
demonstrate which cusp is sensitive by using the tooth slooth. Place the tooth slooth on various cusp tips and bite and if there is a sharp quick pain, especially when releasing the biting pressure- there may be a cusp crack pinching the nerve during chewing.
If there’s a crack in a tooth cusp, adjusting the occlusion so the cusp is out of occlusion helpful for the short term, but we could also try a temporary crown. If symptoms resolve, we may not need the root canal, but it’s important to inform the patient the root canal may be needed later depending how it responds to the crack.
When the patient may need a root canal
Irreversible pulpitis (from deep decay or a previously deeply filled tooth) may have prolonged pain after the cold stimulus. After the cold is placed on the tooth, the pain lingers. There also could possibly be some heat sensitivity indicating that the nerve’s not likely to recover and that we need to do a root canal treatment.
The necrotic pulp, may have no cold response and may or may not have response to heat, could be percussion sensitive, and could indicate that the pulp has died and the tooth may need a root canal. This is most apparent when adjacent teeth are cold normal and
percussion normal, or if a periapical lesion is spotted on the xray of the necrotic tooth.
And symptomatic apical periodontitis means that there’s pain on percussion or palpation, and also possible evidence of periapical pathology on the radiograph that may suggest the need for endodontic treatment.
If there’s swelling or drainage from the root, or we might see a crack in the root, or there may be just an abscess from the root and the tooth has no cold response, this can indicate a necrotic tooth that needs a root canal.
If the tooth is percussion sensitive and the cold lingers a long while after being applied, especially if there’s also reports of spontaneous pain at home from the tooth associated with it, this may be irreversible pulpitis.
We need to plan for the root canal when the tooth nerve is necrotic or has irreversible pulpitis.
When the X-ray shows a radiolucency and the tooth doesn’t feel cold, then probably we’re going to need a root canal.
Explaining the treatment options to the patient
The next thing is having conversations with the patient. If a root canal is indicated, explain to the patient when the nerve is dead or dying, a filling is not going to help.
You need to treat the nerve with a root canal and then a crown, or we need to extract the tooth.
If there’s a crack in the tooth, you could explain that when the crack flexes, when biting, you can try a crown, to hold and support and hold the cusp and tooth together to try to keep that crack from pinching the nerve and getting worse- but we still may need endo in the future.
The crown alone may help, but if the nerve’s inflamed, it is possible the nerve might require a root canal in the future.
There are opportunities to try a filling for teeth with deep decay that have vital nerves and no symptoms.
If the tooth has no symptoms, it’s percussion normal, it’s cold normal, and cold sensitivity doesn’t linger and there is no spontaneous pain- we can try a filling when there is deep decay when the tooth is completely asymptomatic. But you can see and show the patient on the X-ray, it has a deep cavity and it needs treatment. You need to tell the patient that this tooth is currently alive and no symptoms.
We can try the filling, but there’s a chance it might need a root canal in the future.
Document in the notes the discussion with the patient about a possible need for a root canal after the deep filling.
Trauma can create the need for a root canal and also a deep cavity may have bacteria already affecting the nerve. The cavity may go deeper than it appears on the X-ray, and you can see the x-ray, how close decay is to the nerve.
If untreated, we expect the decay will progress and get worse, and more than likely, we will need a root canal in the future.
The only way to be sure that you’re not going to have any symptoms after the treatment is to do the root canal.
But in the case of having an asymptomatic, vital tooth, you can try the filling first because the tooth does seem to be alive without any symptoms, but it’s important to know and explain that even though this tooth hasn’t been hurting, it could hurt after the filling, and so that if it does start to hurt later, we’ve got a plan.
We will know what we need to do, we can use the root canal to help treat the symptoms. Or extract the tooth.
And so document that conversation in the notes so that we know that the patient has the right expectations. And then later we’ll talk about how to treat that deep cavity.
The AAE has a nice summary for pulp diagnosis at the link below:
https://www.aae.org/specialty/wpcontent/uploads/sites/2/2017/07/endodonticdiagnosisfall2013.pdf