Carious vs Sound Dentin

[TXftw]

So I’m almost a year into clinic and I’m still having some difficulty distinguishing dentin with caries from sound dentin. I usually just start with a high speed and once I get rid of the very obvious decay I switch to a slow with a round bur to get what’s left. To check and see if I’ve removed it all I check visually and then I’ll take a explorer and see if the structure feels (not leathery/tachy). Without fail, there’s one faculty member that always says there’s still caries in dentin that appears to me to be completely sound. She doesn’t even use tactile techniques to check, just looks at it and says there’s still decay. I’ve worked with other faculty who usually tell me I got everything. This has made me think I’m missing something and that I don’t know how to distinguish sound from carious dentin. Does anyone have any advice/clinical techniques for telling the difference between the 2??

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[cooliyak]

So I’m almost a year into clinic and I’m still having some difficulty distinguishing dentin with caries from sound dentin. I usually just start with a high speed and once I get rid of the very obvious decay I switch to a slow with a round bur to get what’s left. To check and see if I’ve removed it all I check visually and then I’ll take a explorer and see if the structure feels (not leathery/tachy). Without fail, there’s one faculty member that always says there’s still caries in dentin that appears to me to be completely sound. She doesn’t even use tactile techniques to check, just looks at it and says there’s still decay. I’ve worked with other faculty who usually tell me I got everything. This has made me think I’m missing something and that I don’t know how to distinguish sound from carious dentin. Does anyone have any advice/clinical techniques for telling the difference between the 2??

Your technique sounds right on. There is most likely a misunderstanding (between the professors, not necessarily you) as to what type of dentin is necessary to remove and what is ok to leave.
Infected dentin is something that should be removed completely. This is the leathery, soft, easily scratched w/ an explorer dentin.
Affected dentin is usually considered sound and, depending on where it is in your prep, is something you can leave. This is dentin that is hard to an explorer tip, but has discoloration, usually darker.
As long as all of the infected dentin is gone and the affected is at least 2-3mm away from your DEJ, you should be good. The frustration you are experiencing is the lack of calibration between professors. One is ok with the affected dentin where it is, and the other wants all of the stain (affected dentin) removed no matter what and is not interested in the tactile presentation of your prep. We all go through this and eventually figure out what professor prefers what type of prep. It is a horrible way to teach unless you are explaining yourself along the way, which it sounds like your professors are not doing. You probably aren’t missing as much as you think. I would just ask your professors what their expectations are before you start your prep.

 

[TanMan]

Infected dentin feels like wet leather that you peel off in layers. I don't think that an explorer is sufficient to determine infected/affected dentin, neither is a pure visual examination. I like to use a spoon excavator. If the dentin peels off with the excavator, then it's infected. If you can scrape off the dentin like wax on a candle, then it's affected. If your excavator slides with no sign of anything being scraped off, you're in solid dentin (assuming you are in dentin and not in pulp/enamel). You need to push AND pull your excavator onto the dentin to make sure you are on solid dentin. If you pulled off leather dentin resulting in a pulp exposure, more than likely, you will need endo on the tooth, especially if the tooth is hyperemic, signs of purulent discharge, or overall necrotic pulp (looks like grey boogers).

These are my criteria for dentinal removal. I don't use the slow speed as they create a lot of uncomfortable chatter for the patient and increased heat generation is more likely to cause pulpitis. As @cooliyak mentioned, know what your instructor wants. Passing is more important at this rate, due to the subjectivity of grading.

Always be weary of supernumerary cusps/talon cusps/MB pulp horn and the long axis of the tooth when prepping. The deeper you go, the increased likelyhood of pulpitis. You can always use gluma, selective etch, and/or self etch bonding systems.

 

[cooliyak]

Infected dentin feels like wet leather that you peel off in layers. I don't think that an explorer is sufficient to determine infected/affected dentin, neither is a pure visual examination. I like to use a spoon excavator. If the dentin peels off with the excavator, then it's infected. If you can scrape off the dentin like wax on a candle, then it's affected. If your excavator slides with no sign of anything being scraped off, you're in solid dentin (assuming you are in dentin and not in pulp/enamel). You need to push AND pull your excavator onto the dentin to make sure you are on solid dentin. If you pulled off leather dentin resulting in a pulp exposure, more than likely, you will need endo on the tooth, especially if the tooth is hyperemic, signs of purulent discharge, or overall necrotic pulp (looks like grey boogers).

These are my criteria for dentinal removal. I don't use the slow speed as they create a lot of uncomfortable chatter for the patient and increased heat generation is more likely to cause pulpitis. As @cooliyak mentioned, know what your instructor wants. Passing is more important at this rate, due to the subjectivity of grading.

Always be weary of supernumerary cusps/talon cusps/MB pulp horn and the long axis of the tooth when prepping. The deeper you go, the increased likelyhood of pulpitis. You can always use gluma, selective etch, and/or self etch bonding systems.

Newer techniques based on studies show that you can actually leave caries with pretty high success as long as the DEJ is clean. I was taught that it is better to leave a little under an indirect pulp cap (incomplete caries removal technique) than to plow into the pulp because you are trying to get everything. That is why I believe an explorer is sufficient.

 

[TanMan]

Newer techniques based on studies show that you can actually leave caries with pretty high success as long as the DEJ is clean. I was taught that it is better to leave a little under an indirect pulp cap (incomplete caries removal technique) than to plow into the pulp because you are trying to get everything. That is why I believe an explorer is sufficient.

DPC/IPC's have never been predictable in my hands (predictable meaning 90%+ success rate). I would rather remove all the caries, reassess, and previously warned the patient that it MAY turn into a root canal during or after the procedure. The worst thing you can do is to make an asymptomatic tooth into a symptomatic one, all for the sake of trying to save the pulp. It's bad for the patient and it's bad for business. The patient will most likely be in pain, and it's bad because you have to go back in. You'll be surprised how many patients I get that say they never had problems until they got a filling... and they can't eat/the doctor says that there's nothing wrong with the filling.

I find that wet leathery dentin that results in carious pulp exposure, almost always results in an endo. With affected dentin, not so much, but tends to be more symptomatic to cold.

When presenting to a patient that has extremely deep caries (but not radiographically evident in the pulp chamber (<1mm to pulp and asymptomatic), better to give both options (DPC/IPC). Give the pros and cons and execute accordingly. If they choose endo and you don't have to do an endo, you're a hero. If they choose DPC/IPC w/ fill and it doesn't work, at least you tried. Patients love options.

 

[cooliyak]

DPC/IPC's have never been predictable in my hands (predictable meaning 90%+ success rate). I would rather remove all the caries, reassess, and previously warned the patient that it MAY turn into a root canal during or after the procedure. The worst thing you can do is to make an asymptomatic tooth into a symptomatic one, all for the sake of trying to save the pulp. It's bad for the patient and it's bad for business. The patient will most likely be in pain, and it's bad because you have to go back in. You'll be surprised how many patients I get that say they never had problems until they got a filling... and they can't eat/the doctor says that there's nothing wrong with the filling.

I find that wet leathery dentin that results in carious pulp exposure, almost always results in an endo. With affected dentin, not so much, but tends to be more symptomatic to cold.

Understandable. I’ve had very good success doing pulp caps (both direct and indirect) as well as the incomplete caries removal technique so I will continue doing them. You do what works for you, but studies do support leaving caries when done correctly.

 

[TXftw]

Thank you for all the advice cooliyak and TanMan I really appreciate it!

@TanMan when you describe affected dentin coming off more like candle wax with spoon excavator instrumentation are you describing when it comes off more in more of a grainy consistency instead of in shavings (infected dentin)?

 

[TanMan]

Thank you for all the advice cooliyak and TanMan I really appreciate it!

@TanMan when you describe affected dentin coming off more like candle wax with spoon excavator instrumentation are you describing when it comes off more in more of a grainy consistency instead of in shavings (infected dentin)?

Yes.