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Ask Dr. Michael Salkin Your Own Question
Dr. Michael Salkin
Dr. Michael Salkin, Veterinarian
Category: Cat Veterinary
Satisfied Customers: 28503
Experience:  University of California at Davis graduate veterinarian with 45 years of experience.
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If a resorptive lesion is not extracted on a tooth, will the

Customer Question

Hi - if a resorptive lesion is not extracted on a tooth, will the tooth simply fall out? or will it simply be absorbed by the gum?
Submitted: 1 year ago.
Category: Cat Veterinary
Expert:  Dr. Michael Salkin replied 1 year ago.

The tooth is eventually lost if resorption involves the tooth root(s) which then can't anchor the tooth in the gum any longer. It's not unusual for the crown to crumble away and leave retained roots, however. The resorptive process isn't fully understood. There are compelling histologic studies showing that the very early tooth resorption in cats in noninflammatory which is quite different from caries (cavities) in us.

Most important is that resorptive teeth are quite painful and need to be extracted as soon as possible. Full mouth dental X-rays are essential because much of the resorption can occur under the gum line invisible to the naked eye. Please respond with further questions or concerns if you wish.

Customer: replied 1 year ago.
I don't mean to sound hard hearted but could they just take care of themselves. I've taken other cats in for dental work in the past and it seems like all the stress combined with the anasthesia and medication leaves them with more issues than they came in with. In some cases with elevated kidney values after.
Expert:  Dr. Michael Salkin replied 1 year ago.

I'll have to leave that decision to you. I understand that I'm anthropomorphizing but when I have a painful tooth I want it taken care of as soon as possible. Please continue our conversation if you wish.

Customer: replied 1 year ago.
Okay just a couple of last questions, how long does it take for a tooth to be re-absorbed and just become bone? And his last bloodwork in late November showed a BUN of 11.1 mmol/l. The range is 5.0 to 12.9. Should this be a concern for his kidneys? Also the BUN/Creatinine ratio is 71, but there isn't a normal range listed. Do you know if that is normal? Thank you.
Expert:  Dr. Michael Salkin replied 1 year ago.

Allow me to clarify what occurs: Feline teeth may appear clinically healthy but they often show histologic and radiographic changes of periodontal and dental tissues such as periodontal ligament degeneration, hypercementosis, and hyperosteoidosis. Narrowing of the periodontal space may result in ankylotic fusion (dentoaveolar ankylosis) between the tooth and alveolar bone. These findings demonstrate events that occur before obvious tooth resorption and suggest that the very early lesion is probably noninflammatory. Ankylosed roots are at risk of being incorporated into the normal bone remodeling process resulting in gradual resorption of the root and replacement by bone. This is a gradual process occurring over years.

I need a bit more information to be more accurate. When evaluating the kidneys a complete urinalysis is necessary; in particular, the specific gravity and degree of proteinuria (protein loss through the urine) needs to be known. BUN, creatinine, serum phosphorus, and hematocrit/packed cell volume round out the values I need to see. Can you upload a copy of all of his test results to our conversation? I understand that you might not have a copy at home but his vet can give you one which you can scan into your computer and then give me file link or you can photograph the pages and upload them by using the paperclip icon above your message box (if you can see the icon) or by using an external app such as

The BUN/creatinine ratio is simply a calculation of convenience that might suggest one renal disorder over another - in particular, why an elevated BUN was found. It's normally quoted as 4-33.

You're welcome.

Customer: replied 1 year ago.
Thanks for all that info. So if it is probably non-inflammatory, does that mean less pain? and if it is a gradual process over years - is it painful over the whole duration of years? Perhaps not a good example, but I have had cavities and I didn't even know I had a cavity.I am attaching the bloodwork file for your review.
Expert:  Dr. Michael Salkin replied 1 year ago.

Unfortunately, no. The pain results from nerve exposure and increases as the nerve is more and more exposed as tooth continues to crumble away.

Thank you for the bloodwork. Nicely normal. No indication of renal insufficiency.

Customer: replied 1 year ago.
the 11.1 BUN which is pretty close to the 12.9 threshold is no reason for concern? The reason I ask is because it seems with kidney failure by the time they pass the upper limit they have already lost 70% of their kidneys
Expert:  Dr. Michael Salkin replied 1 year ago.

The BUN is too volatile to make any kind of assessment from one value. For example, eating within 4 hours of a blood draw can double the BUN. The creatinine is a better value to monitor over the long term. You're correct, it often takes over 75% of normal functioning nephrons to be be lost before the BUN and creatinine elevate over high normal.