Expert: Mark Bornfeld DDS - 2/17/2009

Question
I have a cracked molar, #19 that is covered by a porcelain onlay.  The crack occurred after I had the onlay on.  My dentist told me the next step is a crown and possibly root canal.

My question is: what are the pros and cons of going for the crown or doing nothing?  I have already had this crack for 3.5 months without doing anything to it, except going to the dentist to have it looked at and x-rayed.  Dentist said tooth looks ok, but that I should get crown and maybe root canal.  

I only have mild-moderate pain on chewing (nothing super painful) and it is not sensitive to hot or cold.  Also, it never hurts by itself, only when chewing (certain foods).  I'd say it only hurts 50% of the time when I am chewing in general.

I'm worried that if I go for the crown it will cause more problems and potentially lead to a root canal or not work at all and I'll still have pain on chewing.

What are your thoughts?  I've already left it 3.5 months and it has not gotten worse, only stayed the same.

Thanks!

Answer
Dear Cindi,

The answer really depends on the location, orientation, and extent of the crack. What is ominous here is that biting pressure elicits pain (not withstanding its being relatively mild), and that phenomenon suggests that there is strain being generated across the fracture line. It is a fairly reliable engineering principle that any structure will eventually experience failure with repeated application of physical force-- especially if there is already a structural weakness (here, the crack). So you can be fairly confident that the crack in your tooth will propagate and eventually cause a more complete separation of the fractured parts-- this is more a matter of "when" than "if".

What cannot be determined here is whether a crown will be sufficient to manage the fracture in the tooth. In some cases, it will-- especially if the fracture does not extend under the gum line. However, I have seen fractures extend vertically right through the tooth, through the dental pulp, and deeply into the bony socket-- such fractures make a tooth unsalvageable, regardless of what heroic efforts are made to save it.

So, before you embark on any treatment plan, your dentist needs to do a bit more diagnostic due diligence-- take that inlay out, and follow the trajectory of the crack. Truth be told, your dentist's enthusiastic endorsement of a crown before doing this important step may prevent him from doing a truly impartial evaluation, so you might wish to ask him for a referral to an endodontist (root canal specialist), who is better trained and equipped to trace the crack and determine its extent.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY