Crown shape and related questions

[Alex_NYC]

Several of my teeth have issues including damage from grinding, etching possibly due to acid reflux, and old fillings. My dentist is suggesting crowns for these teeth to protect from further decay and restore the tooth length/shape/surfaces. We're considering porcelain-fused-to-metal crowns for the upper/lower back teeth and all-porcelain for the upper front.

Given this is a consequential and quite irreversible procedure, I want to understand as much as possible and have these questions:

1. Why do porcelain crowns tend to have this "inflated" / bulging look? I mean, natural teeth have some flatter contours esp. towards the gum line, and most caps bulge out by comparison. Are there any options to avoid this appearance?

2. Sometimes gums recede showing the edge of the crown. With metal-bonded crowns, this can be quite noticeable - however my primary concern is for the front teeth. What crown design/installation options can minimize tooth/crown interface problems in terms of any imperfections increasing bacteria, interfering with cleaning, and appearance?

3. What is the state of the art in crown materials (including bonding)? Is there anything around the corner (in FDA approval/on shows) that can make a difference?

4. How long can I reasonably expect these crowns to last, assuming the doc does a good job with applicable best practices and up to date materials, but grinding (with night guard) and acidic mouth chemistry issues remain to some extent?

Many thanks

Alex

[StratRebel]

I cannot say who is right without seeing the x-ray, but I can give you some information.

Did your tooth hurt when you bit down on it after the root canal and before the crown was placed?  If so, it might be the infection still healing (although you should not have had the permanent crown placed without this going away first.
If not, your crown might be hitting high and needs to be adjusted,

As for crown lengthening, its a procedure that was not done a long time ago and older dentists just put crowns in and let things happen.  Now we know that a crown that has a margin too close to the bone will cause bone loss.  Your teeth need 2mm of space, called the biologic width, and if you do not have the, the body will adjust....which takes a lot of time and can cause long term discomfort and irritated gums.

Ideally, crown lengthening should have been done first if it was necessary, but it can be done after as well.

As for what to do: I would have your dentist check the occlusion/infection first. Its not infection if antibiotics do not make the pain go away in 3-5 days.  Sinus problem would not usually cause pain just upon biting.

To crown lengthen or not to crown lengthen...like I mentioned, without seeing the x-rays, I cannot tell you which dentist is right.  I would suggest you listen to each and go with the one who's opinion makes the most sense to you.

[StratRebel]

1. Scottma is correct, its all in how the tooth is prepared by the dentist.  A bulky looking crown means the dentist was being way too conservative, which damages the final esthetic look (and poor margins with full porcelain crowns).

2. Again, has to do with the skill of the dentist and lab technicians he uses.  Since you are getting full porcelain crowns in the front, if your gums ever do receed, this should not be a major problem esthetically.

3. You have been correctly told about the best crowns there are to offer.  As for bonding, the dentist should use a different cement for the full porcelain and PFM crowns (PFM cement is stronger, but will expand and crack a full porcelain crown).  To my knowledge, there is nothing new coming out that is better.

4. Current research puts average crown life at 7-10 years.  The most common cause of failure is recurrent decay.  As long as you have great oral hygiene, I have seen porcelain crowns last upwards of 20 years.  
You NEED to have a nightguard will that many crowns...its the cheapest insurance you can buy for them.  And get your gerd under control...the acid wont affect the crown much, but it will eat away at the crown/tooth margin.

[emg454]

Hi I had a root canal and a perment crown put in, since I had it done I have had discomfort when biting down. My Dr said it was my sinuses , I have had trouble in past with sinuses so figured he was right. I am having real bad pain in my cheek bone he said same thing and gave me antibiotics. I felt so crappy I went to ENT he did a scope into sinuses and said there fine and clear. So I went to a dentist that only does rootcanals/crowns well the specialist wasn't there but the general practioner xrayed  the heck of the area. The permenant crown shows its into the bone. He said I would need a crown lengthing done. I wanted to talk to my regular dentist 1st, I have known for years and think of him well. He got defensive,said its not in bone, all I care about is not being in pain. I don't know how to read films but crown does look like its pointing into something. hurts like hell

[scottma]

1. Bulging of crown is created by insufficient reduction of tooth.As long as the dentist prepares the tooth well, bulky crown is not supposed to happen.
2. The issue is more related to dentist and technician's skill.
3. Porcelain fused to metal crown has been in the market for over 50 years. It's highly reliable. The main disadvantage is cosmetically, it's not as naturally looking as full ceramic crown. The strength of full ceramic crown is weaker than that of pfm. In addition, long term reliability is not established yet. That's why most full ceramic crown is used for anterior teeth.
4.It's hard to predict the service life of a crown. Crown may last decades.