dental bridge and crowns always seem dry

[roxie9306]

I got a dental bridge and crowns years ago, most of my front top teeth were done, so it's 6 teeth. I can't remember if I had this problem when I first got it done but I've noticed for at least a couple of years that the bridge and crowns always feel really dry. At first I thought it was dry mouth but that doesn't seem to fit. I drink a lot of water, and breathe through my nose. No matter what I do, I always feel that they are dry and sometimes I feel like they are sticking to my top lip, and it can make smiling and laughing difficult. I haven't found anyone else who has this problem so I hope I can find some help here.

 

[Busybee]

If you have a dry mouth condition your tongue will feel dry too, it won't just be the front teeth. It won't matter how much water you drink if there is a problem with the salivary glands. Front teeth crowns can feel like they are sticking to the top lip and they can get dry from air. I don't know how old you are but some of this could just be down to ageing or a change in elasticity of your lip. Medication could have changed the conditions in your mouth. Diet can affect the amount of saliva, e.g. high salt. Drinking water on its own doesn't always hydrate the body adequately. it's better to have milk or something with a suspension to retain the liquid in the body. Perhaps over rigorous cleaning has roughened the porcelain. It may be helped if the dentist polishes the crowns slightly.

 

[honestdoc]

There are a few possibilities. You could be taking medication(s) that could dry your mouth. Another possibility is Sjogren's Syndrome (for females which you name suggests) and possible autoimmune response. You may consider dry mouth products like Biotene.

 

[Busybee]

These are whole mouth conditions honestdoc. I had dry mouth from medication, it's unpleasant but doesn't affect your top lip. I thought it might be sjogrens at the time but I didn't have dry eyes and thankfully it resolved.

But if the restorations are old then dental wear and subsequent adjustments of the soft tissues of the face to changes in the architecture of the dentition could cause this discomfort. If the crowns have become shorter then the lip will feel different. It will feel weird smiling/ talking. The change can be difficult to discern as it happens gradually. Reductions in tooth height have many manifestations for functionality and feel of the lips. It could be the back teeth have worn too. It's an interesting area of dentistry that I don't think many dentists explore.

 

[MattKW]

• BusyBee, the patient doesn't always know it's whole mouth dryness. I see it often during routine examinations, and it's sometimes not unless I ask patients that they recognise the signs because it can be such a slow change. It is most commonly due to medications (Sjorgens is rare).
  
• About 80% of drugs have this side effect to varying degrees. Aging will also cause diminished mucin production so that although the total amount of saliva seems the same, the " lubricability" is decreased. There are simple salivary tests that can give quantitative assessments.
  
• Crowns don't wear or roughen because they're made of porcelain; no amount of scrubbing with toothpastes or toothbrushes will affect the porcelain in the way you suggest.
  
• Logically (and in reality), if the back teeth wear down, the the front teeth must wear down too in order to maintain an even occlusion. Sometimes the old feldspathic crowns on upper front teeth would wear down the opposing lower front teeth. If the mouth closes down (front and back), then the lips close more easily. Crowns don't wear down faster than teeth, if at all.
  
• Overclosure leads to an inverted smile, risk of angular cheilitis, and risk of TMD - all of which dentists have known about for a very, very long time. It used to be much more common when there were more dentures about and the resorption of the jaws or wear of the acrylic teeth resulted in rapid overclosure.
• Aging will cause soft tissue changes in the lips: epidermal thinning, loss of collagen, which results in increased water loss and decreased elasticity of the skin. As dentists, we can't do anything about that, so there's nothing to "explore" from a dental perspective.
  
• I agree with honestdoc that medication-induced xerostomia would be first on my list of differential diagnoses for the sensation that OP describes, and generalised aging would be second, or act as a contributing factor. "When you hear hoofbeats, think horses, not zebras."

 

[Busybee]

Porcelain crowns most certainly do wear, it depends on the material & the bite. They are supposed to wear equally to teeth but sometimes what I have heard described as "functionality vs aesthetics" is balanced towards aesthetics in the dentist's psyche.

 

[honestdoc]

Porcelain (ceramic) will wear over time but is harder than enamel and will wear against opposing teeth. Despite being harder (higher compressive strength) than enamel, porcelain will also fracture (lower tensile strength). The functionality of porcelain is not as good as gold or metal. Enamel will wear against gold and metals and you never heard of gold or metals fracturing. Guess which is more esthetic (sorry, American English?).

 

[Busybee]

Doesn't it all depend on how polished the restorations are? I've always needed adjustments to porcelain and I do think that's what makes them more prone to wear. Surely adjustments create greater surface area which is more prone to friction?

 

[Busybee]

By the way I had the line about there being a trade off between functionality and aesthetics from a "smile design" dentist that was the root cause of all my semi-recent problems. She managed to cement a front incisor crown so crookedly that I could not close my mouth. She then insisted on adjusting one of my natural premolars after about 45 mins of trying to adjust her precious crown. This was her line after that. I can't believe dentists like her are allowed to practise. I needed her crowns replacing as my bite was a mess.

 

[MattKW]

Doesn't it all depend on how polished the restorations are? I've always needed adjustments to porcelain and I do think that's what makes them more prone to wear. Surely adjustments create greater surface area which is more prone to friction?

Hardness of the ceramic does not determine the wear against opposing teeth. The roughness of the ceramic and subsequent exposure of the crystalline structure will cause more wear of the opposing teeth. So, softer ceramics will wear fractionally more than harder ceramics and lose their smoothness, and this can lead to more wear of the natural teeth.. If the crown is adjusted and not repolished well, this also will increase the wear of the opposing tooth. Sometimes it's better to adjust the opposing tooth rather than the crown; sometimes the crown should be sent back to the lab for reglazing; sometimes it's best to admit defeat and have the crown remade.

 

[honestdoc]

Hardness of the ceramic does not determine the wear against opposing teeth. The roughness of the ceramic and subsequent exposure of the crystalline structure will cause more wear of the opposing teeth. So, softer ceramics will wear fractionally more than harder ceramics and lose their smoothness, and this can lead to more wear of the natural teeth.. If the crown is adjusted and not repolished well, this also will increase the wear of the opposing tooth. Sometimes it's better to adjust the opposing tooth rather than the crown; sometimes the crown should be sent back to the lab for reglazing; sometimes it's best to admit defeat and have the crown remade.

When I was in school, we were taught that ceramic has higher compressive strength (hardness) than enamel thus causing wear. In your case, I also remembered different particle sizes in a matrix play a role where the larger particles (rougher surface) can cause more wear or resist wear as in composites. However, the larger particles are more difficult to polish smooth.