Keeping in touch by blog!

Thank you for spending a few minutes and checking out my blog!

This is a great way for me to keep you informed about what's new at Oakdale Dental.  You'll find stories about todays dentistry and how it can make your life better and healthier, and sometimes some random thoughts I hope you find interesting. 

If you are already one of my patients, let me know what you think.  Any topics you would like to read about or questions you have, just send me an email.There is lots of information already on this site and my other practice website: Oakdale Dental! 

For those of you who I have not had the pleasure to meet yet, I'm glad to have here and feel free to drop by and pay us a visit at Oakdale Dental in beautiful Oakville.

So, come back once in a while...I try to post regularly and have some interesting things for you to check out and maybe a story or two to tell.


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"Great things start with a smile!" Dr Rosenblat

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Monday
Sep212009

How long should a crown last?

This has got to be one of the most common questions I get from my patients. 

A lot of research and science goes into the technology used to make crowns.  High tech ceramics used in crowns are need to be strong, function like real teeth and are designed to have optical qualities that mimic the real thing so they look natural.   They need to be “installed” into a wet environment and survive in a wet environment for their entire lifespan of many, many years.

Not asking much are we? 

Firstly, why does anyone need a crown?  

They are usually made for teeth with large fillings.  If a tooth is heavily filled, it is much weaker and so a crown is often recommended to hold the remaining tooth together.  Teeth with large fillings often break and can break in a way that cannot be repaired, resulting in tooth loss.   When preparing a tooth for a crown, I will usually replace the old filling in a tooth with a new bonded “core” filling to reinforce the remaining tooth structure (and remove any residual decay).  Some tooth structure will also be removed to fit the new crown.  (Yes… a crown is still better than a “big filling”.  Think of it this way; even a well bonded filling is trying to hold together parts of a tooth from the inside- while biting pressure acts to push apart tooth from the filling.  A crown surrounds the remaining tooth and filling, reinforcing it physically…way better). 

 

There are many reasons a crown on a tooth can fail and I’ll go over a few. 

The tooth itself is already a weakened structure- which is why it needed the crown in the first place. So there is one.  

Decay at the edges of crowns where it meets the natural tooth structure is one of the most common reasons for a crown to fail.  Even the best crown made will have some “roughness” at the place the tooth meets the crown edge.  Bacteria will accumulate here if left undisturbed (ie not brushing well), and can decay the tooth at the cement or bonded seal of the crown and scoot underneath the crown where you cannot get at it no matter how hard you brush or floss your teeth.  So, excellent dental care will help prevent this.  (Brush, floss and see the dentist regularly!) 

The way a person uses his teeth can make a big impact on how long a crown (or natural tooth for that matter) survives.  Many people grind and clench their teeth and don’t even realize it.  These abnormal habits can cause lots of wear and tears on teeth/crowns and roots of your teeth too.  Ceramics can fracture as they cannot flex and bend like natural teeth. 

 

There are cosmetic reasons for a crown to fail as well.  Your diet can affect the ceramics of crowns.  Acidic diets can eat away at the porcelain surface of a crown.  (You would be surprised how acidic many of the everyday foods you consume are!).  This can damage the appearance making the crowns a flatter white appearance.  The surface of the porcelain becomes more porous so that some foods (i.e. tea) can stain the crowns too.   Not to mention sugars in your diet that feed the bacteria causing decay as I mentioned above.  Gum disease can cause recession of the gum line exposing the edges of crowns and that is unacceptable in cases where it shows when smiling.

The way a dentist prepares your tooth for a crown can also play a role in the longevity of the final crown.  Errors like inadvertent moisture during insertion can damage the complex bonding of crowns to teeth so that the cement bond fails earlier than it should.  So, there are lots of factors that can affect the lifespan of a crown.

But on average I’d say a crown lasts about 10 years.  There is great variation in that number too. 

When my patients ask about how long a crown will last I like to compare any dental work, like crowns to automobiles.  Very few people are able to keep a car longer than ten years.  We’ve all seen those gorgeous vintage autos of 50 years ago that look like new.  But they are the result of loving care and maintenance and are often rebuilt from cars found in a state of disrepair.  I see many patients whose teeth are like that.  And I’ve rebuilt many. When cared for, with our help, new crowns can easily last far longer than 10 years.  I saw a patient recently with a full mouth of crowns and bridges that I placed about 15 years ago that look like the day I placed them in his mouth (and I’ve seen some crowns that were even older and in fine shape).  With the way that patient care of his oral health, I bet those restored teeth will be there another 15 years.  But I also have patients who don’t maintain their teeth and have to have crowns replace much sooner.  There often isn’t any discomfort in a person’s mouth until problems become quite large.  Again, just like a car, if you don’t change the oil, the car still runs fine and you don’t know there is a problem until the engine seizes up and then it’s too late.  So with good home and professional dental care you can beat the average.