Your Smile Dental Care

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Cavities under Dental Crown

Tooth Decay and Your Crown

Q: Can I get a cavity if my tooth is covered by a cap?

This is a common question. Actually, it’s a good question because people are often surprised to learn that the tooth is still susceptible to the decay process even with a strong crown fitting snugly over it. It is one of the valuable pieces of information that your dentist should pass on to you about your new crown.

A thorough explanation of why you need a crown should also be given. When a dentist recommends that you consider having a crown placed over one or more of your teeth, it is for their protection or to improve their appearance.


Crowns are recommended for teeth if they:

– have a very large filling and it needs to be covered with a crown for added support and strength.

– are weak because they are cracked, broken or worn down

– have cosmetic imperfections

– have undergone root canal treatment


The Destruction Process

What’s important to understand is that even though a crown is very durable, you have to treat it like your natural tooth because it is attached to your own tooth structure underneath. This tooth is still vulnerable to corrosive effects of repeated attacked by highly acids foods and bacterial acids. As acid continually accumulates along the seal between the crown and the tooth, it can soften enough of the tooth to cause a hole into which more bacteria can gather. Eventually it begins to make inroads underneath the crown and farther into the tooth. So, it’s important to understand that it is the tooth, not the crown, that is being destroyed and the cavity can only be cleaned away properly by removing the crown. During the cleaning and repair process, it is virtually impossible to retain the original shape of the underlying tooth and the existing crown will no longer fit this modified tooth precisely enough to protect it from future damage.


Bacterial plaque can accumulate along margin where crown meets tooth


Lifespan of Crowns

Like your tooth, crowns are subject to normal wear and tear and, as mentioned, can be under minded by tooth decay. Crowns generally last anywhere from 5-15 years before they may need to be replaced. However, we have seen crowns last as long as 25 years or more! Full metal ones tend to resist wear and breakage more than all porcelain one or those that are covered in porcelain. Simple chips to the white porcelain covering the crown can sometimes be smoothed by the dentist and in some cases, minor damage and holes due to wear can be covered using white dental filling material. However, all crowns can be compromised by the decay process and usually have to be replaced if it has to be removed. This is why keeping your crown free of plaque and maintaining healthy dental habits are critical to the life of a crown.

As with the care of natural teeth, these 4 habits are the most important factors in caring for your crown:

  1. Space out your meals and reduce, if not entirely eliminate, snacking in between meals.
  2. Brush 3 times/day and floss daily
  3. Eat well balanced, nutritional meals and avoid foods that are high in refined sugars and acids.
  4. See your dentist regularly for professional care.


Regular dental visits are important so that your dentist can monitor the integrity of your crown and the health of the tissues surrounding it.  Your dentist will be extra careful in checking the margin of your crown. Ideally, they would like to be able to detect and repair small issues while keeping your crown in tact before they become more advanced. Regular visits also allow your dental care team to evaluate your home care and advise you as needed.


Early Detection

Monitoring your teeth on a regular basis allows your dentist to assess the health of your teeth and gums. They will check around the margins of your crown to ensure that the area is being kept free of plaque and tartar and that the seal between crown and tooth is still sound. But detecting decay is not always easy. Sometimes there is a cavity growing underneath the crown that goes undetected because there it is showing no clinical evidence of it’s existence and x-rays do not penetrate through metal crowns. A cavity can be growing for a long time before it is caught and can advance to such a stage that the inside of the tooth can turn to mush and the crown loosen without the patient even knowing. At this point, the tooth itself may be at risk and the concern lies in saving the tooth.

Extending the Life of Your Crown

Replacing a crown can be costly in terms of the crown itself and in saving the tooth underneath. The best prevention strategy is to stay one step ahead of tooth decay by practicing good cleaning around where the crown meets the natural tooth at what we call the “margin”. The little time that it takes to clean away destructive bacterial plaque before it has a chance to buildup and become hard to remove is certainly worth the effort to help keep your tooth and surrounding gums healthy for years to come.

Of course, nothing last for ever, but the wise phrase, “An ounce of prevention is worth a pound of cure” is a fitting one when it comes to caring for your crown so it will serve you well for many years.


Yours in Better Dental Health,
The Your Smile Dental Care team
(905) 576-4537 (Oshawa)
(416) 783-3533 (Toronto)
















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Alzheimer’s Drug in Dentistry

Alzheimer’s Drug may be sinking it’s teeth into dental care!


Needless to say, tooth aches have plagued humans for years, but a recent discovery may soon sink it’s teeth into this age old problem.


Scientists have been looking for ways to repair rotten teeth for years. Now it seems that a team of researchers at Kings College in London may have found a way to regenerate tooth dentin using a drug that is usually used to treat people with Alzheimer’s.


wearing-timeThe outer layer of the tooth, called enamel, is the hardest substance in the human body. It is very densely calcified and contains no stem cells. Currently, the only way to repair enamel is to hope that a person’s mineral-rich saliva can reverse the very early stages of enamel demineralization cause by bacterial acids.


There is always a daily battle during and after meals between the mouth bacteria and our mineral-rich saliva. Simply put, the bacteria metabolize the sugars we eat and create a erosive acid that can dissolve and break open enamel rods allowing minerals to leech out. Our saliva plays a reparative role by then depositing minerals into this surface damage to try to harden the weakened area of the tooth. This repair process takes upwards of 4-5 hours in between meals which is why frequent eating/snacking interferes with our saliva’s reparative ability. Unfortunately, when the amount of demineralization far outweighs the restorative work of saliva and the damage is deep enough, repair is irreversible and the tooth must be cleaned out and filled with a dental material.


the-toothHowever, researchers at Kings College were concerning themselves with very large areas of decay – cavities that ate through the enamel and into the next tissue called dentin. Dentin is roughly 50% less harder (calcified) than enamel, but unlike enamel, it  is capable of some regeneration to protect the pulp. Just like bone, dentin is able to acquire more calcified tissue in the event of repair. We call this secondary or reparative dentin and the stem cells needed to produce extra dentin comes from the pulp. That repair is limited, however.


Until now….


Dentistry already has dental products that attempt to soothe and protect the more vulnerable pulpal tissue from deep tooth decay, but it can only do so much,  especially if the decay is very close or has reached into the pulp. What these scientists have done essentially is found a more natural way for dentin to repair itself. Using a biodegradable collagen sponge soaked with the Alzheimer’s drug called “tideglusib”, they placed it on the dentin where the decay had reached the pulp.


Essentially, Tideglusib switches off an enzyme called GSK-3, which is known to prevent dentin formation from continuing.  The testing was done using mice, but the results were very promising. Not only did their body defence systems begins growing natural dentinal tissue, but testing showed the damaged tissue replaced itself in as little as six weeks – much more quickly that the body’s current natural ability. And, unlike the dental materials currently used in dentistry that remain after placement, the sponge eventually dissolves over time after the new dentin replaces it.


A Great Step Forward

Image B shows exposed dentin. When drilling continues the pulpal tissue is eventually reached as in Image C. CREDIT: KING’S COLLEGE

This discovery is exciting because, not only do we, as dentists, try to repair decayed teeth, we try to stop it in it’s tracks before it reaches the pulpal tissue. Once the pulp chamber is exposed to the oral environment, we use dental materials designed to cap the exposure and encourage the growth of dentinal stem cells to preserve the health of the pulp, but it’s success rate is not what we’d like it to be.

Many factors play into the repair process and if the body does not cooperate and form a sufficient layer of dentin to seal the pulp, then the vitality of the pulpal tissue will become compromised and eventually begin to rot. Once this happens root canal treatment is necessary to save the tooth from extraction. In addition, tideglusid is not a new pharmaceutical. It has undergone testing and is already being used as a drug for patients with Alzheimer’s.


“In addition, using a drug that has already been tested in clinical trials for Alzheimer’s disease provides a real opportunity to get this dental treatment quickly into clinics.”

Professor Paul Sharpe, lead author of the study
Dental Institute of King’s College,  London  UK


At Your Smile Dental, we know that, “Not all that glitters is Gold”, but with more than 30 years of dental experience, we also know that many of the technologies we use today in dentistry were the impossible dreams of yesterday. The dentin is a very important protective layer between the enamel and the vital centre of the tooth. Once decay gets into this layer, it can advance quickly. Finding a way to regenerate this tissue faster, before it poses a threat to the nerve, will be a great step forward in the treatment of dental disease.


It may not be the end of fillings since enamel cannot grow back, but we’re happy to stick around a little longer to help you with all of your dental care needs!


Your Smile - Copy


The Your Smile Dental Care Team
(9050 576-4537
(416) 783-3533