Do you remember the last time your dentist recommended a crown for your tooth with a large filling in it? Recent studies have shown that your dentist was right all along.

In this study, scientists measured the amount of force needed to break teeth with different sized fillings. The teeth in this study ranged from ones with no filling to ones with fillings that are 1/4 of the width of the tooth, as well as 1/3 and 1⁄2 of the width of the tooth.

You will be shocked at what they have found. They discovered that when a filling in a tooth exceeds 1/3 of the width of the tooth, you will be twice as likely to break the tooth or crack the tooth. When a filling in a tooth exceeds 1/2 of the width of the tooth, you will be 3 to 4 times more likely to break the tooth.

Now, this does not mean you will break all of these largely filled teeth. However, it means that when you have a large filling, you are at a significantly higher risk for a tooth fracture or a crack.

Here is the concern. When you wait for a tooth to break, there is a possibility that your dentist may not be able to fix that tooth. Even if the tooth is fixable, the underlying tooth structure could be damaged where by the longevity of that tooth would be reduced.

If you happen to crack a tooth (rather than fracture the tooth), the problem is more significant. A crack, once it starts, cannot be stopped. Sometimes these cracks can run down to the nerve of the tooth or the bone, which makes it extremely difficult to fix and can cause some serious discomfort. Unfortunately, a lot of the cracked teeth end up being extracted.

Here is the good news. Some of these weak teeth can be effectively protected with full coverage restorations (crowns, onlays, caps) which can cover the biting surfaces of the teeth. Since there are less wedging effects compared to fillings, these restorations can give long lasting treatment options for your largely restored, structurally weak teeth. The key is to get these type of restorations earlier rather than later, before the cracks occur.