The Dental Blog

The Trouble With Finding Cavities

While we suggest that our patients avoid sugar and brush and floss to avoid cavities, let’s face it, for most people, some cavities are a part of life. In fact, dental cavities are the most common disease known to mankind. The real trick is to get them detected, cleaned out and filled before they get too big and require a root canal or crown. And then once detected, what methods can be used to fill them. Finding cavities, even big ones, is not as simple as it sounds for many reasons.

1. First of all, most cavities, even when they are quite large, don’t hurt or feel sensitive to the usual stimulants like hot, cold, biting or sweets.

Pain is a great mechanism to tell us that there is something wrong in our bodies, but unfortunately for reasons that no one understands, it often does not work.   Pain is a good indicator that there is a problem, but it often is not an early indicator.  We have all heard all too many stories of friends or family members who have undetected severe heart disease or large tumors that gave no hint of being there until they became extremely severe.  It is the same with cavities in teeth.  They usually just do not hurt and we do not know that they are there.

2. Second, dental x-rays can miss most cavities.

This will shock most people, but it is true.  Teeth are the hardest part of the human body and although dental x-rays have been the standard of care for over a hundred years, they cannot see it all.  There are two reasons for that.  First of all, if a cavity is in the middle of a tooth, there is a lot of solid tooth structure that can obscure the area of decay.  It is like looking at a bagel from the side.  You can not see the hole, even a big one in the middle.  All dental x-rays are taken from the side.  So some cavities are revealed with x-rays but many others are not.

3. The third reason is that the trusty old dental pick that most dentists use to look for cavities really is not that reliable and can also miss many cavities.

There was an article in the Journal of the American Dental Association debating this point in November 2005.  That is because many cavities, even very large ones, have very narrow openings on the outside because the enamel; on the outside of the tooth is so hard.  But once the decay breaks through and gets into the softer underlying structures, it can spread quite rapidly. Even though the pick looks pretty sharp, in fact it cannot get into the narrow openings that are often the start of a big cavity underneath.

4. Lastly, the worst cavities are actually under old fillings and that makes them hardest to find.

That is because old fillings block dental x-rays from revealing decay. They also prevent the dentist from seeing the teeth structure. And cavities that start under old fillings actually start at the bottom of the original cavity where the tooth structure is softest and least resistant to new decay. That makes reoccurring decay under old fillings much worse than new cavities because they are harder to find and deeper and more destructive than new cavities from the very start.

Everyone realizes that things wear out or spoil over time over time. Automobile tires wear out, shoes wear out and food spoils. The same happens with fillings. It is kind of like a jar of mayonnaise. You can take it home from the store and leave it for years, as long as the jar is sealed, the mayonnaise will not spoil. But once you break the seal and open the jar, the air and germs can get in and the mayonnaise will eventually spoil. Fillings are like that too. Once the dentist removes the decay and puts in a filling, it fills and most importantly seals the cavity so germs and food cannot get in to start a new cavity. Regardless of what type of filling the dentist uses, eventually it will lose its seal and germs and food will get under the old filling and into the tooth and a new cavity will start. That is why regular and thorough examinations of your teeth are so important to prevent major problems. The mouth is a perfect place to grow germs since it is warm, moist and has a plentiful supply of food.