Very badly decayed teeth are easy to see, and you will probably have felt pain from them before seeing them. Black holes and/or jagged edges make them difficult to miss. But at earlier stages some tooth decay (dental caries) stands out as a very white, roughish looking spot where the outer layer of the tooth (enamel) is starting to crumble. Later, decay can look like a dark shadow, or a dark spot or line on individual teeth. While these can be seen on the front surfaces of the front teeth, and between these teeth as well, they are far harder to see on the back ones.
This brings us to an important point. Each tooth has five surfaces, although the front eight teeth (the top and bottom incisors) have a fine edge as their fifth surface, and the teeth next to them (the four canines) are pointed. While you can easily see the front and biting surfaces of the back teeth you cannot see between them. Unfortunately this is where much of our tooth decay starts.
A major problem of decay is that although it might appear to be a very small patch on the outside of a tooth it may well have spread a great deal inside the tooth. In this way it is just like a rotten apple. The bug enters through a tiny break in the apple skin and creates a lot of destruction inside the apple before it gets big enough show the extent of the damage on the outside. We only find that out after we have bitten into it. This is why you can have an apparently healthy tooth one day, but bite something hard and find the tooth has broken in half the following day. We must emphasize that because you cannot see anything wrong, it does not mean that everything is all right. Finding color changes tells you that something is wrong - finding no color changes doesn't tell you that everything is well. If you can see things starting to go wrong get in touch with your dentist. And if things look all right to you, you should still go for your next regular dental check-up
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