Fillings are needed when there’s small or moderate levels of decay (cavities) in a tooth. It is caused by a sticky substance called plaque that forms when we eat a lot of starches and sugars but don’t brush them all off.
It’s true that our teeth are really complicated. There are many crevasses and angles, so it can be hard to brush off every little bit of food residue. Then the bacteria start eating the food residue, which produces acid and this causes tooth erosion and cavities.
Left unchecked, tooth infections can become more serious and start to reach deeper into the layers below your teeth. When tooth decay reaches your dentin layer (the softer layer below our enamel), you might start feeling sensitive teeth. This is because the dentin has tiny tubes that directly communicate with the nerves of the tooth.
Past the dentin, cavities can reach your pulp which is where the tooth’s nerves and blood vessels are.
That’s why fillings are so important in these situations! They help prevent decay from growing and destroying additional tooth structure, which can lead to weak teeth and/or infected nerve tissue. This also helps avoid root canals or the need for tooth extraction.