Acidic foods such as lemons, citrus juices, or soft fruit drinks don’t cause cavities, but they may be putting your enamel in danger. Acids can cause erosion of the tooth-protecting enamel, thus weakening the tooth. If you lose the enamel's protection and expose the underlying dentin, the tooth is more prone to decay.
With the help of fluoride in the water or toothpaste, preventative care and the judicious use of sealants, tooth decay in school age children has been dramatically reduced. However, there’s been an increase in cavities in older people, for a number of reasons. For example, some medications dry out the mouth and reduce saliva. Saliva is vital in fighting tooth decay because it helps neutralise acids, has a disinfectant quality, washes away bacteria, and helps prevent food from sticking to the teeth.
Swallowing aspirin is what helps relieve toothache pain. Since aspirin is acidic, placing it beside the tooth can actually burn your gum tissue, causing an abscess.
An amalgam or composite filling needs to be replaced if it breaks down or a cavity forms around it, or if the tooth fractures. If none of those problems occur, you may be able to keep the same filling for life. Fillings do have a life expectancy, but much depends on things like tooth wear and oral hygiene habits. If you brush your teeth properly at least twice a day with a fluoride toothpaste, and floss or use an interdental cleaner at least once a day, you’ll have less tooth decay and your fillings may last longer.
That really is a myth. Mild tooth decay does not cause symptoms. The pain we associate with cavities comes when tooth decay is more advanced and causes damage to the nerve. Allowing tooth decay to advance can lead to much more complicated and expensive dental procedures, like root canal treatment and crowns. That’s why regular dental check-ups are so important. Also, once a cavity starts, it doesn’t repair itself. It will always grow once you get to a point where you can’t clean it out any longer. Once decay penetrates the dentin of the tooth -- below the enamel -- the cavity will continue to grow.
You need root canal treatment if the nerve inside a tooth is damaged. Untreated cavities may eventually lead to nerve damage, but there are other causes. Cracks, fractures, or other types of trauma to the tooth can also cause nerve damage, and clenching and grinding can traumatise a tooth severely enough to need root canal treatment.