A cavity, or carious lesion, is a form of tooth decay that results in a hole in the tooth enamel. Cavities are caused by an increase in the acidity of the mouth due to the presence of certain bacteria. These bacteria feed on the sugars and carbohydrates in food, releasing acids that break down the enamel and cause cavities. Cavities are a common problem in dentistry and can be prevented with good oral hygiene practices. Brushing the teeth twice a day, flossing regularly and using a fluoride toothpaste can help reduce the risk of developing cavities. Regular dental checkups can also help detect cavities in their early stages and help to prevent further damage. Cavities can also be treated with fillings, inlays and crowns. Fillings are used to fill in the cavities, while inlays and crowns are used to cover and protect the more extensive damage. In some cases, a root canal may be necessary to remove the decayed area and replace it with a dental implant. Cavities can lead to other dental problems, such as gum disease, bad breath, and even tooth loss if left untreated. Therefore, it is important to practice good oral hygiene, visit the dentist regularly, and get any cavities treated as soon as possible.