A cavity is a hole in a tooth that caused by the dissolution of dental enamel. This is formed when bacteria living in the mouth digest carbohydrate debris on the teeth and subsequently excrete acids that combine with saliva to dissolve enamel. Since there are no nerves in the enamel of a tooth, it is unlikely that you will feel any increased pain or sensitivity during the earliest stages of a cavity. As the cavity progresses towards the dentin and pulp of a tooth, you are likely to feel more teeth sensitivity. Dentists can easily identify cavities during a routine dental examination by reviewing dental x-rays and inserting a probe around suspicious areas. 

Cavities may be grouped into six different categories. Class I cavities are on the indentations and grooves on the surface of the teeth. Class II cavities are on the side and chewing surfaces of the premolars and molars. Class III cavities are on the surfaces between the front teeth. Class IV cavities are on the surfaces between two anterior teeth that include the incisal edges. Class V cavities are at the gum line on the surface of a tooth facing the lips, cheek, or tongue. Class VI cavities are on the incisal edge of an anterior tooth or cusp of a posterior tooth. 

The sites of cavities may also be identified using the different surfaces of a tooth. Facial cavities are on a front tooth surface, buccal cavities face the cheek, and lingual cavities face the tongue. A cervical cavity is a cavity near the place on the tooth where the enamel surface of the crown meets the cementum surface of the tooth. Occlusal and incisal cavities refer to cavities on the chewing surfaces of posterior and anterior teeth, respectively. Mesial and distal cavities refer to cavities closer to or farther away from the midline on a given tooth, respectively. Interproximal cavities are cavities on the surfaces between two teeth, most commonly referring to premolars and molars. 

Excessive consumption of sweet and sugary foods increases the risk of developing a cavity. Even in the absence of a cavity, those with sensitive teeth are likely to feel more sensation when eating sugary foods. To decrease the likelihood of developing cavities, it is imperative to brush at least twice daily and rinse your mouth following the consumption of soda or sugary foods. 

Most early stage cavities can be easily treated with a simple filling. The cost of a filling will vary depending on the complexity of the cavity and the number of surface areas that need to be filled. More complex cavities may be treated with inlays or onlays. If a cavity is not treated during the initial stages, it may be necessary to perform a root canal in the future. During the process of filling a cavity, the dentist initially administers an injection to numb the area around the cavity. Once the area is numb, the dentist uses a drill to remove decayed material and insert a filling material inside the void. The most commonly used restorative material today is a tooth-colored resin. There are a wide variety of resin color shades available which can closely blend in with the surrounding tooth structure and appear virtually identical to an unrestored tooth.