Dental Cavities: Treatment and Prevention Dental Cavity Treatment Duration Filling a cavity typically takes between thirty minutes to an hour, depending on the dentist’s expertise and the extent of tooth decay. Understanding Dental Decay Dental caries, commonly known as cavities, occur when bacteria on the tooth surface break down food residues. The byproducts of this breakdown corrode the tooth, creating cavities. Once present, cavities cannot heal on their own. Moreover, the presence of dead tooth tissue and bacteria within the cavity leads to continual tooth decay, which can potentially affect the dental nerve in severe cases. Types of Dental Caries... Learn more