Techniques such as stepwise caries removal are designed to avoid exposure of the dental pulp and overall reduction of the amount of tooth substance which requires removal before the final filling is placed. Often enamel which overlies decayed dentin must also be removed as it is unsupported and susceptible to fracture. The modern decision-making process with regards the activity of the lesion, and whether it is cavitated, is summarized in the table.Destroyed tooth structure does not fully regenerate, although remineralization of very small carious lesions may occur if dental hygiene is kept at optimal level. For the small lesions, topical fluoride is sometimes used to encourage remineralization. For larger lesions, the progression of dental caries can be stopped by treatment. The goal of treatment is to preserve tooth structures and prevent further destruction of the tooth. Aggressive treatment, by filling, of incipient carious lesions, places where there is superficial damage to the enamel, is controversial as they may heal themselves, while once a filling is performed it will eventually have to be redone and the site serves as a vulnerable site for further decay.In general, early treatment is quicker and less expensive than treatment of extensive decay. Local anesthetics, nitrous oxide ("laughing gas"), or other prescription medications may be required in some cases to relieve pain during or following treatment or to relieve anxiety during treatment. A dental handpiece ("drill") is used to remove large portions of decayed material from a tooth.
Dental sealants have been shown to be more effective at preventing occlusal decay when compared to fluoride varnish applications.Calcium, as found in food such as milk and green vegetables, is often recommended to protect against dental caries. Fluoride helps prevent decay of a tooth by binding to the hydroxyapatite crystals in enamel. Streptococcus mutans is the leading cause of tooth decay. Low concentration fluoride ions act as bacteriostatic therapeutic agent and high concentration fluoride ions are bactericidal. The incorporated fluorine makes enamel more resistant to demineralization and, thus, resistant to decay. Fluoride can be found in either topical or systemic form. Topical fluoride is more highly recommended than systemic intake to protect the surface of the teeth. Topical fluoride is used in toothpaste, mouthwash and fluoride varnish. Standard fluoride toothpaste (1,000–1,500 ppm) is more effective than low fluoride toothpaste (< 600ppm) to prevent dental caries. It is recommended that all adult patients to use fluoridated toothpaste with at least 1350ppm fluoride content, brushing at least 2 times per day and brush right before bed. For children and young adults, use fluoridated toothpaste with 1350ppm to 1500ppm fluoride content, brushing 2 times per day and also brush right before bed. American Dental Association Council suggest that for children <3 years old, caregivers should begin brushing their teeth by using fluoridated toothpaste with an amount no more than a smear. Supervised toothbrushing must also be done to children below 8 years of age to prevent swallowing of toothpaste.