Acidulated phosphate fluoride (APF) is a specialized dental treatment designed to strengthen tooth enamel and offer protection against tooth decay. It is commonly used in professional dental settings to enhance tooth resilience. Its primary role involves making the tooth surface more resistant to the acidic conditions that contribute to cavity formation.
Understanding Acidulated Phosphate Fluoride
APF solutions contain sodium fluoride, hydrofluoric acid, and orthophosphoric acid. The “acidulated phosphate” refers to phosphoric acid, which significantly contributes to its effectiveness. This acidic environment, with a pH between 3.0 and 4.5, allows for enhanced fluoride uptake by the tooth enamel.
The specific low pH of APF differentiates it from other fluoride forms by helping to slightly etch the tooth enamel. This etching creates a more receptive surface for fluoride ions to bind, thereby improving absorption. While acidic solutions can sometimes cause demineralization, phosphoric acid was specifically chosen for APF because it does not lead to this issue. This unique formulation ensures effective fluoride penetration and interaction with tooth structure.
How APF Protects Teeth
APF strengthens tooth enamel through remineralization. When applied, fluoride ions react with calcium and phosphate minerals in the enamel. This forms a more acid-resistant compound, primarily fluorapatite, on the tooth surface.
The newly formed fluorapatite makes enamel harder and less susceptible to acid attacks from bacteria and sugars. This enhanced resistance helps prevent demineralization, the breakdown of tooth enamel that leads to cavities. Regular APF treatments can significantly reduce the risk of dental caries. The protective layer also helps reduce tooth sensitivity by blocking dentinal tubules.
Application and Safety Considerations
APF is applied in a dental office using trays, gels, or foams. The dental professional applies the APF gel or foam to the teeth for one to four minutes. After application, patients are instructed to spit out any excess and avoid eating, drinking, or rinsing for at least 30 minutes to allow the fluoride to fully absorb.
While APF is considered safe and effective when used as directed, precautions are necessary. Accidental ingestion, especially in children, can lead to gastrointestinal irritation, causing nausea and vomiting. Therefore, professional supervision during application is important. Prolonged daily ingestion can also lead to abnormal tooth enamel, so following application guidelines is necessary.