Tooth sensitivity, scientifically known as dentine hypersensitivity, is a common issue affecting many people. It is often described as a short, sharp pain when teeth encounter stimuli like cold water or air. Fluoride is recognized as a primary and highly effective treatment for reducing this pain. Consistent application helps manage the underlying cause, offering reliable relief.
What Causes Tooth Sensitivity
A tooth consists of several layers, including the hard outer enamel and the softer dentin beneath it, which surrounds the nerve-containing pulp. Dentine is composed of millions of microscopic channels called dentinal tubules that run toward the pulp. These tubules contain fluid and act as a direct pathway to the tooth’s nerve.
Sensitivity occurs when dentin loses its protective covering due to gum recession or enamel erosion. When dentinal tubules are exposed, external stimuli like cold temperatures or pressure cause the fluid inside the tubules to move rapidly. The nerve endings in the pulp register this pressure change as a sudden, sharp pain, a mechanism known as the hydrodynamic theory.
How Fluoride Works to Reduce Pain
Fluoride acts as a desensitizing agent by physically blocking the open dentinal tubules, stopping the fluid movement responsible for pain. When applied to exposed dentin, fluoride reacts with calcium and phosphate ions present in the mouth. This reaction forms precipitates, such as calcium fluoride (\(\text{CaF}_2\)), which are deposited directly into the tubule openings.
These precipitates eventually mature into fluorapatite (FAp), a stable mineral structure resistant to acid. By creating this mineral plug, fluoride effectively occludes the pathways leading to the nerve. Blocking these channels prevents rapid fluid shifts, reducing the sensation of pain. Remineralization also strengthens the tooth surface, helping maintain the integrity of the sealed tubules.
Different Fluoride Treatments for Home and Professional Use
Fluoride treatments for sensitivity are available in varying concentrations and delivery methods, catering to different levels of discomfort.
At-Home Treatments
For individuals with mild to moderate sensitivity, over-the-counter (OTC) products are a common starting point. Desensitizing toothpastes typically contain sodium or stannous fluoride in concentrations around 1,000 to 1,500 parts per million (ppm).
Dentists may also prescribe high-concentration fluoride toothpastes, which can contain up to five times the amount of fluoride found in OTC products. These prescription-strength options are intended for daily home use but are overseen by a professional to ensure appropriate application.
Professional Treatments
Professional applications administered by a dentist offer significantly higher concentrations of fluoride for persistent or severe cases. These in-office treatments include gels, foams, and varnishes, which are applied directly to the tooth surface for a concentrated, therapeutic dose. Fluoride varnishes, such as those containing 5% sodium fluoride, are painted onto the exposed areas and adhere for several hours, allowing the fluoride to penetrate deeply and effectively seal the dentinal tubules. The decision between at-home and professional treatment is based on the severity and frequency of the sensitivity, with higher-dose professional options often providing more immediate and lasting relief.