Custom fluoride trays are specialized dental appliances designed to deliver high concentrations of topical fluoride directly to a patient’s teeth. These devices are particularly important for individuals undergoing cancer treatment, especially those receiving head and neck radiation or certain types of chemotherapy. The trays function by holding a prescription-strength fluoride gel in close contact with the tooth surfaces for an extended period. This targeted application is an aggressive preventive measure necessary to protect the teeth from the severe and rapid decay that can accompany cancer therapy. The creation and use of these trays involve collaboration between the oncology team, the dental professional, and the patient.
The Necessity of Custom Trays in Oncology Care
Cancer treatments, particularly radiation therapy directed at the head and neck region, can cause significant damage to the salivary glands. This damage severely reduces the quantity and quality of saliva produced, a condition known as xerostomia, or dry mouth. Saliva normally acts as a natural buffer, neutralizing acids and washing away food debris. Its loss removes a fundamental defense mechanism for oral health.
The resulting lack of saliva makes teeth highly susceptible to demineralization and aggressive decay. This rapid deterioration, often called radiation-induced caries, can quickly destroy entire tooth structures within months. For patients receiving high radiation doses (60 to 70 Gray) for head and neck tumors, severe salivary dysfunction is an expected side effect.
Standard, over-the-counter fluoride products are insufficient to counteract this severe, treatment-induced risk. Dental professionals recommend the daily use of custom-fitted trays with high-concentration, prescription fluoride gel to mitigate this extreme risk. This aggressive, localized application is the primary method to reinforce the enamel and prevent the rapid onset of decay.
Professional Fabrication: The Step-by-Step Process
The creation of custom fluoride trays is a precise procedure performed by a dental professional or specialized laboratory technician, beginning with a detailed mold of the patient’s mouth. The first step involves taking an impression of the patient’s dental arches, typically using an impression material like alginate. This captures the exact contours of the teeth and surrounding gum tissue.
A dental professional then pours a gypsum material, often called dental stone, into the impression to create a physical model or cast of the teeth. This stone model serves as the template for forming the final plastic trays. To ensure the fluoride gel has a reservoir space for maximum contact, a block-out material is applied to the teeth on the stone model, creating a slight space between the finished tray and the tooth surface.
The actual tray fabrication uses a vacuum-forming machine. This machine heats a soft plastic sheet, typically 2mm thick, before sucking it down tightly over the stone cast. This process precisely molds the plastic to the shape of the teeth and the applied block-out material, retaining the exact custom shape of the dental arch.
The final stage is trimming and finishing the tray. The dental professional carefully cuts the excess plastic material, ensuring the tray covers the entire tooth surface and extends slightly onto the gumline. This precision is important for cancer patients who may be experiencing painful oral mucositis. All edges are smoothed and polished to prevent irritation before the finished trays are delivered.
Patient Use and Tray Maintenance
Once the custom trays are delivered, consistent daily use is paramount to prevent decay. The patient must first thoroughly clean their teeth by brushing and flossing to ensure the fluoride fully contacts the tooth surfaces. Any dentures or removable appliances should be removed before beginning the treatment.
To apply the medication, a thin ribbon or a few small drops of the prescribed fluoride gel are placed into the tray, ensuring gel is placed in the space for each tooth. The most common prescription is a high-concentration 1.1% neutral sodium fluoride gel. The trays are then seated over the teeth and worn for the recommended duration, typically five to ten minutes daily.
After the wear time is complete, the patient removes the trays and must spit out any residual fluoride. To allow the fluoride to absorb into the enamel and maximize its protective effect, the patient must avoid rinsing their mouth, eating, or drinking anything for a minimum of 30 minutes following the treatment. For those who have undergone head and neck radiation, this fluoride regimen is usually required daily for the rest of their lives.
Proper cleaning of the trays is necessary to prevent bacterial growth and maintain the plastic’s integrity. After each use, the trays should be rinsed thoroughly with water and gently cleaned with a soft toothbrush and mild toothpaste. The trays should be allowed to air dry completely before being stored in their case. To prevent warping, the plastic trays should never be exposed to boiling water or high heat.