A cavity, known scientifically as dental caries, is a localized breakdown of tooth structure caused by acids produced by bacteria in the mouth. These bacteria feed on carbohydrates and produce acids that demineralize the hard outer layers of the tooth, the enamel and dentin, creating a small hole. A dental filling is necessary to stop the progression of this decay, which would otherwise penetrate deeper into the tooth, potentially causing pain, infection, and eventual tooth loss. The filling procedure is a common restorative treatment that removes the diseased material and restores the tooth’s shape and function.
Preparing the Tooth for Restoration
The process begins after an examination, often including X-rays, confirms the presence and extent of the decay. To ensure the patient’s comfort, the dentist administers a local anesthetic to numb the affected area. A topical numbing gel is often applied first, followed by an injection, which typically takes effect within three to five minutes. The resulting numbness usually lasts a few hours after the procedure is complete.
Once the area is numb, the dentist isolates the tooth to keep it dry and free from saliva, which is necessary for the filling material to bond correctly. Isolation is usually achieved using a rubber dam or by strategically placing cotton rolls and using suction. Maintaining a dry field is important for the success and longevity of the final restoration.
Removing the Decayed Material
With the tooth isolated and anesthetized, the dentist uses a high-speed dental handpiece fitted with a specialized burr. The burr spins rapidly to precisely cut away the demineralized and infected tooth structure. The patient may feel pressure or vibration during this part of the procedure, but the local anesthetic prevents pain.
The dentist removes all infected material, often checking for remaining decay using a caries indicator dye. The remaining healthy tooth structure is shaped to create a stable base for the filling material. For small or shallow decay, some dentists may utilize alternatives like air abrasion or laser dentistry, which remove decay with less heat and vibration. The prepared space is cleaned thoroughly to remove debris before the restoration material is placed.
Selecting and Applying Filling Materials
The choice of restorative material is a collaborative decision between the patient and the dentist, depending on factors like the tooth’s location and the size of the cavity. Composite resin is the most frequently used material today, favored because it is tooth-colored, allowing it to blend seamlessly with the natural tooth. Composite is a mixture of acrylic resin and powdered glass, and its application involves chemical bonding.
Before the resin is applied, the tooth structure is treated with a mild acid gel to microscopically etch the surface, creating tiny pores. A liquid bonding agent then flows into these pores. The composite resin is applied in thin layers, with each layer cured, or hardened, using a specialized high-intensity blue light, a process that takes only a few seconds per layer. This layering technique helps ensure a complete cure, minimizing shrinkage and maximizing the material’s strength.
In contrast, dental amalgam, a mixture of metals including silver, tin, copper, and mercury, is known for its durability and is often used for less visible back teeth. Amalgam is packed into the prepared cavity and allowed to set, a process that relies on mechanical retention rather than chemical bonding.
The final step involves shaping and contouring the material to mimic the natural anatomy of the tooth. The dentist then uses articulating paper to check the patient’s bite, making any necessary adjustments so the filling ensures a proper, comfortable occlusion.
Immediate Aftercare and Recovery
Following the procedure, the patient will experience lingering effects of the local anesthetic, causing the lip, tongue, and cheek to remain numb for up to several hours. During this period, it is important to avoid chewing to prevent accidentally injuring the soft tissues. The treated tooth may exhibit temporary sensitivity to hot or cold temperatures, which usually subsides within a few days to a couple of weeks as the tooth recovers.
Patients should wait until the numbness completely wears off before attempting to eat a full meal. For the first 24 hours, it is best to stick to soft foods and avoid chewing directly on the new filling, especially if amalgam was used, as it takes time to reach maximum strength. If the filling feels consistently high, or if severe pain persists beyond a few days, the patient should contact the dental office for an immediate adjustment to prevent complications like jaw pain or fracture.