A common source of confusion in dental health is the difference between a cavity and a filling. The two terms are related, but they describe entirely different things. A cavity is the physical damage—a hole in the tooth structure resulting from dental caries. Conversely, a filling is the treatment, representing the restorative material used by a dentist to repair and seal that damaged area.
Understanding the Difference: Cavity vs. Filling
A cavity is a hole in the tooth that forms when the hard outer layers break down due to bacterial decay. This decay is an infection that erodes the tooth structure, and if left untreated, the hole will grow larger and deeper, compromising the entire tooth. The filling is a custom-designed restoration intended to occupy the space left after the dentist removes the decayed material, restoring the tooth’s structural integrity and function.
The Anatomy of a Cavity: How Decay Happens
The formation of a cavity begins with the interaction of oral bacteria, dietary sugars, and saliva. Specific bacteria, such as Streptococcus mutans, feed on carbohydrates and produce acids that dissolve the mineral structure of the tooth enamel. This process, called demineralization, gradually weakens the tooth’s surface, initially appearing as a small, chalky white spot. Once the acid breaks through the enamel, it reaches the softer dentin layer, where decay accelerates rapidly and can eventually penetrate the pulp, causing intense pain and infection.
The Filling Procedure: From Decay Removal to Restoration
The filling procedure aims to restore the tooth’s form and function by halting the active disease process. Treatment begins with applying a local anesthetic to numb the area. The dentist then uses specialized instruments, typically a drill, to remove all infected and softened tooth material.
This removal step converts the cavity into a clean, prepared space ready for repair. After clearing the decay, the dentist cleans the area and may use an acid gel to etch the surface, improving the bond of the restorative material. The material is then carefully shaped to match the natural contours of the tooth. If composite resin is used, a curing light hardens the material quickly, followed by polishing and checking the bite.
Common Types of Filling Materials
Modern dentistry offers several options for restorative materials, each with distinct properties. These materials vary in appearance, durability, and cost, allowing dentists to choose the best option based on the location and size of the cavity.
Composite Resin
Composite resin is the most popular choice because it is tooth-colored, blending seamlessly with the natural tooth. This material is a mixture of plastic and fine glass particles that bonds directly to the tooth structure. Using composite often requires less removal of healthy tooth tissue compared to other materials.
Dental Amalgam
Dental amalgam, often called a silver filling, is an alloy of metals including silver, tin, copper, and mercury. Amalgam is known for its strength and durability, making it a cost-effective and long-lasting option for back teeth that endure heavy chewing forces. However, its metallic appearance is a drawback for visible areas.
Glass Ionomer
Glass ionomer is made from a blend of acrylic and glass. This material is useful for small cavities near the gum line or in children because it releases fluoride. While it is tooth-colored, it is less durable than composite or amalgam, making it suitable for areas under lower stress.
Protecting Your Teeth: Preventing Future Cavities
Preventing future cavities centers on disrupting the cycle of bacterial acid production. Brushing for two minutes twice daily with fluoride toothpaste is foundational, as fluoride helps strengthen the enamel. Daily flossing is equally important because it removes plaque and food particles from between teeth, where a toothbrush cannot reach. Limiting the frequency of consuming sugary and acidic foods and drinks reduces the fuel source for decay-causing bacteria, and regular professional check-ups allow a dentist to address any signs of decay while they are minor.