A dental filling is a restoration used to repair a tooth damaged by decay or minor fracture. The process involves removing the compromised material and filling the space to restore the tooth’s shape and function. Fillings are not designed to last indefinitely, as they are constantly subjected to stress from chewing forces and the oral environment. Over time, every filling will eventually require maintenance, repair, or complete replacement to protect the underlying tooth structure.
The Expected Lifespan of Different Filling Materials
The lifespan of a dental filling depends heavily on the material used. Modern dentistry primarily utilizes two common materials, offering different trade-offs in durability and aesthetics. Amalgam, often called a silver filling, is known for its strength and ability to withstand significant chewing forces, particularly in back teeth. These metal fillings typically last between 10 and 15 years.
Composite resin, a tooth-colored material, is preferred for its natural appearance but is less durable than amalgam. A composite filling typically lasts about five to ten years, with an average functional life often cited around seven years. Glass ionomer is sometimes used for small, non-load-bearing areas, and these tend to have a shorter lifespan, often lasting only five to seven years.
Warning Signs That a Filling Needs Attention
Several indicators alert a person that an existing filling is compromised and needs professional evaluation.
- Sudden or lingering sensitivity to temperature changes, which suggests the filling has pulled away and exposed the sensitive dentin layer.
- Pain when biting or chewing, which can indicate the filling has cracked or is loose.
- A visible chip or crack in the filling material itself.
- A noticeable dark margin around the edge of the restoration, suggesting leakage and recurrent decay beneath the filling.
- Food consistently catching in a specific area, signaling that the filling’s contour has worn down or the seal has been lost.
Factors That Accelerate Filling Deterioration
The lifespan of any filling is significantly influenced by mechanical and biological forces. Fillings on molars, which absorb the greatest impact from chewing, wear down faster than those on front teeth. Bruxism, the involuntary grinding or clenching of teeth, places constant pressure on fillings, causing them to chip, crack, or fail prematurely.
Poor oral hygiene is a primary driver of failure because it allows recurrent decay to develop at the interface between the filling and the natural tooth. This decay breaks down the marginal integrity, allowing bacteria to penetrate the tooth beneath the restoration. Diet also plays a role, as frequent intake of hard, sticky, or acidic foods can erode the material or place excessive stress on the filling.
The Replacement Process and Alternatives
When a dentist determines a filling has failed, the first step is to remove the old restoration and any underlying decay. Subsequent treatment depends on the extent of damage found in the remaining tooth structure. If the decay is minor and the tooth walls are largely intact, a simple replacement with a new filling material may be sufficient. If the damage is extensive, however, the tooth may no longer have enough healthy structure to support a direct filling.
Indirect Restorations
In extensive cases, the dentist may recommend an indirect restoration, which is custom-made in a laboratory. An inlay is used when the decay is contained within the cusps on the biting surface of the tooth. An onlay is a more extensive restoration that covers one or more cusps, offering greater structural support than a simple filling. Both inlays and onlays are considered more durable than traditional fillings and reinforce the remaining tooth structure.
Crowns and Monitoring
If the tooth structure is severely compromised, a full-coverage crown may be required to protect and restore the entire biting surface. Regular dental check-ups and X-rays are important for monitoring existing restorations. This allows the dentist to detect early signs of leakage or failure before the damage requires a more involved procedure.