A dental filling is a restoration that replaces tooth structure lost to decay, aiming to preserve the function and integrity of the tooth. Fillings do not dissolve or vanish, but they are not permanent fixtures. They are designed to be durable but will eventually fail, requiring replacement due to wear and tear over time.
Lifespan and Material Types
The durability of a dental filling depends greatly on the material chosen, the size of the restoration, and its location in the mouth. Tooth-colored composite resin fillings, which are popular for their aesthetic match to natural teeth, typically have an average lifespan of five to ten years. This material is a mixture of plastic and fine glass particles bonded directly to the tooth structure.
Silver-colored amalgam fillings are known for their high durability and ability to withstand heavy chewing forces, particularly in back teeth. Amalgam restorations often last longer than composite, with an expected lifespan ranging from ten to fifteen years or more. The material is a combination of metals, including silver, copper, and tin.
For maximum longevity, gold and porcelain restorations, often placed as inlays or onlays, are the most enduring options available. Gold fillings can last significantly longer, often for twenty years or more, because the metal does not corrode and is highly resistant to fracture. Porcelain fillings also offer good durability, usually lasting between ten and fifteen years, while providing a natural appearance.
Mechanisms of Filling Deterioration
A filling’s eventual need for replacement is due to mechanical or structural failure that compromises the seal with the tooth, rather than the material dissolving. The most common reason for failure is secondary or recurrent decay, which is new decay that forms at the margin of the existing filling. This occurs when microscopic gaps develop between the filling and the natural tooth structure, allowing bacteria and food particles to seep underneath. This breakdown of the seal, known as microleakage, creates a pathway for decay-causing bacteria to attack the underlying tooth.
Over time, the filling material itself can wear down, leading to marginal ditching or a gap large enough to trap plaque. This process ultimately undermines the integrity of the entire restoration, making it susceptible to failure.
Mechanical failure is another significant mechanism of deterioration, especially for larger fillings subjected to intense biting forces. Consistent pressure from chewing, clenching, or grinding can cause the filling to chip, crack, or fracture. In some cases, the pressure can even cause a fracture in the surrounding tooth structure, which necessitates replacing the filling with a larger restoration or a full crown.
Recognizing the Need for Replacement
A compromised filling often sends signals that it is failing, with increased sensitivity being a frequent patient-perceived symptom. Experiencing discomfort when consuming hot or cold foods and drinks can indicate that the protective seal is no longer intact. Sensitivity to pressure when biting down on the affected tooth is also a sign that the filling may be cracked or that decay is progressing underneath.
Visible Signs of Failure
Visible signs of failure include:
- A rough edge, chipping, or cracking of the filling material.
- Darkening or staining around the perimeter of a tooth-colored filling, signaling marginal leakage.
- A persistent bad taste or foul odor that does not resolve with brushing.
- The filling is lost entirely, leaving an obvious gap or hole that requires immediate attention.
Extending the Life of Your Fillings
Maximizing the lifespan of a dental filling relies heavily on consistent and proper oral hygiene practices. Diligent brushing and flossing are necessary to remove plaque, particularly around the margins where the filling meets the natural tooth. Preventing plaque buildup at this junction reduces the risk of secondary decay, which is a primary cause of filling failure.
Avoiding habits that place undue mechanical stress on the teeth can prevent premature fracture of the restoration. This includes refraining from chewing on hard items like ice or hard candies, and managing conditions like teeth grinding or clenching. Regular checkups and X-rays allow a dental professional to monitor the condition of the margins and detect microleakage or small cracks before they lead to extensive decay.