Dental fillings are restorative materials used to repair teeth damaged by decay or trauma. The purpose of a filling is to stop the progression of a cavity by removing the diseased portion of the tooth and replacing it with a material that restores the tooth’s original form and function. This process prevents bacteria from further compromising the tooth structure. Although the procedure is routine, the safety of the materials used is a common concern for many patients. Understanding their composition provides a clearer perspective on their role in long-term oral health.
Understanding the Primary Filling Materials
Two types of filling materials are most commonly used: dental amalgam and composite resin. Dental amalgam, often called a “silver filling,” is a durable mixture of metals, primarily consisting of liquid mercury and an alloy of silver, tin, and copper. This material is resistant to wear, making it a reliable and cost-effective choice for restoring back teeth that endure heavy chewing forces.
Composite resin fillings are tooth-colored, made from a blend of acrylic plastic and finely ground glass particles. A primary advantage is its ability to chemically bond to the tooth structure, which supports the remaining tooth and often requires less removal of healthy material. These fillings are preferred for visible areas of the mouth because they match the natural color of the surrounding teeth. Other options, like gold and ceramic, are also used but make up a smaller portion of restorations performed today.
Addressing Safety Concerns About Dental Fillings
The safety debate centers on dental amalgam due to its mercury content, which comprises about 50% of the material. A small amount of elemental mercury vapor can be released from the filling over time, particularly during chewing or brushing. This potential for low-level exposure has led to public concern regarding systemic health effects.
Major health organizations, including the U.S. Food and Drug Administration (FDA) and the American Dental Association (ADA), have reviewed the scientific evidence. Their consensus is that the evidence does not demonstrate that the mercury vapor released from amalgam fillings leads to harmful health effects in the general population. The exposure levels are below the thresholds considered hazardous for individuals aged six and older.
However, the FDA recommends that certain groups may want to avoid new amalgam fillings, based on limited data and the precautionary principle. This includes:
- Pregnant women, women planning to become pregnant, and nursing mothers.
- Children younger than six.
- People with existing neurological diseases or impaired kidney function.
For composite resins, concerns have been raised about trace amounts of compounds like Bisphenol A (BPA) which can leach out, but this release is minute and ceases quickly after placement.
Immediate Issues Following a Filling Procedure
Following the placement of a new filling, patients often experience common, short-lived sensations that are a normal part of the healing process. Post-operative sensitivity is the most frequent issue, often a sharp, momentary pain triggered by hot or cold temperatures, or sweet foods. This occurs because the drilling and cleaning process can temporarily irritate the tooth’s inner nerve tissue.
This sensitivity usually diminishes within a few days to a couple of weeks as the nerve heals. Another common issue relates to bite adjustment if the new filling surface is slightly too high. An elevated filling places excessive pressure on the tooth when biting down, potentially causing pain or discomfort once the local anesthetic wears off. If the bite feels uneven or causes pain when closing the mouth, a simple adjustment by the dentist is necessary to correct the issue.
Recognizing When a Filling Needs Attention
Although modern fillings are durable, they do not last indefinitely and will eventually require replacement due to normal wear. Constant chewing forces subject the material to stress, which can lead to structural compromise over many years. A filling may begin to fail if it develops a chip, a visible crack, or if the seal between the filling and the tooth breaks down.
This loss of a tight seal, known as leakage, allows food debris and bacteria to seep beneath the restoration, causing a new cavity called secondary decay. Signs that a filling may need attention include increased sensitivity that is persistent rather than momentary, a dark spot or shadow appearing near the edge, or a piece of the filling feeling rough or sharp to the tongue. Any pain when biting or a visible gap around the restoration indicates a structural failure that should be examined by a dental professional to prevent more extensive damage.