White or dark fillings?

White fillings are made of composite resin. They are used instead of the old dark-colored amalgam fillings to restore a tooth after it has been cleaned of decay.

Composite resin fillings give the dentist the ability to modify the shape, size, and color of the front teeth, while they are also suitable for large restorations (usually posterior teeth).

The advantages of a white filling are:

• Better aesthetic result, as it can mimic the natural color of the teeth.
• Greater bonding of the material to the tooth and removal of less tooth structure during placement, compared to amalgam fillings. It can also be used in more cases than amalgam.
• Its “repair” is easier in case a piece becomes detached.
• Complete avoidance of the mercury that was contained in old amalgams.

Although amalgam has not yet been officially discontinued, it is used less and less because there has been great advancement in composite resin materials based on nanotechnology and an even greater advancement in bonding materials.

Amalgam toxicity

Since the early 1980s, growing concern began to develop regarding the danger of amalgam and specifically its mercury content. Mercury is considered the most toxic non-radioactive element. This concern was based on and fueled by two main factors. The first was the multitude of research studies reporting the emission of mercury vapors and its detection in the human body, and the second was the environmental contamination from dental amalgam waste.

There is no doubt that mercury is a dangerous element for the health of humans and animals when exposure exceeds the permissible daily amount, which has been set at 20-40 μg (micrograms).

To date, any attempt to link the low levels of mercury detected in body fluids and tissues with various degenerative conditions, mainly of the central nervous system (Alzheimer’s disease, Parkinson’s disease, multiple sclerosis), is unfounded and has not been proven. To date, there has been no documented evidence of the harmful effects of the mercury contained in amalgam.

The mercury contained in dental amalgam cannot cause poisoning. If you have metallic fillings in your mouth, the amount of mercury that can be released into the mouth during chewing is extremely small and essentially harmless. Finally, it is worth noting that mercury can be found in the air, food, and water. The amount of mercury to which we are exposed from these sources is greater than that from having amalgam fillings in our mouth.

The problem, however, seems to focus more on the impact of amalgam mercury on the environment. Increased mercury levels in atmospheric air are recycled into the food chain through plants and vegetables, where mercury, after being converted to methyl mercury, becomes fat-soluble and accumulates in fatty tissue.

Dental mercury, through the sewage system, certainly contributes to environmental pollution. The proper and complete trapping of amalgam residues is the only solution for environmental protection, even during a period of phasing out this material from dentistry.

It is known that mercury can cross the placenta from mother to fetus and can also be detected in breast milk, but there is no evidence of any connection between the use of amalgams and birth defects or abnormalities. In general, it is reasonable to minimize medical interventions during pregnancy. The 1998 report by the European Commission on toxicity states that there is no reason to believe that the placement or removal of amalgam fillings during pregnancy was harmful. The Committee on Toxicity agreed with the European Commission’s expert group; however, that the placement or removal of amalgam fillings should be avoided, where possible, during pregnancy.

This does not constitute a ban on the use of dental amalgam during pregnancy.
In children who need dental treatment, safe composite resins and glass ionomer cements can be used with great success.

Composite resin toxicity

Observations that began in 1980 generated increasing interest regarding whether components of composite resins have estrogenomimetic action — that is, whether they can mimic the effects of estrogen. The mild estrogenomimetic and toxic action of agents such as bisphenol A, which is a product released from the resin after incomplete polymerization, raised concerns in the scientific community.

However, it is observed that bisphenol A and other resin components would need to be present at extremely higher concentrations in order to affect the reproductive and other systems of the body. Given, however, that the safety of patients and especially children should be our first priority, further research should be conducted on this matter.