Amalgam filling

Amalgam filling or dental amalgam was the most commonly used dental restorative material used for dental fillings. it contains a mixture of mercury with at least one other metal. Amalgam has been the restorative method of choice for many years due to its low cost, ease of application, strength, durability, and bacteriostatic effects. Factors that have led to recent decline in use are a lingering concern about detrimental health effects, aesthetics, and environmental pollution.

Amalgam fillings or silver fillings: are they harmful to my health?

Dentists have used dental amalgam for more than 150 years. However, over the past decade, more and more people are concerned about the safety of this longest-lived and most affordable filling material. Amalgam is an alloy of many metals, including silver, copper, zinc and mercury. The main concern of this material is about its 45% mercury content. According to many people’s understanding, mercury is very toxic. However, there is detailed information about this that people oversee. Mercury in its elemental form, such as in old-fashioned mercury thermometers, is toxic. But when it is mixed with other metals, and turned into an alloy as the one in the silver fillings, it becomes inactive and safe. Nonetheless, the media and other anti-amalgam groups including some consumer groups, environmentalists, lawyers, and holistic dentists have been successful to lead many people to believe the contrary. Their argument is based on some studies claiming that the mercury in amalgam fillings is hazardous and directly related to Alzheimer’s disease, autism and multiple sclerosis. On the other hand, some important scientific and public health organizations argued that these studies was based on faulty science and they insist that 150 years of scientific research and real-world application of amalgam fillings have proven its safety. These organizations include the Food and Drug Administration (FDA), World Health Organization (WHO), U.S. Public Health Service (UDPHS), Centers for Disease Control and Prevention (CDC), American Dental Association, Canadian Dental Association, and Academy of General Dentistry. Are you confused about this issue as well? What can you do as a dental consumer? First, you have to understand the pros and cons of amalgam fillings as compared to its alternative, i.e. composite or white fillings.

Amalgam is a very good filling material based on the followings:

  1. Cheapest and most affordable as compared to the white filling. The dental fee for white filling is about 30-40% higher than amalgam fillings.
  2. It is more forgiving to be worked in a wet field as compared to composite fillings. In the case of a very deep fillings and difficult to keep the area dry because of too much saliva or too much bleeding or patient cannot tolerate the use of rubber damp to isolate a dry field, composite filling placed in this situation will not last long because it has to be bonded onto the tooth structure and this bonding will not take place when the field was wet. In contrast, amalgam filling does not depend on this bonding mechanism. It stays in place in the tooth by “mechanical inter-locking.”
  3. Amalgam, being a metal alloy, is very strong and long lasting material, as compared to the plastic-like synthetic composite material used in white fillings. In addition, it does not shrink in size after setting. In contrast, composite filling will shrink after setting. This may create some sensitivity to biting. However, recent advancement in dental material science has produced some composite materials with very strong and very high wear-resistance as well minimal shrinkage. Personally I do not encounter a significant difference in post-operative sensitivity complaints between white fillings and amalgam fillings.

White or composite fillings may be your choice over amalgam based on the followings:

  1. It is more esthetics, since it is tooth-colored while amalgam is silver colored.
  2. It is more conservative in the preparation of the tooth to receive the filling. Because amalgam stays onto a tooth by mechanical retention, the dentist has to create some specific form in order to create an interlocking effect to hold the amalgam physically. This requires removing some good tooth structure in addition to removal of the decayed tooth structure. In contrast, because white filling stays onto a tooth by chemical bonding, only removing the decayed tooth structure is all needed most of the time prior to placing the filling. This is especially significant when the cavity is very small and the dentist wants to conserve the good tooth structure as much as he can.
  3. When a tooth has lost the majority of its structure, ideally a crown will be the choice of restoration. But if you cannot afford having a crown placed, then a huge filling is your next option. In this case, I have found composite filling is often better than amalgam filling because of its bonding mechanism to stay onto the tooth (just like being “glued” to the tooth surfaces). If amalgam is used in this case, dental pins are normally necessary in order for it to stay onto the tooth because there is not enough tooth structure to physically “lock” the amalgam in place. Research has shown dental pins create micro-cracks which increase the chance of tooth fracture or the need of root canal therapy.
  4. If the “amalgam controversy” has given you sleeplessness.


Now let me share with you my personal stance. Because of its superior esthetics and its lack of controversy, composite restorations have become my primary filling material. I rarely insert amalgam fillings nowadays unless patient specifically asks for it. On the other hand, I will not suggest to patients to have their existing amalgam fillings replaced for the reason that they are hazardous to their health. If the patients want to change the amalgam fillings to white fillings because of cosmetic reasons, I will be pleased to have them done. However, I always make sure the patients understand that it is an elective procedure and there is a possibility that the tooth can turn into inflammation and eventually requires root canal therapy because of this elective procedure.