Mercury in dental amalgam
Safe or toxic?
Dental amalgam, a dental restorative material that contains a mercury alloy, has been used since the early days of dentistry. Most dentists consider amalgam harmless. It is the restorative material of choice for dentists and patients alike because of its many qualities, particularly the following:
- Physical properties
- Ease of handling
- Resistance
- Effectiveness
- Durability
- Cost advantage over other materials
Until the 1970s, the only criticism surrounding the use of dental amalgam was its silver colour. No one worried about the fact that it contained a metal alloy mixed with mercury, a substance with toxic properties. Given that it presented no danger once mixed and chemically bonded to the alloy, dental amalgam was considered innocuous.
This belief was called into question in the 1970s, when a researcher discovered that mercury vapour could escape from the amalgam. Thus began the mercury controversy and its attendant fear campaign that proved groundless in the long run. A U.S. study conducted by the American Council on Science and Health (ACSH), a consumer watchdog association, concluded in 1998 that questions raised by the presence of mercury in dental amalgam had been an unnecessary concern.
In fact, scientists who subsequently studied the issue established that while mercury vapour emanating from amalgam is a recognized fact, the quantities thus released and to which patients are exposed are minimal and pose no health threat.
Research has shown that only a fraction of the mercury vapour (approximately 10%) is absorbed from dental amalgam and that most of this amount is absorbed by the lungs and expelled by the body.
A comparison was made of mercury content in patients before and after receiving an amalgam restoration and before and after its extraction. It was noted that dental amalgam did not significantly contribute to an individual's total daily mercury exposure or absorption.
Another study showed that total daily mercury absorption in all its forms (including from dental amalgam, food, air and water, through natural means or from human activity) was 2.3 micrograms per day. The Environmental Protection Agency (EPA) has set the reference dose (daily oral exposure likely to be without an appreciable risk of deleterious effects during a lifetime) at 5.8 micrograms per day.
In addition, the International Union of Pure and Applied Chemistry has established the lowest-observed-effect level (LOEL) for mercury at 38 micrograms per day. The World Health Organization has established this level at 40 micrograms per day.
This reassuring data, without trivializing mercury exposure, clearly establishes the safety of dental amalgam as currently used in modern dentistry.
ODQ Board of Directors
May 2005
Guidelines - Managing Obstrutive Sleep Apnea with Mandibular Advancement Devices
|
Bloodborne Infections
and Public Protection
ODQ Guidelines Relative to Fluoride Supplements
The Ordre des dentists du Québec supports the appropriate use of fluorides in the prevention of dental caries as one of the most successful preventive health measures in the history of health care. The availability of fluorides from a variety of sources, however, is a current reality which the practising dentist needs to take into account in dealing with patients. This is particularly true of children under the age of six, where exposure to more fluoride than is required simply to prevent dental caries can cause dental fluorosis. There is no evidence of any health problems being created by such exposure, but it is prudent to attempt to limit exposure to the optimal levels required for continuing dental caries protection. Current levels of fluoride intake from all sources are difficult to establish for any given area, but the dentist should consider general intake to the extent possible in recommending fluoride supplementation.
The following suggestions are consistent with these principles:
- Fluoride supplements are only required for high dental caries risk patients and may be unnecessary if the patient is receiving adequate fluoride from other sources.
- Before prescribing fluoride supplements, a thorough clinical examination, dental caries risk assessment and informed consent with patients/caregivers are required.
- The Canadian Consensus Conference on the Appropriate Use of Fluoride Supplements for the Prevention of Dental Caries in Children, held in November 1997 suggested that high caries risk individuals or groups may include those who do not brush their teeth (or have them brushed) with a fluoridated dentifrice twice a day or those who are assessed as susceptible to high caries activity because of community or family history, etc.
- The estimation of fluoride exposure from all sources should include use of fluoridated dentifrice and all home and child care water sources. Dentists should be aware of the average fluoride exposure in their area. The possible impact of fluoride reducing factors within the home such as the use of unfluoridated bottled water of some reverse osmosis devices should be taken into account.
- Lozenges or chewable tablets are the preferred forms of fluoride supplementation. Drops may be required for individual patients with special needs.
- The use of fluoride supplements before the eruption of the first permanent tooth is generally not recommended. When, on an individual basis, the benefit of supplemental fluoride outweighs the risk of dental fluorosis, practitioners may elect to use these supplements at appropriate dosages on younger children. In doing so, the total daily fluoride intake from all sources should not exceed 0.05-0.07 mg F / kg body weight in order to minimize the risk of dental fluorosis.
- Following the eruption of the first permanent tooth and the associated decrease in the risk of dental fluorosis at this stage of development, fluoride supplements in the form of lozenges or chewable tablets may be used to deliver an intra-oral fluoride dose. A lozenge or chewable tablet containing 1 mg fluoride delivers the same amount of fluoride intra-orally as brushing with an average load (1 mg) of a 1000 ppm fluoride dentifrice.
ODQ Board of Directors
May 2001
Safety of Human Cells, Tissues and Organs for Transplantation
The final version of the Guidance Document Safety of Human Cells, Tissues and Organs for Transplantation is now available on the Health Canada website, located at: www.hc-sc.gc.ca/dhp-mps/brgtherap/reg-init/cell/index-eng.php.
This document provides an overview as well as an interpretation of the Safety of Human Cells, Tissues and Organs for Transplantation Regulations (CTO Regulations). It is intended to help readers determine whether the CTO Regulations apply to their activities and if so, give more details as to meeting the regulatory requirements. If you have any questions concerning the CTO Regulations themselves or this guidance document; please contact the CTO Unit of the Biologics and Genetics Therapies Directorate email at BGTD_PPD_DPP@hc.gc.ca.
Implant-Supported Rehabilitation - Guidelines
Implant-supported rehabilitation - Training required
Answers to your questions
Declaration on the frequency of
recall examinations adopted by the ODQ
Recall frequency is patient specific, based on the individual needs of the patient. In the best interest of the oral health of the majority of patients in Quebec, a minimum of twice yearly recall is indicated.
ODQ Board of Directors
November 1998
Guidelines for the use of pit and fissure sealants
Objectives
Recognize the use of pit and fissure sealants for the prevention of dental caries and the control of incipient caries limited to enamel.
Scientific evidence
Since the end of the 1970s, numerous random comparative studies have demonstrated that sealants are effective in preventing pit and fissure caries of permanent teeth. Furthermore, longitudinal studies have demonstrated the effectiveness and safety of sealants in stopping the progression of caries in enamel.
Benefits
Reduction in the prevalence of dental caries and control of caries in enamel at a minimal biological cost.
Recommendations
Based on scientific evidence, pit and fissure sealants may be recommended for the prevention of dental caries and the control of caries in enamel. Their judicious and selective use must be based on caries risk assessment of each patient and each tooth by a dentist. The dentist is also required to render a diagnosis, prepare the tooth surface, apply an adequate amount of sealant and provide the appropriate follow-up.
Validity
A bibliography supporting these recommendations is available upon request at the head-office of the Ordre des dentistes du Québec. These guidelines will be subject to periodic revision.
ODQ Board of Directors
October 1998
Position of the Ordre des dentistes du Québec on teeth whitening products
Whitening natural teeth using products containing peroxide or special whitening toothpaste is becoming increasingly popular with the public. Given this widespread interest, a vast range of products is now available on the market in various forms, from gels to self-adhesive strips, kits with trays, chewing gum and mouthwash.
The term "whitening" refers to any process intended to brighten teeth. Two types of products are used for this purpose. First, there are bleaching products that actually alter the colour of the tooth enamel by means of peroxide, a product that can reduce deep and surface stains. Then there are whitening products that do not change the colour of the enamel, but simply remove surface stains.
Bleaching products containing peroxide
There are two main types of bleaching products: those with a high concentration of peroxide, used under a light or laser in a dentist's office, and products distributed by dentists or sold over the counter, for use at home.
The most common side effects associated with bleaching products are temporary tooth sensitivity and occasional irritation of soft tissues. In some exceptional cases, teeth have been irreversibly damaged.
Whitening products
Whitening products, including toothpaste, chewing gum and mouthwash, contain abrasives or chemicals to improve tooth appearance. They reduce surface stains using light polishing or other actions that do not alter tooth colour.
The ODQ's position
Tooth bleaching using colour-altering products is a safe therapeutic choice, when carried out under a dentist's supervision and according to the manufacturer's recommendations. It may not be suitable for everyone, however.
The Ordre des dentistes du Québec recommends that patients, especially those with many fillings or crowns or heavy staining, consult their dentist to decide on the treatment that best suits them.
The Order also suggests that pregnant women delay bleaching treatment until after they have given birth. Children under age 12 should not use bleaching products.
ODQ Board of Directors
May 23, 2008
Temporomandibular Joint Disorders: Some considerations concerning diagnostic methods and treatments
L’utilisation des mesures de contention
Publication :
|
September 2009 |
Editor :
|
Ordre des dentistes du Québec |
Download : |
Document (PDF 84 Kb) (French only) |