Overview

The dental profession has always emphasized preventive care. Now, this spirit of prevention needs to extend to preventing the release of amalgam to the environment.

Amalgam is typically 50 percent mercury by weight. However, the mercury in amalgam chemically combines with other metals to render the mercury stable and safe for use in dental applications.

Given that dental amalgam contains mercury, dentists must safely dispose of amalgam waste to ensure it does not inadvertently become incinerated or disposed of in a way that would release mercury back into the environment in a free form.

Amalgam is, and will likely remain, an efficient and effective restorative material. Dentists will continue using it for the foreseeable future, although its use continues to gradually decline. Even if dentists completely stopped using amalgam for new fillings, the removal of old amalgam will continue to generate waste.

At dental offices, vacuum systems discharge amalgam to the sewerage system when dentists place or remove amalgam fillings. Mercury pollution has caused the Wisconsin Department of Natural Resources to issue a statewide fish consumption advisory.

The DNR requires sewage treatment facilities to implement a mercury minimization program to address mercury in wastewater. A primary element of this program is reducing the amount of amalgam discharged by dental offices.

The WDA also has identified best management practices for amalgam waste disposal. While important, best management practices alone may not be enough for regulated wastewater systems to meet the Environmental Protection Agency’s discharge standards. Some local wastewater systems will require dentists in their service areas to install amalgam separators.

If your community requires an amalgam separator, they are available from several suppliers and are decrease amalgam in wastewater by 95 percent or more. See more information below.  The WDA endorses HealthFirst for this service.

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Types of amalgam

  • Non-contact amalgam (scrap) is excess mix leftover at the end of a dental procedure. Many recyclers will pay for this clean up.
  • Contact amalgam is amalgam that has been in contact with the patient. Examples are extracted teeth with amalgam restorations or amalgam captured by chair-side traps, filters or screens.
  • Chair-side traps capture amalgam waste during amalgam placement or removal procedures. (Traps from dental units dedicated strictly to hygiene may be placed in with regular garbage.)
  • Vacuum pump filters or traps contain amalgam sludge and water. Some recyclers will accept whole filters. Others will require special handling of this material.
  • Amalgam sludge is the mixture of liquid and solid material cleaned up from vacuum pump filters or other amalgam capture devices.
  • Empty amalgam capsules are the containers leftover from precapsulated dental amalgam.

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Steps for recycling

  1. Use universal precautions such as gloves, masks and protective eyewear when handling amalgam waste.
  2. Contact an amalgam waste recycler about any special requirements for collecting, storing and transporting amalgam waste.
  3. Store amalgam waste in a covered plastic container labeled “Amalgam for Recycling”, or as directed by your recycler. Consider keeping different types of amalgam wastes in separate containers – talk to your recycler about any advantages.

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Choosing a separator

More dentists are considering purchasing amalgam separator units to decrease the amount of amalgam in the wastewater leaving their offices. Although this decision is a positive one for the environment, it is not necessarily an easy one for the dentist. While the WDA endorses HealthFirst for amalgam separators, there are a variety of providers to choose from.

These units differ in terms of capacity, physical dimensions, amalgam removal process, how captured amalgam is removed and recycled, how easily they are serviced and how often, and how much they cost to buy and operate. Without some guidance, evaluating amalgam separators can be like comparing apples and oranges. This guide was designed to help dentists identify their specific needs and the key aspects of their office systems that determine which separator unit(s) will be most suitable for their operations.

Step 1: Decision flow sheet

By answering a series of questions relating to your office set-up, the dentist is led to an initial list of separator units that will probably work for his or her office.

These questions include:

  • Are your amalgam generating chairs centrally plumbed?
  • Does your office have a wet ring or dry vacuum pump system?
  • Is the space available for installing a separator unit at office grade or below grade?
  • Do you need to install the separator ahead of or after either the wet ring or dry vacuum pump system?

The dentist’s answer to each of these questions will lead him or her to an appropriate set of potential separators for evaluation.

Step 2: Separator comparison matrix

This matrix allows a comparison of the initial list of separator units generated in the decision flow sheet above, helping the dentist zero in on which unit(s) is the best for his or her dental practice. The matrix provides both qualitative and quantitative comparisons of 15 different amalgam separator units produced by 11 different companies. The units have been commercially available since early 2004. It also provides telephone and Web site contact information for each manufacturer.

The evaluation criteria include:

  • Model Dimensions – shows the height, width and depth, indicating how much space each unit requires.
  • Flow Capacity – indicates the number of chairs (anywhere from 1 to 25) that can be serviced by one unit.
  • Ease of Maintenance – a ranking of 1 to 3 shows the relative ease of maintenance compared to other units.
  • Frequency of Maintenance – a ranking of 1 to 3, along with more specific information where available, indicates how often amalgam waste must be removed from the unit.
  • Recycling Program Included – indicates whether the manufacturer provides for an automatic system for removing and recycling the waste amalgam captured in the unit.
  • Purchase Cost – provides both actual cost and a relative (1 to 3) ranking among units.
  • O&M Cost – provides a relative ranking of operation and maintenance costs as well as specific information where available.
  • Five-Year System Cost – provides both an estimated five-year cost (purchase plus O&M costs) and a relative ranking among units.

After working through the decision flow sheet (Step 1) and the matrix (Step 2), the dentist should have a good idea about which unit(s) is most suitable for his or her specific circumstances. Hopefully, this exercise will also result in a list of more specific questions for your dental equipment supplier or the separator manufacturer. Working together with your supplier or manufacturer’s rep, you should now be sufficiently prepared to purchase an amalgam separator unit that will meet your needs and protect the environment for many years to come.

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Recyclers

The WDA frequently receives member inquiries regarding the selection and installation of amalgam separators. Presently, certification under ISO 11143 (as issued by the International Organization for Standardization) has been the standard adopted by those local sewerage districts in Wisconsin that have previously mandated separators and this standard should provide a good starting point for selection of a separator for any dental practice that has not already installed one.

The Environmental Protection Agency has announced that it intends to issue a final rule regarding its national plan for a reduction of mercury waste from dental offices before the end of 2012; this could include a national amalgam separator mandate.

While many options are available, the WDA endorses HealthFirst for amalgam separators, LB Medwaste for the removal of medical waste, and Scientific Metals for the recycling of precious metals.

Also, below is a list of amalgam recyclers.  This list is provided solely as a service to members and should not be viewed, or in any way interpreted, as a recommendation or endorsement of companies included on the list. Similarly, absence of a company from the list should not be interpreted as a negative comment on that company or on the quality or suitability of its product. While the WDA strongly encourages the installation and use of amalgam separators, we assume no responsibility or liability in connection with separator selection and urge that each member conduct their own independent evaluation from among all available products.

*Note if you choose a recycler not on this list, be sure they are licensed to receive and handle these materials.

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Best management practices

DO DO NOT
Use precapsulated alloys and stock a variety of capsule sizes Use bulk mercury
Recycle used amalgam capsules Put amalgam capsules in biohazard containers, infectious waste containers (red bags) or regular garbage
Salvage, store and recycle non-contact amalgam (scrap amalgam) Put non-contact amalgam in biohazard containers, infectious waste containers (red bags) or regular garbage
Salvage amalgam pieces from restorations after removal (contact amalgam) and recycle the amalgam waste Put contact amalgam in biohazard containers, infectious waste containers (red bags) or regular garbage
Use chair-side traps to retain amalgam and recycle their contents Rinse chair-side traps containing amalgam over sinks or other drains
Recycle the contents retained by the vacuum pump filter or other amalgam collection device Rinse vacuum pump filters or other amalgam collection device over sinks or other drains
Recycle extracted teeth that contain amalgam restorations* Put extracted teeth with amalgam restorations in biohazard containers, infectious waste containers (red bags) or regular garbage
Use line cleaners that do NOT contain bleach or other chlorine compounds Use line cleaners that contain bleach or other chlorinecompounds
RECYCLE AS MUCH AMALGAM WASTE AS POSSIBLE FLUSH AMALGAM WASTE DOWN A SINK, TOILET, OR OTHER DRAIN

*Confirm with your recycler whether it accepts extracted teeth. Disinfect extracted teeth by storing them in an airtight container with a solution of glutaraldehyde or 10 percent formalin until they are removed for recycling with your other amalgam waste.

Amalgam capsules

  1. Stock amalgam capsules in a variety of sizes
  2. After mixing amalgam, place the empty capsules in a wide-mouthed, airtight, plastic container that is labeled Amalgam Capsule Waste for Recycling*
  3. Place any non-empty capsules into this container
  4. Ensure that the container is tightly sealed at all times
  5. When the container is full, send it to a recycler

Non-contact (scrap) amalgam

  1. Place non-contact (scrap) amalgam into a widemouthed, airtight, plastic container that is labeled Non-contact Amalgam Waste for Recycling*
  2. Ensure that the container is tightly sealed at all times
  3. When the container is full, send it to a recycler

Disposable chair-side traps

  1. Remove the trap and place it into a wide-mouthed, airtight, plastic container labeled Contact Amalgam Waste for Recycling*
  2. Ensure that the container is tightly sealed at all times
  3. When the container is full, send it to a recycler
  4. If a chair is strictly dedicated to hygiene, then place the trap into the regular garbage

Reusable chair-side traps

  1. Remove the trap and empty the contents into a widemouthed, airtight, plastic container labeled Contact Amalgam Waste for Recycling*
  2. Ensure that the container is tightly sealed at all times
  3. When the container is full, send it to a recycler
  4. Do NOT rinse the trap under running water

Vacuum pump filters

  1. Obtain instructions and schedule for filter replacement from the manufacturer
  2. Change the filter according to the recommended schedule
  3. Obtain instructions for handling the used filter from your recycler
  4. If you are required to decant water from the filter before recycling, pour the water into a tray or other container that can catch any spills and pour very carefully to avoid losing any amalgam

Line cleaners

Use line cleaners that do NOT include bleach or other chlorine compounds.

Disinfection

Disinfecting amalgam waste for recycling is unnecessary, except for extracted teeth that contain amalgam restorations. For disinfection use glutaraldehyde or 10 percent formalin rather than bleach. Bleach dissolves amalgam and releases mercury. Use bleach only if your recycler accepts the disinfectant solution along with the amalgam waste.

*Some recyclers allow you to place all amalgam waste, including capsules, non-contact amalgam, contact amalgam, traps, filters, and teeth into the same container. If so, you may use one container labeled Amalgam Waste for Recycling. Follow your recycler’s instructions for packaging and shipping amalgam waste.

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Links and resources

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