MERCURY CONTROL

To minimize personnel exposure and environmental contamination of elemental mercury in DTF's, follow the handling procedures in BUMEDINST 6260.30.

Mercury, which vaporizes at room temperature, is a significant health hazard if a sufficient amount is ingested, absorbed through the skin, or inhaled. The potential for personnel exposure to elemental mercury vapor has been greatly reduced by the use of pre-encapsulated amalgam.

Because of the health hazard potential of mercury, control procedures for the handling and disposal of amalgam, or mercury-contaminated items are mandatory.

Dental amalgam is an inter-metallic compound comprised of various proportions of silver, copper, tin, and zinc alloy mixed with pure mercury. This mixture of metals forms a compound that is stable both physically and chemically and will not break down into the original elements.

Personnel Hygiene

Proper mercury handling and hygiene procedures are required for all dental personnel and will be emphasized during training and indoctrination periods. Before working with mercury-bearing materials (amalgam or scrap amalgam), personnel must remove all jewelry that could potentially become contaminated and permanently damaged. Eating, smoking, or drinking is not permitted while working with mercury-bearing materials. The use of patient examination gloves should be used to minimize skin contact. You should always wash your hands after working with mercury-bearing materials before leaving the DTR.

Work Surfaces

Work surfaces are made of impervious (non-porous) material, usually made of stainless steel or plastic laminate.

Handling

Personnel should use a no-touch technique for handling amalgam. After trituration (mixing) of the pre-encapsulated amalgam, personnel should use an amalgam well for loading the amalgam carrier. Personnel must also use water spray and the high-volume evacuator when cutting or grinding ^{amalgam restoration.} Collect all amalgam scraps before removing the rubber dam.

Amalgamators that completely enclose the capsule during amalgamation (mixing) should be used. The amalgamator enclosure should be inspected weekly for mercury globules and cleaned. The amalgamator should be disassembled only by a qualified dental repair specialist. Amalgamators, capsules, and other items that may be contaminated ^{with mercury} should be stored in an impervious catch tray. These items must be checked at least weekly for mercury droplets.

Amalgam Scraps (Waste)

Amalgam scraps are left over pieces of amalgam generated from dental procedures. During the placement of amalgam in a tooth, the amalgam is a soft and malleable compound that quickly turns into a solid hard mass. When amalgam turns solid, it is no longer useful for dental procedures and must be stored in a solids container.

Dental amalgam scrap is stored in a dry state in an approved solid container without any vapor suppressant solution and is not considered a hazardous waste. It is also necessary to clean the solids strainer (collector) of the dental evacuation system and recover any scrap amalgam that has been evacuated (suctioned) during dental procedures. Place any scrap amalgam from the solids strainer into a solids container. The following containers are approved to store scrapamalgam:

Surgical needle jar with cover.

Urine specimen cup with cover.

It is very important to keep the dental scrap amalgam cover in place to prevent spillage when not in use. When the container becomes full, follow your clinic procedures for turning in scrap amalgam for disposal.

Floors

Vinyl sheeting is the preferred floor covering material for DTRs; carpet is not permitted. The use of pre-encapsulated amalgam products has not precluded dental waste or scrap from falling to the floor and being crushed into crevices; therefore, seamless floors are preferred. Floors should be kept clean and free of amalgam debris.

Mercury Decontamination and Spill Cleanup Procedures

A mercury decontaminant should be readily available for immediate mixing and application to a contaminated surface. The decontaminant works by binding with the elemental mercury. If larger droplets of mercury are present, the decontaminant only reacts with the outer surface of the droplet forming a shell. This shell can easily be broken, releasing elemental mercury. Care must be taken during removal of large droplets.

When mercury contamination occurs, it must be cleaned up immediately with a mercury decontamination kit. Follow the manufacturer's instructions for use of these kits. Use the following guidelines for mercury cleanup and decontamination:

Do not eat, drink, or smoke during cleanup procedures.

Wear patient examination gloves during cleanup.

Place collected mercury in a sealed, suitable liquid- and vapor-tight container, and remove to a designated area for disposal as mercury waste.

Scrub contaminated surfaces with mercury decontaminant to convert any trapped mercury.

Clean thoroughly any equipment or instrument, such as amalgamator, that becomes contaminated with mercury with a mercury decontaminant.

Contact the cognizant industrial hygiene office to test the decontaminated area and equipment for residual mercury.

Mercury Disposal

Mercury and mercury compounds will not be dumped into any body of water including open seas or oceans, or intentionally released into any ship's waste disposal system. Shipboard mercury storage and handling areas should not be connected to deck drainage systems.

For shipboard only, all mercury-contaminated waste, including scrap amalgam, will be collected, and packaged with a double boundary of confinement using plastic bags, sealable drums, or polyethylene bottles and labeled.

For shore facilities, dispose packaged mercury waste in cooperation with the base environmental public works department.

Special disposal procedures are not required for items contaminated with trace amounts of mercury, such as used disposable amalgam capsules. Reclose amalgam capsules after use, or seal used capsules in a denture bag.

BURNS

The major causes of burns are inattentiveness and rushing through a task. Two types of burns are possible in DTFs\thermal and chemical. Whether thermal or chemical, burns are injuries that can be avoided by exercising caution.

Thermal

Thermal burns are caused by open flames and hot surfaces. Common dental items using open flames are Bunsen burners and torches. Dental items that may be hot include compound and wax heaters, sterilizers, and items in the sterilizers, such as instruments. Constant awareness of the use, condition, and location of these items is essential to prevent thermal injury. Equipment should be located in an area convenient for use while minimizing the chance of accidental burns. Flames are difficult to see, so make a habit of keeping them away from flammable liquids, materials, and yourself. Always use heat-resistant gloves or the device supplied by the manufacturer to remove items from sterilizers. Always allow sterilized items to cool before using. Items should never be taken out of the sterilizer and placed directly on the instrument tray for use or placed directly into a patient's mouth.

Chemical

Chemical burns result from contact with a caustic agent, whereas, damage from thermal burns cease when the heat source is removed. Chemical burns may continue below the skin long after removing the agent from the skin's surface. A caustic chemical burn must be neutralized. When handling caustic chemicals, you should know what the neutralizer is and where it is located. Often, the neutralizer cannot penetrate the skin with the same efficiency as the caustic agent. Immediate treatment by professional medical personnel is essential.

Chemical burns of the eyes and skin can result from careless use of many materials such as etchant acids, radiographic solutions, endodontic materials, and bleaching agents. Protective eyewear should always be worn when handling hazardous liquid chemicals for protection against splash hazards. Proper storage of chemicals is critical for safety.