Dental professionals are predisposed to a large number of workplace injuries and hazards.  These include the following: 

Physical Hazards - Back Injury

The most common injury reported in the health care sector is back-related injuries and strains.  Musculoskeletal complications are very common with dental workers because of the postural situations where there is an increased risk of twisting and contorting the body during dental procedures.

Strained posture leads to a spine that is no longer straight and causes strain on other groups of muscles and joints that are involved.  Bad posture leads to diseases of the musculoskeletal system.   

It is very important to maintain good posture while working in the dental chair.  The back should be straight, sitting up tall and feet flat on the floor to maintain good posture and to avoid many musculoskeletal problems. 

It is highly recommended to schedule regular massage or chiropractic appointments to alleviate back strain, as well as core strengthening or exercises designed to strengthen the back. 

Carpal tunnel injuries are also a concern in the dental field.   There are many physiotherapeutic routines that can be repeated on a daily basis that can help prevent carpal tunnel injuries.  See your doctor for a recommendation to a physiotherapist. 

Slip, trip and fall accidents are also a high concern in the health care field and some sixty thousand workers get injured from these accidents every year.   Health care workers need to slow down and take extreme care in protecting themselves from accidental injuries. 

There is also a high risk of varicose veins.

Infectious Hazards

Dental personnel have an increased risk of exposure to infections such as HIV or hepatitis.  Dental personnel work with needles and other sharp objects and are at risk of poke or cut injuries. There is also a risk of splatter with bodily fluids and a risk posed by aerosols (air-borne) that can transmit viral infections. 

Dental office personnel need to be diligent in having sound infection control practices, professional development courses and maintaining currency with required vaccinations.  Dentists and staff should maximize individual protective measures, have appropriate and up to date sterilization techniques, and have a high level of disinfectant knowledge. 

Latex allergies are significant with dental health care personnel because of the high exposure to latex in latex gloves and other supplies.

Dental materials, detergents, lubricating oils, solvents, and x-ray processing chemicals can also be causes of skin allergies.  Gloves should be worn when dental staff is working with any of these chemicals. 

 Mercury Health Hazards

Mercury is highly toxic to humans and animals.  High doses of exposure can lead to biological and neurological problems affecting the brain and spinal cord.   In children with elevated mercury exposure effects include lowered cognitive abilities, impaired hearing, and poor coordination.  Chronic, elevated exposure can eventually affect the kidneys, liver and the immune system. 

For this reason, Dental personnel must be diligent in following the proper guidelines when using, and disposing of amalgam mercury filling materials:

  • Ensure amalgam capsules remain sealed tightly until use.
  • Use amalgam capsules with lower mercury levels.
  • Use water irrigation and high suction when placing amalgams or removing old amalgam fillings.
  • Have good ventilation in the office.
  • Amalgam should not be treated as biomedical waste and should not be disposed of in regular garbage that can be incinerated or autoclaved.  The mercury will volatilize and enter the atmosphere and cause immediate health hazards to anyone breathing in the vapours.
  • Place extracted teeth with amalgam restorations in a scrap amalgam container.
  • Use amalgam substitutes like composite fillings in areas where they can be used instead of amalgam.
  • Do not store waste amalgam in radiographic fixer as both are hazardous waste and each should be disposed of accordingly.
  • Do not discard scrap amalgam down the drain. 
  • The empty capsule left after mixing amalgam can be disposed of in the regular garbage as long as no visible amalgam is left.
  • Scrap amalgam can be kept in scrap amalgam containers and then recycled through an amalgam recycler.  Any amalgam capsules with any remaining amalgam or defective capsules should also be recycled in the scrap amalgam containers as well.
  • Mercury spill kits can be purchased and used in the event of mercury spills.  Ensure the kit contains proper instructions on what to do and have staff trained in advance. 

Ionizing Radiation - Radiology Guidelines

Dental radiography is a very valuable tool for diagnosis within modern dental health care offices.  It would be very difficult to diagnose dental conditions with out it.  It must be managed very carefully because of the risks of x-radiation damaging healthy cells and tissue.   The radiation dose for individual x-rays is low and no observable damage is ever seen.  To limit radiographic exposure over a lifetime, it is recommended that dental personnel only take x-rays when it is absolutely necessary for diagnosis and treatment. 

There are 4 main concerns:

  1. Patients should not be subjected to any unnecessary dental radiography.
  2. Patients need to be protected from any unnecessary exposures.
  3. Dental staff should be protected from any unnecessary exposures.
  4. There must be adequate protection to protect the public from any unnecessary exposures.

Safety guidelines for protection from x-radiation:

  • Design the dental room so that the operator is not exposed to the primary radiation beam, and can be at least 3 meters away from the tube and the patient, as well as a shielded barrier that allows the operator to stand behind while still being able to observe the patient.
  •  Having adequate shielding where they are necessary (floor, walls, ceiling and doors) taking into account the distance, x-ray tube voltage and workload.
  • Adequately supported lead shielding should be used and maintained to support and protect it from sagging and causing a broken barrier.
  • Ensure the primary radiation beam and stray radiation is absorbed as close as possible to the source. 
  • Ensure that the primary radiation beam is always directed towards a shielded or unoccupied area.
  • Place the switch for the x-ray machine outside the room and behind the shielded barrier at least 3 meters away from the tube.
  • Use proper lead shielding to drape over the patient with a higher neckpiece to ensure maximized coverage. 
  • Ensure that dental staff has proper education and know how to use the x-ray machine to ensure the time and voltage are set appropriately for the area the x-ray is being taken to avoid any unnecessary excess radiation.
  • Everyone except the patient must leave the room when an x-ray is being taken.
  • Use radiograph-holding devices when there is a need to support children or weak patients.
  • If dental staff must remain in the room to assist with a patient x-ray, ensure the staff member wears an appropriate lead shield with as much coverage as possible and stand as far away from the primary beam as possible. 
  • Do not take radiographs on pregnant patients or anyone who believes they may be pregnant. The unborn child is very sensitive to ionizing radiation even at very low exposures.  Pregnant staff should take any and all precautions to protect their unborn child.
  • Have x-ray machines properly maintained and book regular maintenance and checks with properly trained individuals. 

Disposal of Used X-ray Films

Used x-ray films contain a high enough concentration of silver that it is considered dangerous waste.  It is best to collect any used x-ray film that are no longer required and sent them to the appropriate companies for silver recycling.   

Silver Recovery Systems of Canada at 1-800-267-8498 will accept used films. Offices can mail packages of film or they will pick them up, if there is a minimum of 100 – 200 lbs. per pick up.  The company works out of Alberta but will accept films from Saskatchewan dentists. 

Disposal of Lead Foil in Film Packages

Lead foils from dental film packages must be properly disposed of and never placed into regular biomedical garbage.  Lead foils should be placed into proper lead foil pails and then recycled through appropriate companies such as ECS Cares Incorporated.

It should be noted that there is also lead in the aprons and in some x-ray film storage boxes; proper disposal is required and may not be placed in regular or biomedical garbage. 

Disposal of Fixer and Developer

Used and unused fixer from x-ray machines is considered a dangerous waste because it contains high concentrations of silver (3000-8000 parts per million) and anything over 5000 parts per million is considered dangerous waste. 

In Saskatchewan, disposal of used and unused fixer is covered under municipal bylaws not provincial bylaws.  That said, dental staff should check with their particular city or town environment branch to confirm if bylaws exist pertaining to the disposal of small volumes of used and unused fixer at medical sites. 

Regina Environmental Services has confirmed that it is acceptable within Regina to pour fixer down the sink.  They rationalize that the silver is a heavy metal and usually settles out as the water passes through the sewage treatment facility.  They also mentioned that having plaster traps in the sink drains helps by allowing the silver to settle there before reaching the city sewer system.  The City of Regina has indicated that to date they have not had excess silver in the wastewater testing.  They recommend running water from the tap to dilute the fixer as it goes down the drain to lower the concentration of the silver. 

In areas where disposal down the sink, septic systems or garbage is not recommended due to the high levels of silver, dental staff should collect the fixer into an appropriate container marked with a “used fixer only” label.  Never mix fixer and developer together in the container.   Have a waste management service company pick it up for recycling or dangerous waste disposal. 

Unused developer contains hydroquinone, a highly toxic substance, and it cannot go down the drain, into septic systems or into the garbage.  However, because the hydroquinone is used up in the developing process, used developer is considered non-hazardous and can be disposed of down the drain, into septic systems or into the garbage, or even flushed down the toilet. 

Non-Ionizing Radiation

Non-ionizing radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules like ionizing radiation does.  It cannot completely remove an electron from an atom or molecule but it has enough energy for excitation, which causes the movement of an electron to a higher energy state.  Non-ionizing radiation has a lower frequency and longer wavelength than ionizing radiation.  In general, elaborate radiation protection measures are not needed with non-ionizing radiation. 

Non-ionizing radiation is a new concern in dentistry.  It has become a concern since the use of composites and other resin materials have been used.  Lasers also contribute to non-ionizing radiation and have added anther potential hazard to the eyes and other tissues directly exposed in dental laser procedures.  

Eye exposure is the main concern with the use of lasers.  Dental personnel must be careful with mirrors or stainless steel equipment that can cause reflection and accidental exposure.  It is extremely important that all dental staff in the laser treatment area, as well as the patient, wear safety eyewear that contains the appropriate protective wavelength. 

Laser generated air contaminants are usually not a huge concern as they can be contained with the use of conventional high volume dental evacuation systems. 

Proper Disposal of Dental Materials/Biomedical Waste

Biomedical waste may be in a solid or liquid form.  Infectious waste includes discarded blood, sharps, microbiological cultures and stocks, body parts, human or animal tissue, used bandages and dressings, discarded gloves, other medical supplies that may have been in contact with blood and body fluids, and laboratory waste.   Waste sharps include potentially contaminated needles, scalpels, lancets and other instruments capable of penetrating skin.

Dental waste includes all of the biomedical waste as well as:

  • Suturing materials
  • Hand piece burs
  • Endodontic files and instruments
  • Ortho bands and ligatures
  • Sharp old or broken dental instruments

*Biomedical waste, including all sharps containers, cannot be put into regular garbage containers and should be placed into puncture resistant sharps containers.  Call “Waste Management” in the yellow pages to have the proper secure disposal containers provided.

Anesthetic Gases - Nitrous Oxide

Nitrous Oxide, otherwise known as laughing gas, has a chemical compound with the formula N20.  Other names include; dinitrogen monoxide, E942, nitrous, nitro, or NOS.  It is an oxide of nitrogen gas.  At room temperature it is a non-flammable, and colorless gas.  It has a slightly sweet odor and taste.  Dentists use it because of its anesthetic and analgesic effects.  The euphoric effect caused when inhaling it is why it is called laughing gas. 

Nitrous oxide should not be used on pregnant women.  Studies have shown it can cause vitamin B12 depletion, hyperhomocysteinemia, and can result in malformed children.   

Nitrous Oxide is dangerous to be used on anyone with middle ear disease, bowel obstruction, or pneumothorax due to the fact that N20 diffuses into air-filled spaces into the body.  It will likely only cause a mild gastrointestinal discomfort in cases where Nitrous oxide is in the intestines.  It could cause temporary or permanent hearing loss in people with middle ear disease so it should not be used if a person has an ear infection or any other ear or hearing disease.    Nitrous oxide should never be used in cases of a Pneumothorax where there is a collapsed lung and accumulation of air in the pleural cavity as this is already a very serious medical emergency and there are already many dangers involved with the air around the lungs. 

Employers are required to handle, use, store, produce and dispose of any chemical substance by:

  • Providing adequate controls to prevent the release of the substance into the place of employment
  • Provide protective equipment that meets the requirements to prevent risk to employees from the substance
  • Ensure that no workers personal exposure exceeds the contamination limits set for the chemical being used
  • Not requiring employees to work more than 8 hours a day or 40 hours a week in workplaces where airborne concentrations may be hazardous to the employee
  • Take steps to minimize exposure to workers who are pregnant or assign the employee to alternate work away from the area where a possible exposure could occur
  • Employers should provide protective respiratory devices in cases where it is not practical to reduce the workers personal exposure to the chemical substance

Resource Websites

http://en.wikipedia.org/wiki/Nitrous_oxide

http://www.drugsforum.com/forum/showwiki.php?title=Nitrous_Oxide#ixzz1cZEmeKCm

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3283973/

http://des.nh.gov/organization/commissioner/p2au/pps/ppdpp/mercury_mgmt.htm

http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/99ehd-dhm177/index-eng.php

http://www.ecs-cares.com/dental-leadfoil.php

http://www.ecy.wa.gov/mercury/mercury_dental_xray.html

http://en.wikipedia.org/wiki/Non-ionizing_radiation

https://www.b4brands.com/blog/latex-vs-nitrile-vs-vinyl-gloves-which-to-choose/

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 Saskatchewan Radiation Safety Agency of Dental Facilities

Radiation Safety Unit

Department of Human Resources
Labour and Employment

Government of Saskatchewan

1870 Albert Place

Regina, Saskatchewan
  S4P 3V7

  EVENT CALENDAR
Saskatchewan Dental Assistants’ Association
P.O. Box 294 Kenaston SK S0G 2N0
T 306.252.2769 | F 306.252.2089
E sdaa@sasktel.net