1. Safe Handling of Dental Materials
Chapter 4

2. REFERENCE TEXT AND MATERIALS
Hatrick, Eakle, Bird. Dental Materials Clinical Applications for Dental Assistants and Dental Hygienists. Second Edition. St. Louis: Saunders, 2011 Chapter 4
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Overview
Requirements of WHMIS
Hazards of working with dental materials
Routes of chemical contamination in the body
Differences between acute and chronic chemical toxicity
Precautions for storing, controlling spills, and disposing of chemicals in the office
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4. Canadian National Institute of Health Inc.
WHMIS
Workplace
Hazardous
Materials
Information
Systems
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Class A - Compressed Gases
Class B - Flammable and
Combustible Materials
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8. Poisonous and Infectious Materials
Class C - Oxidizing Materials
Class D - 1
Poisonous and Infectious Materials
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Class D-2
Materials Causing Immediate and Serious Toxic Effects Subdivision A - Very Toxic Materials Subdivision B - Toxic Materials
Class D-3
Biohazardous
Infectious Materials
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Class E - Corrosive Materials
Class F - Dangerously
Reactive Materials
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Requirements of WHIMS
Canada’s national hazard communication standard implemented in 1988
Key elements include:
provision of material safety data sheets;
Manufacturers must send an MSDS with products that meet the definition of a hazardous material
cautionary labeling of containers
worker education and training programs
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12. WHMIS Symbols/Consumer Symbols
WHMIS symbols always found in a circle
Consumer product symbols found in squares, triangles or hexagons
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15. General Handling and Safety
The dental office uses a wide variety of materials that contain chemicals.
All chemicals are capable of producing harmful effects if not handled correctly.
The dental professional must know how to correctly manipulate, clean up, and dispose of materials.
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Particulate Matter
The manipulation of dental materials, especially dry, powdered materials, may generate particulate matter.
Materials such as gypsum, alginate, and various restorative materials that generate dust may be inhaled, causing damage or reactions within the lungs.
Personal protective equipment (PPE) should be worn at all times to inhibit exposure to chemical agents.
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17. Biological Contaminants
Microorganisms such as blood, body fluids, and oral and respiratory secretions are present during patient care.
Microorganisms may contain hepatitis B, hepatitis C, and HIV, along with other viruses and bacteria.
When Bloodborne Pathogen Standards and infection control guidelines are followed, transmission of disease may be kept to a minimum.
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18. Hazardous Materials in the Dental Office
Five job-related health and safety hazards for dental personnel:
Exposure to particulate matter
Exposure to mercury
Exposure to toxic effects of chemicals
Exposure to airborne contaminants
Exposure to biological contaminants
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Hazardous Chemicals
Defined as any chemicals that have been shown to cause a physical or health hazard
Hazardous chemicals can
Catch fire
React or explode when mixed
Be corrosive or toxic
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20. How Chemicals Enter the Body
Inhalation
Absorption through the skin
Ingestion
Invasion directly through a break in the skin
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Dental HazMat
Particulate matter generated by products that produce dust that can be inhaled
Exposure to mercury when amalgam is mixed
Toxic effects from polymerization
BLOOD!!!!!!!!
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Chemical Safety
Hazardous chemicals are defined as any chemicals that have been shown to cause a physical or health hazard.
Skin is typically an effective barrier, but some materials may be absorbed. Breaks in the skin allow chemicals easier access.
Inhalation of gases, vapors, or dusts can affect lungs.
Ingestion is another way that chemicals can enter the body.
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Chemical Toxicity
Classified by length of exposure, dose, and frequency
Acute chemical toxicity results from high levels of exposure over a short time.
Chemical spill may cause irritation, nausea, and dizziness.
Chronic chemical toxicity results from repeated exposure, at generally lower doses, over a longer time, even years.
Benzene, used in the construction of prosthetics, eventually may cause leukemia or autoimmune disease.
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24. Personal Protective Equipment
Gloves: Latex or vinyl gloves used during patient care typically do not provide adequate protection when chemicals are handled.
Eyes: Serious damage to the eyes may occur if proper eye protection is not used.
For example, glasses with side shields
Clothing: Lab jacket or cover gown should be impervious to fluid.
Inhalation: Use a mask or respirator as warranted by the material.
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25. Control of Chemical Spills
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Mercury
Mercury, even in small amounts, is hazardous to a worker’s health.
Mercury can be both absorbed and inhaled.
A mercury spill kit, along with proper PPE, should be used when one is cleaning up mercury.
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Flammable Liquids
Many of the solvents used in dentistry have very low flash points and can easily ignite.
Use away from an open flame.
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Acids
Phosphoric
Hydrofluoric
Hydrochloric
Flush area with water immediately for at least 5 minutes.
Seek medical care.
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Eyewash
An eye wash station is required in any facility that utilizes chemicals.
Irrigates the eye with a soft flow of water
Bathes the eye without causing additional damage
Stations should be inspected and flushed periodically.
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Ventilation
Lab facilities need good ventilation to disperse fumes and dust.
Lack of proper ventilation may allow chemical vapors and dust to cause contact dermatitis or eye, nose, or throat irritation.
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Storage and Disposal
Always store chemicals according to manufacturers’ directions.
If the material changes in appearance or texture, dispose of it according to manufacturers’ directions.
Empty containers can be hazardous, so never use an empty container for anything other than its original purpose.
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32. Hazardous Waste Disposal
Waste is considered hazardous if it contains certain properties or chemicals.
Ignitable: flammable or combustible
Corrosive: highly acidic or basic
Reactive: unstable or explosive
Toxic: contains amounts of arsenic, barium, chromium, mercury, lead, silver, or certain pesticides
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33. Hazardous Waste Disposal
Disposal of hazardous waste varies from Province to Province
Empty containers should never be reused or repurposed.
Very heavy fines may be imposed for improper disposal of
Chemicals
Sharps
Blood
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Chemical Inventory
A comprehensive list of every product used in the office that contains chemicals, such as
Amalgam
Bond
Impression materials
Acrylics
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Patient Safety
All patients should wear safety glasses.
Keep patient’s airway clear with high-velocity evacuation (HVE).
Use a rubber dam with hazardous materials.
Cover the patient with a napkin that is plastic-backed, so that material does not get on clothing or skin.
Have patient rinse with a pre-procedure mouth rinse.
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Summary
The management of a safe environment in the dental office is the responsibility of the employer and of all who work there.
The safe use of any chemical is the responsibility of the user.
Safety regulations vary from province to province.
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37. Do the objectives on page 20 #’s 1 & 3 only Due: next class
Homework
Do the objectives on page 20 #’s 1 & 3 only Due: next class
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