health and safety in the dental health care

Health and safety in the

dental health care facilities

Dr. Ghada Elmasuri

Introduction

The safety of the health care system is defined by the National

Health Performance Committee as the avoidance or reduction to

acceptable limits of actual or potential harm from health care

management or the environment in which health care is

delivered.

Dental workers are at risk to many workplace hazards, including,

pathogens, pharmaceuticals, ergonomic and psychological

hazards

Introduction to OSHA

OSHA “Occupational Safety and Health Administration” is a

government agency within the US Department of Labor

created in 1970 by the Occupational Safety and Health Act,

responsible for worker safety and health protection by

developing specific standards to protect biological, chemical,

environmental, physical, and psychological workplace hazards

that may apply to dentistry.

OSHA's Mission

1. To assure safe and healthful working conditions for workers by

setting & enforcing standards and by providing training,

outreach, education and assistance.

2. Requires employers to implement programs to reduce workplacesafety and health hazards

3. Investigates workplace fatalities or catastrophic accidents

4. Enforces safety and health standards through workplaceinspections by compliance officers

5. Monitors job-related injuries and illnesses through requiredrecord-keeping

6. Provides assistance, training, and other support programs to helpemployers and workers

The Occupational Safety and Health Act 1984

aims to:

1. Promote and secure the safety and health of people at work;

2. Protect people at work from hazards;

3. Assist in securing a safe and hygienic working environment;

4. Eliminate, reduce and control hazards; encourage cooperation

and consultation between employers and employees;

5. Provide for the formulation of policies and for the co ordination

of the administration of laws relating to occupational safety and

health; and

6. Promote education and awareness of occupational safety and

health

Source: section 5, Occupational Safety and Health Act 1984

OSHA's Control


Duties of employers towards their employees

Engineering

Controls

Administrative

controls

Personal

Protective

Equipment

Training

Engineering Controls

Engineering Controls: 1st defence line in employee protection,

directed at the source.

Common engineering controls include:

• Elimination

• Substitution

• Local exhaust ventilation

• General ventilation (only appropriate for non toxic chemicals)

• Isolation/enclosed processes

• Proper chemical storage

• Facility design



Administrative controls

Policies & procedures that establish;

• Codes of practice “practical information on how to achieve safetyand health standards at the workplace”.

• Staff placement, work schedules,

• Good housekeeping

• Labeling products containing any form of hazards

• Dental worker immunization policies and programs

• Medical screening and surveillance

• Workplace monitoring

• Information, instructions and training.



Administrative controls (cont)

Training in biological hazards and controls should be provided to

all dental workers by;

1. Organising groups information

2. Audio visual aids;

3. Provision of written information;

4. Using graphics;

5. Access to computer based information through the Internet.

Training records should be maintained.



Personal Protective Equipment (PPE)

PPE - used in conjunction with other controls (engineering and

administrative) to provide additional protection to workers.

PPE - designed to protect workers from infectious disease by

breaking the chain of infection at the “portal of entry or exit” of

the microorganisms.

PPE as Gloves, gowns, eye protection and other protective

clothing.



Occupational Hazards Associated with

dentistry

Blood borne

pathogens

Nitrous

oxide

Amalgam

Radiation

MSDs

Psychological

Blood borne Pathogens

Human T-lymphotrophic virus

Type 1

Malaria

Syphilis

Babesiosis

Brucellosis

Leptospirosis

Arboviral infections

Relapsing fever

Creutzfeldt-Jakob disease

Viral hemorrhagic fever

Pathogenic microorganisms that are carried in the bloodstream

or transmitted by Other Potentially Infectious Materials.

There are over 20 different blood borne pathogens

Blood borne Pathogens

Of most concern are

Human Immunodeficiency Virus (HIV)

Hepatitis B Virus (HBV)

Hepatitis C Virus (HCV)

Both patients and dental health care personnel can be exposed to

pathogens through Contact with blood, oral and respiratory

secretions, and contaminated equipment.

Modes of Transmission in the dental

settings

Direct; from contact with blood or body fluids of an infected

patient

Indirect; from contact with a contaminated instrument or

surface

Droplets; from splatter contact of mucosa of the eyes, nose, or

mouth

Inhalation of airborne microorganisms

Patient Dentist

Patient Patient

Transmission can be ;

The Infectious Process

“Chain of Infection”

Break in skin integrity

Needle sticks

Cuts, scrapes & skin breaks

Mucous Membranes

Splashes to eyes, nose & mouth

IV drug use

OSHA’s Blood borne Pathogens standard

Was developed by OSHA in 1992.

OSHA’s Blood borne Pathogens standard (29 CFR 1910.1030)

prescribes safeguards to protect workers from exposure to

blood-borne pathogens in the workplace, that must be

available in every dental office and clinic.

The standard requires an employer to protect employees from

exposure to blood and other potentially infectious materials

(OPIM) in the workplace and to provide recommended care if

such an exposure does occur.

Requirements of OSHA 1910.1030

1. Exposure determination

2. Exposure control plan

3. Annual awareness training

4. Implementation of engineering and work practice controls

5. Proper labeling of blood or other potentially infectious

materials

6. Free HBV vaccinations

7. Free medical evaluations for incidents of exposure

OSHA Exposure prevention strategies

The goal of these strategies is to “break the chain” of infection

by practicing protocols that can prevent cross-contamination

from one host to another .

1. Engineering controls: refers to removing or isolating the

hazards

2. Work practice control: refers to reduce the exposure by

altering the manners of performing tasks.

3. Administrative control: through implementation of policies,

procedures and enforcement of measures.

ENGINEERING CONTROLSharps disposal containers

“Needle stick Safety and Prevention Act” was passed by OSHA in2000.

Sharps disposal containers must be provided and used.

It must be leak-proof, puncture resistant, able to be closed, andlabeled or color-coded.

Hand washing facilities should be readily accessible orappropriate antiseptic hand cleanser in conjunction with cleanpaper towels or antiseptic towelettes if hand washing facilities isnot feasible.


One hand needle recapping, and needle bending directly by fingers should be avoided.

Using instruments in stead of fingers to place disposable

contaminated sharps in an accessible sharps container.

Washing hands immediately after removing gloves.


Contaminated reusable sharps should be placed in

immediately after use in a puncture-resistant and labeled

containers until properly reprocessed.

Eating, drinking, smoking, applying cosmetics or lip balm, and

handling contact lenses are prohibited in work areas where

there is a reasonable likelihood of occupational exposure.


Appropriate sizes of personal protective equipment (PPE)

“provided at NO COST to the employee” must be used

and then removed prior to leaving a work area or upon

contamination.

Personal protective equipment

Disposable Gloves shall be readily accessible, replaced as soon

whenever their ability to function as a barrier becomes compromised.

Masks with eye protection devices, as goggles or glasses with solid

side shields, or chin-length face shields, shall be worn whenever

splashes, spray, spatter, or droplets of blood or OPIM may be

generated.

Work practice controls

Housekeeping

Regulated waste must be placed in closeable, leak proof containers

built to contain all contents during handling, storing, transporting or

shipping and be appropriately labeled or color-coded.

Work practice controls

Housekeeping

Sharps containers:

must be located as close as is feasible to where sharps are used,

must be maintained upright throughout use,

must not be overfilled,

must be closed prior to disposal.

Immunization & health surveillanceHepatitis b vaccination

The employer shall make available the Hepatitis B vaccine and

vaccination to all employees who have occupational exposure.

Employees who decline the vaccination must sign a declination

form.

A confidential medical evaluation and follow-up shall

immediately be made available to an employee following an

exposure incident. This must be offered at no cost to the

employee.

Paragraph (f)(3 – 5)

Medical Record keeping

An accurate record should be established & maintained “forduration of employment “plus 30 years” for each employee withoccupational exposure.

Employee medical records must be kept confidential and notdisclosed or reported without the employee’s written consent(unless required by law).

Paragraph (h)(1)

Medical Record keeping

The record shall include :

(A) Name and social security no of employee;

(B) Employee Hepatitis B vaccination status;

(C) Results of examinations, medical testing, and post-exposure evaluation and follow-up procedures;

(D) Healthcare Professional’s (HCP’s) written opinion;

(E) Copy of information provided to the HCP.

Paragraph (h)(1)

Information and training

Occupational exposure training program must be provided at

no cost to the employee.

The training shall be provided:

At the time of initial assignment to tasks where occupational

exposure can occur;

At least annually thereafter.

Additional training shall be provided when tasks are modified

or new procedures affect the employee’s occupational

exposure.

Mercury exposure “Dental Amalgam”

Dental amalgams are metal alloys composed primarily of

mercury (42%-58%), silver (21%-40%), tin (5%-17%) and

copper (1%-16%). Mercury is the largest component in a

silver filling.

Current scientific evidence supports dental amalgam as a

safe and effective dental filling.

However, it represent a significant biological source of

environmental mercury. The OSHA maximum allowable

environmental level of 50 µg/day in the workplace.

Exposure is through : inhalation of vapours, ingestion and

skin absorption. Skin sensitizer. Corrosive as liquid.

Health effects for dentists

A study reported that 180 dentists had 4 times the urinary

mercury excretion levels of 180 people in a control group.

Dentists were also significantly more likely than control subjects

to have had disorders of the kidney or memory disturbance.

“Ritchie et al.,2002”

A 2004 study also found a link between cognitive impairment

(including mood) and mercury exposed-dentist.

“Ritchie et al.,2004”

A Norwegian study has documented a decline in cognitive

abilities of the studied dental professionals greater than the

non-mercury exposed individuals.

“Moen et al., 2008”

Environmental concerns

The WHO reports that one-third of the mercury in the sewage

system comes from dental amalgam flushed down the drain.

It is estimated that about half of the mercury released from

current and historical dental amalgam use remains potentially

bio available, making all individuals exposed to mercury pollution

to some degree.

Economically this pollution is considered an external cost not

factored into the dental amalgam costs.

Environmental mercury may enter the biosphere through

discharges into the atmosphere (by incineration as medical or

general solid waste or by the dental evacuation system) or

through discharges into the water.

Environmental concerns

The European Commission reported dental amalgam as a

significant contributor to overall EU environmental emissions of

mercury. Mercury released to the air can be partly deposited in

to soil, water, vegetation making mercury emissions in the

environment more difficult to quantify.

Health and Environmental Concerns

Of Dental Amalgam

Mercury and mercury

compounds regulation

EPA

OSHA FDA

1. The Environmental Protection Agency:

responsible for regulating mercury and

mercury compounds discharges into the

environment (atmosphere, waters and

landfills).

2. The Food and Drug Administration: for

regulating mercury levels in food, drugs,

cosmetics and medical devices.

3. The Occupational Safety and Health

Administration responsible for regulating

workplace mercury &worker exposure to

mercury and its compounds, both in industry

as well as in professional practices.

Mercury exposure control

1. Elimination of mercury containing equipment. Substitution

with less harmful product.

2. Mechanical amalgamators to ensure no physical contact.

3. P-Protective clothing, gloves, eye and face protection, and

respiratory protection based on hazard assessment.

4. Properly designed and maintained ventilation systems. Local

exhaust ventilation may be required.

5. Education of workers in the nature of the hazard.

6. Monitoring of the work environment.

7. Good hygiene practices.

8. Appropriate storage of products to decrease exposure.

Nitrous Oxide (N2O)

Commonly called laughing gas, is exists as colourless,

nonexplosive, non-flammable gas at room temperature. The

gas promotes combustion similar to oxygen and has a slightly

sweet odour and taste.

Is an anaesthetic agent Dental workers are exposed to Nitrous

Oxide (N2O) during administration of this anaesthetic gas to

patients.

NIOSH

The National Institute for Occupational Safety and Health

(NIOSH) recommended a Time Weighted Average (TWA)

concentration of 50 ppm when N2O is used in dental offices,

and 25 ppm when it is used during anesthetic administration.

Overexposure health effects

Chronic

1. Irritability

2. Headache

3. Reduced fertility

4. Spontaneous abortion

5. Liver and kidney effect

6. Central nervous system effect

Acute

1. Dizziness

2. Headache

3. Nausea

4. Fatigue

5. Irritability

6. Decrease in visual acuity.

Source of overexposure 1. Poor scavenging system design

Clinical evaluation of the 3 major scavenging system brands

“Accutron, Porter brown & Matrx indicated that Porter brown

is better performing compared to others.

Porter brown

Mask within a mask

Source of overexposure 1. Poor scavenging system design

Accutron and Matrx design: a single nasal hood with a connector

cap.

Matrx designAccutron design

Source of overexposureMissing damaged or poorly maintained

Hole in Supply Tubing Torn Reservoir Bag

Damaged scavenging components

Source of overexposure

Missing damaged or poorly maintained

Damaged cylinder head

Small metal section missing on

the cylinder head prohibiting

adequate seal

Source of overexposureMissing damaged or poorly maintained

Sever discoloration indicates prolonged use

Worn components

Source of overexposurePoor employee work practice

Engaging patient in to unnecessary conversation during the

administration of N2O.

Activating the flow of N2O before the mask is placed on the patient.

Tightening the tube retention device to much on the patient.

Failure to deploy exhaust

N2O exposure Controls

The exposure limit recommended by NIOSH approximately 25

ppm during analgesia administration,

NIOSH recommended 3methods of control:

1. System Maintenance

Inspect and maintain the anaesthetic delivery system to

prevent N2O leaks in the worker's personal breathing zone,

connections, fittings. Repair all leaks immediately.

Qualitative test for leaks using water

and soap solution


2. Ventilation

Control waste N2O with a well-designed scavenging system that

includes the following:

1. Securely fitting masks

2. N2O flow rates from the patient's mask should be maintained at

an air flow rate of 45 LPM and measured by a calibrated flow

device, and vented outdoors -- not into the room ventilation

system.

3. If concentrations of N2O are above 25

LPM, Increase the airflow into the room

and an auxiliary local ventilation

should be placed near the patient's

mouth to capture excess N2O from

breathing.


3. Work Practices

Select scavenging masks of proper sizes to fit patients.

Prudent use of N2O to appropriately sedate patients is

encouraged.

Monitor the air concentration of N2O to insure Controls are

effective in achieving low levels during dental operations.

N2O exposure ControlsEmployee training

1. All dentist, dental hygienist, assistants and technicians should

receive proper training on dealing with nitrous oxide.

2. how to properly secure the scavenging mask on patient

according to each manufacture

3. Avoid unnecessary conversation with the patient during N2O

administration.

4. When to deploy and when to terminate the administration of

N2O.

5. How to setup the scavenging unit`s exhaust system.

6. how to inspect the unit for any leak.

7. How to install multi use gasket when installing new cylinder.

X-ray radiation

Dental radiography is one of the most valuable dental tools that

help to diagnosis physical conditions that would be difficult to

identify.

X-radiation has the potential for damaging healthy cells and tissues

as well as carcinogenic and causing genetic changes.

Dental practitioner who used to hold the dental X-ray films inside

the patient’s mouth (for obtaining better quality of image)are at risk

for developing radiation dermatitis on hands, or on a squamous cell

carcinoma of the figures.

Overexposure control

PPE

OSHA Limits: Whole body limit = 1.25 -2 rem/qtr per year.

Hands and feet limit = 18.75 rem/qtr.

Skin of whole body limit = 7.5 rem/qtr.

A range of PPE may be used to reduce radiation exposure as:

Lead gloves, aprons, etc. as required.


Engineering control

1. The room containing the dental X-ray equipment should be

designed so that during the examination the operator is not

exposed to the primary radiation beam and can keep a distance of

at least 3 metres from the X-ray tube and from the patient or

2. An adequately shielded barrier, which allows observation of the

patient, must be provided for the operator to stand behind during

radiography.

3. Appropriate shielding materials, where necessary, for floor, walls,

ceiling and doors.

4. Equipment design to minimize scatter.

5. Replacement of older dental X-ray equipment with newer

equipment with additional safety features.


Administrative control

1. Worker education and training.

2. Safe work procedures reduce exposure time (procedures

requiring fewer workers in area, etc.).

3. Scheduling.

4. Radiation safety program.

5. Radiation exposure monitoring and regular checking of

leakage from X-ray machine should always be performed.

6. All ionizing radiation protective clothing must be uniquely

identified and inspected annually with an x-ray machine for

any sagging, cracks or holes in the shielding material.

7. These inspections results must be recorded and saved.

Ergonomic hazard

Research has found, symptoms of discomfort for dental workers

occurred in the wrists/hands (69.5%), neck (68.5%), upper back

(67.4%), low back (56.8%) and shoulders (60.0%).

Also 93% of those surveyed stated that they had at least one job-

related ache, pain, or discomfort in the 12 months prior to the

survey

(Anton, 2002)

According to an evaluation from the Bureau of Labor Statistics

(2002), dental hygienists ranked first above all occupations in the

proportion of cases of carpal tunnel syndrome per 1,000

employees.

Back, Neck Disorders

Risk factors The pressure in the lumbar discs increases by 50% as compared to

standing.

Sitting in an unsupported posture can cause twice the amount of

stress as compared to standing.

During bending (forward flexion) and twisting (rotation) motions

of the spine, the pressure on the lumbar discs increases by 200%

(Fisk, 1987), causing compression on a spinal nerve.

Inadequate work breaks.

Repeated stresses from over the years begin to add up and slowly

cause degeneration of various parts of the spine, resulting in low

back pain.

Back, Neck Disorders

Myofascial Pain Disorder (MPD)

Possible causes : overloaded neck/shoulder muscles.

Pain and tenderness in the neck, shoulder, arm

muscles, and a restricted range of motion.

Cervical Spondylosis

chronic neck and shoulder pain or stiffness, headaches,

hand and arm pain, numbness, tingling, and

clumsiness.

Possible causes: time spent with the neck in sustained

awkward postures.

Shoulder

Dropping

Hand and Wrist Disorders

Carpel tunnel syndrome

when the median nerve, which runs from the forearm

into the hand, becomes pressed or squeezed at the

wrist

caused by prolonged use of the elbow while flexed,

resting the elbow on an armrest.

It is characterized by pain, numbness, tingling and

impaired sensation in the little and ring fingers, side

and back of hand, and reduced grip strength.

Guyon’s syndrom

Ulnar nerve entrapmnet at the ulnar tunnel in the

wrist

characterized by pain, weakness, numbness,

tingling, burning in the little finger and part of the

ring finger.


Trigger Finger

sustained forceful grips and repetitive motion irritates

the tendon and tendon sheath causing warmth,

swelling, and tenderness of the tendon. Pain occurs

during movement that place tendons in tension. The

fingers lock in the “Trigger Position”.

Tendonitis of the Wrist

Prolonged grasping of light objects and twisting

activities (e.g. polishing and scaling) can reduce blood

flow and strain tendons, leading to tendonitis.

pain, swelling and inflammation


Risk factors

Risk factors

1. Repetitive movements of the hand and wrist

2. Abnormal or awkward positions of the wrist

3. Mechanical stresses to digital nerves such as sustainedgrasps on instrument handles

4. Forceful work

5. Extended use of vibratory instruments

6. Inadequate work breaks

Source: USAF Dental Evaluation & Consultation

Service

Applying Ergonomics to Dentistry

Workplace Intervention

Currently there are no occupational safety and health (OSHA)

standards for ergonomic, only recommendations.

Equipment used should be placed within comfortable reach

(within 20 inches of the front of the body).

Use mobile carts for less commonly used equipment


Working Posture and Techniques

Scaling task performed with three different finger positions Source: Dong, 2005

Goal: avoid static and/or awkward positions Potential strategies

Position patient so that operator’s elbows are elevated no morethan 30 degrees.

Adjust patient chair when accessing different quadrants


Working Posture and Techniques Avoid bent or unnatural

postures.

Alternate between standing

and sitting .

– DHCP should adjust equipment

to the appropriate height

– Position the patient to allow

easy access from the desired

position

– Brief but frequent rest pauses

can minimize fatigue and

enhance productivity.


Instrument Design

When selecting dental tools

– Overall shape/size

– Handle shape/size

– Weight

– Balance

– Ease of operation

– Ease of maintenance

When selecting hand pieces

– Lightweight, balanced models

– Sufficient power

– Built-in light sources

– Angled vs. straight-shank

– Swivel mechanisms

– Easy activation

– Easy maintenance

Goal: reduce force exertion; maintain hand/wrist in neutral position


Magnification

Through the use of such magnification systems dental practitioners

are able to maintain a neutral working posture while increasing their

visual acuity, level of motor control, and diagnostic ability (UBC,

2008).

Goal: improve neck posture; provide clearer vision

When selecting magnification systems consider

– Working distance

– Depth of field

– Power of magnification

– Lighting needs

– Adjustability of system

– Weight


Personal Protective Equipment

Clothing

– Fit loosely, lightweight, pliable

Gloves

Poor fitting gloves can cause pain in the hands, particularly at the

base of the thumb. This is often due to compression of the tissues

when gloves are either too small or too loose as “bunching” occurs.

Be of proper size, lightweight, and pliable

Should fit hands and fingers snugly

Should not fit tightly across wrist/forearm


Lightening

Source: Optimal overhead light positioningSource: UBC, 2008

The goal of proper lighting is to produce even, shadow-free

illumination concentrated on the operating field. It serves to increase

visibility and can also reduce awkward working postures.

For optimal illumination

the light-line must be as

close to the sight-line as

possible. The greater the

deviation of the light-line

from the sight-line the

greater shadowing (UBC,

2008).


Operator Chair

Goal: promote mobility and patient access; accommodatedifferent body sizes

consideration:

– Stability

– Lumbar support

– Hands-free seat height adjustment

– Fully adjustable

Researchers recommend that:

a shorter clinician have a seat adjustment range from 16 to21 inches, taller individuals have a range of 21 to 26 inches.

Ideally, a clinician should be able to function from a heightrange where their thighs are parallel with the floor and thelegs are in fully supported position (Sanders, 1997).


Patient Chair When seating a patient, optimal results will be achieved when their

oral cavity is positioned at a height equal to the seated height ofthe clinician’s heart.

Goal: promote patient comfort; maximize patient access

consideration:

– Stability

– arm rests for the patient

– Fully adjustable head rest

– When patient is properly positioned your shoulders, elbows, and wrists of the dentist should be in a neutral position, meaning that:

– the upper arms are close to the body

– the dentist`s elbow / forearm angle is close to 90º

– the dentist`s wrists are in line with the forearm with no more than 20-30º extension

Psychological hazards

Stress: coping with difficult or uncooperative patients, over

workload, constant drive for technical perfection,

underuse of skills and challenging environment are important

factors contributing to stress among dentist.

Professional burnout: “A syndrome of emotional exhaustion,

depersonalization and reduced personal accomplishment.

Anxiety disorder and Depression, are accompanied by intense

physical symptoms like feeling sweaty, weak, faint, dizzy, flushed

or chilled; having nausea, chest pain, smothering sensations, or a

tingly or numb feeling in the hands.

GAD is characterized by chronic exaggerated worry and tension,

even though little or nothing has provoked it.

Coping Psychological hazards

Management policies and procedures that support work-life balance

and procedures related to no tolerance of violence or abuse.

Scheduling to avoid overwork load. Worker should be involved in

design of shift schedule.

Training to increase awareness of signs and symptoms of critical

incident stress.

Management policies and procedures that ensure no discrimination

between workers.

Self education about stress cope and change strategies as healthy

lifestyles, adequate sleep, deep breathing exercises; Physical exercise,

relaxation; meditation , time management, communication.

Stressors such as failing to meet personal expectations, seeing more

patients working quickly can be managed by breaking the large task

into small ones.

Health Hazards Associated with dental

Lab

Blood borne pathogens

Beryllium

Chemical hazards

Physical hazards

Ergonomics

Health Hazards Associated with dental

Lab

Transmission

of infection

Bloodborne

pathogens

Dental laboratory

personnel are at risk of

acquiring infections

from dental prostheses

that have not been

properly disinfected.

Bloodborne pathogens control in the

dental lab

Barrier system: it includes

• Hand washing with plain or antimicrobial soap.

• Use of personal protection equipment


dental lab

American Dental Association (ADA) guidelines state that

impressions should be rinsed to remove saliva, blood and

debris and then disinfected before being sent to the

laboratory.

Plastic disposable trays should be used

All brushes, rag wheels and other laboratory tools should be

heat-sterilized or disinfected daily.

Wet rag wheels should be stored in a disinfectant solution

when not in use.

The lathe machine should be cleaned and disinfected daily.


dental lab

Disposables that can be considered “sharps” items (e.g.

wire, disposable blades, burs, etc.) should be disposed of in

appropriate containers designated as “sharps” disposable

containers.

Exposure to Beryllium in Dental

Laboratories

Dental laboratory technicians that work with alloys containing

metals such as beryllium that is used for castings of bridge

framework and other dental prosthesis components are at risk for

developing beryllium sensitization and chronic beryllium disease.

While the amount of beryllium used in dental alloys is small ‘’ 0.05

- 2%’’, there is still a risk of developing beryllium sensitization or

CBD through breathing the dust and fumes produced while

altering the alloys.

OSHA beryllium standard

Current Federal OSHA standard

Less than 2 µg/m3 as an 8-hour average

Compliance with these levels may not prevent chronicberyllium diseaseThere is no level that assures zero risk ofBeS or CBD.

The International Agency for Research on Cancer (IARC)classifies beryllium as a human carcinogen.

The World Health Organization’s listed beryllium as a"known human carcinogen.

Chronic Beryllium Disease

Chronic Beryllium Disease may occur among dental laboratory

technicians when they inhale dust containing beryllium when

working on items such as dental crowns, bridges, and partial

denture frameworks made from dental alloys containing

beryllium.

CBD is a serious lung disease that can be disabling and even

fatal, it may develop within months after initial exposure to

beryllium or may have a very slow onset and not develop until

years after exposure to beryllium has occurred.

It has been reported by OSHA among dental laboratory

personnel in the past and recent letter OSHA indicating that

these cases continue to occur.

79

Health Effects of Beryllium exposure

• Lungs

– Acute beryllium disease

– Lung cancer

– Beryllium sensitization (BeS)

– Chronic beryllium disease (CBD)

Skin

Breathing

Routes of Exposure Health Effects

Illustration by National Jewish Health

Health Effects of Beryllium exposure

1. Slow wound healing

2. Nodules

– Response to beryllium under the skin

3. Allergic rash

– Beryllium salts

4. BeS

– Broken skin & cuts

– Rash

– Even unbroken skin may not be a complete barrier

80

Photo by National Jewish

Health

Nodules

Skin Effects

Signs & symptoms of Chronic

Beryllium Disease

1. Unexplained dry cough;

2. Shortness of breath

3. Fatigue;

4. Weight loss or loss of appetite;

5. Fever; or night sweats.

Because the disease may develop slowly over a period of many

years, workers may have the disease for a long time without

knowing it. The individuals with CBD, who do not have clinical

symptoms of disease are generally referred to as having

asymptomatic CBD, or subclinical CBD.

Beryllium Sensitization

A sensitized worker is one who has developed an allergic type

reaction to beryllium through inhalation of beryllium dusts or fumes.

beryllium particles containing become lodged under the skin causing

skin lesions and may induce sensitization.

Some workers may become sensitized within weeks or months of

exposure on the job, while others may not become sensitized until

after leaving a job.

Can be detected through the use of a blood test called the BeLPT,

“Beryllium Lymphocyte Proliferation Test” that measures how

lymphocytes react to beryllium.

It is currently estimated that individuals with beryllium sensitization,

but without CBD, have about a 10% chance per year of progressing to

CBD.

Beryllium Exposure Control

Engineering Controls

To ensure that dental laboratory technicians exposures to

beryllium are maintained below the current OSHA PELs. The

following engineering controls are recommended:

1. Where possible, alloys that do not contain beryllium should

be substituted for beryllium-containing alloys in dental work;

2. All procedures related to casting, cutting, grinding, or

polishing beryllium-containing dental alloys should be

conducted using properly designed and installed local

exhaust ventilation;

3. Vacuum systems and local exhaust ventilation systems

should be equipped with high-efficiency particulate air

(HEPA) filters.


Work Practices control

Gloves and arm sleeves to minimize skin exposure;

To minimize take-home exposures, workplace protective

clothing or equipment dusts containing beryllium should not

taken outside or take it home for laundering . CBD cases have

been reported among family members of many beryllium-

exposed workers.

Vacuum work clothing before removal (clothes must not be

cleaned by blowing or shaking) and place clothes in a covered

container at the end of the workshift.

Food items, drinks, cosmetics, or tobacco products should be

avoided into the work area;


Training and Information

Employees exposed to beryllium should be trained in and have

access to the following information;

1. Material Safety Data Sheets (MSDSs) for identification of

dental alloys that contain beryllium;

2. The seriousness of the lung disease (CBD) that may occur as a

result of exposure;

3. The signs and symptoms of CBD;

4. The potential for developing lung cancer as a result of

exposure;

5. The importance of avoiding skin contact with dust containing

beryllium;

Hazard Information Bulletin

To inform about the risk of CBD to individuals involved in

casting, sprue cutting, grinding, polishing and finishing of

dental alloys containing beryllium.

It also provides information on the ways in which beryllium

exposures can be reduced,

and the type of medical surveillance procedures that can be

used to identify to identify beryllium-sensitized individuals or

those who may be in the early stages of CBD

It also offers information on the types of engineering controls,

work practices, training, personal protective equipment and

housekeeping procedures that can be used to reduce

beryllium exposure.


workplace monitoring

Monitor employee exposures to airborne beryllium dust and fume, can be:

Air samples

– Measure the amount of beryllium in air

– Estimate the amount a worker might inhale into their lungs

– Different types of air samples:

• Personal samples

• Area samples

Surface Samples

– Measure the amount of beryllium on a surface

87

Beryllium collected on filter

and tested by laboratory

Photo by National Jewish Health

Routine medical surveillance

Beryllium medical surveillance

Routine testing with the BeLPT for

beryllium sensitization

Chest x-rays.

88

Photo by US Navy

available under public

domain from Wikimedia

Commons

http://upload.wikimedia.org/wikipedia/commons/f/f1/US_Navy_050419-N-5134J-002_Hospital_Corpsman_2nd_Class_Bilal_Muhammed_draws_a_vile_of_blood_from_a_donor_on_board_Naval_Air_Station_Whidbey_Island,_Wash.,_during_a_National_Bone_Marrow_drive.jpg

http://upload.wikimedia.org/wikipedia/commons/f/f1/US_Navy_050419-N-5134J-002_Hospital_Corpsman_2nd_Class_Bilal_Muhammed_draws_a_vile_of_blood_from_a_donor_on_board_Naval_Air_Station_Whidbey_Island,_Wash.,_during_a_National_Bone_Marrow_drive.jpg

http://commons.wikimedia.org/wiki/File:US_Navy_050419-N-5134J-002_Hospital_Corpsman_2nd_Class_Bilal_Muhammed_draws_a_vile_of_blood_from_a_donor_on_board_Naval_Air_Station_Whidbey_Island,_Wash.,_during_a_National_Bone_Marrow_drive.jpg

Chemical hazards

Dental technologist are exposed to various dusts and chemical

fumes, many of which are known carcinogens. The problem may be

compounded where the technologist works in a confined space

and in conditions of poor ventilation.

it is well known that levels of indoor pollution can be 100 times

higher indoors than outdoors,

Chemical hazards

Including solvents, mineral acids, gases and vapours releasedduring polymerisation, metal casting, and porcelain baking.

Among many chemicals, several should be mentioned includingsilica, butylene glycol, hexane, ethyl acetate, glutaraldehyde,benzoyl peroxide, hydroquinone, oxides of titanium, iron, andmost importantly is :

Methyl methacrylate (MMA)

Also known as methyl methacrylate monomer (or just‘monomer’). Used in making dentures and plates, it can beabsorbed into the body by inhalation, through the skin, and byingestion.

Chemical hazards

Methyl methacrylate (MMA) Over exposure may lead to development of persistent

olfactory disorders in dental laboratory workers.

Methyl methacrylate was subject to control by the Control ofSubstances Hazardous to Health (COSHH) regulations .

The long-term (8 hour) Workplace

Exposure Limit (WEL) of is 50 parts per

million (ppm)

short-term exposure WEL is 100

ppm.

Chemical hazards

Repeated and prolonged exposure may cause a wide range of

adverse health effects , such as irritation to skin, eyes, or

mucous membranes, allergic dermatitis, asthma, as well as

central and peripheral nervous system disorders (headache,

pain in the limbs, nausea, loss of appetite, fatigue, sleep

disturbances, neuropathy, loss of memory, etc).

Electroplating chemicals: The process of electroplating can

release hazardous contaminants into the air that pose a variety

of risks to the dental lab worker. The contaminants include

various acid and alkaline mists that can cause respiratory and

skin irritations.

Chemical hazards

Silicosis

Source: What Dental Technicians Need to Know

About Silicosis. NJDHSS.

Occupational exposure to respirable crystalline silica is associated

with Silicosis which is serious but preventable pulmonary diseases

caused by inhalation of free crystalline silica (silicon dioxide).

Silica (silicon dioxide) is the most abundant mineral on earth. It

occurs in a crystalline or noncrystalline (amorphous) form.

Dental lab materials that contain silica

1. sand

2. investment materials

3. porcelain

4. shop dust

Permissible exposure limit

The current OSHA standards for noncrystalline (amorphous)

form is 20 million particles per cubic foot of air avarged over 8

hours work shift.

NIOSH has recommended a permissible exposure limit of 50

micrograms (50 μg/m3—or 0.05 mg/m3) respirable free silica

per cubic meter of air averaged over a work shift of up to 10

hours.

Routes of over exposure

Inhalation

Silica dust coming in contact with eyes

Dental Lab tasks causing Silica

exposure

1. Casting: exposure can occur when mixing

investment materials and during breaking of

castings. Investment materials contains 20-

70% of cristobalite that is a very toxic form of

crystalline silica.

2. Sandblasting of castings: by exposure to

the Silica sand that is used to clean castings.

Exposure also occur when the blasting box has

leaks. Or by opening the blasting box door

before the dust has settled or been removed.

Dental Lab tasks causing Silica exposure

• Grinding porcelain: Exposure can occur when mixing porcelain

powders or when grinding or polishing dried porcelain

material.

Dental Lab tasks causing Silica

exposure

Cleaning/Maintenance: Tasks that involve cleaning

dusts that contain silica and when maintaining local

exhaust ventilation or dust collection systems.

Health Effects of

over exposure

Acute silicosis: follows a large exposure to dust

Symptoms

1. cough,

2. shortness of breath,

3. Pleuritic pain; may develop in days to several weeks.

4. Followed by weight loss and fatigue in months to years.

Health Effects of over exposure

Chronic silicosis: can be

1. Simple silicosis : Symptoms often appear in 1-3 decades after

initial exposure.

• Patients may be asymptomatic

• or present with exertional dyspnea and cough with sputum

production.

2. Complicated silicosis “progressive massive fibrosis”; symptoms

develop within 10 years after initial exposure.

• A distinction between simple and complicated chronic silicosis

is based on the chest radiographic appearance

Silica exposure control in a dental Lab

Engineering Control of Dust

1. Substitution of materials containing crystalline silica.

Aluminum oxide is an acceptable substitutes for

sandblasting media.

2. Ventilation: when there are no good substitutes, dust

exposure should be minimized through the use of local

exhaust ventilation systems that capture dust at its

source and transport it to a dust collection system.


work practice control

1. Using personal protective equipment: The worker should weara respirator when other control methods are missing or donot work. The type of respirator recommended is, at aminimum, a half-mask air-purifying respirator with type N-100 particulate filters.

2. Good housekeeping– Wet wiping, wet moping, andvacuuming with a HEPA vacuum are recommended. Drysweeping, dry dusting, use of com-pressed air, and use ofordinary vacuum cleaners should be avoided because theyreintroduce the dust into the air.


Dental technicians should be trained in the hazards of crystallinesilica exposure and the methods to control exposure

Good housekeeping– Wet wiping, wet moping, and vacuuming

Labeling products containing silica

Medical screening

Physical hazards

The noise in the dental labs is mostly caused

by grinding, cutting, sandblasting, polishing

operations and other dental lab machinery

can make noise that may cause hearing loss.

It is discontinuous and wide‐band, but often

with predomination of high frequencies.

During cutting and grinding metal surfaces

and plaster casts, the noise approaches and

exceeds the levels for harmful noise up to

92 dB(A), according to the measurements performed by

the Institute of Occupational Health.

Physical hazards

During the work with metal and porcelain furnaces, dentaltechnicians are intermittently exposed to heat.

long term exposure may result in “white finger syndrome”.

Dental technicians are exposed to hand/arm vibrations whileworking with various appliances and tools.

Ergonomics

Musculoskeletal problems was reported as the most common

complaints among technicians “Jacobsen et.,al 1996”.

Sitting posture during work, with precise manual handling of small

objects, may lead to back pain and strains of the musculoskeletal

system.

Prolonged visual efforts due to inspection and shaping of small

pieces, often using magnifying lenses, result in eyestrain.

General Measures

1. Toxic, irritant, and sensitising materials should be

replaced by less harmful alternatives, where possible.

2. Adequate general and local ventilation systems must be

properly constructed in dental laboratories to prevent

respiratory and skin exposure to airborne contaminants.

3. Protective clothing should be made available and worn,

including eye and respiratory protection, and gloves. Properly

selected gloves are of vital importance among control

measures.

General Measures

4. Hearing protection must be worn during critical operations, when

the noise reaches the harmful levels—that is, 80 dB(A) and above.

5. Eating, drinking, and smoking should be prohibited in workplaces.

6. Job rotation can be used to reduce the exposure time while

working with vibrational tools.

7. Regularly undergo specific medical examinations

Conclusion

Although not frequently reported, dental professionals may be

at risk for exposure to numerous occupational health hazards

wither in the dental clinic or during manufacturing dental

prostheses in the dental labratory. there is an ever growing

need for occupational health practitioners to be aware of the

work processes in this occupation, to recognise possible

hazards, and to implement specific measures to control and

reduce hazards associated with their occupations.

Recommendation

Compliance to OSHA standards.

Further studies are needed to evaluate the occupational

carcinogenic risk of exposure to a variety of chemical agents

used in dental technology.

Introduction of new dental materials that is free of hazards

Air filtration system designed to capture and retain exactly

those kinds of carcinogenic chemicals found in the dental

laboratory.

PPT-056-01 53

Guidebook for Health Care Professionals

References Aspden P, Corrigan J, Wolcott J, et al., editors. Patient safety: achieving a new

standard for care. Washington, DC: National Academies Press; 2004.

Kotloff RM, Richman PS, Greenacre JK and Rossman MD. "Chronic beryllium

disease in a dental laboratory technician." Am Rev Respir Dis 147:205-207,

1993.

Muller-Quernheim J, Zissel G, Schopf R, Vollmer E and Schlaak M. "

Differential diagnosis of berylliosis/sarcoidosis in a dental technician." Dtsch

Med Wschr 121:1462-1466, 1996. [Ger].

Brancaleone P, Weynand B, DeVuyst P, Stanescu D and Pieters T. "Lung

granulomatosis in a dental technician." Am J Indust Med 34:628-631, 1998.

Newman L, "Beryllium exposure and chronic beryllium disease caused from

working with dental alloys." Letter to Charles Jeffress, Assistant Secretary,

OSHA, dated January 3, 2001.

Kelleher PC, Martyny, JW, Mroz MM, Maier LA, Ruttenber AJ, Young DA and

Newman LS. "Beryllium particulate exposure and disease relations in a

beryllium machining plant." J Occup Environ Med 43: 238-249, 2001.

Newman LS, Mroz MM, Maier LA, Daniloff EM and Balkisson R. "Efficacy of

serial medical surveillance in a beryllium machining plant." J Occup Environ

Med 43: 231-237, 2001.

References McInerney JR, Beryllium health surveillance. "Presented at US Department of

Energy Chronic Beryllium Disease Prevention Program (CBDPP) Rule

Implementation Workshop, March 6-8," Washington, DC, 28 slides.

Cotes JE, Gilson JC, McKerrow CB and Oldham PD. "A long-term follow-up of

workers exposed to beryllium." Br J Indust Med 40: 13-21, 1983.

Cullen MR, Kominsky JR, Rossman MD, Cherniak MG, Rankin JA, Balmes JR,

Kern JA, Daniele RP, Palmer L, Naegel GP, McManus K and Cruz R. "Chronic

beryllium disease in a precious metal refinery." Am Rev Resp Dis 135: 201-208,

1987.

Henneberger PK, Cumro D, Deubner DD, Kent MS, McCawley M and Kreiss K.

" Beryllium sensitization and disease among long-term and short-term workers in

a beryllium ceramics plant." Int Arch Occup Environ Health 74:167-176, 2001.

Kreiss K, Mroz MM, Newman LS, Martyny J and Zhen B. "Machining risk of

beryllium disease and sensitization with median exposures below 2 ug/m3." Am J

Indust Med 30: 16-25, 1996.

Stange AW, Hilmas DE, Furman FJ and Gatliffe TR. "Beryllium sensitization and

chronic beryllium disease at a former nuclear weapons facility." Appl Occup

Environ Hyg 16:405-417, 2001.

Balkissoon RC and Newman LS. "Beryllium copper alloy (2%) causes chronic

beryllium disease." J Occup Environ Med 41: 304-308, 1999.

References Cotes JE, Gilson JC, McKerrow CB and Oldham PD. "A long-term follow-up of

workers exposed to beryllium." Br J Indust Med 40: 13-21, 1983.

Cullen MR, Kominsky JR, Rossman MD, Cherniak MG, Rankin JA, Balmes JR,

Kern JA, Daniele RP, Palmer L, Naegel GP, McManus K and Cruz R. "Chronic

beryllium disease in a precious metal refinery." Am Rev Resp Dis 135: 201-208,

1987.

Henneberger PK, Cumro D, Deubner DD, Kent MS, McCawley M and Kreiss K.

" Beryllium sensitization and disease among long-term and short-term workers in

a beryllium ceramics plant." Int Arch Occup Environ Health 74:167-176, 2001.

Kreiss K, Mroz MM, Newman LS, Martyny J and Zhen B. "Machining risk of

beryllium disease and sensitization with median exposures below 2 ug/m3." Am J

Indust Med 30: 16-25, 1996.

Stange AW, Hilmas DE, Furman FJ and Gatliffe TR. "Beryllium sensitization

and chronic beryllium disease at a former nuclear weapons facility." Appl Occup

Environ Hyg 16:405-417, 2001. Balkissoon RC and Newman LS. "Beryllium

copper alloy (2%) causes chronic beryllium disease." J Occup Environ Med 41:

304-308, 1999.

Deubner DC, Goodman M and Iannuzzi J. "Variability, predictive value, and

uses of the beryllium blood lymphocyte proliferation test (BLPT): Preliminary

analysis of the ongoing workforce survey." Appl Occup Environ Hyg 16: 521-

References Kreiss K, Newman LS, Mroz MM and Campbell PA. "Screening blood test

identifiessubclinical beryllium disease." J Occup Med 31: 603-608, 1989.

Kreiss K, Wasserman S, Mroz MM and Newman LS. "Beryllium diseasescreening in the ceramics industry: Blood test performance and exposure-disease relations." J Occup Med 35: 267-274, 1993.

Kreiss K, Mroz MM, Zhen B, Martyny JW and Newman LS. "Epidemiology ofberyllium sensitization and disease in nuclear workers." Am Rev Respir Dis148: 985-991, 1993. Kreiss K, Mroz MM, Zhen B. Wiederman H and Barna B."Risks of beryllium disease related to work processes at a metal, alloy andoxide production plant." J Occup Environ Med 54: 605-612, 1997.

Ritchie, KA; Gilmour, WH; MacDonald, EB; Burke, FJ; McGowan, DA; Dale,IM; Hammersley, R; Hamilton, RM et al. (2002). "Health andneuropsychological functioning of dentists exposed to mercury". Occupationaland Environmental Medicine 59 (5): 287–93.

BE Moen, BE Hollund, and T Riise, Neurological symptoms among dentalassistants: a cross-sectional study, J Occup Med Toxicol. 2008; 3: 10. Publishedonline 2008 May 18. doi:10.1186/1745-6673-3-10.

BE Moen, BE Hollund, and T Riise, Neurological symptoms among dentalassistants: a cross-sectional study, J Occup Med Toxicol. 2008; 3: 10. Publishedonline 2008 May 18. doi:10.1186/1745-6673-3-10.

References BE Moen, BE Hollund, and T Riise, Neurological symptoms among dental

assistants: a cross-sectional study, J Occup Med Toxicol. 2008; 3: 10.Published online 2008 May 18. doi:10.1186/1745-6673-3-10.

WHO. (2005).Mercury in Health Care ^ Jump up to: MCMANUS, KEVINR.; F, P (2003). "Purchasing, installing and operating dental amalgamseparators: Practical issues". The Journal of the American Dental Association134 (8): 1054–65. PMID 12956345.

The European Commission ;Final report, July 11, 2012 (PDF)

• Bylund S H, Burstrom L, Knutsson A. A descriptive study of women injuredby hand‐arm vibration. Ann Occup Hyg 2002. 46299–307.307. [PubMed].

• Jacobsen N, Derand T, Hensten‐Pettersen A. Profile of work‐related healthcomplaints among Swedish dental laboratory technicians. Community DentOral Epidemiol 1996. 24138–144.144. [PubMed].

• Nakladalova M, Fialova J, Korycanova H. et al State of health in dentaltechnicians with regard to vibration exposure and overload of upperextremities. Cent Eur J Public Health 1995. 3(suppl)129–131.131. [PubMed].