Lab materials and procedures Flashcards
(39 cards)
1
Q
what procedures take place in the laboratory
A
- any procedures that take place away from the patient
2
Q
uses of the dental laboratory
A
- make models from preliminary impressions
- trim and finish diagnostic models/study casts
- prepare custom trays
- polish (provisional coverage, partial or full dentures, indirect restorations)
3
Q
what is a provisional coverage
A
- a protective covering worn temporarily while the fixed prosthesis is being fabricated in the dental laboratory
4
Q
dental lab equipment
A
- fire extinguisher
- eye-wash station
- wall-mounted bins and work pans
- heat source
- model trimmer
- vacuum former
- dental vibrator
- laboratory handpiece
- sandblaster
- articulator
- dental lathe
- lab instruments
5
Q
3 main points of safety in the lab
A
- physical safety
- chemical safety
- biohazards
6
Q
what does physical safety include
A
- know the location of the fire extinguisher and fire escape routes
- know the location of the eye wash station
7
Q
what does chemical safety include
A
- take care in the handling of corrosive, toxic, or carcinogenic substances
8
Q
what do biohazards include
A
- items brought into the laboratory can harbour blood and saliva that could be potentially infective
9
Q
what material hazards could we potentially be exposed to in the lab
A
- particulate matter
- mercury
- toxic effects of chemicals (acute and chronic)
- bio-aerosols/airborne contaminants
- biologic contaminants (hep B, hep C, HIV, TB)
10
Q
in what cases could we be exposed to mercury in the office
A
- placing or removing amalgam
- leaking amalgam capsules (less frequent with factory-sealed capsules)
- sterilizing instruments contaminated with amalgam
- avoid carpeted operatories or flooring that can collect spilled mercury/amalgam
11
Q
methods for mercury vapor reduction
A
- use copious amounts of water and high-volume suction when removing old amalgam
- use rubber dam whenever possible
- use facemask and shield to avoid splatter and vapors
- clean instruments of any adherent amalgam before sterilization
- remove professional protective clothing before leaving the workplace
12
Q
precautions when working with mercury
A
- work in a well-ventilated area
- avoid direct skin contact
- avoid inhaling
- when preparing amalgam for restorations use preloaded capsules
- when mixing amalgam, always close the cover before starting the amalgamator
- empty amalgam capsule containers considered non-hazardous - can throw into regular garbage
- scrap amalgam can be suctioned using HVE
- national legislation (2005): every office, by law, must have a certified international organization of standardization (ISO)11143; separates amalgam waste in the suction apparatus
13
Q
toxic effects of chemicals depends directly on (3):
A
- dose: how much of the material one is exposed to
- length: how much time one is exposed to this material
- frequency: the number of times one is exposed to the material
14
Q
acute toxicity
A
- results from high levels of exposure over a short period of time
- ex. chemical spill
- symptoms:
- dizziness
- syncope (fainting)
- headache
- nausea
- vomiting
15
Q
chronic toxicity
A
- repeated exposures to lower doses over a longer period of time (months-years)
- effects:
- cancer
- neurological deficits
- infertility
- ex. beryllium which is a metal found in partial dentures
16
Q
skin chemical contamination
A
- direct contact: breaks such as cuts, open sores or inflamed hands
- repeated contact: dermatitis
- burns: acid on the skin
17
Q
inhalation chemical contamination
A
- cleaning chemicals
- sprays (to coat models)
- mouth guard/bleaching tray plastics during fabrication
18
Q
eyes chemical contamination
A
- splatter
- aerosols
19
Q
ingestion chemical contamination
A
- eating in an area where chemicals are used
- eating with hands which are contaminated with chemicals
20
Q
chemical precautions
A
- storage: dry, cool, dark place, not exposed to direct sunlight
- controlled skills: spill kit for mercury
- disposal: never fill an empty container with another substance due to potential dangerous chemical reaction
- empty containers must be placed in a special place specifically for these used containers where they will be collected at a specified collection
21
Q
minimizing exposure to chemical hazards in the dental office/dental lab
A
- read the labels and use as directed
- store according to the manufacturer’s directions
- keep containers tightly covered
- wear appropriate PPE when handling hazardous substances
- wash hands immediately after removing gloves
- avoid skin contact with chemicals; immediately wash skin that has come in contact with chemicals
- always have an operational fire extinguisher handy
- always have an eye-rinse station available
- proper ventilation for fumes and dust in lab and rad area
22
Q
MSDS
A
- report containing information from the manufacturer on every material present in the clinic. it includes: chemicals present, hazards, handling, cleanup and PPE required
23
Q
flammable liquids
A
- flash point: low = easily ignites, butane for the bunsen burner will ignite in air
- flammable liquids (liquid monomer for acrylic or acetone) - work away from an open flame
- acids: phosphoric, hydrofluoric and hydrochloric - used for manipulation of many dental materials. rinse skin or eyes (for at least 5 mins)
24
Q
things we can do/not do to minimize exposures
A
- do not eat, drink, smoke, apply lip balm or insert contact lenses in ares where chemicals are used
- keep vaporizing chemicals away from open flames and heat sources
- know and use proper cleanup procedures
- keep neutralizing agents available for strong acid and alkaline solutions
- dispose of all hazardous chemicals according to CDA instructions
25
what are bio-aerosols
- bio = living
- aerosols = mist
- a cloud-like mist containing microbes such as:
- bacteria
- viruses
- molds
- fungi
- yeast
26
what are biocontaminants
- microorganisms from exposure to blood, body fluids, oral and respiratory secretions
- ex. hep B, hep C, HIV
27
how can we manage aerosols in the dental office
- use HVE during all procedures that produce aerosols
- use rubber dams (minimize exposure to oral fluids)
- pour chemicals rather than spraying
- clean air and vacuum filters frequently
- use lids on ultrasonic cleaners and other chemical containers
- minimize the use of latex products
- use powder-free gloves
- use vacuum dust collection system during dust-producing laboratory procedures
- wear appropriate PPE
28
what is disinfection
- a process that kills most microorganisms but rarely kills all spores. through the use of chemicals the reduction or lowering of the number of microorganisms on objects/hard surfaces is disinfection
29
what is sterilization
- any process that kills all microorganisms, including bacteria, viruses, spores and fungi
30
what is PPE and what does it include
- PPE = personal protective equipment
- includes
- gloves
- masks
- lab coats (long sleeves)
- eyewear
- face shield
- hair covering
- ear plugs
31
patient safety
- eyes: protect with glasses (clear vs shaded)
- airway: HVS/E = high velocity suction or evacuator
- rubber dam
32
managing bio-aerosols/minimize their effects by
- frequently cleaning the air-filtration system
- using proper oral and lab evacuation techniques during bio-aerosol-producing procedures
- wear appropriate PPE
- keep all containers of chemicals tightly covered
- keep al extraneous equipment off countertops
- keep all drawers closed
33
what is ultimate strength
- maximum pressure a material can withstand
34
what is fatigue failure
- slow process of wearing resulting in microscopic flaws
35
what are the 6 factors that affect bonding strength
1. wetting
2. viscosity
3. film thickness
4. surface characteristic
5. restoration
6. adhesives used
36
what is wetting
- the degree to which a liquid adhesive is able to spread over the surface of a tooth and restorative material
37
what is viscosity
- the resistance of a liquid material to flow
38
what is film thickness
- the minimal thickness obtainable by a layer of a liquid material after it sets under pressure and is particularly important in working with dental cements
39
what is surface characteristics
- other factors that affect the adhesives retention of a material, like cleanliness of a surface, moisture contamination, surface texture and surface energy of the restoration and the tooth
