no eating, drinking, or smoking is permitted. Keep all cosmetics away from the area. Wear personal protective equipment (PPE) when working in lab. Keep hair pulled back. Report all accidents to dentist immediately. Follow the manufactures instructions for
Discuss the safety precautions that should be taken in the dental laboratory
away from patient treatment area
Where would the dental laboratory be located in a dental office
specialty, pediatric, orthodontics
What specialty practices might have a more extensive laboratory setup
an impression
What is an example of a contaminated item in the dental laboratory
Baseplate
pattern, light pink, sheet, fabricate plastic form of a denture
Shellae baseplate wax
pattern, light pink mauve, flat, part plastic-fabricate plastic portion of denture
Sticky wax
processing, red/orange, bead, to hold items temporarily together
Inlay wax
pattern, blue/black , bead, inlays, onlays, gold crowns and bridges
Boxing wax
processing, red, sheet, boxing an impression to create a form to pour gypsum into
Utility
processing, red/clear bead, make alterations on impression trays, extend margins and posterior and build up palate.
Occlusal rims
pattern, pink, U, pink portion of dentures.
Casting wax
pattern, no color , sheets, wax pattern of metal framework for removable partial and complete dentures
Bite wafers
impression, yellow, U , check occlusion-imprints bite registration
Occlusal indicator wax
impression, green, sheet (small), check fine detail occlusion-imprints bite registration
The types of equipment commonly found in a dental laboratory and describe their use in dental laboratory
Heat sources, model trimmer, vacuum former, vibrating table, laboratory hand piece,sandblaster, articulator, face-bow, dental lathe, specialized spatulas and bowls.
Uses of the dental laboratory
Making models from preliminary impressions. Trimming and finishing diagnostic models. Preparing custom trays. Polishing. Provisional coverage, Partial or full dentures, Indirect restorations
Physical safety
-know the location of the fire extinguisher and fire-escape routes
Chemical safety
take care in the handling of corrosive, toxic, and carcinogenic substances
Biohazards
Items brought into the laboratory can harbor blood and saliva that may be infective
Dental models
are three-dimensional reproductions of the teeth and the surrounding soft tissue of a pt maxillary and mandibular arches. They are also referred to as study casts
Uses of Dental Models
diagnosis for a fixed or removable prosthetic device. Diagnosis of orthodontic treatment. Visual presentation of dental treatment, Production custom trays. Creation of orthodontic appliances. Making of provisional coverage. Making of mouth guards
Gypsum Products
used extensively in dentistry to make dental models. Many characteristics and properties affect the use of gypsum
Dihydrate
when referring to a gypsum product indicates that there are two parts of water to every one part of calcium sulfate.
Hemihydrate
removal of water to become one half part water to one part of calcium sulfate forming the powder products of gypsum......converted into a powdered
Reaction of Gypsum (Nuclei Crystallization)
when you mix powder with water the hemihydrate crystals dissolve in water to form clusters known . Crystals grow during the setting process, they intermesh and become entangled with each other.
Three forms of gypsum products
Model Plaster
Dental Stone
High-strength stone and the only difference between the three are the size, shape, and porosity of the hemihydrate crystals
Heat Sources
heat wax or other materials. A propane or butane torch is used for this purpose. If gas line has been installed in lab rubber hosing will be attached to Bunsen burner and then to the gas outlet
Model trimmer
is a machine that is used to trim stone or plaster models. Has an abrasive grinding wheel used to grind away excess plaster or stone. This wheel works more effectively if it is kept clean.
Vacuum Former
is a small electrical appliance used to construct custom trays for bleaching, mouth guards, and positioners for orthodontics. The upper part of the unit is heating element that warms and softens a sheet of thermoplastic resin
Vibrator
is used to remove air from the mix of plaster or stone and to aid in the flow of material when a diagnostic model is poured up. Has a flat working surface bowl or tray. To help keep clean a disposable cover can be placed on work surface before it is used
Laboratory Handpiece
a low speed is used for many tasks such as trimming custom impression trays, adjusting dentures, and polishing provisional and indirect restorations
Sandblaster
is handheld unit that sprays sand at a high a rate of speed creating an etching or pitting on a surface area of metals, porcelains or acrylic . Is a suitable for the repair of crowns, dentures, and appliances, as well as for the cementation of crowns, bri
Homogeneous
a material that is uniform in quality and consistent throughout is said to be
Lathe
a machine used for cutting or polishing dental appliances
Gypsum
is the mineral used in the formation of plaster of Paris and stone.
Volatile
a substance is said to be if it has an explosive property
Dimensionally Stable
if an object is resistant to change in width, height, and length it is said to be
Face bow
is portion of an articulator used to measure the upper teeth and compare with temporomandibular joint
Polymer
is the compound of many molecules
Crystallization
is a chemical process in which crystals form into a structure
Model
is a replica of maxillary and mandibular arches made from an impression
Anatomical Portion
refers to the structural portion of dental model
Articulator
is a dental laboratory device that simulates the movement of mandible and the temporomandibular joint when models of dental arches are attached
Monomer
a molecule that when combined with others forms a polymer
Slurry
is a mixture of gypsum and water used in the finishing of models
in a separate space away from the patient care
Where would you commonly find the dental lab in a dental office
oral surgery and orthodontics
Which specialty practices might have a more extensive laboratory setup
impression
An example of a contaminated item that could be found in dental lab would be an
model trimmer
which piece of lab equipment would be used to grind away plaster or stone?
articulator
Which piece of lab equipment would the dentist use to determine centric relation from a diagnostic model
#7
The size of the wax spatula most commonly used in laboratory
dental cast
Another name for dental model?
gypsum
What dental material would be selected to fabricate a dental model ?
high-strength stone
Which form of gypsum is used to fabricate a die for making an indirect restoration ?
50/100
The powder/water ratio of plaster for pouring a dental model?
add powder to the water
When a gypsum material is mixed how is the powder and water incorporated?
using a spatula and rubber bowl
How are gypsum materials mixed?
anatomic and art
Which of the following is section of dental model?
most posterior tooth
When pouring an impression where would you begin placing the gypsum material in a mandibular impression?
40-60 min
How long should you wait before you separate a model from its impression?
maxillary
Which of the two models (maxillary or mandibular) do you begin trimming first?
anterior portion
what is one specific area of dental model in which the maxillary and mandibular models are trimmed differently
wax bite
What should be placed between the two models when they are trimmed together?
acrylic resin
Of the three types of custom trays discussed in the chapter, which technique uses a volatile hazardous material
thermoplastic resin
What type of custom tray would be made for a vital bleaching procedure?
powder and liquid; putty
Acrylic resin for the fabrication of trays takes which of the following forms during the procedure used to construct a custom tray?
boxing wax
What type of wax is used to form a wall around a preliminary impression when it is poured up?
rope utility wax
To extend an impression tray, what type of wax is used
baseplate wax
What type of wax is used to get a patients tube?
spacer stops
What is placed to prevent a tray from seating too deeply onto the arch or quadrant ?
model trimmer
What piece of equipment is used to grind away plaster or stone?
face bow
What piece of equipment does the dentist use to determine centric relation on diagnostic model?
study casts
What is another term for dental model
gypsum
What dental material are used to make dental model?
model plaster (Paris), Dental Stone, and High-strength stone
what are three forms of gypsum
45-50ml /100g
What is the water to powder (ml/g) ratio of plaster?
rubber mixing bowl
In what are gypsum materials mixed?
1/2 above palatal area
When pouring impression where the maxillary impression do you begin to place the gypsum material?
low water content
Which is stronger, gypsum with high water content or low water content?
F
T/F : spatulation is described as a whipping action.
Plaster
What kind of gypsum product is used for study models?
temperature of the water
What is the best way to control the setting of gypsum materials?
slower
Cold water = _____ set
faster
Hot water= ____ set
initial
______ set is when the mixed gypsum is strong enough to handle and has lost its gloss. The item is strong enough to where you can move it without distorting it
final
____ set is when the mixed gypsum has obtained full strength
retarder
What is put in by a manufacturer to give you more time to work with the material?
no, once it's set it is chalky
If stone is setting does it get shinny?
no, the particles expand but not the model
Does stone expand when it sets?
no
Does the stone change color when it sets?
accelerate in set
If we are going to decrease the amount of time it takes for the stone to set up what do we do?