CHAPTER 47: Laboratory Materials and Procedures Flashcards
A heat source is required in the laboratory to heat wax or other materials. A ____ or _____is used for this purpose.
propane
butane torch
a machine used to trim stone or plaster models
model trimmer
a small electrical appliance used to construct custom trays for bleaching, mouth guards, and positioners for orthodontics
vaccum former
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
vibrator
is used for many tasks, such as trimming custom impression trays, adjusting dentures, and polishing provisional and indirect restorations.
low-speed laboratory handpiece
a handheld unit that sprays sand at a high rate of speed, creating an etching or pitting on a surface area of metals, porcelain, or acrylic
sandblaster
sandbasting is suitable for what procedures?
repair of crowns
dentures
cementation of crown
bridges and inlays
is a mechanical device used in dentistry to hold the maxillary and mandibular dental
models in a position to aid in reproduction of the mandible in relation to the maxilla
articulator
what does the articulator fabricate ?
dentures crowns bridges inlays, and onlays orthodontic appliances
the first step the dentist takes to determine the positional relationship of the maxillary arch to the temporomandibular joints.
the face bow
a measurement of where the teeth are positioned when the joints are aligned correctly and before the teeth come in contact.
centric relation or bite record,
is used to trim and polish custom trays, provisional coverage, dentures, and indirect restorations.
dental lathe
spatula that is used most often in the laboratory
7 wax spatula
used for mixing of alginate in the treatment area and for mixing of stone or plaster in the laboratory setting.
rubber bowls
dental models are also reffered to as :
study casts
When gypsum is heated during the manufacturing process, the water is removed, and the gypsum is converted into a powdered
________
hemihydrate
gypsum is the
_______form of calcium sulfate, which means it consists of 2 parts water to every 1 part calcium sulfate.
dihydrate
the five types of gypsum
- impression plaster type I & II
- dental stone (type III)
- Die stone (type IV)
- high strength stone ( type V)
dental model consists of these 2 part :
anatomic portion
art portion
major disadvantage of Self-curing acrylic resin
hazard of working with liquid monomer, which is highly
volatile.
When a self-curing resin is used, polymerization begins when the
_____ and the
______are mixed together.
monomer
polymer
a visible light–cured material that does not contain methylmethacrylate monomer (hazardous material) has very low shrinkage, which provides excellent adaptation of the cast.
Light-Cured Resin Tray Materials
what acts as a catalyst in light cured resin to bring about polymerization?
curing light
Dental waxes are categorized into three general classifications:
pattern waxes
processing waxes
impression waxes
this gypsum is commonly referred to as plaster of Paris,is white and used primarily for pouring preliminary impressions for the fabrication of an edentulous model
impression plaster type I and model plaster type II
this type of gypsum requires the greatest quantity of water for mixing, which produces the weakest form of a study model.
impression plaster I and model plaster type II
this gypsum is typically yellow and is used when a more durable diagnostic cast is required, or when a working model is needed for the fabrication of fixed or removable prosthetics, retainers, and custom trays.
dental stone type III
this gypsum is also known as densite or improved dental stone.
has strength, hardness, and dimensional accuracy that make it ideal for use by the dental laboratory technician in creating a
die for use in the fabrication of a wax pattern with the production of crowns, bridges, and indirect restorations.
die stone type IV
This stone is the strongest, with the least amount of expansion.
It is not recommended in the use for the fabrication of inlays and onlays because of creating too tight of a casting fit.
high strength stone (type V)
most common method of pouring an impression
inverted pour method
the three types and classifcation for pattern waxes
inlay wax
casting wax
baseplate wax
The dental laboratory technician uses this type of pattern wax to create a pattern of the indirect restoration on a model.
inlay wax
Inlay waxes are classified according to how they flow (hardness), as follows:
- Type A: a hard wax used for direct wax patterns in the mouth.
- Type B: medium inlay wax used for indirect wax patterns on dies
- Type C :a soft inlay wax used for indirect waxing techniques in the dental laboratory.
type of pattern wax used for single-tooth indirect restorations and fixed bridges and for casting metal portions of a partial denture.
casting wax
type of pattern wax used to record the occlusal rims for the initial arch form, for setting denture teeth, and for denture wax-up.
baseplate wax
The ADA classifies baseplate wax as the following three types:
- Type I is a SOFTER wax used for impressions in COOL climates.
- Type II is a wax of MEDIUM hardness used for impressions in MODERATE climates.
- Type III is a HARDER wax used for impressions in TROPICAL climates.
classification of waxes used either in the clinical or laboratory setting for multiple procedures.
processing wax
The three types of waxes in processing wax classification are :
- boxing wax
- utility wax
- sticky wax
type of processing wax often used to form a wall or box around a preliminary impression when it is poured.
boxing wax
this type of processing wax is used for extending the borders of an impression tray and covering brackets in orthodontic treatment when they are irritating the cheek or lips.
utility wax
type of processing wax best used in the laboratory in fabrication of castings.
useful in the casting procedure, creating a wax pattern, or JOINING acrylic resin together.
sticky wax
classification of waxes used to take impressions within the oral cavity.
impression waxes
two types of classification of impression waxes are :
- corrective impression wax
- bite registration wax.
this type of impression wax is commonly used in the procedure of taking edentulous impressions.
flows easily at the temperature of the oral cavity, making it useful with other impression materials.
Corrective Impression Wax
After this type of impression wax is softened under warm water, the patient is instructed to bite down, so the wax forms an imprint of the teeth.
bite registration wax
