Ch 47 Laboratory materials and procedures study guide DA105
Light cured resin can be used to make trays for which type impressions?
All types
Which statement is incorrect regarding safety precautions in the laboratory?
This is the appropriate place for eating and drinking in the dental office.
Water should be running through a model trimmer:
When trimming
After fabrication, when can a self-cured resin custom tray be used?
after 24 hours
A trimmed maxillary model will be __ at the anterior portion, and the mandibular model will be ____ at the anterior portion.
pointed; rounded
When would a light gauge, vacuum-formed resin material be used?
provisional coverage and bleaching trays
Which type of resin is formed into a diagnostic model using heat and a vacuum former?
thermoplastic
How will gypsum material be affected if additional powder is added after mixing has begun?
weaker
How should light-cured resin tray material be cured?
For 2 minutes
What is the powder-to-water ratio for high-strength stone?
19
A custom impression tray should fit and adapt well to the model ad should maintain ___ mm of impression material between itself and the teeth.
3 to 4
In minutes, how long should one wait before removing a model from an impression after pouring?
45 to 60
When constructing ___ with a vacuum former, use a heavier-gauge, flexible plastic that does not require a spacer but does require an attachment for the strap.
A mouth guard
A model consists of the ___ portion, which represents the teeth and tissues of the mouth, and the __ portion, which forms the base of the cast.
Anatomical; art
Which type of dental wax is used to constrict occlusal rims and set denture teeth in the wax-up?
Baseplate
Which type of wax is performed with a thin sheet of aluminum foil between the layers?
Bite registration
The ___ is the measurement of where the teeth are positioned when joints are aligned correctly an before the teeth actually come together.
Bite registration & centric relation
How should a plaster mix not be manipulated?
Complete mix in 30 seconds
Which item is used to polish or trim custom trays, provisional coverage, dentures, and indirect restorations?
Dental lathe
Which methods are used to protect against biohazard contamination from impressions?
Disinfecting laboratory benches and other contaminated inters after use
When constructing custom trays it is best to remove excess material with a lab knife after it has cured.
False
Which form of gypsum products is used for the creation of dies?
High-strength stone
What causes air bubbles in a model?
Improper pouring of the impression
Which technique listed would be incorrect when pour an impression ?
In large amounts
Which statement regarding infection control in the dental laboratory is accurate ?
It is equally as important as when you are with a patient.
When taking a face-bow registration, the vertical indicator rod should be aligned with which oral landmark?
Midline
Which form of gypsum products has the highest powder-to-water- ratio?
Model plaster
The first step in making a custom tray is to:
Prepare a diagnostic model
before constructing a light cured tray, what would be painted on the model?
Separation medium
How should the patient bite when positioning the bite fork during a face bow registration?
Slowly
Which of the following is used to prevent a custom impression tray from sitting too deeply when taking the impression?
Stops
What is one advantage of having laboratory equipment and trained personnel in the dental office?
The dentist or private laboratory technician can handle larger cases.
Which of the following statements correctly describes the pouring methods used to create the base portion of a dental model?
The inverted- pour method consists of mixing one large mixture of plaster or stone
Which type of baseplate wax is a softer and used for denture construction?
Type I
What should be done to an impression before pouring ?
Use a gentle stream of air to remove excess moisture
What device that holds maxillary and mandibular models in an occlusal relationship
articulator
