Deck 47: Laboratory Materials and Procedures

Question 1

The powder-to-water ratio for high-strength stone is ___:100.

A)45
B)30
C)19
D)12

Answer 1

19

Question 2

When constructing ________ with a vacuum former,you will use a heavier-gauge,flexible plastic that does not require a spacer but does require an attachment for the strap.

A)an impression tray
B)provisional coverage
C)a vital bleaching tray
D)a mouth guard

Answer 2

a mouth guard

Question 3

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.

A)art; anatomical
B)anatomical; foundation
C)anatomical; art
D)oral cavity; foundation

Answer 3

anatomical; art

Question 4

The _________ is the measurement of where the teeth are positioned when the joints are aligned correctly and before the teeth actually come together.

A)bite record
B)articulator
C)centric relation
D)both a and c

Question 5

Infection control in the dental laboratory is:

A)as important as it is when you are with a patient.
B)not as critical as it is when you are with a patient.
C)not a consideration because impressions are disinfected before entering the dental laboratory.
D)all of the above.

Question 6

A custom impression tray should fit and adapt well to the model and should maintain ____ mm of impression material between itself and the teeth.

A)1 to 2
B)2 to 3
C)3 to 4
D)5 to 6

Question 7

The dental wax that is used for recording occlusal rims and for denture wax-ups and that is supplied in sheets is called ________ wax.

A)bite registration
B)baseplate
C)utility
D)boxing

Question 8

Which form of gypsum products is used for the creation of dies?

A)Plaster
B)Model plaster
C)Dental stone
D)High-strength stone

Question 9

Which of the following statements correctly describes the pouring methods used to create the base portion of a dental model?

A)The art portion of the cast is poured first when the double-pour method is used.
B)The completed box should extend at least 1 inch above the palatal area of the maxillary impression when the box-and-pour method is used.
C)The inverted-pour method consists of mixing one large mixture of plaster or stone and pouring both portions of the model in a single step.
D)The "box" used in the box-and-pour method is made of baseplate wax.

Question 10

The advantage of more equipment and expertise in the office dental laboratory is that:

A)overhead costs rise.
B)the dentist or private laboratory technician can handle larger cases.
C)more work will be completed by the commercial laboratory.
D)there is less work to do for the private dental laboratory technician.

Question 11

Which of the following gypsum products has the highest powder-to-water ratio?

A)Model plaster
B)Dental stone
C)High-strength stone
D)All gypsum products have the same powder-to-water ratio.

Question 12

________ wax is pre-formed with a thin sheet of aluminum foil between the layers.

A)Sticky
B)Inlay casting
C)Baseplate
D)Bite registration

Question 13

Which are methods used to protect against biohazard contamination from impressions?

A)Disinfecting impressions in the treatment room before bringing them to the laboratory
B)Disinfecting laboratory benches and other contaminated items after use
C)Disinfecting laboratory benches and other contaminated items before use
D)All are methods that can reduce contamination from impressions.

Question 14

A trimmed maxillary model will be _____ at the anterior portion,and the mandibular model will be _____ at the anterior portion.

A)pointed; rounded
B)rounded; pointed
C)rounded; rounded
D)pointed; pointed

Question 15

When mixing gypsum,it is important to use the correct amount of water and powder.If additional powder is added after mixing has begun,the mix will be:

A)stronger.
B)weaker.
C)unaffected.
D)none of the above.

Question 16

Type _____ baseplate wax is a softer wax used for denture construction.

A)I
B)II
C)III

Question 17

The _____ is used to polish or trim custom trays,provisional coverage,dentures,and indirect restorations.

A)sandblaster
B)model trimmer
C)vacuum former
D)dental lathe

Question 18

Safety precautions in the laboratory include all except:

A)PPE should be worn while working in the laboratory.
B)manufacturer's instructions should be followed for equipment operation.
C)this is the appropriate place for eating and drinking in the dental office.
D)the work areas should be kept clean before and after procedures.

Question 19

Water should be running through a model trimmer:

A)never.
B)at all times when trimming.
C)after trimming.
D)before trimming only.

Question 20

The purpose of ________ is to prevent a custom impression tray from sitting too deeply when taking the impression.

A)a spacer
B)stops
C)undercuts
D)all of the above

Question 21

Before constructing a light-cured tray,paint the model with a(n):

A)adhesive.
B)plaster.
C)monomer.
D)separator.

Question 22

A self-cured resin tray should be used:

A)after the heat has diminished.
B)while it is giving off heat.
C)immediately after construction.
D)after 24 hours.

Question 23

A device that holds maxillary and mandibular models in an occlusal relationship is a(n):

A)face bow.
B)occlusal register.
C)bite block.
D)articulator.

Question 24

Light-cured resin tray material should be cured:

A)for 10 minutes.
B)off the model.
C)for 2 minutes.
D)without the spacer.

Question 25

A plaster mix should not be:

A)completed in 2 minutes.
B)pressed lightly on the vibrator.
C)completed in 30 seconds.
D)mixed slowly.

Question 26

Air bubbles in a stone cast are caused by:

A)using a vibrator.
B)adding stone in small increments.
C)impression material that is too thick.
D)improper pouring of the impression.

Question 27

When constructing custom trays it is best to remove excess material with a lab knife after it has cured.

Question 28

When pouring an impression,the plaster should not be placed:

A)in small increments.
B)in large amounts.
C)to the same place.
D)in a continuous flow.

Question 29

The first step in making a custom tray is to:

A)prepare the resin.
B)make a spacer.
C)prepare a diagnostic model.
D)place blockout material.

Question 30

When positioning the bite-fork in the patient's mouth during a face-bow registration,the patient should bite:

A)quickly.
B)firmly.
C)slowly.
D)and slide.

Question 31

The type of resin that is formed into a diagnostic model using heat and a vacuum is:

A)self-cured.
B)light-cured.
C)thermoplastic.
D)auto-cured.

Question 32

When preparing impressions for pouring,it is important to:

A)dry the impression completely with a blast of air.
B)use a gentle stream of air to remove excess moisture.
C)have the impression saturated with moisture.
D)leave disinfecting solution in the impression.

Question 33

A light gauge of vacuum-formed resin material is used for:

A)bleaching trays.
B)provisional coverage.
C)impression tray.
D)both a and b.

Question 34

A dental assistant should wait _____ minutes before removing a model from an impression.

A)10
B)15
C)30
D)45 to 60

Question 35

Light-cured resin can be used to make trays for ________ impressions.

A)edentulous
B)dentulous
C)partially edentulous
D)all types of impressions

Question 36

When taking a face-bow registration,the vertical indicator rod should be aligned with the patient's:

A)midline.
B)upper first molar.
C)lower cuspid.
D)nose.