Prosthodontics3 Flashcards Preview

Part II > Prosthodontics3 > Flashcards

Flashcards in Prosthodontics3 Deck (55):
1

Prolonged sensitivity to heat, cold, and pressure after cementation of a crown or a fixed bridge is usually related to:
• recurrent decay
• a periodontal problem
• occlusal trauma
• an open margin

occlusal trauma

2

In a posterior fixed bridge, which of the following are true? Select all that apply.
• a pontic should be in contact in centric occlusion
• a pontic may or may not be in contact in working-side movements
• a pontic should be in contact in non-working side movements

• a pontic should be in contact in centric occlusion
• a pontic may or may not be in contact in working-side movements

3

occlusion of gold restorations is best checked with ?

silver plastic shim stock.

4

Decreased vertical dimension of occlusion refers to an occluding vertical dimension that results in:
• a loss of interocclusal distance when the mandible is in the rest position (decreased freeway space)
• an excessive interocclusal distance when the mandible is in the rest position (increased freeway space)
• neither of the above, vertical dimension of occlusion does not affect interocclusal distance

an excessive interocclusal distance when the mandible is in the rest position (increased freeway space)

5

Condylar guidance is a factor which:
• is totally controlled by the dentist
• is totally dictated by the patient
• is partially dictated by the patient but can be adjusted by the dentist if necessary
• can be adjusted by the laboratory technician

is totally dictated by the patient

6

Centric occlusion (CO) is a:
• "muscle-guided" position
• "ligament-guided" position
• "tooth-guided" position

"tooth-guided" position

7

All of the following statements concerning the functionally generated pathway technique are true EXCEPT one. Which one is the EXCEPTION?
• a prerequisite for the use of this technique for the restoration of a single tooth is the presence of a Class III occlusion
• this technique allows the cuspal movements of the dentition to be recorded in wax intraorally and transferred to the articulator in the form of a static plaster cast
• this static plaster cast is also called the functional index
• by registering the pathways of the opposing tooth surfaces during mandibular movements, the technique allows a laboratory technician to provide a restoration with an occlusal surface less likely to incorporate occlusal interferences

a prerequisite for the use of this technique for the restoration of a single tooth is the presence of a Class III occlusion (This is false; a prerequisite for the use of this technique for the restoration of a single tooth is the presence of an optimal occlusion)

8

The important consideration in generating functional pathway is that all motion of the mandible must be directed from ? to ?

an eccentric to a centric position, never the reverse

9

One disadvantage of dental porcelain restorations is:
• poor esthetics
• expansion
• brittleness
• radioactivity

brittleness

10

How does porcelain chemically bond to metal?
• interposition of an intermediate metal layer
• mixing of oxidized metal layers with porcelain oxides
• wetting of the porcelain onto the metal surface
• mixing of the metal atoms with the porcelain structure

mixing of oxidized metal layers with porcelain oxides

11

• the saturation or strength of a color (degree of saturation of the hue)
• the relative amount of lightness or darkness in a color
• refers to color tone (e.g., red, blue, yellow, etc.) and is synonymous with the term color.

• Chroma
• Value (or brightness)
• Hue

12

? is the single most important factor in shade selection

Value

13

Teeth that appear to be color matched under one type of light may appear very different under another light source. This phenomenon is called:
• fluorescence
• metamerism
• opaqueness
• opalescence

metamerism (Staining of the porcelain will increase metameric responses)

14

property by which a material, (for example, teeth) reflects ultraviolet radiation ?

Fluorescence (makes a definite contribution to the brightness and vital appearance of natural teeth)

15

? is the light effect of a translucent material (incisal edge of some teeth) appearing blue in reflected light and red-orange in transmitted light

Opalescence

16

Glazed porcelain is:
• obtained by heating the previously fired body very slowly for 60 minutes at its fusing temperature
• nonporous, resists abrasion, possesses esthetic ability and is well tolerated by the gingiva
• not as durable (in its surface characteristics) as an over-glazed porcelain
• all of the above

nonporous, resists abrasion, possesses esthetic ability and is well tolerated by the gingiva

17

Low-fusing porcelain is usually used for the manufacture of:
• denture teeth
• all ceramic crowns
• metal-ceramic crowns
• all of the above

metal-ceramic crowns
• High-fusing used for denture teeth
• Medium fusing used for all-ceramic and porcelain jacket crowns

18

The process by which a casting is heated in a porcelain furnace to a temperature of 980"C to burn off any remaining impurities prior to adding porcelain is called:
• quenching
• pickling
• degassing
• investing

degassing (sometimes called heat treatment)

19

Feldspars are used in the preparation of many dental types of porcelain designed for porcelain fused to metal (PFM) restorations.
The most important property of feldspar is its tendency to form the crystalline mineral leucite when melted.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

both statements are true

20

Sintering of a ceramic:
• involves heating the raw materials above the melting point
• results in an increase in porosity
• decreases its mechanical strength
• increases its density

increases its density (Firing porcelain causes the powders to become sintered)

21

When porcelain is fired too many times, it may ?. This appears as a "milky state" and makes glazing very difficult

devitrify

22

? is added to low-fusing dental porcelains (during its manufacture) in order to increase its resistance to "slumping down" during firing

Aluminum oxide

23

cause of acidulated fluoride on ceramic restorations ?

ceramic restorations are severely damaged

24

How would you classify a removable partial denture in which a portion of the functional load is carried by the residual ridge at one end of the denture base segment while the other end of the base segment is supported by natural teeth?
• a tooth-borne removable partial denture
• a bilateral distal extension removable partial denture
• a unilateral distal extension removable partial denture
• none of the above

a unilateral distal extension removable partial denture

25

The major connecter is:
• the connecting tang between the denture and other units of the prosthesis
• the part of the denture base which extends from the necks of the teeth to the border of the denture
• the unit of a partial denture that connects the parts of the prosthesis located on one side of the arch with those on the opposite side
• none of the above

the unit of a partial denture that connects the parts of the prosthesis located on one side of the arch with those on the opposite side

26

A minor connector is the connecting link (or tang) between the major connector or base of the partial denture and other units of the prosthesis, such as ?

clasps, indirect retainers and occlusal rests.

27

When designing an anterior-posterior palatal bar maxillary major connector, the anterior, posterior, and lateral straps should be about:
• 2-4 mm wide
• 6-8 mm wide
• 8-10 mm wide
• at least 12 mm wide

6-8 mm wide — this allows for adequate strength while allowing for maximum tissue exposure both over the palate and in the area of the marginal gingiva but could be too bulky and could interfere with tongue function. anterior-posterior palatal straps are much better

28

A mandibular lingual bar major connector requires a minimum of:
• 3 mm of vertical height between the gingival margin and the floor of the mouth
• 5 mm of vertical height between the gingival margin and the floor of the mouth
• 7 mm of vertical height between the gingival margin and the floor of the mouth
• 9 mm of vertical height between the gingival margin and the floor of the mouth

7 mm of vertical height between the gingival margin and the floor of the mouth (the upper border is a minimum of 3 mm below the gingival margins and at least 4 mm is required for the vertical height of the lingual bar; simplest and most commonly used major connector)

29

? interfere most frequently with major mandibular connectors

Lingually inclined mandibular premolars

30

All of the following are advantages of using a cast chromium-cobalt alloy for removable partial dentures EXCEPT one. Which one is the EXCEPTION?
• resistance to tarnish
• low material cost
• low density (weight)
• high flexibility
• high modulus of elasticity (stiffness)

high flexibility (The gold alloys are approximately twice as flexible as the chromium-cobalt alloys, which is a distinct advantage in the optimum location or retentive elements of the framework in many instances)

31

The type or form of clasp is generally selected after:
• looking at the x-rays
• talking to the patient
• surveying the cast
• the initial try-in of the metal framework

surveying the cast

32

The stiffness of the chromium-cobalt alloys can be overcome by including ? in the framework

wroughtwire retentive elements

33

? retainers are not used when a partial denture depends upon an edentulous area for support (distal extension)

Intracoronal (in distal extensions, functional motion must be permitted without torquing the abutment teeth.)

34

Suprabulge retainers (clasps) originate:
• below the height of contour
• above the height of contour
• above the 0.08" undercut
• above the occlusal surface of most molars

above the height of contour

35

All of the following are advantages of infrabulge retainers as compared to suprabulge retainers EXCEPT one. Which one is the EXCEPTION?
• more efficient retention
• less distortion of coronal contours
• less tooth contact
• cleaner
• less bothersome to vestibular tissues
• less prone to caries
• esthetically superior in most cases
• greater adjustability

less bothersome to vestibular tissues

36

Which of the following indirect retainers will provide the best leverage against lifting of the denture base?
• the one located the closest to the clasp tips which is located furthest from the edentulous area
• the one located the furthest from the clasp tips which is located nearest to the edentulous area
• the one located the furthest from the clasp tips which is located furthest from the edentulous area

the one located the furthest from the clasp tips which is located nearest to the edentulous area

37

Which of the following Kennedy classes of removable partial dentures are not tooth-borne? Select all that apply.
• class I
• class II
• class III
• class IV

• class I
• class II

38

It is important that a wrought wire clasp have an elongation percentage of ?, allowing the clasp to bend without microstructure changes that could compromise its physical properties

more than 6%

39

The most important mechanical property involved when a wrought wire clasp is adjusted is ?

elongation

40

Which of the following are true regarding indirect retention? Select all that apply.
• it is a rest seat
• it is located as far anterior as possible
• the function is to prevent vertical dislodgement of the distal extension base of a removable partial denture
• it is usually an MO rest seat on a first molar

• it is a rest seat
• it is located as far anterior as possible
• the function is to prevent vertical dislodgement of the distal extension base of a removable partial denture
(Indirect retention is usually found on a canine or premolar and assists the direct retainers (clasps))

41

The strength, hardness, and tensile strength of wrought wire is approximately:
• 5% greater than the cast alloy from which it was fabricated
• 25% greater than the cast alloy from which it was fabricated
• 50% less than the cast alloy from which it was fabricated
• 75% greater than the cast alloy from which it was fabricated

25% greater than the cast alloy from which it was fabricated (also tougher than cast clasps)

42

In the mesial rest, guide plane and l-bar design, reciprocation is achieved by all of the following EXCEPT one. Which one is the EXCEPTION?
• rigid plating
• minor connectors
• guide planes extended around the vertical line of abutments
• achieving balanced occlusion
• contact areas of proximal teeth
• reciprocal clasp arms

achieving balanced occlusion (Reciprocation as applied to partial dentures refers to the function of the lingual clasp arm (which is the reciprocal clasp arm or stabilizing clasp arm) to counteract forces exerted by the buccal clasp arm (which is the retentive clasp arm))

43

The cingulum rest is usually confined to preparation on:
• maxillary lateral incisors
• maxillary canines
• mandibular lateral incisors
• mandibular canines

maxillary canines

44

The retentive clasp arm should be passive (no active force) until a dislodging force is applied.
In a clasp only the tip of the retentive arm should be flexible, the other components are rigid.
• both statements are true
• both statements are false
• the first statement is true, the second is false
• the first statement is false, the second is true

both statements are true

45

Which of the following is defined as "The quality of a restoration to be firm, steady, constant and not subject to change of position when forces are applied?"
• retention
• stability
• adhesion
• reciprocation

stability

46

A patient of yours walks into your office with the following complaint. "When I smile, my upper denture does not hold." Which area of the denture base needs to be adjusted?
• labial notch and labial flange
• buccal notch and buccal flange
• posterior border
• distobuccal flange

buccal notch and buccal flange (Excessive thickness of this area can lead to this problem)

47

Free end saddles are liable to be displaced under occlusal pressure (anteroposterior rocking around the abutment tooth, which acts as a pivot). This is a result of the displaceability of the mucosa. Which technique is employed to try and prevent this by taking an impression of the mucosa under controlled pressure?
• the functional load technique
• the altered cast technique
• the residual ridge technique
• the total occlusal load technique

the altered cast technique (is a secondary impression system which utilizes the metal framework to hold customized impression trays for the edentulous area)

48

The complaint that the denture becomes loose when the mouth is wide opened as in yawning, could be due to ? of the denture being too thick. This may interfere with the movement of the coronoid process

the distobuccal flange

49

Most designs of stressbreakers will rather effectively dissipate vertical forces to terminal abutments. However, this occurs at the expense of what supporting entity?
• the periodontal ligament of the abutment teeth
• the alveolar support of the abutment teeth
• the residual ridge
• all of the above

the residual ridge (Since vertical and horizontal forces are concentrated on the residual ridge, increased ridge resorption frequently occurs. Relining of the free-end saddle area must be done when needed to prevent excessive ridge resorption.)

50

All of the following are advantages of precision attachment restorations EXCEPT one. Which one is the EXCEPTION?
• they provide retention without an unsightly display of metal
• they are easy to repair
• the functional load is dispersed down the long axis of the abutments by virtue of the low central loading at the base of the attachments
• the restorations permit the patient access to all areas of the tissues when the denture is not in place
• If both sides of the dental arch have this type of restoration and are joined by a rigid major connector, excellent bilateral stabilization is provided to the abutments

they are easy to repair

51

When surveying casts, the clinician/technician must perform an important step in order to correctly record the path of insertion, the position of the survey line and the location of undercut and non undercut areas. Which of the following is considered to be that step?
• the recontouring of proximal walls of abutments parallel to the path of insertion
• the use of indelible lead marker
• placing tripod marks on the cast to record the orientation of the cast to the surveyor
• fixing the casts with screws on the surveying table
• all of the above steps are equally important

placing tripod marks on the cast to record the orientation of the cast to the surveyor (reproducible orientation of the cast to the surveyor.)

52

Which primary design-quality of the occlusal rest would categorize it as a "positive" rest?
• allow no tilting of the appliance
• prevent the movement of the appliance
• transmit stress down the long axis of the tooth
• form acute angles with the minor connectors that connect them to the major connectors
• have a thickness of 1.5 mm
• all of the above

form acute angles with the minor connectors that connect them to the major connectors — this defines the positive rest and also permits maximum bracing

53

Areas used for ? cannot be determined by surveying.

support

54

The size of posterior teeth for a removable partial denture is determined primarily by which TWO of the following?
• the characteristics of the denture-supporting tissues
• the lip line of the patient
• the age of the patient
• the useful posterior tooth space
• the face-bow transfer

• the characteristics of the denture-supporting tissues
• the useful posterior tooth space

55

A wire-gauge is selected on the basis of its active length. A short arm clasp ?

20-gauge (or finer)