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Flashcards in Fixed Q4 Deck (86)
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1
Q

What is worse, an open margin or an over-contoured crown?

A

Over contoured

plaque trapped underneath

2
Q

What is the most critical and neglected aspect of occlusion?

A

Lateral excursive movements

3
Q

Most errors in crown contours are found where?

A

Embrasure spaces

4
Q

If crown is deficient, how would you add matl IP or occlusally?

A

Ceramic - stack low fusing porcelain

Metal - solder

5
Q

What type of luting material needs anesthesia?

What type strengthens restorative material?

A

Bonded Resins

for both

6
Q

What is the advantage to a Luted crown?

What is the disadvantage of a Bonded crown?

A

sectioned and removed easily

prepped off

7
Q

What type of cement will increase the flexural strength of glass ceramic crowns?

A

Adhesively bonded resin

8
Q

T/F

You can bond zirconia and metal

A

False

*crystal/metal won’t adhere to bonding agent

9
Q

For emax, would you lute or bond if you lacked resistance form?

A

bond

10
Q

For emax, if you can’t isolate, would you lute or bond?

A

lute

*adhesive cement very difficult if can’t isolate

11
Q

T/F

Bonding strengthens, holds over time better but if you have retention/resistance you often don’t need it

A

True

12
Q

T/F

Bonding is very difficult to remove and more technical to apply

A

True

13
Q

Name 3 advantages to luting with RMGI:

A

postcementation sensitivity minimal

higher strength than normal GI

strength similar to resin luting agents (but not really)

14
Q

Zinc Phosphate has a film thickness of ___ um, is easy to clean, and has a long track record of success

A

25

15
Q

What has better biocompatibility than Zinc Phosphate b/c polyacrylic acid molecule is large and does not penetrate into the dentinal tubules?

A

Zinc Polycarboxylate

16
Q

What luting agent is superior to Zinc Phosphate and Zinc Plycarboxylate and is susceptible to moisture?

A

GI

17
Q

What luting agent is extremely biocompatible but has mechanical properties inferior to other cements?

A

Zinc Oxide Eugenol

18
Q

Why are resin cements susceptible to incomplete seating?

A

High film thickness

19
Q

2 goals of provisional cements?

A

seal margin

prevent leakage/pulpal irritation

20
Q

What type of provisional cement does ASDOH use?

A

tempbond NE - zinc oxide bases cement

*NE stands for Non-Eugenol

21
Q

Why is Eugenol bad in resins?

A

free radical scavenger that can inhibit resin setting

22
Q

Normal Provisional cement we use is tempbond NE, what is the stronger one we use?

What type of cement is it?

A

Durelon

Polycarboxylate

23
Q

Sequence of check when seating a crown:

A

IP

Margins

Occlusal

Contour

Esthetics

24
Q

If crown isn’t seated all the way and you adjust the occlusal contacts, you will be in…

A

Hypo-occlusion

25
Q

Check IP contact with…

A

accufilm

26
Q

A removeable die system is set in Type ___ gypsum, and it can abrade the IP contacts so adjustments are made on another poured up non-removeable system

A

IV

27
Q

You can’t get an explorer in all IP contacts, so what to do?

If you don’t have adjacent teeth, do you still need to take a radiograph?

A

Radiograph

NO - not if detectable with an explorer

28
Q

How thick is accufilm?

A

21 microns - fold over technique to see how much to grind (by measuring adjacent teeth to the one in hyperocclusion)

29
Q

Sequence to bond a veneer:

A

Veneer

HF

Silane

Bonding (No primer)

luting

Bonding (w/ primer)

HPO4

Veneer prep

30
Q

What is the purpose of a primer?

Why don’t use on veneer?

A

Hydrophilic to hydrophobic

no dentin - no need

31
Q

We can’t use adhesive bonding if the Intaglio is…

A

Metal or Crystal

*so no zirconia, no PFM

32
Q

Would we lute or bond empress?

A

Bond

-will increase strength

33
Q

Would we lute or bond emax?

A

Either

  • if min. occlusal thickness bond
  • if good retention/resistance lute
34
Q

Why do we add grooves and boxes to a gold crown prep?

A

Irregularities help luting agent - and prevents leakage

35
Q

Brand name of the RMGI we use to lute in clinic:

A

FujiCEM

  • increases strength, lowers solubility
  • RMGI is still considered luting
36
Q

In an endo tooth - If 3 or more walls have a 1mm thickness following crown prep, do what?

A

Chamber retained core buildup

37
Q

When should a post be used in an endo tooth?

A

Retention inadequate

*two walls or less

38
Q

To put Amalgam in a core buildup, how thick should the wall be after a prep is made?

A

1 mm

39
Q

What type of build up is used for multi-rooted teeth that have gone through endo?

A

Chamber retained core build up

*has dentin thickness and pulp chamber adequate

40
Q

The height of a core build up has to be at least what?

A

4 mm

*either height of pulp chamber or into root canal

41
Q

As a core material composite has a _____ CTE

____ modulus of elasticity

Bonding to denting that is _____

A

high

low

not strong

42
Q

What is the disadvantage of GI as a core material?

A

Strength

*also moisture sensitive and low tensile strength

43
Q

What is the purpose of a Post?

What does it NOT do?

A

retain core build up

reinforce tooth

44
Q

A post should only be considered to retain core build up when?

A

all other forms of retention are inadequate

*only two walls

45
Q

A post is ideally ____ the length of the root

An apical seal of at least ___mm of GP is to remain

A

2/3

4mm

46
Q

What is more important, 4mm of GP remaining when placing post or it being 2/3 of the length of root?

A

4mm

47
Q

Post diameter should be limited to ____ the root diameter

A

1/3

48
Q

T/F

Strength of an endo treated tooth is directly related to bulk of dentin structure

A

True

49
Q

What type of post leads to higher fracture rates?

A

Active

*screwed in

50
Q

What type of Post has enhanced esthetics, excellent biocompatibility, mechanical properties similar to dentin, easy to use/remove, firm retention with adhesive, and lower radiopacity than a metal post?

A

Fiber reinforced

51
Q

Two types of Posts:

A

Fiber and Metal

52
Q

How is a Metal post placed?

Fiber?

A

Luted

Bonded

53
Q

What type of Post is one piece, high cost, and technique sensitive?

A

Cast

54
Q

How big should a ferrule be?

A

2-3mm

55
Q

What is the function of a ferrule?

A

reduces tooth fracture

56
Q

Mechanical loading will produce cracks that progress in what direction?

A

Coronal to Apical

57
Q

Fatigue failure is more catastrophic in what type of tooth?

A

Nonvital

*complete root fracture may occur

58
Q

Libman Nichols found that Ferrule length worked better at 1.5mm than 2mm - why?

A

2mm had to cut tooth structure down, lowering C/R ratio

59
Q

Ideal Crown to Root ratio:

Minimum:

A

2: 3
1: 1

60
Q

If we have less than 1:1 Crown to Root ratio, what type of occlusal trauma will ensue?

A

Secondary - reduced peridontium

61
Q

In upper anterior teeth, what wall is the most critical in reducing load fracture?

A

Palatal

62
Q

We want how many mm of Ferrule above the margin?

A

2mm

63
Q

T/F

Ferrule effect is for resistance/retention

A

False

*designed to prevent tooth splitting

64
Q

2 techniques to gain adequate tooth structure:

A

Crown lengthening

Orthodontic extrusion

65
Q

Crown to Root ratio better with extrusion and crown lengtheing

A

Yes?

66
Q

Junctional Epithelium + Connective Tissue

A

Biologic Width

67
Q

On average we want __ mm from the bone to where the core material starts

A

5

*2 bio width +1 sulcus +2 Ferrule

68
Q

One article concluded that a post doesn’t strengthen a tooth, but weakens it

A

True

69
Q

Do you have to crown a tooth that has been endo treated?

A

No

70
Q

Endo Tx teeth last how long?

A

1-25 years

71
Q

Sorensen et al concluded that _____ didn’t significantly improve that rate of clinical success for Mx and Mb teeth

A

Coronal coverage of anterior teeth

72
Q

Sorenson et al concluded that intracoronal reinforcement (a post) didn’t do what?

A

increase resistance to fracture

73
Q

The purpose of a post:

A

Retain core build up

74
Q

Bridge, aka

A

FPD - fixed partial denture

75
Q

FPD, dummy tooth:

Crowns:

Crown prep:

between dummy tooth and crowns:

A

Pontic

Retainer

Abutment

connector

76
Q

Ante said that the combined pericemental area (root structure) should be greater than or equal to the area of the teeth being replaced

A

True

*all root area

77
Q

Does an FPD have to fulfill Ante’s Law?

A

No

  • most don’t and are fine
  • now it’s more like Ante’s Guideline
78
Q

an FPD only one side of which is attached to a retainer

A

Cantilever

79
Q

Why is a Cantilever not ideal?

A

Doesn’t direct forces along long axis of the tooth

*why generally don’t do and recommend implants instead

80
Q

Greatest failure rate in Sorensen study was pulpless (endo Tx) teeth with?

A

No crown

81
Q

3 reasons a tooth needs a crown:

A

Tooth structure

Improve esthetics

change contours

82
Q

A crown that supports a removable partial denture (RPD)

A

Survey Crown

83
Q

RPD abutments fail 2x as often as FPD

A

True

84
Q

A Post will decrease the success rate of an FPD

A

True

85
Q

What tooth should be prepped 1st in FPD?

A

Smaller

premolar rather than molar - errors can be corrected w/ greater tooth structure

86
Q

What instrument can detect undercuts when prepping an FPD?

A

Surveyor Instrument

*also CEREC

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