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BDS4 CDS Restorative, Pros & Endo > Rest: Indirect Restorations > Flashcards

Rest: Indirect Restorations Flashcards

Includes crowns, bridges, veneers, luting agent, inlays, onlays, ceramics.

1
Q

INDIRECT RESTORATIONS

What are the five treatment options for treating an edentulous space ?

A
  1. Accept.
  2. RPD or modified Essix retainer.
  3. Bridge.
  4. Implant.
  5. Close space with orthodontic treatment.
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2
Q

What are the benefits of treating an edentulous space ?

A

Function. Occlusal stability. Speech, Aesthetics. Psychological.

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3
Q

What are the indications for bridges ?

A

Epileptics. Good OH. Good diet. No active disease - caries/PD.

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4
Q

What are the features of a good abutment tooth for a bridge ?

A

Large tooth.
Good enamel quality.
Heavily restored and requiring crown.
Favourable angulation.
Favourable occlusion.
Good bone levels.
No PA pathology or successfully RCT’d.
Large roots.

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5
Q

What are the contra-indications for bridges ?

A

Possibility for future tooth loss.
Abutments of poor prognosis.
Loss of ridge and soft tissues.
Large length of span.
Tilting of abutment teeth.
Poor PA status - unstable.
Significant bone loss - <50%.
Small roots of abutment.

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6
Q

What are the contra-indications for a resin-retained bridge ?

A

Long span.
Soft tissue loss.
Tilting of abutment teeth.
Bruxists/heavy occlusion.

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7
Q

What are the indications for a resin-retained bridge ?

A

Replacement of single tooth.
Temporary measure until implant placement (hypodontia).
Tooth with minimal occlusal load.
Large abutment tooth surface area.
Young patients with large pulps.

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8
Q

What are the possible advantages of a resin-retained bridge ?

A

Low cost/time.
No LA required.
Can be used as temporary measure until implant placement.
Minimal tooth prep required.

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9
Q

What are the possible disadvantages of a resin-retained bridge ?

A

Risk of debonding.
Metal shine through abutment tooth.
Chip porcelain.
No trial period possible.

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10
Q

What can cause a resin-retained bridge to debond ?

A

Poor moisture control during cementation.
Heavy occlusal contact.
Secondary caries.
Deterioration over time of materials.
Poor lab technique - poor fit.
Poor retentive components i.e. wings.

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11
Q

What are the advantages of a fixed bridge ?

A

Robust.
Maximum retention and strength.
Straight forward lab technique.

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12
Q

What are the disadvantages of a fixed bridge ?

A

Difficult operator technique.
Common path of insertion of abutments.
Greater tissue removal required.

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13
Q

What are the indications for a fixed bridge ?

A

Abutment teeth requiring crowns/replacement.
Longer edentulous spans.
Heavy occlusal interference.
Smaller pulp chambers.
No tilting or angulation of abutment teeth.

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14
Q

BRIDGES

What degree of tapering should the prep for a fixed bridge have ?

A

4-7 degrees.

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15
Q

What are the advantages of a cantilever design vs. fixed-fixed ?

A

Easier operator/lab technique.
Less destructive.

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16
Q

What are the disadvantages of a cantilever design vs. fixed-fixed ?

A

Can only replace short span.
Mesial pontic îs preferred.

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17
Q

Why is a mesial pontic preferred ?

A

Reduces occlusal load on pontic - more heavy occlusal contacts posteriorly.

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18
Q

What is the benefit of a fixed-moveable bridge ?

A

Two abutment teeth can have different paths of insertion.

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19
Q

Why are hybrid bridges rarely done anymore ?

A

High risk of caries formation.

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20
Q

Describe the anterior preparation for resin-retained bridge.

A

Rest seat - occlusal contact reduction where metal will be (0.7mm).
Cingulum undercut removal.
180 degrees wrap around preparation on palatal/lingual surface.
+/- proximal grooves.
Supragingival chamfer 0.5mm from gingival margin to make cleansable.
SHOULD REMAIN IN ENAMEL.

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21
Q

Describe the posterior preparation for resin-retained bridge.

A

2mm occlusal rests.
SHOULD REMAIN IN ENAMEL.

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22
Q

BRIDGES

How can the edentulous space be temporised during resin-retained bridge construction ?

A

Immediate RPD or Essix.
If in enamel - no temporisation is required.
If in dentine - DBA over to reduce sensitivity.

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23
Q

BRIDGES

What two materials can be used for retainer of a bridge ?

A

CoCr or NiCr.
Both sandblasted with aluminium oxide.

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24
Q

Describe the process of cementation of a bridge.

A

Isolate the tooth.
37% etch.
Rinse.
Primer.
Air dry for 2 seconds.
Cement with Panavia 21EX.
Remove excess cement.
Place Oxyguard II for 3 mins.
Rinse.
Check occlusion.
Give OH instructions.

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25
Q

Bridges - what is Oxyguard II ?

A
  • Oxygen inhibitor gel.
  • Enables complete curing of cement in anaerobic setting.
  • Contains polymerisation accelerator - for effective setting.
  • Placed around margins of cemented abutment for 3 mins & rinsed.
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26
Q

Bridges - what is a active monomer in Panavia 21EX and what is its function ?

A
  • 10MDP phosphate monomer.
  • Allows molecular bonding of tooth to metals.
  • Acidic end reacts with metal oxide and renders surface hydrophobic.
  • C=C bonds with luting agent.
  • And methyl methacrylate monomer.
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27
Q

BRIDGES

What is the survival rate of a RR bridge >5 years ?

A

80%

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28
Q

LUTING AGENTS FOR CEMENTING INDIRECT RESTORATIONS

What luting agent should be used to cement a resin-retained bridge ?

A

Panavia 21EX.

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29
Q

Bridges - what type of material is Panavia 21EX ?

A

Anaerobic cure composite luting cement.

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30
Q

Describe a wash-through pontic design.

A

Makes no contact with soft tissues.

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31
Q

What are the benefits of a wash-through pontic ?

A

Easy cleaning.
Improves function (but poor aesthetics).
Consider in lower molar area.

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32
Q

BRIDGES

In what part of the mouth would a dome-shaped pontic design be most appropriate ?

A

Lower incisors.
Lower premolars.
Upper molars.

When occlusal 2/3 of buccal surface is visible (poor aesthetics in gingival 1/3).

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33
Q

What is the benefits and disadvantages of a dome-shaped pontic ?

A

Good cleansability.
Compromised gingival 1/3 aesthetics.

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34
Q

Describe a modified ridge lap pontic.

A

Buccal surface looks as much like a tooth as possible and makes contact with the soft tissues (line contact with buccal of ridge). Lingual surface is cut away.

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35
Q

What is a benefits and disadvantages of modified ridge lap pontic ?

A

Good aesthetics buccally.
More cleansable palatal/lingually.
Risks of food packing on lingual surface of ridge.

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36
Q

What are the benefits and disadvantages of a ridge lap pontic ?

A

With good technique, can be made cleansable.
Less food packing.
Good aesthetics.
Causes gingival moulding.
Avoid displacing soft tissue or cause blanching.

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37
Q

What is the disadvantage of an ovoid pontic ?

A

Requires surgical preparation.

38
Q

BRIDGES

What materials can be used for a bridge ?

A

Metal - gold, NiCr.
Metal ceramic - most robust.
All ceramic - zirconia (LAVA 3M ESPE), lithium disilicate (EMAX).

39
Q

BRIDGES

Describe an all ceramic zirconia bridge (LAVA 3M ESPE).

A
  • Milled zirconium oxide core.
  • Feldspathic porcelain overlying.
40
Q

What are the benefits of an all ceramic zirconia bridge (LAVA 3M ESPE) ?

A

Withstands high occlusal forces.
Can be used for 3-4 unit bridges.
Good aesthetics.
Similar reduction to MCC.

41
Q

How can a conventional bridge be temporised - explain the procedure ?

A

Take primary imps. Request vacuum-formed stent - allows you to check reduction during tooth preparation and construct provisional bridge.
OR
Make pre-operative putty matrix.

42
Q

How can you assess parallelism in your preparation for a conventional bridge ?

A

By direct vision with one eye close.
Large mouth mirror for posterior.
Use straight (right angle) probe like surveyor.
Take impression, pour model and use laboratory surveyor - use for long span bridges.

43
Q

What luting cement should be used to cement a conventional metal bridge ?

A

Aquacem or RelyX.

44
Q

What type of material is Aquacem ?

A

GI luting cement.

45
Q

Explain the bonding of Aquacem.

A

Acid base reaction between glass and acid, then dissolution, gelation and hardening stages.
Ion exchange with calcium in enamel and dentine and hydrogen bonding with collagen in dentine.
Same chemistry as GI filling cement - just smaller particle size.

46
Q

What type of material is RelyX ?

A

Adhesive RMGI cement.

47
Q

What type of material should be used to cement an all ceramic conventional bridge ?

A

NEXUS

48
Q

What type of material is NEXUS ?

A

Dual cure resin cement.

49
Q

What are the main benefits to Panavia and why it is used in cementation of resin-retained bridges ?

A

Chemical adhesion to tooth surface.
Low film thickness - prevent occlusal interference.
Moisture tolerance.

50
Q

What are the disadvantages of distal cantilever bridges ?

A

Occlusal forces on pontic will produce leverage forces on abutment tooth causing tilting.
Only consider where patient has 4-4 and want to achieve SDA.

51
Q

What is the five year survival rate of conventional bridge work ?

A

94%

52
Q

You are preparing an anterior MCC - what finish lines would you use buccal/palatally ?

A

Buccal/labial - shoulder (1.5mm).
Palatal/lingual - chamfer (1mm) - ensure removal of cingulum undercut.

53
Q

You are preparing a posterior MCC - what finish lines would you use buccal/palatally ?

A

Buccal/labial - shoulder (1.5mm).
Palatal/lingual - chamfer (1mm).

54
Q

You are preparing a posterior MCC - how much occlusal reduction would you prepare ?

A

1.3-1.7mm reduction of the cusps.
0.8-1.2mm reduction in central fissure.

55
Q

CROWNS

You are preparing an anterior MCC - how much incisal reduction would you prepare ?

A

1.5mm.

56
Q

You are preparing a posterior MCC - how much degrees of taper would you ensure ?

A

4-7 degrees.

57
Q

You are preparing an anterior ACC - what finish margins would you use ?

A

Shoulder on all surfaces (1-2mm from gingival margin).

58
Q

You are preparing a posterior ACC - what finish margins would you use ?

A

Shoulder on all surfaces (1-2mm from gingival margin).

59
Q

You are preparing an anterior ACC - what incisor reduction would you prepare ?

A

1mm.

60
Q

You are preparing a posterior ACC - what occlusal reduction would you prepare ?

A

1mm.

61
Q

What are the reasons for temporising a crown preparation between preparation and fit appointment ?

A

Aesthetics.
Degrade tooth function due to occlusal reduction and destabilised occlusion.
Renders vital teeth sensitive.
Compromises coronal seal of RCT.

62
Q

INDIRECT RESTORATION MATERIALS

What material can be used for custom resin provisional crowns ?

A

Protemp.

63
Q

What type of material is Protemp ?

A

Chemically cured, bis-acrylic composite resin.

64
Q

What is the key difference between decorative and dental ceramic ?

A

Less Kaolin (<5%).
More feldspar (70-80%) - gives translucency.

65
Q

CUSPAL COVERAGE INDIRECT RESTORATIONS

What are the three indications for a cuspal coverage restoration ?

A

Loss of more than one cusp.
No retentive wall.
2mm ferrule.

66
Q

What are the benefits of a cuspal coverage restoration ?

A

Provide good coronal seal for root treated teeth.
Prevent cusp fracture of undermined cusps (particularly in posterior teeth with heavy occlusal load).

67
Q

CROWNS

What two burs should be used for crown preparation ?

A

Long diamond tapered fissure bur.
Chamfer bur.

68
Q

Why can porcelain not be used as a crown material on its own ?

A

Can form microcracks leading to catastrophic failure. Must be reinforced with alloy metal core - high flexural strength.

69
Q

Describe an inlay.

A

Intra-coronal indirect restoration.

70
Q

What materials can an inlay be made from ?

A

Gold, composite, porcelain.

71
Q

When would it be appropriate to use an inlay ?

A

Premolars or molar.
O, DO or MO restorations.
MOD only if prep kept narrow.
Low caries rate.
Replace failed direct restorations.

72
Q

What are the advantages of an inlay ?

A

Superior materials and margins.
Less deterioration over time.
More aesthetic.

73
Q

What are the disadvantages of an inlay ?

A

Time and cost.

74
Q

Describe the technique of inlays.

A

FIRST VISIT
1. Cavity prep.
2. Occlusal reg & imp (Impregum).
3. Restore temporarily.
SECOND VISIT
4. Cement.

75
Q

LUTING AGENTS FOR INDIRECT RESTORATIONS

What cement should be used for ceramic inlays ?

A

NX3

76
Q

What cement should used for gold inlays ?

A

Aquacem or Panavia or relyX.

77
Q

Describe an onlay.

A

Extra-coronal indirect restoration similar to inlays but with cusps coverage.

78
Q

ONLAYS DMS

What are the four materials onlays can be made of ?

A
  • Composite.
  • Gold.
  • Porcelain.
  • EMAX - lithium disilicate.
79
Q

ONLAYS

What are the indications for an onlay ?

A
  • Occlusal tooth loss with loss of one or more cusps but buccal and/or palatal cusps remaining.
  • Remaining tooth substance weakened by caries or pre-existing large restorations (MODs with wide isthmus).
80
Q

When are cast metal inlays/onlays preferable to amalgam ?

A

Higher strength required i.e. parafunctional habits or failed restoration due to heavy occlusion.
Significant tooth recontouring required.

81
Q

In what circumstances are onlays used ?

A

Toothwear cases to increase OVD.
Fractured cusps.
Restoration fo RCT teeth.
Replace failed restorations.

82
Q

INDIRECT RESTORATIONS

What are the benefits of an onlay vs. crown ?

A

Less destructive.

83
Q

What are the alternative treatment options for an inlay/onlay ?

A

Direct restoration - amalgam, composite, RMGI.
Crowns - 3/4 crown or full crown.
Extract.

84
Q

VENEERS

What are the indications for veneers ?

A

Improve aesthetics - discolouration.
Change shape of teeth.
Correct pegs shaped laterals.
Reduce or close proximal spaces.
Align labial surfaces of instanding teeth.

85
Q

What are the contraindications to veneers ?

A

Poor OH.
High caries rate.
Gingival recession.
High lip lines.
Root exposure.
Labially positioned teeth.
Severe rotations.
Overlapping teeth.
Significant discolouration.

86
Q

What margin should be used for veneers ?

A

Chamfer 0.3mm supra gingival or slightly sub gingival.

87
Q

How much should the mid facial reduction be for veneers ?

A

0.5mm

88
Q

How much should the incisor reduction be for veneers ?

A

1-1.5mm

89
Q

How can a veneer preparation be temporised ?

A

May not need it.
Spot bonded composite with no etch.

90
Q

What material can be used to cement a veneer ?

A

NEXUS - adhesive system.

91
Q

What are the alternative treatment options for veneers ?

A

Nothing.
Micro-abrasion with acid pumice.
Penetrative resin restorations.
Direct composite.
Crowns.

92
Q

What are some reasons why a bridge might fail ?

A

Poor operator technique. Wrong luting agent used. Poor moisture control on seating. Secondary caries from microleakage.

BDS4 CDS Restorative, Pros & Endo (13 decks)

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