Operative techniques Flashcards

1
Q

What are the principles of cavity preparation

A
  • dentify and remove carious enamel
  • Remove enamel to identify the maximal extent of the lesion at the ADJ & smooth the enamel margins
  • Progressively remove peripheral caries in dentine - from the ADJ first then circumferentially deeper and only then remove deep caries over the pulp
    • This is to ensure that if there is a pulpal exposure that the caries does not fall into the pulp and so gives a better prognosis
  • Outline form modification
    • Enamel finishing
      • Remove any unsupported enamel
      • Occlusion
      • Requirements of the restorative material
  • Internal design medication
    • Internal line and point angles
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2
Q

What are indications for crowns

A
  • Protect weakened tooth structure
  • Improve or restore aesthetics
  • For use as a retainer for fixed bridge
  • When indicated by RPD design
  • Restore tooth function
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3
Q

What are principles of crown preparation (that can be used to evaluate a crown)

A

PRS MPA

  • preservation of tooth structure
  • retention and resistance
  • structural durability
  • marginal integrity
  • preservation of periodontium
  • aesthetic considerations
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4
Q

What are we looking at when preserving tooth structure

A
  • Has it been over or under prepared?
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5
Q

What do we need to do to provide retention and resistance in a crown prep

A
  • Is it tapered? Want taper of 6 degrees
  • How long are the walls? Want longer walls for retention
  • Want limited number paths of insertion
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6
Q

How do we provide structural durability in a crown prep

A
  • Has enough been removed so there is adequate room for bulk of material
    • Occlusal reduction
    • Functional cusp bevel
    • Axial reduction
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7
Q

How do we ensure marginal integrity in a crown prpe

A
  • What is the finish line? Shoulder or chamfer?
  • Chamfer more aesthetic
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8
Q

How do we preserve the periodontium in a crown prep

A
  • Margins of restoration should be
    • Smooth and full exposed to a cleansing action
    • Placed where the dentist can finish them and px can cleen them
    • Placed at gingival margin whenever possible
    • Dont want to impinge on supracrestal attachment (junctional epithelium + connective tissue)
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9
Q

What are aesthetic considerations for a crown prep

A
  • Does it work for px smile line
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10
Q

What is the axial reduction for a metal crown: full veneer gold crown

A

0.5mm

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11
Q

What is the axial reduction for ceramic crowns (traditional porcelain)

A

1mm

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12
Q

What is the axial reduction for a metal ceramic crown

A

1.3

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13
Q

What is the axial reduction for an all ceramic crown (porcelain bonded to alumina or zirconia framework

A

1.5

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14
Q

What is the occlusal reduction for the functional and non functional cusps for a metal crown (full veneer gold crown)

A

F - 1.5mm

NF - 0.5mm

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15
Q

What is the occlusal reduction for the functional and non functional cusps for a ceramic crown (traditional porcelain)

A

F - 1.5mm

NF - 1mm

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16
Q

What is the occlusal reduction for the functional and non functional cusps for a metal ceramic

A

F - 1.8mm

NF - 1.3mm

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17
Q

What is the occlusal reduction for the functional and non functional cusps for a all ceramic crown (porcelain bonded to aluminia or zirconia framework)

A

F - 2mm

NF - 1.5mm

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18
Q

What is the finish line for a metal crown (full veneer gold crown)

A

chamfer

.5

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19
Q

What is the finish line for a ceramic crown (trad porcelain)

A

shoulder

1mm

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20
Q

What is the finish line for a metal ceramic crown

A

chamfer 0.5 where only metal required

shoulder 1.3mm for where metal and porcelain required

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21
Q

What is the finish line for all ceramic crowns (porcelain bonded to zirconia/alumina)

A

chamfer

1-1.5mm

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22
Q

What are the types of inlays

A
  • Gold
  • Composite
  • Porcelain
  • Ceromeric
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23
Q

What are the uses of inlays

A
  • Occlusal cavities
  • occlusal/interproximal cavities
  • Replace failed direct restorations
  • Minor bridge retainers
24
Q

What are the indications of inlays

A
  • premolars/molars
  • Occlusal
  • Narrow MODs
  • MOs/DOs
25
What are advantages of inlays
Better materials and margins
26
What are the tools for inlay and onlay prep
handpiece burs (no 170L, 169L, flame) enamel hcahets binangle chisel gingival magin trimmers
27
What is the inlay preparation for a ceramic inlay
1. 5mm-2mm isthmus 1. 5mm depth 1. 5-2mm proximal box 1mm shoulder/chamfer margin
28
What is the inlay preparation for a gold inlay
1mm istmus width 1.5mm depth 1mm proximal box 0.5mm chamfer margin
29
What degree of tapered walls do we want for inlay
4-6 degrees
30
Where do we want our shoulder chamfer margins for an inlay
supra gingival
31
Where must the margins be for an inlay
clear of occlusal contact points
32
What sort of bevel do we want for inlays
none for ceramic 15-20 degrees bevel in upper ⅓ isthmus wall
33
What features do we want in an inlay
occlusal key/dovetail grooves for retention (optional)
34
How are onlays differnet to inlays
* Similar to inlays but have cuspal coverage and so require some cuspal preparation
35
What are types of onlays
* Gold * Composite * Porcelain * Ceromeric
36
What are indications of onlays
* Sufficient tooth substance loss * Remaining tooth substance weakened * Wide MODs
37
When are onlays preferable to a large amalgam
* when higher strength is needed and significant tooth recontouring is required
38
What are uses of onlays
* ooth wear cases * Increase OVD * Fractured cusps * Restoration of root treated teeth * Replace failed direct restoration * Less destructive than crowns
39
What is the occlusal reduction for a porcelain onlay
non working cusp - 1.5mm working cusp -2mm reduction
40
What is the occlusal reduction for a gold onlay
non working cusp - 0.5mm working cusp -1mm reduction
41
how big should the proximal box be for a gold onlay
1mm
42
How big should a proximal box be for a ceramic onlay preparation
2mm
43
What are the margins for a porcelain onlay
1mm shoulder or chamfer
44
What is the margins for a gold onlay
0.5mm chamfer
45
What are features of a onlay prep
no bevels for ceramic - butt joint CSM bevels for gold - 15/20 degree bevel for upper ⅓ of isthmus wall margins clear of occlusal CP 4-6 degree tapered walls
46
What is the first appointment for an inlay and onlay
LA reduction template impression for temp tooth prep make temp impressions, bite registration and record shade cement temp
47
What is the second appointment for inlays and onlays
remove temp isolate, clean and dry prepared tooth try in cement minor occlusal adjustment if needed
48
What are the types of veneers
* Ceramic * Composite * Gold
49
What are indications for veneers
* Aesthetic * Change teeth shape/contour * Correct peg shaped laterals * Reduce or close proximal spaces and diastemas * Align labial surfaces of instanding teeth * Enamel defects * Discoloration (intrinsic or bleach doesnt work for it)
50
What are contraindications for veneers
* Poor OH * High caries rate * Gingival recession * Root exposure * High lip lines * Extensive prep needed
51
What is the cervical reduction for veneer
0.3mm chamfer margin within enamel supragingival or slightly sub
52
What is the midfacial reduction for a veneer
0.5mm within enamel
53
What is the incisal reduction for a veneer
1-1.5mm
54
What is the first appointment for a veneer
if tooth prep required 1. LA 2. putty index 3. impression for temp 4. tooth prep 5. make temp 6. impression, bite reg, record shade 7. cement temp
55
What is the second appointment for a veneer
1. remove temp 2. isolate, clean and dry tooth 3. try in and assess fit, adaption and occlusion 4. cement
56
What are alternatives to veneers
* Bleaching/tooth whitening * Microabrasion * Direct composite restorations * crowns