4. Posterior Indirect Restorations

Question 1

Definition of inlay or only (indirect restoration)

Answer 1

Partially or fully intracoronal indirect restoration retained using a cement or bonding system, normally made outside the mouth

Question 2

Difference between inlay and only (2)

Answer 2

Inlay - usually covers just the occlusal surface

Onlay - usually covers one or more functional cusps

Question 3

Types of indirect restoration materials (2)

Answer 3

Gold

Aesthetics - composite, ceromeric, ceramic

Question 4

Advantages of gold indirect restorations (6)

Answer 4

Indirect nature allows for ideal contour and occlusion
Strength, support, protection
Wear and antagonist wear
Marginal adaptation can be improved at fit
Corrosion resistant
Extremely durable and long-lasting when fitted properly

Question 5

Disadvantages of gold indirect restorations (5)

Answer 5

Costs (laboratory)
Extra visits
Need for placement of a provisional restoration
Aesthetics
Skill required for preparation/intra-oral waxing

Question 6

Indications for gold use (4)

Answer 6

Small lesions leading to complete coronal breakdown
Occlusal protection
Production of ideal occlusal/morphological contours
Prevention of galvanism

Question 7

Basic principles of tooth prep for gold indirect restorations (1)

Answer 7

Conservation of tooth structure
Consider cusps coverage
Retention and resistance form
Contours
Finish lines
No undercuts
Adequate strength of remaining tissue
Precise prep critical
Bases and liners

Question 8

What does inlay prep involve (2)

Answer 8

Inlay prep

With partial or full occlusal coverage

Question 9

Types of aesthetic indirect restorations (4)

Answer 9

Composite
Ceromeric
Ceramic
CAD-CAM

Question 10

Advantages of indirect composite restorations (4)

Answer 10

Avoids common technical errors with direct composites
Avoids polymerisation contraction
Avoids polymerisation contraction stresses
Avoid cuspal flexture

Question 11

Disadvantages of indirect composite restorations (4)

Answer 11

Secondary polymerisation
More destructive than direct composite (block out undercuts)
Bonding still technique sensitive
Lab stage required and provisional restoration required
Little evidence of any benefit over a well-placed direct composite

Question 12

Features of indirect ceromeric restorations (7)

Answer 12

Ceramic optimised polymer
More destructive as undercuts must be removed
May be reinforced with fibre additions
Excellent aesthetics
Less suitable for inlays (retention)
Bonding still technique sensitive
Lab stage required and provisional restoration required

Question 13

Features of indirect ceramic restorations (11)

Answer 13

High-strength porcelain
Bonding technique maximises strength
More destructive as undercuts must be removed
Best aesthetics
Less marginal leakage
Better wear resistance than ceromeric
Better retention than ceromeric
More suitable for onlays (retention)
Bonding is still technique sensitive
Lab stage required and provisional restoration required
Differential wear

Question 14

Types of ceramic (3)

Answer 14

Hand modelled (refractory die technique)
Pressed (lost wax technique)
Milled (CAD-CAM)

Question 15

Advantages of indirect CAD-CAM restorations (7)

Answer 15

Excellent marginal fit
Single visit
Optical impression
3D computer modelling if restoration
Antagonist and articulation functions
Correlation and replication functions
Pre-formed factory manufactured ceramic blocks

Question 16

Gold finishing and occlusal adjustment (3)

Answer 16

Hand and rotary burnishing
Greenies and Brownies
ZnO and alcohol

Question 17

Aesthetic finishing and occlusal adjustment (4)

Answer 17

Composite finishing burs
Astropol
Soflex discs
Enhance polishers

Question 18

Advantages/disadvantages of gold indirect restorations (7)

Answer 18

Excellent durability and life
Demanding tooth preparation
Intra-oral or extra-oral wax up
Impression may be required
Provisional restoration required
Cuspal coverage required to add strength to tooth
Non-conservative

Question 19

Principles of preparation for indirect aesthetic restorations (8)

Answer 19

No bevels – shoulder and butt joints
No sharp internal or point angles
No sharp angle transitions
No undercuts
Minimal taper of axial walls
Smooth cavosurface margins and correct angles
Rounded internal anatomy
Consider bulk of restoration: strength