Inlay/Onlay preps and restorations

Question 1

What are the two major materials used in Inlays/Onlays?

Answer 1

Metal

Ceramic

Question 2

What are the indications for Metal In/Onlays?

Answer 2

Large restorations
Endo treated teeth (Esp posterior)
Teeth at risk for fracture
Dental rehab with cast metal alloys
Diastema closure and occlusal plane correction
Removable abutment

Question 3

What are the contraindications for metal In/Onlays?

Answer 3

High caries rate
Young patients (large pulps)
Esthetics
Small restorations - more conservative options

Question 4

What are the advantages of metal Inlays/Onlays?

Answer 4

Strength
Biocompatable
Low wear
Control of contours/contacts

Question 5

What are the disadvantages of metal Inlays/Onlays?

Answer 5

Lots of apts and chair time
Temp restorations
Cost
Technique sensitive
Splitting forcaes (inlays only)

Question 6

What makes a metal Inlays/Onlays prep different than and amalgam prep?

Answer 6

Wider isthmus (about 2mm)
Divergent walls
1mm interproximal clearance
45’ bevel

Question 7

What is the difference between an inlay and an onlay?

Answer 7

Onlays cover at least one cusp

Question 8

What are the indications for a ceramic Inlays/Onlay?

Answer 8

Esthetic
Large defects
Large previous restoration

Question 9

What are the contraindications for ceramic Inlays/Onlays?

Answer 9

Heavy occlusal forces
Inability to maintain a dry field
Deep subgingival prep

Question 10

What are the advantages for ceramic Inlays/Onlays?

Answer 10

Improved physical properties
Variety of materials/techniques
Wear Resistance
Reduced polymerizaiton shrinkage
Support of remaining tooth structure
More precise control of contours/contacts
Biocompatability
Good tissue response
Increased auxiliary support

Question 11

What are the disadvantages of ceramic Inlays/Onlays?

Answer 11

Increased cost/time
Technique sensitive
Difficult try-in/delivery
Ceramic is brittle
Wear of opposing dentition and restorations
Short clinical track record
Low potential for repairs

Question 12

What are the different types of ceramic Inlays/Onlays?

Answer 12

Feldspathic porcelain
Pressed-glass
Lithium disilicate
CAD/CAM
Composite

Question 13

How are ceramic Inlays/Onlay preps different from the metal ones?

Answer 13

Deeper (about 2mm)
No bevels - 90’ exit angles
Less conservative than metal

Question 14

What should the tapering be for ceramic Inlays/Onlays?

Answer 14

6’-10’

Over tapering causes thinner occlusal margins and increased marginal stress