Inlays and Onlays

Question 1

What are advantages of indirect restorations?

Answer 1

• Esthetics
• Control of restoration contours
• Strength of material

Question 2

What are disadvantages of indirect restorations?

Answer 2

• Expensive
• Impression Needed (digital or impression material)
• Requires two appointments (unless you mill in office)

Question 3

What are indications for inlay?

Answer 3

• Used on teeth with minimal caries
  o Occlusion must be acceptable
  o Buccal and lingual cusps must be STRONG

Question 4

Does an inlay provide cuspal protection?

Answer 4

NO

Question 5

What are indications for an onlay?

Answer 5

Teeth with:
o LARGE carious lesions or existing defective restorations o Cracked teeth
o Endodontically treated teeth
- must have sufficient tooth structure to retain the onlay and allow for removal of undercuts

Question 6

Inlay or onlay - buccal-lingual width of prep 1/2 way between central groove and cusp tip

Answer 6

CONSIDER onlay

Question 7

Inlay or onlay - buccal-lingual width of prep 2/3 way between central groove and cusp tip

Answer 7

SHOULD onlay

Question 8

Inlay or onlay - undermined cusps after caries removal?

Answer 8

Onlay

Question 9

Inlay or onlay - when occlusion must be altered?

Answer 9

Onlay

Question 10

What are the advantages of gold when used as indirect restorative material?

Answer 10

• strength
• wear resistance
• will maintain smooth surface (does not tarnish or
  corrode)
• better control or contact and contour
• potential for greater longevity

Question 11

What are the disadvantages of gold when used as indirect restorative material?

Answer 11

• esthetics

Question 12

What are the advantages of ceramic when used as indirect restorative material?

Answer 12

• Esthetics
• Wear resistant
• Reduced polymerization shrinkage compared to
  direct composite restoration

Question 13

What are the disadvantages of ceramic when used as indirect restorative material?

Answer 13

• Require removal of more tooth structure for adequate material bulk
• Ceramics require dry field to bond
• Expense (compared to direct composite)
• TECHNIQUE SENSITIVE
• Wears on opposing dentition
• Low potential for repair

Question 14

What are the walls of a gold inlay prep?

Answer 14

NO undercuts
Walls are DIVERGENT

Question 15

How does a restoration fit on a gold inlay?

Answer 15

Passively

Question 16

What are the line angles like on a gold inlay?

Answer 16

NO sharp line angles

Question 17

What is acceptable in a gold inlay if the walls are longer?

Answer 17

More divergence acceptable (5°-7°)

Question 18

What is acceptable in a gold inlay if the walls are shorter?

Answer 18

walls should be closer to parallel (2° divergence)

Question 19

What material inlays are beveled?

Answer 19

Gold

Question 20

Where are bevels on gold inlays?

Answer 20

Occlusal, axiopulpal, gingival bevels
1mm bevel @ 45*

Question 21

What are other characteristics of gold inlay preparations?

Answer 21

o Flared exit angles
o Contacts broken at least 0.5 mm
o If 2 surface (MO or DO)
- dovetail is present
- NO reverse S (gold strong enough)

Question 22

What is the occlusal depth of a ceramic inlay?

Answer 22

1.5-2mm

Question 23

What is the isthmus of a ceramic inlay prep?

Answer 23

2.0 mm

Question 24

Is there a bevel on a ceramic inlay?

Answer 24

NO bevel

Question 25

What are other features of a ceramic inlay prep?

Answer 25

o Flared exit angles o Contacts broken at least 0.5 mm o No sharp line angles o Smooth, flat walls o If 2 surface (MO or DO) - dovetail is present

Question 26

How do you do a gold onlay prep?

Answer 26

1. Cut depth cuts into cusps - 1.5 mm reduction on functional cusp - 1.0 mm reduction on nonfunctional cusp 2. Add bevels - 1 mm functional bevel - 0.5 mm non-functional bevel 3. Ferrule margin (same as light chamfer?)

Question 27

What are specifications of ceramic onlay?

Answer 27

- 2mm reduction functional cusp - 1.5 reduction nonfunctional cusp - 90 degree cavosurface angles - Smooth line angles - No external bevels - Need adequate (0.5mm) clarence from adjacent teeth for die separation

Question 28

Order the ceramic materials used at UMKC from weak to strong

Answer 28

Nano resin ceramic< feldspathic porcelain < leucite reinforced < lithium disilicate < zironia No < Friend < LEts < Lauren < Zyn

Question 29

What are examples of nano resin ceramic?

Answer 29

Enamic, lava ultimate

Question 30

What is the MPa of nano resin ceramic?

Answer 30

140-200MPa

Question 31

What are examples of feldspathic porcelain?

Answer 31

Vita and sirona blocks

Question 32

What is the MPa of feldspathic porcelain?

Answer 32

154 +/- 15 MPa

Question 33

What are examples of leucite reinforced?

Answer 33

IPS Empress

Question 34

What is the MPa of leucite reinforced?

Answer 34

160 MPa

Question 35

What are examples of lithium disilicate?

Answer 35

Ivoclar e.max

Question 36

How does ivoclar e.max work?

Answer 36

Starts in an intermediate phase and must be crystallized

Question 37

What is the MPa of lithium disilicate?

Answer 37

360 MPa

Question 38

What can the shortened firing cycle of Ivoclar e.max cause?

Answer 38

Loss of strength and color shift

Question 39

What is the MPa of zirconia?

Answer 39

600-900 MPa

Question 40

What are the characteristics of zirconia?

Answer 40

Strong, less esthetic

Question 41

What are challenges associated with inlay seating?

Answer 41

* Cannot have any undercuts (walls are DIVERGENT) * Restoration fits PASSIVELY * NO SHARP LINE ANGLES

Question 42

Vocab hints: TAPER can mean convergence OR divergence (taper means “a gradual narrowing”, but not specific to which direction gets narrower)

Question 43

Vocab hints: porcelain and ceramic will be used interchangeably on this exam (porcelain is a type of ceramic)