Inlays and Onlays Flashcards
What are advantages of indirect restorations?
- Esthetics
- Control of restoration contours
- Strength of material
What are disadvantages of indirect restorations?
- Expensive
- Impression Needed (digital or impression material)
- Requires two appointments (unless you mill in office)
What are indications for inlay?
- Used on teeth with minimal caries
o Occlusion must be acceptable
o Buccal and lingual cusps must be STRONG
Does an inlay provide cuspal protection?
NO
What are indications for an onlay?
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
Inlay or onlay - buccal-lingual width of prep 1/2 way between central groove and cusp tip
CONSIDER onlay
Inlay or onlay - buccal-lingual width of prep 2/3 way between central groove and cusp tip
SHOULD onlay
Inlay or onlay - undermined cusps after caries removal?
Onlay
Inlay or onlay - when occlusion must be altered?
Onlay
What are the advantages of gold when used as indirect restorative material?
- strength
- wear resistance
- will maintain smooth surface (does not tarnish or
corrode) - better control or contact and contour
- potential for greater longevity
What are the disadvantages of gold when used as indirect restorative material?
- esthetics
What are the advantages of ceramic when used as indirect restorative material?
- Esthetics
- Wear resistant
- Reduced polymerization shrinkage compared to
direct composite restoration
What are the disadvantages of ceramic when used as indirect restorative material?
- 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
What are the walls of a gold inlay prep?
NO undercuts
Walls are DIVERGENT
How does a restoration fit on a gold inlay?
Passively
What are the line angles like on a gold inlay?
NO sharp line angles
What is acceptable in a gold inlay if the walls are longer?
More divergence acceptable (5°-7°)
What is acceptable in a gold inlay if the walls are shorter?
walls should be closer to parallel (2° divergence)
What material inlays are beveled?
Gold
Where are bevels on gold inlays?
Occlusal, axiopulpal, gingival bevels
1mm bevel @ 45*
What are other characteristics of gold inlay preparations?
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)
What is the occlusal depth of a ceramic inlay?
1.5-2mm
What is the isthmus of a ceramic inlay prep?
2.0 mm
Is there a bevel on a ceramic inlay?
NO bevel
What are other features of a ceramic inlay prep?
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
How do you do a gold onlay prep?
- Cut depth cuts into cusps
- 1.5 mm reduction on functional cusp
- 1.0 mm reduction on nonfunctional cusp - Add bevels
- 1 mm functional bevel
- 0.5 mm non-functional bevel - Ferrule margin (same as light chamfer?)
What are specifications of ceramic onlay?
- 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
Order the ceramic materials used at UMKC from weak to strong
Nano resin ceramic< feldspathic porcelain < leucite reinforced < lithium disilicate < zironia
No < Friend < LEts < Lauren < Zyn
What are examples of nano resin ceramic?
Enamic, lava ultimate
What is the MPa of nano resin ceramic?
140-200MPa
What are examples of feldspathic porcelain?
Vita and sirona blocks
What is the MPa of feldspathic porcelain?
154 +/- 15 MPa
What are examples of leucite reinforced?
IPS Empress
What is the MPa of leucite reinforced?
160 MPa
What are examples of lithium disilicate?
Ivoclar e.max
How does ivoclar e.max work?
Starts in an intermediate phase and must be crystallized
What is the MPa of lithium disilicate?
360 MPa
What can the shortened firing cycle of Ivoclar e.max cause?
Loss of strength and color shift
What is the MPa of zirconia?
600-900 MPa
What are the characteristics of zirconia?
Strong, less esthetic
What are challenges associated with inlay seating?
- Cannot have any undercuts (walls are DIVERGENT)
- Restoration fits PASSIVELY
- NO SHARP LINE ANGLES
Vocab hints: TAPER can mean convergence OR divergence (taper means “a gradual narrowing”, but not specific to which direction gets narrower)
Vocab hints: porcelain and ceramic will be used interchangeably on this exam (porcelain is a type of ceramic)
