Ceramic veneers II

Question 1

What does veneer prep depend on?

Answer 1

Method of fabrication
Occlusion
Desired aesthetics
Any parafunction
Presence of enamel at all proposed margins

Question 2

What can make up a veneer?

Answer 2

Resin composite

Porcelain (ceramic)

Question 3

Indications for direct composite veneers?

Answer 3

Extensive damage to incisal or buccal surface
Defective restoration
Discolouration not amendable to bleaching
Malaligned teeth - pt does not want ortho
Congenitally deformed teeth
Pt not have time or finances for indirect porcelain veneer
Where indirect porcelain veneer would require excessive tooth structure removal

Question 4

Contraindications of direct composite veneers?

Answer 4

Inability to obtain correct shades to blend with adjacent teeth
Inability to obtain correct contours or surface characteristics
No proper isolation
Multiple teeth - difficulty in achieving consistent shade, contours and surface characteristics

Question 5

Advantages of direct composite veneers?

Answer 5

Very little/no tooth prep
Composite can wear similarly to natural tooth and do not cause iatrogenic wear of opposing dentition
Chairside repairs
Can be made chairside or in lab

Question 6

Disadvantages of direct composite veneers?

Answer 6

Colour stability - composite takes stain from environment
Not as long lasting as porcelain alternative
Not as strong as ceramic
Wears more compared to ceramic

Question 7

What is the direct technique? What is required?

Answer 7

Veneers are made by dentist chairside
One appointment only
Minimal/no prep
Colour modifiers and resin composite (microfilled, hybrid) required

Question 8

Indirect composite technique features?

Answer 8

Minimal prep
0.25-0.5mm tooth reduction
Resin cement for cementation
Bonding procedure similar to porcelain veneers
Variety of systems:
- Artglass
- Belleglass
- Sculpture

Question 9

Advantages of indirect over direct composite veneers?

Answer 9

Reduced polymerisation shrinkage = smaller marginal gap
Reduced marginal leakage, sensitivity, recurrent caries and staining
Physical properties of composite can improve with additional curing
Better control over interproximal contours and contacts
Less technique sensitive than direct one
Done in lab for you

Question 10

Porcelain laminate veneer components?

Answer 10

Porcelain veneer
Acid etched enamel surface
Silane coupling agent
Resin cement

Question 11

Advantages of porcelain laminate veneers?

Answer 11

Superior aesthetics
Long term durability
Strength
Marginal integrity
Soft tissue compatibility
Minimal tooth reduction

Question 12

Disadvantages of porcelain laminate veneers?

Answer 12

Time consuming - multiple appointments
Fragility
Repair difficult
Colour matching challenging
Irreversibility
Inability to trial cement the restoration

Question 13

What materials are used for porcelain technology?

Answer 13

Lithium disilicate
Feldspathic
Glass infused

Question 14

Negatives of not prepping the veneer tooth?

Answer 14

pain, overcontoured margins, hygiene, gingival inflam, high failure rates

Question 15

Positives and negatives of veneer prepping a tooth?

Answer 15

Stress conc is less on veneers fitted to prepared teeth
Prep removes aprismatic and hypermineralised enamel layers = more resistant to acid etching
Should aim for prep to be completely in enamel to maximise resin bond strength and reduce tensile stress in the porcelain

Question 16

What does veneer tooth prep involve?

Answer 16

Minimal prep
0.5-0.5 mini chamfer
0.6 to 0.8 for incisal and buccal reduction
Facial reduction in 2 planes
Special bur kits
Depth grooves/pits

Question 17

Veneer prep types?

Answer 17

Window preparation
Long bevel - done in IRS
Complete veneer coverage

Question 18

Why extend the preparation over the incisal edge?

Answer 18

To increase strength of veneer-tooth

Question 19

When is intra-labial/window veneer prep useful?

Answer 19

Useful in canine guidance, class II div II and class III incisor relationships

• Contained within labial surfaces
• No temp restoration needed
• Minimal prep - does not involve the incisal edge so not involved in occlusion BUT join between veneer and tooth can be visible

Question 20

Why do a temporary veneer?

Answer 20

Aesthetics
Reduce sensitivity
Diagnostic - contour, shape, length

Question 21

Types of temporary veneers?

When are temps necessary?

Answer 21

Direct composite build up with spot etching of enamel (used for 1 or 2 preps)
Chairside - clear matrix made on diagnostic wax up, then spot etch and protemp/composite in matrix and placed over multiple preps
Indirectly made temps in labs

Not always necessary - needed when more aggressive and dentine exposed - sensitivity, aesthetics
Can serve as provisionals

Question 22

Why cement the veneer in place?

Answer 22

Veneer becomes integral part of tooth structure
Share part of loading stresses during mastication
Light cured composite luting agent (for thin veneers)

Question 23

What cement use for the try in stage of the veneer? Why do this?

Answer 23

Resin luting agent
Veneers tried before cementation to assess fit and aesthetics
Try in paste - water soluble, optical contact
Handle veneer with care
Use of veneer carrier

Question 24

How to prepare the veneer for cementation?

Answer 24

Veneer surface treated with HF acid
Clean fitting surface of veneer with acetone (40ml) to remove try in paste
Treating the surface with phosphoric acid can improve bonding
Rinse and dry
Silane application and keep away from light

Question 25

How does silane coupling agent work?

Answer 25

Apply to internal etched surface
Chemically bonds to ceramic
Makes ceramic surface hydrophobic

Question 26

Features of cementation?

Answer 26

Variety of resin cements - Variolink II, nexus, calibra
Standard material - translucent
Can get more opaque ones for darker teeth

Etch tooth
Bonding agent
Resin cement

Veneer carrier avoids handling and too much pressure - can crack veneer
Veneer must be held in 2 planes during initial palatal polymerisation
If veneer not held firmly during initial polymerisation = suck back occurs = gaps in margins
Resin spaces can be caused by insufficient luting resin and incorrect sequence of seating multiple veneers
Remove excess cement with floss, finishing burs and check occlusion, finish with polishing points

Question 27

What can cause resin spaces?

Answer 27

Insufficient luting resin

Incorrect sequence of seating multiple veneers

Question 28

How can veneers fail?

Answer 28

Fracture - especially with unfavourable occlusion, parafunction, bonding to existing restorations
Types of fracture
- Static
- Cohesive
- Adhesive
Microleakage/marginal staining
Debonding

Question 29

What is a static fracture?

Answer 29

When segment of veneer fractures but remains on tooth

Due to excess loading or polymerisation shrinkage

Question 30

What is a cohesive fracture?

Answer 30

Within body of porcelain due to tensile load from excessive functional or parafunctional loading
Results in loss of fragment

Question 31

What is an adhesive fracture?

Answer 31

Failure of bonding interface

Due to weak bond or severe occlusal loading