ceramic veneers

Question 1

What is a veneer?

Answer 1

Layer of tooth coloured material applied to a tooth to restore localised or generalised defects and intrinsic discolourations

Improves shape, colour, position

Ceramic or composite

Most conservative and aesthetically pleasing indirect restoration

Question 2

What are the indications?

Answer 2

Colour defects or abnormalities eg. Amelogenesis imperfecta, meds, fluorosis
Abnormalities of shape eg. Microdontia
Abnormal structure or texture eg. TSL, dysplasia
Malpositioning
Diastema
Missing teeth
Palatal veneers eg. To correct guidance
Lengthening (need to ensure no unsupported ceramic)

Question 3

What are contraindications?

Answer 3

Insufficient surface enamel
Pulpless teeth (colour changes)
Unsuitable occlusion
Parafunction eg. Bruxism
Unsuitable morphology
Heavily restored teeth (related w poor OH and caries)

Single veneers (difficult to match neighbouring teeth)

Question 4

What needs to be considered?

Answer 4

Problem
Patient
Oral Health
Teeth in question
Quality and quantity of enamel
Occlusion

Question 5

What is tetracycline discolouration?

Answer 5

Med taken when teeth are developing
Leads to discoloured band across teeth
Rare

Question 6

How is the face assessed?

Answer 6

Shape of face, lips
Smile analysis (lip lines)
Skin tone eg. Sun tan
Skin will change colour in future

Question 7

How do you do a smile analysis?

Answer 7

View from front and sides
(Shape of face and size of lips, visible coronal and gingival levels at rest, talking and broad smile)

Contour of lower lip should mirror shape of upper teeth

Harmony and proportion of cervical line, line of incisal edges and lip line

Tooth colour (hue, value, chroma, translucency, texture, luster)

Tooth shape (height:width, incisal edges, contour, triangular tooth shape

Static and dynamic occlusion
Special arrangement of teeth
(ICP, centric, protrusive, left and right excursions)

Question 8

Why should occlusal movements not coincide with veneer margins?

Answer 8

Placement can cause the resin to wear away and the unsupported ceramic to chip and break

Question 9

How could you demonstrate the proposed aesthetic change?

Answer 9

1. Diagnostic wax up
2. Composite w/o etch or bond
3. Temp composite
4. Wax up + matrix + pro temp
5. Composite shell/overlay on diagnostic cast (placed intra oral)
6. Computer imaging
7. Demo models
8. Photography

Question 10

How do you treatment plan?

Answer 10

1. Pros and cons of each option
2. Informed consent (post op sensitivity, marginal discolouration, fracture, debonding)
3. Short and long term maintenance
4. Financial implications (survival rate)
5. Don’t make decision on first appt

Question 11

How are veneers prepped?

Answer 11

Method of fabrication
Occlusion
Desired aesthetics
Parafunction
Presence of enamel at margins

Question 12

What are indications of direct composite resin veneers?

Answer 12

Extensive damage to incisal/buccal surface
Defective restoration
Discolouration but can’t bleach
Mal-aligned teeth but can’t ortho
Congenitally deformed teeth
No time or finances for ceramic
Indirect method may require excessive tooth removal

Question 13

What are contraindications for direct composite veneer?

Answer 13

Inability to have correct shades
Can’t have correct contour or surface characteristics
Can’t have proper isolation
Multiple teeth

Question 14

What are advantages of direct composite veneer?

Answer 14

V little or no tooth prep
Composite has similar wear to teeth
Chair side or lab
Can repair chair side
Usually one appt

Question 15

What are disadvantages of direct composite veneer?

Answer 15

Composite takes stain from environment
Result isn’t as long lasting
Not as strong as ceramic
Wears more than ceramic

Question 16

What is an indirect composite technique?

Answer 16

Minimal prep
0.25-0.5mm tooth reduction
Resin cement
Bonding similar to ceramic
Eg. Artglass, Belleglass, Sculpture, Targis, Paradigm MZ100 (CADCAM)

Question 17

What are advantages of indirect composite veneers?

Answer 17

Less polymerisation shrinkage
Smaller marginal gap
Less marginal leakage, sensitivity, recurrent caries, staining
Physical properties improved due to lab curing
Better control over interproximal contours and contacts
Less technique sensitive

Question 18

What are the components of ceramic veneer?

Answer 18

Ceramic veneer
Acid-etched enamel
Silane coupling agent
Resin cement

Eg. Feldespathic (mirage II), leucite reinforced (empress I), lithium disilicate (empress II, Emax)

Question 19

What are advantages of ceramic veneers?

Answer 19

Superior aesthetics
Excellent long term durability
Strength
Marginal integrity
Biocompatibility
Minimal tooth prep

Question 20

What are disadvantages of ceramic veneers?

Answer 20

Time consuming- multiple appts
Fragility until bonded
Repairs difficult 
Colour matching challenge (less translucent)
Irreversibility
Can’t trial cement

Question 21

Do you prep for a ceramic veneer?

Answer 21

If you don’t-
-reversible, painless
-over contoured, potential ledges leading to poor hygiene, inflam and higher failure rates

1. Stress conc is less on prepped
2. Prep removes aprismatic and hypermineralised enamel which are more resistant to etch
3. Prep completely in enamel to maximise bond strength and reduce tensile stress in ceramic

Question 22

What is the ideal tooth prep for ceramic?

Answer 22

0.3-0.5mm mini chamfer
0.6-0.8mm for incisal and buccal reduction
Facial reduction in 2 planes
Use depth grooves and silicone index
Special bur kits available
Should consider occlusion when placing margin
Intra labial (aka ‘window’) when canine guidance, class II div II and class III incisor relationships
- wholly labial, no temp needed, minimal prep

Question 23

Why is temporisation done?

Answer 23

Aesthetics
Reduce sensitivity
Diagnostic- contour, shape, length

Not always necessary due to minimal prep
If aggressive prep- required (although in that case is dentine bonded crown more appropriate?)

Question 24

What are types of temporaries?

Answer 24

Direct composite w spot etch
Clear matrix on wax up, spot etch and protemp/composite (multiple preps)
Indirect by lab

Question 25

How do you cement the veneer?

Answer 25

Important as bond strength helps share loading stresses

Light cured composite luting agent (translucent veneer)
OR
Dual cured system (if opaque)

Use veneer carrier and hold veneer in 2 planes during initial polymerisation (if not causes suck back—> gaps at margins)

Question 26

How is the try in done?

Answer 26

Resin luring agent
Calibra system
Try in paste (water soluble, colour matches cement, optical contact)
Handle veneer w extra care as v fragile so use veneer carrier

Question 27

How do you prepare the veneer for cementation?

Answer 27

1. Treat veneer w HF acid (in lab)
2. Clean fitting surface w acetone to remove try in paste (at least 40ml)
3. Treat surface w phosphoric acid to improve bonding
4. Rinse and dry
5. Apply silane and keep away from light

Question 28

How does the silane coupling agent work?

Answer 28

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

Question 29

How might resin spaces occur?

Answer 29

Insufficient luting resin
Incorrect sequence of seating multiple veneers

Question 30

How might the veneer fail?

Answer 30

Fracture due to
-unfavourable occlusion
-parafunction
-bonding to existin restorations

Micro leakage/marginal staining

Debonding

Question 31

What are the types of veneer fracture?

Answer 31

Static- segment of veneer fractures but remains on tooth (due to excess loading/p. shrinkage)

Cohesive- within body of ceramic resulting in loss of fragment (due to tensile loads from excess para/functional loading)

Adhesive- failure of bonding interface (due to weak bond or severe occlusal loading)

Question 32

How should a debonded veneer be managed?

Answer 32

Determine which interface has failed

If luting agent on tooth-
Inadequate etching of veneer or no silane coupling

If luting agent on veneer-
Problem w material, placement technique or substrate (esp dentine bond)