ceramic veneers Flashcards
What is a veneer?
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
What are the indications?
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)
What are contraindications?
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)
What needs to be considered?
Problem
Patient
Oral Health
Teeth in question
Quality and quantity of enamel
Occlusion
What is tetracycline discolouration?
Med taken when teeth are developing
Leads to discoloured band across teeth
Rare
How is the face assessed?
Shape of face, lips
Smile analysis (lip lines)
Skin tone eg. Sun tan
Skin will change colour in future
How do you do a smile analysis?
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)
Why should occlusal movements not coincide with veneer margins?
Placement can cause the resin to wear away and the unsupported ceramic to chip and break
How could you demonstrate the proposed aesthetic change?
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
How do you treatment plan?
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
How are veneers prepped?
Method of fabrication
Occlusion
Desired aesthetics
Parafunction
Presence of enamel at margins
What are indications of direct composite resin veneers?
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
What are contraindications for direct composite veneer?
Inability to have correct shades
Can’t have correct contour or surface characteristics
Can’t have proper isolation
Multiple teeth
What are advantages of direct composite veneer?
V little or no tooth prep
Composite has similar wear to teeth
Chair side or lab
Can repair chair side
Usually one appt
What are disadvantages of direct composite veneer?
Composite takes stain from environment
Result isn’t as long lasting
Not as strong as ceramic
Wears more than ceramic
What is an indirect composite technique?
Minimal prep
0.25-0.5mm tooth reduction
Resin cement
Bonding similar to ceramic
Eg. Artglass, Belleglass, Sculpture, Targis, Paradigm MZ100 (CADCAM)
What are advantages of indirect composite veneers?
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
What are the components of ceramic veneer?
Ceramic veneer
Acid-etched enamel
Silane coupling agent
Resin cement
Eg. Feldespathic (mirage II), leucite reinforced (empress I), lithium disilicate (empress II, Emax)
What are advantages of ceramic veneers?
Superior aesthetics
Excellent long term durability
Strength
Marginal integrity
Biocompatibility
Minimal tooth prep
What are disadvantages of ceramic veneers?
Time consuming- multiple appts
Fragility until bonded
Repairs difficult 
Colour matching challenge (less translucent)
Irreversibility
Can’t trial cement
Do you prep for a ceramic veneer?
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
What is the ideal tooth prep for ceramic?
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
Why is temporisation done?
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?)
What are types of temporaries?
Direct composite w spot etch
Clear matrix on wax up, spot etch and protemp/composite (multiple preps)
Indirect by lab
How do you cement the veneer?
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)
How is the try in done?
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
How do you prepare the veneer for cementation?
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
How does the silane coupling agent work?
Apply to internal etched surface
Chemically bonds to ceramic
Makes ceramic surface hydrophobic
How might resin spaces occur?
Insufficient luting resin
Incorrect sequence of seating multiple veneers
How might the veneer fail?
Fracture due to
-unfavourable occlusion
-parafunction
-bonding to existin restorations
Micro leakage/marginal staining
Debonding
What are the types of veneer fracture?
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)
How should a debonded veneer be managed?
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)
