Veneer - 2 Flashcards
What does veneer prep depend on?
Method of fabrication Occlusion Desired aestehtic Parafunction Presence enamel at all proposed margins Material: resin composite/ ceramic
Indications for direct resin composite veneer?
Extensive damage incisal or buccal surface
Defective restoration
Discolouration not amenable to bleaching
Mal-aligned teeth
Congenitally deformed teeth
Pt doesn’t have time/finance for porcelain
Indirect porcelain would require excessive tooth structure removal
Contraindications for direct resin composite veneer?
Inability to obtain correct shade
Inability to obtain correct contour
Inability to obtain correct surface characteristics
Inability to obtain proper isolation
Multiple teeth - extensive time and difficult achieve consistency
Advantages of direct resin composite?
Very little or no tooth prep
Composite wear similar natural teeth - no iatrogenic damage adjacent teeth
Chairside repair
Disadvantages of direct resin composite?
Colour stability - take up stain
Not as long lasting as porcelain
Not as strong as ceramic
More wear compared to ceramic
What is longevity of direct RC veneer?
100% functional survival rate
Overall 84.6% at 5 years
What is a direct RC veneer?
Veneer made chairside
One appointment needed
No or minimal prep
What is an indirect RC veneer?
Need minimal preparation - 0.25-0.5mm reduction
Resin cement for cementation
Adv indirect> direct
Reduced polymerisation shrinkage
Reduced marginal leak, sensitivity, recurrent caries, stain
Less technique sensitive
Physical properties composite improve with additional curing
4 components of ceramic veneer?
Ceramic veneer
Acid-etched enamel surface
Silane coupling agent
Resin cement
Advantage ceramic veneer?
Excellent aesthetic Excellent long term durability Strength Marginal integrity Soft tissue compatibility Minimal tooth reduction
Disadvantage ceramic veneer?
Time consuming - multiple appts Fragility Repairability difficult Irreversible Inability to trial cement restoration
What are the 5 lab based techniques for making veneer?
- Foil based
- Castable ceramic
- Refractory
- CAD-CAM
- Pressable
How is foil based veneer made?
Porcelain layered on foil
Before try-in foil removed and porcelain etched
Foil permit repeatable removal of veneer from die
Thickness of foil creates space for cement
How is castable ceramic veneer made?
Lost wax technique
Eliminate need for multiple firing
Require extrinsic staining
How are refractory veneers made?
Most commonly used Veneer fired onto die Makes repeated fires impossible once veneer removed die Tighter contacts Absence of gaps No room for tints
What is a pressable veneer?
High pressure into mould
Excellent fit
Thin veneers
Why should you prep teeth for veneers?
Stress concentration is less on veneers fitted to prepped teeth
Preparation remove prismatic and hyper mineralised enamel -resistant to etch
Prep completely in enamel to maximise resin bond
What should the ideal tooth prep be?
Minimal
0.3-0.5mm mini chamber
0.6-0.8mm for incisal and buccal reduction ;
Buccal reduction 2 planes
How can you increase strength of veneer-tooth?
Extend preparation over incisal edge
When is a window prep useful?
Class II div II and class III incisors
- Contained on labial surface
- Minimal prep
Why are tempories used?
Aesthetic
Reduce sensitivity
Diagnostic: contour, shape, length
Not always necessary - if dentine exposed mandatory
What different tempories are available?
Direct composite - spot etch
Indirect made in lab
Matrix w/ protemp
Why is cementation vital?
Allows veneer to become integral part of tooth structure
Share part of applied load during mastication
