laminate veneers Flashcards
What is a good smile associated with?
Good health
Youth
Good social status
Success
What can a not very good smile effect?
Personality
Sociability and sociality
What do you ask a patient if they dont like how their teeth
What they dont like How long had this problem Why it has occurred Has it improved How would they like it altered Look and listen to the pt
What questions does the dentist need to decide?
Alternative treatment? Ortho, crowns, implants, surgery
Pre-treatment? bleaching, crown lengthening, restoration
Which veneer prep?
What is a veneer?
A layer of tooth-coloured material that is applied to the tooth to restore localised or generalised defects and intrinsic discolourations
A thin and translucent fabricated by either ceramic or composite material
What can a veneer improve?
Shape, colour and position
When did ceramic laminate veneers start being an option?
1980’s
After the introduction of acid etching, bis-GMA, ceramic surface treatment and bonding
These all triggered the use of veneers
What are the indications for veneers?
Colour defects or abnormalities Abnormalities of shape Abnormal structure or texture Malpositioning Diastema Missing teeth Lingual laminate veneers Lengthening
What could cause discolouration/abnormalities in the tooth?
Amelogenesis imperfecta, medication, fluorosis, age, trauma, extrinsic staining with infiltration of tissues
What are the different abnormalities in shape of teeth?
Microdontia
Atypical tooth shape
Malformed incisor
retained deciduous teeth
What can cause abnormal structure or texture of teeth?
Dysplasia, Erosion Attrition Abrasion Coronal fracture
What do lingual laminate veneers correct?
correct anterior guidance
create canine guidance
palatal erosion
What are the contraindicationsd for ceramic veneers?
Insufficient surface enamel
Pulpless teeth - fragile and will change colour
Unsuitable occlusion - pronounced overbite
Parafunction - bruxism/nail biting
Unsuitable anatomical morphology
Single laminate veneers - difficult to match with
Heavily restored dentition; caries and fillings
What gives the veneer strength?
The bond of the glass ceramic to the tooth
by assigning a coupling agent that infiltrates into the silica bonds in the ceramic and forms a bond
What needs to be checked at the examination and assessment?
The problem The pt The OH The teeth in question quantity and quality of enamel the occlusion
What are the things that could cause the problem to the teeth leading to the patient wanting veneers?
Hereditary - amelogenesis imperfecta
Systemic
Traumatic
Parafunction - bruxism
Could veneers be an option for tetracycline discolouration?
Causes banding on teeth
Needs to be very opaque to mask out
Lower anteriors have less bonding surface
If have dead pulp what can be done to prepare for a veneer?
Discolouration would show through
Need to do RCT, internal bleaching then can place the veneer
When treatment planning what needs to be considered?
OH, caries, restorations
Smile analysis
Occlusal analysis - if on occlusal surface will cause resin to wear and unsupported ceramic to eventually fracture or chip
Must co-incide with veneer margins
What needs to be assessed about the face?
lips, maxillary and mandibular lip lines
skin colour
What is included in a smile analysis?
View from front and sides: shape of face, size of lips and visible coronal and gingival levels
Harmony and proportion of cervical line, line of incisal edges , lip line
Tooth colour: Value, hue, chroma and translucency, texture and luster
Tooth shape: size of tooth, incisal edges, contour, assessing triangular tooth shape
How does occlusion need to be checked during the smile analysis?
Analysis of static and dynamic occlusion - models articulated using face bows and records
Spatial arrangement of teeth
Check centric, intercuspal, protrusive, left and right excursions
What happens if any of the occlusal contacts are on the margin of the veneer?
It will chip away and cause the resin to wear and unsupported ceramic will eventually chip and break
What are the different ways to demonstrate to the patient the proposed aesthetic changes before and after
Diagnostic wax up
Direct placement of composite resin with no etch or bond
Temporary composite resin restorations
Resin composite shell or overlay on diagnostic cast
Computer imaging
Demonstration models
Photography
Why is replacing veneers not good?
First bond gives the best bond
Every time replace there will be some cement left over reducing the bond
Every time it is replaced will lose some enamel - then will need a dentine bonded crown
What needs to be discussed at treatment planning?
Evaluate and discuss all options, advantages and disadvntages of each
Informed consent - post op sensitivity, marginal discolouration, fracture and debonding
Short and long term maintenance
Financial implications
Wouldnt want to do till >20 as they wont have enough recession
Why do veneers need to be relpaced?
Last 5-10 years, get recession then can see margins
Margins can become stained over time
What does veneer preps depend on?
Method of fabrication Occlusion Desired asesthetics Parafunction Presence of enamel at all proposed margins
What can a veneer be made out of?
Resin composite or Porcelain (ceramic)
What are the indications for a direct composite veneer?
Extensive damage to incisal or buccal surface
Defective restorations
Discolouration non-amendable to bleaching
Mal-aligned teeth
Congenitally deformed teeth
Patient that doesnt have time or finances for indirect porcelain veneer
Where a porcelain veneer would require excessive tooth structure removal
What are the contraindications for direct composite veneer?
Inability to obtain: correct shades to blend with adjacent teeth, correct contours, correct surface characteristics, proper isolation
Multiple teeth due to the extensive time and difficulty in achieving consistent shade, contours and surface characteristics
What are the advantages of direct composite veneer?
Very little or no tooth prep required
Wear similarly to tooth structure and do not cause iatrogenic wear of opposing dentition
Chair-side repairs
What are the disadvantages of direct composite veneer?
Colour stability - takes in colour from environment but this can be pre-polished and repaired
Result isnt as long lasting as porcelain
Not as strong
Wears more compared to ceramic
What is the direct veneer technique?
Veeners made by dentist chairside
only one appointment needed
minimal or no preprequired
Why may you do a chamfer when doing a direct veneer technique?
To avoid ledges around the periphery and can remove some colouring
What composite is used for the indirect technique?
Colour modifiers
Resin composite; microfilled, hybrid
What is the longevity of composite veneers?
Frese et al 2013
Restoration showed a functional survival rate of 100%, an overall survival rate of 84.6% after 5 years
What is the indirect composite technique?
Minimal prep
0.25-0.5mm tooth reduction
Resin cement for cementation
Bonding similar to porcelain veneers
What are examples of the systems used for indirect composites?
Artglass Belleglass Sculpture Targis Paradigm MZ100 (CAD/CAM)
What are the advantages of indirect composite veneer over a direct one?
Reduced polymerisation shrinkage Get smaller marginal leakage Less post op sensitivity recurrent caries staining Better control of interproximal contours and contacts - no ledges or catches Less technique sensitive
When was the porcelain veneer re-introduced?
After the introduction of acid-etch technique
In 1980’s the porcelain veneer re-introduced
What are the 4 components of the porcelain laminate veneer?
A porcelain veneer
An acid-etched enamel surface
A silane coupling agent
A resin cement
What are the advantages of porcelain laminate veneer?
Superior aesthetics Excellent long-term durability Strength Marginal integrity - made to the model Soft tissue compatibility Minimal tooth reduction
What are the disadvantages of porcelain laminate veneer?
Time consuming - multiple appointments Fragility Repairing difficult Colour matching difficult Irreversibility Inability to trial cement the restoration
What are the different porcelain technologies?
Feldspathic - Mirage II Leucite reinforced - Empress I, Cerinate Lithium disilicate - Empress II/Emax Glass infused e.g. InCeram Cast glass e.g. Dicor
Why use CAD/CAM for porcelain?
High standard and uniform
Why prepare teeth first for a veneer?
Stress concentration is less on veneers fitted to prepared teeth
Prep also removes aprismatic and hypermineralised enamel layer which are more resistant to acid etching
Why should veneer prep be only into enamel not dentine?
To maximise resin bond strength and reduce tensile stress in the porcelain
What is the tooth prep for porcelain veneers?
Minimal prep and even reduction
0.3-0.5mm mini chamfer
Facial reduction in 2 planes
How can you adjust the veneer prep if the incisal edge is in occlusion?
Would want more ceramic on the incisal edge to withstand the occlusal forces
When may you use the ‘window’ or intra-labial technique for veneer prep?
What is different about this prep?
Useful in canine guidance
Class II div II and class III incisor relationship
It is contained all on the labial surface not on the incisal edge
Don’t need a temp restoration
What is involved in the long bevel preparation?
Keep the length if the incisal edge
Half of the incisal edge has been reduced
Why do they need to be temporised?
Aesthetics
Sensitivity
Diagnostic - test the contour, shape, length
What are the different types of temporaries that can be made?
Spot-etch direct build up
Chairside - clear matrix on diagnostic wax up, then spot-etch and pro-temp
Indirectly made composites made in lab
When are you more likely to need to temporise the prep?
When preps more aggressive and dentine is exposed
They can also serve as provisionals?
What type of cement is used and why?
Light cured composite luting agent - may want dual cured, less opaque
Share part of applied loading stresses during the masticatory cycle
What happens at the try-in veneer stage
Try-in before cementation
Using resin luting agent
Use a try-in paste: Water soluble, Matches cement , optical contact
Use veneer carrier as very fragile
How do you prepare the veneer for cementation?
Veneer surface treated with HF Clean the fitting surface of veneer with acetone to remove try-in paste Rinse and dry Silane application Keep away from light
Why treat the veneer with phosphoric acid?
improves the bonding strength
How much acetone is needed to make sure all try-in paste is removed?
40ml Acetone
What does the silane coupling agent do?
Apply to the internal etched surface
Chemically bonds to ceramic
Makes ceramic surface hydrophobic
When would you use a more opaque cement?
Discoloured/dark teeth
Why use a veneer carrier?
Avoids handling and avoids too much pressure during placement
Veneer must be held in 2 planes during initial palatal polymerisation
If veneer not held firmly enough then get suck back
What happens if the veneer is not held firmly during initial polymerisation?
Suck back occurs causing gaps at the margins
What can resin spaces be caused by?
insufficient luting resin and incorrect sequence of seating multiple veneers
What do you do when finishing the cementation of the veneer?
Use floss to remove the excess cement or finishing burs
Check the occlusion
Finish with polishing points
Why don’t you want ledges or excess cement?
Food trap
Gingival irritation
Recession - then see the margin
What are resin spaces caused by?
Insufficient luting resin
Incorrect sequence if seating multiple veneers
When can you get fracture of the veneer?
Unfavourable occlusion
Parafunction
Bonding to existing restorations
Apart from fracture why else may a veneer fail?
Micro-leakage/marginal staining
Debonding
What are the 3 types of veneer fracture?
Static
Cohesive
Adhesive
What is a static fracture?
When segment of veneer fractures but remains on the tooth
Due to excessive loading or polymerisation shrinkage
What is Cohesive fracture?
Within the body of porcelain due to tensile loads from excessive functional or parafunctional loading
Results in loss of fragment
What is Adhesive failure?
Failure of bonding interface
Due to weak bond or severe occlusal loading
If have a debonded veneer and the luting agent is still on the tooth, what does this mean?
Inadequate etching of veneer or no silane coupling agent
If have a debonded veneer and the luting agent is still on veneer what does this mean?
Problem with bonding materials, placement technique or bonding substrate - more likely when predominately dentine
