CERAMIC VENEERS II Flashcards
venner prep depends on
method of fabrication occlusion described aesthetics any parafunction presence of enamel at all proposed margins
veneer material can be either
composite resin
ceramic
indications of a direct composite veneer
extensive damage to incisal or buccal surface
defective restoration
discolouration not amendible to bleaching
mis aligned teeth (pt no ortho)
congenitally deformed teeth
pt does not have time or finances
contra indications of a direct composite veneer
inability to obtain correct shade to blend with adjacent teeth
inability to obtain correct contours
inability to correct surface characteristics
inability to obtain proper isolation
multiple teeth due to extensive time and difficulty in achieving consistent shade
advantages of direct composite veneer
little or no tooth prep required
many composite wear naturally to natural tooth structure and do not cause iatrogenic wear of opposing dentition
chairside repair
dis of composite venner
colour stability
not as long lasting as ceramic alternative
not as strong
wears more than ceramic
indirect composite technique
minimal prep
0.25-5 mm tooth reduction
resin cement for cementation
advantages of indirect over direct veneer
reduced PS(shrinakge)
smaller marginal gap created
reduced marginal leakage, sensitivity, recurrent caries, staining
better control over interproxmial contours
less technique sensitive than direct one
components of indirect ceramic veneer
veneer
acid etched surface
sialine coupling agent
resin cement
advantages of ceramic veneer
- superior aesthetics
- excellent long term durability
- strength
- marginal integrity
- soft tissue compatibility
- minimal tooth reduction
lab techniques to make veneersf
foil based castable ceramic refractory CAD CAM pressable (high pressure moulding)
prep vs no prep
no prep - reversible painless - overcontoured - margins - gingival infalmation - high failure rates
tooth prep measurements
0.3-5mm chamfer
0.6-8 incisal and buccal reduction
facial reduction in 2 planes
what does pre allow
less stress concentration
removes prismatic and hypermineralised enamel layer which are more resistant to acid etching
types of perparation
incisal edge
feather edge
further over incisal edge
different prep designs
window
long bevel
complete veneer coverage
when is window prep useful
canine guidance class 2 div 2 or class 3 margin short of incisal edge
types of temps
direct composite build up with spot etching of enamel
chariside
protemp
indirect temp from lab
cementation in the try in stage
resin luting agent
veneers should be tried in to assess fit and aestheics
try in paste
- water soluble, matches cement, optical contact
what can cause resin spaces
insufficient luting agent
incorrect sequence of seating mutiple veneers
cementation procedure steps
etching of tooth surface
bonding agent
resin cement
failures of restorations aetiology
unfavourable occlusion parafunction bonding to existing restorations microleakage debonding
types of veneer fractures
static
cohesive
adhesive
static fracture
when a segment of veneer fractures but remains on tooth
cohesive frature
occurs within the body oc ceramic due to tensile loads from excessive functional or parafunctional loading
loss of fragment
adhesive fracture
failure of bonding interface
due to weak bond or severe occlusal loading
debonded veneer cause
determine which bonded interface has failed
- if luting agent still on tooth due to inadequate etch of veneer or no sialine coupling agnet
if luting on veneer
- problem with bonding materials
placement technqiue or bonding substrate
more likely when predominately to dentine
