Gold and ceramic inlays Flashcards
history
1) gold has been used for millennia
2) 3000 BC
3) gold wires, bands, or straps to stabilize teeth
advantages of gold
1) no fracture
2) lower hardness than enamel
3) noble
4) stronger and durable
5) indirect enables better contours
6) burnishable
7) expansion coefficient similar
disadvantages of gold
1) esthetic objections
2) lab expense and material expense
3) multiple appointments are necessary
4) temporary restoration must be fabricated
5) high thermal conductivity
6) noble and cannot be bonded
- only luted
7) galvanic effect
indications for gold
1) carious lesions
2) diastema
3) etc
contraindications
1) poor oral hygiene
2) high caries rate
3) patient too young
metallurgy
1) pure gold is too soft
2)alloys
- gold
- copper
- silvr
- palladium
- platinum
- sinc
type I and II
1) soft
type III
1) inlays, onlays
type IV
1) bridges and PFM
2) it is hard to adapt margins and polish
ductility
1) can be stretched
malleable
2) can be pounded
good for closing
1) diastemas and suberupted teeth
2) composite may cause a plaque trap and be weirdly shaped
root concavities
1 )some teeth have them
2) hard to restore with matrix band
- material will squirt into the side of roo
longevity over cost
1) 4.6% failure over composite
draw
1) needs to be tapered
-3-5 degrees
- do not go beyond because retention decreases
2) need to see inner wall within the other wall
burs
1) #271
2) rounded line angles
concern with wide inlays
1) can fracture the remaining cusp
2) can wedge the cusp apart
maximum width
1) 1/3 intercuspal distance
2) 1.5 mm pulpal depth
3) use hatchet sparingly to prevent undercuts
4) flare with bur or GVE
5) make sure all margins connect smoothly
- including all bevels
why bevel?
1) allows burnishing and smaller gap between crown and tooth
mesial part of dovetail and axial wall
1) make sure there is no undercut
occlusal bevels
1) may be better for teeth with flat occlusal anatomy
2) football diamond or carbide
ceramic inlay prep
1) 2 mm pulpal depth
2) 2 mm isthmus
3) must provide thickness for material
4) slightly more 5 degree taper
5) all line angles rounded
6) no bevels
- 90 degree butt joints
7) 0.5 proximal clearance
advantages of ceramic
1) more wear resistant
2) reduce shrinkage
3) better contours
disadvantages of ceramic
1) harder, expensive
2) more time
3) wear on opposing teeth
ceramic indications
esthetic areas, large preps
ceramic contraindications
heavy occlusion, unable to maintain dry field
4 MO
1) 1.5-2 mm pulpal
2) 2 mm isthmus
3) 10-12 degrees total taper
4) axial wall 1-1.5
5) rounded line angles
6) butt joints, no bevels
7) 0.6 mm clearance
8) smooth margins
