porcelain repair and crown sectioning Flashcards
do we always fix the chipping
1) esthetics
2) plaque accumulation
3) sharp edges
indirect failures
1) leaking margin
2) recurrent caries
- if tooth is restorable => remove crown, address caries, replace crown
3) nonrestorable => extraction
porcelain repair
1 )chipped porcelain
2) chipped porcelain and metal exposed
chipped porcelain
1( diamond bur => HF etch => silane => bond
2) diamond bur => micro etch with AlO2 -> HF etch => silane => bond (strongest)
chipped porcelain and metal exposed
1) porcelain: diamond bur => micro etch with AlO2 (increase surface area only) => HF etch
2) exposed metal => siljet (clean with air no water)
3) silane/bond both substrates
diamond bur
1) scratches in porcelain - mechanical retention
2) lowest strength repair
microetch with AlO2
1) 50 micron AlO2 at 45 psi
- micromechanical
- silica based prior to HF application
- excellent for cleaning intaglio of gold, PFM
microetch with silject
1) tribochemically attaches silica to surface of metal, then appl silane
- very strong bond to metal, zirconia, and alumina
HF etch +silane
1) very strong bond to porcelain, LDS, especially following microetcher at 45 psi
zirconia primer
1) MDP
- improves bond strength to zirconia
2) component scotchbond universal
- z-prime and zirconia primer
danville microetcher
1 )45 -90 psi
tribochemically bonding
1) tribo - friction to rub
2) chemical - relating to chemistry
3) converts kinetic energy to thermal energy that fuses glass to a hard substrate
microetcher body with silject sand
1) makes it a bondable surface
2) high velocity silica balls will fuse to zirconia due to high pressure
- high temp at 1200C
3) portions of alumina will fall out, but some will stay
silane
1) a bifunctional molecule (coupling agent)
2) do not rinse with water like AlO2, you air thin
3) apply HF acid
4) forms a bond between organic resin molecules and silica quartz filler particles
5) acts as a wetting agent for adhesive resins, penetrating etched porcelain
safety of HF
1) wear PPE
- lab coat, gloves, mask, loupes
2) work within the mannequins mouth
- keep mannequin suction running
- direct handpiece spray plume into mouth
3) use constant HVE
4) never work over skin or tissue