porcelain repair and crown sectioning

Question 1

do we always fix the chipping

Answer 1

1) esthetics
2) plaque accumulation
3) sharp edges

Question 2

indirect failures

Answer 2

1) leaking margin
2) recurrent caries
- if tooth is restorable => remove crown, address caries, replace crown
3) nonrestorable => extraction

Question 3

porcelain repair

Answer 3

1 )chipped porcelain
2) chipped porcelain and metal exposed

Question 4

chipped porcelain

Answer 4

1( diamond bur => HF etch => silane => bond
2) diamond bur => micro etch with AlO2 -> HF etch => silane => bond (strongest)

Question 5

chipped porcelain and metal exposed

Answer 5

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

Question 6

diamond bur

Answer 6

1) scratches in porcelain - mechanical retention
2) lowest strength repair

Question 7

microetch with AlO2

Answer 7

1) 50 micron AlO2 at 45 psi
- micromechanical
- silica based prior to HF application
- excellent for cleaning intaglio of gold, PFM

Question 8

microetch with silject

Answer 8

1) tribochemically attaches silica to surface of metal, then appl silane
- very strong bond to metal, zirconia, and alumina

Question 9

HF etch +silane

Answer 9

1) very strong bond to porcelain, LDS, especially following microetcher at 45 psi

Question 10

zirconia primer

Answer 10

1) MDP
- improves bond strength to zirconia
2) component scotchbond universal
- z-prime and zirconia primer

Question 11

danville microetcher

Answer 11

1 )45 -90 psi

Question 12

tribochemically bonding

Answer 12

1) tribo - friction to rub
2) chemical - relating to chemistry
3) converts kinetic energy to thermal energy that fuses glass to a hard substrate

Question 13

microetcher body with silject sand

Answer 13

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

Question 14

silane

Answer 14

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

Question 15

safety of HF

Answer 15

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

Question 16

HF properties

Answer 16

1) chemically etches porcelain, silica, glass
2) corrosive to metal
3) causes severe bio damage
3) metabolic imbalance, resp problems, arrythmia, cardia arrest
- up to 24 hours after exposure

Question 17

siljet

Answer 17

1) can cause air emphysema if pushed into soft tissue

Question 18

project chip in porcelain

Answer 18

1) use diamond t ocut MI corner of 3x3 eMax #9 crown
- cut MI 0.5 mm bevel
2) teflon tape on adjacent tooth
3) HF acid for 10 seconds (very carefully)
- apply from dappen dish microapplicator
- small bore HVE, large bore HVE with rinse
4) silane let air dry 60 seconds and gentle air thin
- do not allow to dry undisturbed
5) apply scotch bone universal for 20 seconds, air dry, light cure
6) composite applied and light cure for 40 seconds

Question 19

porcelain etch

Answer 19

1) 9% HF
2) extremely corrosive, reactive
- loss of vision
- readily penetrates skin

Question 20

apply porcelain etch

Answer 20

1) dappen dish
apply for 10 seconds
2) use HVE to remove it
- rinse it off with water
- spray rinse mannikins throat
3) keep HVE near the etch as it works
4) LDS needs to etch for 10 seconds

Question 21

silane and scotchbone

Answer 21

1) apply silane and scotchbond
2) then you can use composite

Question 22

isolation materials

Answer 22

1) rubber dam REQUIRED for HF
2) opal dam that hardens around soft tissue
3) etch arrest as a barrier and neutralizer of HF

Question 23

after suctioning off the isolation material

Answer 23

1) bone dry it
2) apply bonding material
3) create restoration