dental cements and cementation

Question 1

dental cements

Answer 1

1) indirect restorations crown, bridge, inlay, onlay
2) liners and bases
3) temp restoration material

Question 2

luting

Answer 2

1) viscous material placed between the tooth and prosthesis that hardens through chemical reaction
- firmly attaches

Question 3

properties for performance

Answer 3

1) high compressive ,tensile, and bond strength
2) withstand forces immediately
3) low viscosity and solubility
4) adequate fracture toughness to resist stresses at the restoration/tooth
5) good seal
6) color stability
7) provide good seal
8) biocompatibility

Question 4

mechanisms

Answer 4

1) non adhesive
2) molecular adhesive
3) micromechanical

Question 5

non-adhesive

Answer 5

1) zinc phosphate cement
2) material hardens and acts as a wedge
- friction

Question 6

molecular adhesion

Answer 6

1) glass ionomers and RMGI
2) true chemical rxn to tooth
3) involves van der waals forces
4 )conventional cementation
- ionic bonds
- technically not “bonding process”

Question 7

micromechanical

Answer 7

1) pitted tooth enamel
2) enamel is etched with phosphoric acid
3) ceramics except zirconia are etched with hydrofluoric acid
4) metals and zirconia are sandblasted internally

Question 8

choices for cement

Answer 8

1) zinc phosphate
- powder is MgO and liquid is phosphoric acid
- lots of sensitivity
2) poly carboxylate
- less acidic polyacrylic and more bonding
- hard to work with
3) GI
- lowest post op sensitivity
- takes weeks to fully react
4) RMGI*
- resin is a scaffold for rxn to finish
5) resin cements

Question 9

RMGI

Answer 9

1) fuji Cem
2) range of resin vs GI
3) acid base rxn
4) photo cure
5) chemical polymeization

Question 10

fuji cem 2

Answer 10

1) traditional cementation
2) FVC, PFM, FZ, gold
3) not recommended for LDS
- due to setting expansion and LDS needs to be bonded
4) longer working time

Question 11

resin cements

Answer 11

1) solubility is least
2) much stronger
3) micromechanically
- etched ceramic restorations (5-10% hydrofluoric acid)
- etched enamel (40-340% phosphoric acid)

Question 12

resin cement classification

Answer 12

1) polymerization
- light (NX3, Variolink, RelyX veneer)
- dual (NX3 dual cure, RelyX unicem)
- chemical (Panavia, C&B)
2) adhesive scheme
- total etch (relyX ARC, variolink II)
- self etch (RelyX unicem, panavia)

Question 13

relyX unicem

Answer 13

1) dual cure
2) self-adhesive

Question 14

light cured

Answer 14

1) use photo initiators
2) ex. NX3 light cure, variolink veneer, Relyx veneer
3) can be used with LDS < 2 mm thick
- esthetic zone, thin ceramic
4) extended working time, setting on demand
5) color stability due to the absence of TERTIARY AMINE component

Question 15

dual cure

Answer 15

1 )ex. NX3 dual cure, relyx unicem
2) the tertiary amine + benzoyl peroxide
3) under restorations that attenuate light (thick zirconia)
4) color darkens with time due to tertiary amine

Question 16

chemical cure

Answer 16

1) Panavia, C&B
2) two paste system
3) used under PFM crows and cementing posts

Question 17

total etch

Answer 17

1) 30-40% phosphoric acid to dentin and enamel
2) relyx arc, variolink II, NX3

Question 18

self-etch

Answer 18

1) self-etching primer to prepare the tooth
2) can be in one or two steps
3) rely x unicem !!!

Question 19

when you use self-etch, does it stay acidic

Answer 19

1) weak acid gets buffered

Question 20

self-adhesive

Answer 20

1) need tooth structure for this
2) acidic monomers need to be neutralized
- solubility issue would be an issue
3) so SARC cannot be used if the core is amalgam or other metals

Question 21

when to use what types of cements

Answer 21

1) strength of material
a) weaker material (empress)
- BOND will make it stronger
b) stronger materials (PFM, metal, zirconia, LDS)
- cement or bond

2) retention
a) retentive
- RMGI, SARC, either bond or cement
b) nonretentive
- bond it

Question 22

bond strength

Answer 22

1) RMGI < self-adhesive < adhesive

Question 23

cementation of #19

Answer 23

1) using RelyX unicem2
- can also use Fuji Cem 2
2) a resin based cement
- self-adhesive
- no need to etch, but you can selectively etch the enamel
- cannot use with large restoration as buildup (bc it is a SARC)
- cannot be used with veneers (tertiary amine)
- material is not that strong

Question 24

using relyX unicem 2

Answer 24

1) if metal, PFM, zirconia
- sandblast intaglio
2) if LDS
- phosphoric acid to clean surface (NEVER for zirconia)
3) prepared tooth
- remove temporary and clean cement
- clean with pumice
- dry (no over dry)
4) cementation
- initial bleed
- apply inside restoration
- firmly sit with finger pressure
- dual cure so you can light cure each surface for 20 seconds
- 6 minute setting time

Question 25

restoration pre-treatment

Answer 25

1) sandblaster is used to increased surface intaglio
2) aluminum oxide is the medium
3) the device delivers a small stream
4) good for all metal and zirconia
- not for silica (LDS)
5) microetching using siljet
- necessary for preps without retention that need to be bonded
- introduce silica to intaglio, which enhances dental adhesive

Question 26

clinic protocols for the relyx unicem 2

Answer 26

1) clean tooth with pumice
2) bleed rely x unicem 2
- bleed tip again
3) seal restoration and remove excess
4) tack cure 1-2 seconds
- remove excess
5) fully cure

Question 27

microporosities

Answer 27

1 )silica
- hydrofluoric acid
2) zirconia and metal
- sandblasting
3) tooth
- phosphoric acid

Question 28

remove cement

Answer 28

1 )floss with double knots
- pull floss from buccal

Question 29

for # 9 LDC bonding

Answer 29

1) dual cure resin cement
- NX3 Nexus (ARC)
2) non light accessible (assume >2 mm)
3) non retentive LC, MZ, PFM, PFZ, allow, all ceramic inlays, onlays

Question 30

NX3 nexus

Answer 30

1) stronger bond
2) multiple shades with try in paste
3) light cure
- low strength, thin
4) dual cure
- high strength or when light is not accessible, and prep is non-retentive

Question 31

in addition to Dual cure Nx3 Nexus

Answer 31

1) hydrofluroic acid
2) silane
- couple resin with silica
3) prelude
*applied to restoration

4) if you have enough enamel, you can selective etch with phosphoric acid

Question 32

hydrofluoric acid

Answer 32

1) LDS restorations
2) if not pre-etched

Question 33

silane

Answer 33

1) good for silica based materials like LD
2) coupling agent for the two dissimilar materials

Question 34

teflon tape

Answer 34

1 )for protecting adjacent teeth

Question 35

preparation of #9

Answer 35

1) silane 60 seconds
- air dry
2) apply bonding (black)
- do not cure
- place under UV shield box
3) do not need primer (yellow)
4) polish tooth with pumice, apply teflon
5) add yellow
- 15 seconds scrub
- 10 secs air dry
6) dispense link on both (Red)
7) apply nexus 3

Question 36

cementation options for our two crowns

Answer 36

1) #9 LDS >2 mm
- nexus dual cure
2) #19 monolithic zirconia
- fuji cEM 2
- relyx unicem 2
- panavia

Question 37

nexus 3 light cure

Answer 37

1 )good for veneers and thin LDS
2) pre-etched
3) silane to internal surface for 60 seconds
4) do not need the LINK
- apply prelude adhesive to internal surface of restoration
- OR SCOTCHBOND BECAUSE ITS BETTER!!!

Question 38

cementation clinical tips

Answer 38

1) always work under isolation
- anesthetize as needed
2) keep working time in mind
3) hold down with fingers after seating
4) be very quick to floss the interproximal areas right after seating
5) clean up as much excess as possible before final curing
6) after set, verify contacts and margin closure

Question 39

seating failures

Answer 39

1) tall preps
- be careful
2) incomplete seating can be due to overfilling
- seated too slow
3) place thin wall on axial surface
4) work quickly
5) check margins immediately

Question 40

temporary cements

Answer 40

1) zinc oxide eugenol
- ex IRM, tempbond, tempbond NG
- must be cleaned off COMPLETELY before final crown
2) zinc polycarboxylate
- ex. durelon, ultratemp (non-retentive preps)

Question 41

mixing tempbond

Answer 41

1) base and accelerator
2) smash and mix
3) just line the walls (do not need to fill it all up)

Question 42

know these cements

Answer 42

1) fuji cem
2) rely x unicem 2
3) nexus nx3 dual cure
4) nexus nx3 light cure
5) all the temporary cements
- tembond, IRM, ultratemp, durelon