Cementation Techniques Flashcards
True or False: Long term failure mechanism is unknown for single Zirconia crowns.
True
Ziconia is a _____ not a _____.
ceramic
metal
Why is there concern about Zirconia transforming over time and creating flaws that lead to failures?
it is metastable….low temperature degradation
During stress corrosion, where does the stress occur?
on the underside of the crown
Silanes put a ______ coating on glass particles.
hydrophobic
Silica-based ceramics should be bonded with _____ cements to improve strength.
resin
Non-silica based ceramics are ______ to bond.
difficult
Non-silica based ceramics are strong enough to use _____ cements.
conventional
What are the two broad categories of cements/luting agents?
- Water-based
2. Resin-based
What are the three water-based cements?
- zinc phosphate
- polycarboxylate
- glass ionomers
What is polycarboxylate a combination of?
ZO fillers + liquid of Glass Ionomer
its a combo of the other two water-based cements
Why is Zinc Oxide tedious?
you must mix it (and it heats up, so you need cooled glass slab)
Glass ionomers have a stable interface and release fluoride, but they are fairly ______.
soluble
True or False: Resin Ionomers are more soluble than GI.
False, less soluble
Composites and Compomers are _____-based cements.
resin
What type of connections (2) exist between the tooth and crown and is filled by cement?
mechanical (mostly) and chemical
The key to good cements include: _____film thickness, and _____ working time.
low
long
Do we want a long or short setting time?
short
Cement should have a ______ compressive strength and an elastic modulus that is similar to _____.
high
dentin
Ideal cement has ______ solubility and _____ microleakage.
very low-none
very low-none
Which type of cement should you use for metal or metal-ceramic crowns?
water based (ZO, resin modified GI)
Which type of cement should you use for all-ceramic that are silica based?
resin cements
Which type of cement should you use for all-ceramic crowns that are zirconia based?
water based or resin based
zirconia doesn’t need extra reinforcement
True or False: For stronger ceramics, it is common to use resin based cements because the ceramic doesn’t need reinforcement from stronger bonding agents.
False: water-based cements can be used for stronger ceramics (zirconia)
True or False: Adhesive Resins have a higher compressive strength.
True
Dentin is etched with ______% phosphoric acid or self-etch adhesive.
35
Which step is being removed from many resin systems because it can cause post op sensitivity?
etch
Why does the etching step cause sensitivity?
it removes smear plugs and demineralizes dentin, which exposes tubules
Self-etching adhesives will etch dentin during the ______ _______. This minimizes chances of sensitivity by may form a weaker bond.
adhesive application (good interface makes this possible)
What kind of acid etchant is used for silica based ceramics?
hydrofluoric acid (5.5-5.9 HF)
True or False: Zirconia based ceramics cannot be etched with hydrofluoric acid.
true
After etching silica based ceramics, what is the next application step?
apply silane coupling agent
The reaction of silane coupling with ceramic surface is known as _____.
condensation
What is the purpose of using a silane coupling agent?
the long carbon chains and hydroxide groups are hydrophobic and the hydrogen atoms must be removed so that the oxygen can chemically attach to silane
True or False: Zirconia is cemented similarly to metal but the inner surface is rough.
False: zirconia is cemented similar to metal BUT the inner surface is NOT rough
What are the two conventional methods for cementation of metal to tooth?
- Mechanical Lock
2. Chelation (ionic bonds)
What is the functional group in Glass Ionomer and RMGI?
carboxylic acid
True or False: Conditioners clear the smear layer and demineralize tooth structure.
False: they only clear the smear layer…no demin
Rely X is commonly used to cement Zirconia to tooth structure. What is Rely X Luting Cement?
an RMGI luting cement
What are two characteristics of Phosphate Ester Based Cements when applied to Zirconia?
- Mechanical Bonding is minimal
- Stronger Ionic Bonding than carboxylic acid (RMGI)
* example: Rely X Unicem*
