Dental Cements Flashcards
WHY DENTAL CEMENTS?
(4)
caries
fractures
misalignment
prolong the life of the pulp in the war against oral bacteria- using protective coatings
prolong the life of the pulp in the war against oral bacteria- using protective coatings
(4)
varnish
base
liner
pits and fissure sealants
DENTAL CEMENT
substance that hardens to act as a base, liner, restorative material or luting agent (adhesive) to bind devices and prostheses to tooth structure or to each other
WHAT DO WE WANT A DENTAL
CEMENT TO BE?
(10)
biocompatible
non corrosive and inert
immune to acid attack
dimensionally stable
sets during the dental procedure
low surface tension; handles and palces easily
adapts and adheres to anatomy
insensitive to moisture during procedure
anti microbial/ F release
radiopaque
cost effective
immune to acid attack
insoluble
dimensionally stable
(2)
no cracking of tooth or device by expansion
no leaking because of shrinkage
WHAT MECHANICAL PROPERTIES FOR
THE CEMENT ARE NEEDED?
high values needed for:
(3)
cyclic fatigue
thermal cycling
strength
strength
(4)
tensile
compressive
flexural strength
shear
luting cements
(3)
permanent and provisional indirect restorations
ortho brackets
post and cores
restorative materials
permanent and provisional direct restorations
cavity liners and bases
pulp protection
multiple applications
no one cement can fulfill all requirements
LUTING CEMENT/AGENT
viscous material that fills the microscopic space between the abutment-prosthesis interface; upon setting, it forms a solid that seals the space and retains the prosthesis
Ideal properties of a permanent
luting agent
(8)
deal properties of a permanent
luting agent
1. *Low film thickness (25 m)
2. *Adequate strength (minimum 70 MPa)
3. *Low solubility (0.2% max. @ 24h)
4. *Reasonable setting time (2.5-8.0 min)
5. Adequate working time
6. Biocompatible, does not irritate pulp
7. Cariostatic
8. Adhesion to tooth structure and restorative materials
*ADA and ISO specification requirements
physical bonding
very weak interaction, secondary bonds
-van der waals forces, hydrogen bonds
chemical bonding
strongest bond, primary bonds
-limited occurrence, dissimilar materials
-ex, composite bond to adhesive bond agent
mechanical bonding
interlock undercuts, surface irregularities
-micromechanical retention
-ex: luting agent/tooth/crown, adhesive bond agent/tooth
MICROMECHANICAL RETENTION:
LUTING CEMENT VS ADHESIVE BOND
AGENT
LUTING CEMENT
cement locking into microscopic irregularities in prepared tooth surface and the internal surface of the crown
-non resin cements
-very low bond strength, 1-5 mpa
MICROMECHANICAL RETENTION:
LUTING CEMENT VS ADHESIVE BOND
AGENT
ADHESIVE BOND
AGENT
enamel: resin tags into etched enamel
dentin: hybrid layer
-interdiffusion or micromechanical interlocking of resin with demineralized collagen of intertubular dentin
-20-30 mpa bond strength
Cement
Setting mechanism
CaOH
Acid-base reaction
Cement
Setting mechanism
Zinc oxide (ZO) eugenol
Modified ZO eugenol
ZO non-eugenol
Acid-base
Cement
Setting mechanism
Zinc polycarboxylate Acid-base
Acid-base
Cement
Setting mechanism
Zinc phosphate
Acid-base
Cement
Setting mechanism
Glass Ionomer (GI)
Acid-base
Cement
Setting mechanism
Resin-modified GI
Acid-base AND
polymerization
Cement
Setting mechanism
Resin cement (RC)
Unfilled or Filled
polymerization
LIQUID: ACIDIC COMPONENT
(3)
eugenol/noneugenol oils
polycarboxylic acid
phosphoric acid
POWDER: BASIC COMPONENT
zinc oxide (ZO)
fluroaluminasilicate (FAS) glass
types of luting cements
(4)
- ZINC-OXIDE EUGENOL AND NON-EUGENOL CEMENTS (ZO)
- POLYCARBOXYLIC ACID CEMENTS
- ZINC PHOSPHATE CEMENT
- RESIN-BASED CEMENTS
- POLYCARBOXYLIC ACID CEMENTS
(3)
zinc polycarboxylate cement
glass ionomer cement
resin modified glass ionomer
- RESIN-BASED CEMENTS
(3)
resin modified glass ionomer
unfilled resin cements
filled resin: composite resin cements
ZNO-EUGENOL CEMENTS
types (3)
indications (1)
regular ZEO
reinforced ZEO
ZEO-EBA
temporary/intermediate cementation
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
composition
powder: zn oxide
liquid: eugenol
modifications
- polymer-reinforced: IRM
- EBA, alumina
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
low strength
ZOE
-compressive: 2-15
-tensile: 1-2
ZOE (modified)
-compressive: 40-50
-tensile: 3-5
INC OXIDE EUGENOL CEMENTS
(ACID-BASE)
uses
temp or provisional cement and restorations
ZINC OXIDE – EUGENOL
powder
99% ZnO and radiopaque fillers
ZINC OXIDE – EUGENOL
liquid
oil of cloves
85% eugenol
ZINC OXIDE – EUGENOL
rxn products
zinc oxide, zinc eugenolate
needs h2o to set