autumn quiz; glass ionomer

Question 1

what are the properties of glass ionomer (adhesive, function and esthetic)

Answer 1

• self adhesive; ionic bond to all tooth structure. no adhesive needed. tolerant of moisture. bond improves over time
• function: good caries resistance, POOR wear resistance, fluoride release and recharge
• esthetics; relatively opaque, poor polish some shade selection, esthetics vary with type, loss of contour over time.

Question 2

when is glass ionomer used

Answer 2

• direct provisional restorations (endo treatment prior to crown) caries control stabilization
• root caries/difficult isolation and high caries risks
• used as a. luting cement; for retention
• cavity liner; seal dentinal tubules, indirect pulp cap

Question 3

name the 3 restorative GIs, 2 liners, 2 luting cements

Answer 3

restoratives :
1- conventional (GI- fuji IX)
2-resin modified (RMGI) fuji II LC
3-metal reinforced ketac silver

Liners:
1-resin modified (RMGI) ; vitrebond, activa

Luting Cements:
1-conventional (GI)
2-Resin modified (RMGI) fujicem, rely-x luting

Question 4

what is GI made of

initiator types?

Answer 4

powder (3)
-alumino-silicate glass
-sio2
-al3+
-ca2+
-F-
catalyst

liquid (1)
-polycarboxylic acids (polyacrylic, polymaleic, and polyitaconic acid)
-hydrophylic monomers
-HEMA (2-hydroxyethylmethylmethacrylate)
initiators; chemical cure, light cure, dual cure

Question 5

whats the chemical reactions of GI ; powder and liquid, acid base, and resin polymerization???
how does shrinkage compare gi, composite and RMGI?

Answer 5

• powder + liquid; superficial layers of powder dissolved by acid. al, ca and f are pulled into solution. Al and Ca form ionic crosslinks between carboxylate groups. polyalkenoate salt.
• unreacted glass inhibits crack formation

-acid base reaction; relatively slow. matures over time, responsible for bonding to tooth.

Resin polymerization; light,chem, or dual cured. allows immediate finishing and polishing. some polymerization shrinkage. GI

Question 6

whats stickum

Answer 6

GI ; bonding to tooth structure.

• carboxylate groups ionically bond to calcium in hydroxyapatite.
• no polymerization shrinkage!
• low shear bond strength
• fluoride and water move freely through matrix. exchange with environment!

Question 7

compare RMGI, GIC and CR in terms of ; compressive strngth, flexural strength, wear resistance, fluoride release, fluoride recharge, setting shrinkage, esthetics

Answer 7

• compressive strength: RMGI= med, GIC= low/med, CR = med/high
• flexural strength: RMGI= med, GIC = low med, CR= med high
• wear resistance” RMGI = med, gic = low, CR = high
• fluoride release: RMGI=med high, GIC = med, CR= none
• fluoride recharge: RMGI= med/high, GIC = high, CR = none
• setting shrinkage: RMGI=low med, GIC = LOW, CR= med
• esthetics: RMGI= good, GIC = acceptable, CR= excellent

Question 8

how is GI preparations done

Answer 8

pathology driven preparations
- caries, non carious lesions etc.
-mechanical retention is NOT needed !
about 90 degree cavo surface needed

surface conditioning: polyacrylic acid conditioner. removes smear layer for better ionic bonding to calcium
-no phosphoric acid etching. no hybrid layer! keep surface damp!

Question 9

describe the process of placing GI: mixing , application, matrix, shaping, resin coating

Answer 9

mixing: triturate capsule; spatulated or automixing for liner materials
- application: tip in contact with preparation. 2 mm layers fo rlight cured RMGI, bulk fill for conventional GI!
- matrix use; sectional or tofflemire for approximal lesions. cervical matrix for root caries (curethru)
- shaping (not polishing)
- resin coating; isolates GI while setting.

Question 10

how does glass ionomer stack up for a sealatn

Answer 10

: with proper isolation, resin and composite sealants are retained better than glass ionomers. glass ionomers might be useful for teeth partly covered by gingiva tho.

Question 11

whats a closed sandwich- advantages and disadvantages

Answer 11

gi?

similar to a cavity liner.
covers all prepared dentin surfaces.
advantages; eliminates post op sensitivity
-disadvantages; technically difficult. poor support for composite.

Question 12

whats open sandwich technique; advantages/disadvantages?

Answer 12

gingival margin on root surface sealed with GI or RMGI

• advantage; self adhesive bond to root surface
• disadvantage; margin vulnerable to abrasion or erosion.

Question 13

whats atraumatic restorative treatment

Answer 13

(ART) but not the same as advanced restorative techniques

• no anasthesia
• no handpieces
• no suction
• no reason in USA