Glass Ionomers

Question 1

what are the challenges of glass ionomers

Answer 1

• esthetics
• proximity to pulp
• bonding to dentin
• isolation
• control of sulcular fluids effecting bond/seal
• micro leakage at margin

Question 2

what is the chemical composition of glass ionomer

Answer 2

• polycarboxylic acid
• FAS glass
• water
• tartaric acid

Question 3

what is the mechanism of glass ionomer adhesion

Answer 3

• chelation of carboxyl groups of the polyacrylic acids with the calcium in the apatite of the enamel and dentin
• polyacrylic acid (weak acid) primer may be provided by manufacturer
• smear layer is removed. however weak acid leaves dentinal tubules plugged. do not use phosphoric acid to etch!

Question 4

what is the bond strength of glass ionomer

Answer 4

3Mpa higher with new materials

Question 5

what are the 2 types of glass ionomers

Answer 5

• reinforced glass ionomers
• resin modified glass ionomers

Question 6

what are the the reinforced glass ionomers

Answer 6

• expand use of materials beyond cementing/luting
• miracle mix and ketac silver (amalgam particles)
• ketac molar and fuji IX
• equia forte
• chem-fil rock

Question 7

what are the resin modified glass ionomers and what do they do

Answer 7

• improved esthetics and handling characteristics
• complex setting reactions- class GI acid based reaction as well as light activation resin polymerizaion. some have an additional chemical cure reaction and can set in the absence of light
• fuji II LC, vitremer restorative material, ketac nano, geristore

Question 8

what is compomer

Answer 8

• polyacid modified composite resin (Dyract)
• light polymerized composite resin restoratives, modified to contain ion- leachable glass particles and anhydrous polyalkenoic acid
• have decreased in use due to development of type II GI/RMGI that have more favorable characteristic

Question 9

what is Giomer

Answer 9

• relatively new resin with pre-reacted glass ionomer particles
• the particles are made of fluorosilicate glass that has been reacted with polyacrylic acid prior to being incorporated into the resin
• shofu beautifil

Question 10

what is cavity liner

Answer 10

used at a thickness of no more than 0.5mm under either an amalgam or composite restorative material
- seals deep dentin exposed during caries removal
- vitrebond plus
- fuji liner

Question 11

what are type 1 glass ionomer cements used for

Answer 11

luting crowns, FPP, orthodontic brackets

Question 12

what are type 2 glass ionomer cements used for

Answer 12

esthetic restorative cements GI and RMGI

Question 13

what are type IIb glass ionomer cements used for

Answer 13

reinforced restorative cements

Question 14

what are type III lining cements used for

Answer 14

lining cements

Question 15

what are the advantages and disadvatntages of type II reinforced restorative cements

Answer 15

• advantages: radiopaque, adhesion, fluoride release, quick set for finishing
• disadvantages: weaker than resin, no significant improvement in characteristics or longevity over other RMGIC

Question 16

what are the advantages and disadvantages of esthetic restorative cements

Answer 16

• advantages: useful in high caries risk patients due to fluoride release, adequate esthetics, low polymerization shrinkage, excellent retention
• disadvantages: shade matching not equal to composite resin, low compressive strength

Question 17

what are the indications for type II esthetic restorative cements

Answer 17

• non carious cervical lesions and root caries
• base to replace dentin
• block out undercut or void- not recommended for core build up
• primary dentition small class I or class II
• permanent dentition- open sandwhich or closed sandwhich
• interim therapeutic restoration or sedative filling

Question 18

what are the contraindications for type II esthetic restorative cements

Answer 18

load bearing areas- class IV, II, large class I
- areas where esthetics is extremely important

Question 19

what are the advantages of newer formulas

Answer 19

• improved handling
• decreased viscosity
• lengthens shelf life before gelation
• increased working time
• shortened setting time
• R and D expensive to replace amaglam

Question 20

how is caries control performed with glass ionomer

Answer 20

• SDF for cavitated lesions or partial caries removal and interim restoration of all cavitated caries leisons in 1-2 apointments and restoring with glass ionomer
• this is sufficient to removal the bacterial load and prevent further progression on the lesion
• then perform definitive restorative care once caries control phase is complete

Question 21

describe GI materials and fluoride release

Answer 21

GI materials must be recharged with fluoride which can then be re-released in order to provide protection

Question 22

describe GC equia forte

Answer 22

• bulk fill
• non sticky, packable
• optimal marginal seal for resistance to micro leakage/discoloration
• high fluoride release
• high resistance to wear/erosion
• 8 shades- I recoemmend choosing one shade darker if using on the gingival third.
• if tooth is A2 choose A3-5

Question 23

what is the sandwhich technique

Answer 23

the placing of glass ionomer cement as an intermediate layer between the tooth structure and a resin based composite restorative material; this restoration design combines the adhesion and fluoride releasing nature of a glass ionomer cement with the esthetic quality and durability of a resin based composite

Question 24

what are the indications for open sandwhich technique

Answer 24

when any part of the gingival margin of the class II or class V prep has been extended past the CEJ and no longer has a cavo surface of enamel

Question 25

what are the steps in the open sandwich technique for the class II restoration

Answer 25

- prepare class II prep - place appropriate matrix - scrub dentin at gingival floor with manufacture provided primer - place GI at the dentin/cementum margin to fill until the height of the material is approximately at the level of the CEJ, light cure if using RMGI - etch remaining dentin/enamel keepin etchant clear of GI/RMGI - place bonding resin and composite, light cure - finish and polish

Question 26

what are the advantages to the sandwich technique

Answer 26

- minimize gap formation at margin due to shrinkage of the composite resin - less technqiue sensitive than composite resin systems - fluoride release provides anti cariogenic environment - usefull for class II and class V restorations - use in moderate and high risk for caries

Question 27

what is the treatment of choice in the high caries risk patient

Answer 27

open sandwich technique with RMGIC with resin

Question 28

what are the steps in root caries preparation

Answer 28

- tooth prep with infected caries and dentin removed -retention grooves placed

Question 29

what are the advantages of GI

Answer 29

- minimal cavity prep required - adhesion to enamel and dentin - fluoride release, recahrging, possible caries inhibition - minimal shrinkage - excellent marginal seal - low solubility - good esthetics - excellent tissue compatibility

Question 30

what are the disadvantages to GI

Answer 30

- lower resistance to wear compared to amalgam/resin - lower bond strengths compared to resin - shades sometimes not ideal for highly esthetic areas