1. Glass-Ionomer Restorative Materials
(glass polyalkenoate cements)

2. Glass-ionomer family of materials:
glass-ionomer cements
resin-modified glass-ionomer cement
polyacid-modified resin composites
Note: these are not really a glass-ionomers; there is no ionic reaction

3. Glass-ionomer restorative materials
Alfa-Fil (DMG)
Chemfil Superior (Dentsply)
GC Fuji IX GP (GC America)
Ketac Molar (ESPE)

4. Glass-ionomer cements - development
Wilson-Kent (72) – chemistry
McClean-Wilson (74) – clinical

5. Glass-ionomer Restorative: hand-mixed powder – liquid products:
Acid – soluble
glass
PAA etc
in water
protective
varnish

6. Glass-ionomer cements – initial formulations
acid-soluble glass
polyacrylic acid (~ 50 vol. %) dissolved in water

7. C O C O C O C O C O C O H O H O H O H O H O H O
polyacrylic acid

8. C O C O O H O
carboxyl
group
carboxylate
ion

9. Glass-ionomer cements - powder
Aluminum ions make
the glass soluble in
acids.

10. Glass-ionomer cements – after 1980
acid-soluble glass
polyacrylic acid or other polyalkenoate acid (~ 50 vol. %) dissolved in water

11. O H O H O H O H O H O H O H C O C O C O C O C O C O C O C O C O C O C
polymaleic acid
The number of carboxyl
group is double that of
PAA. Does not seem to
improve the cement.

12. Glass-ionomer cements – after 1980
acid-soluble glass
polyacrylic acid or other polyalkenoate acid (~ 50 vol. %) dissolved in water
10% tartaric acid

13. O O H H O H O C C C C O H H O H
tartaric acid

14. with tartaric acid
w.o. tartaric acid
viscosity
time

15. Glass-ionomer cements - structure of set cement
hydrogel
matrix
Partially
dissolved
glass
particle

16. Glass-ionomer cements - setting reaction
Key concepts:
polyacids are soluble in water
polysalts are insoluble in water

17. Glass-ionomer cements - setting reaction
Dissolution
acid attacks glass
Ca++, complex aluminum ions, & F- released by glass
Ions initially dissolve into the water + polyacid solution

18. Glass-ionomer cements - setting reaction
Gelation - 1
ions react with polyacid
Ca++ react first with COO-
aluminum complexes breakdown to Al+++
Al+++ react later with COO-
form Ca - polysalt & Al - polysalt

19. Glass-ionomer cements - setting reaction
Gelation - 2
form Ca - polysalt & Al - polysalt
polysalts are not soluble in water
long polysalt molecules precipitate
matrix is a hydrogel

20. Glass-ionomer cements - setting reaction
Hydrogel
a tangle of thousands of long polysalt molecules that have precipitated
water is trapped within and between these molecules

21. Glass-ionomer cements - structure of set cement
hydrogel
matrix
Partially
dissolved
glass
particle

22. Glass-ionomer restorative materials – Uses
In general: restoration under low stress
Restoration of cervical lesions (Cl. 5) – smaller lesions especially
Interproximal anterior restoration (Cl. 3)
Small Cl. 1 restorations in deciduous teeth
Bases under resin composite restoration, especially where recurrent caries is a concern (“sandwich” technique)

23. + calcium aluminosilicate glass Ca, Al polysalt hydrogelCH 2
COOH +
Polyacrylic acid
(PAA)
calcium
aluminosilicate
glass CH 2
COO
OOC F Ca 2+ Al 3+
Ca, Al polysalt hydrogel

24. G-I Technique - medium - large Class 5 Preparation - 1
maintain dry field
noncarious lesions: no prep needed
carious lesions: remove only caries
do not bevel enamel margins

25. G-I Technique - medium - large Class 5 Preparation - 2: hydrate dentin
place wet cotton pellet on the preparation while mixing the cement
do not allow contamination by saliva or crevicular fluid
remove wet cotton pellet
blot prep dry with a dry cotton pellet

26. G-I Technique - medium - large Class 5 Initial finishing
use preformed cervical matrix if possible
coat surface with light-cured resin or a water-resistant varnish
remove excess cement with a sharp blade or carbide bur
reapply resin or varnish - light cure the resin

27. G-I Technique - medium - large Class 5 final finishing
Delay finishing 24 hrs for best esthetics and hardest surface
surfaces can be finished after 15 minutes
reapply the resin or varnish - light cure the resin

28. Glass-ionomer restoratives - advantages
fluoride release
low bond strength to enamel & dentin
low solubility after complete set
thermal expansion like that of enamel & dentin
biocompatible

29. Glass-ionomer restoratives - disadvantages
high initial solubility
subject to dehydration
finishing must be delayed
most are radiolucent
weak
subject to wear & erosion
poor esthetics

30. Glass-ionomer Cermets

31. Glass - ionomer cermets - definition
Cermet - A composite consisting of a combination of ceramic and metallic materials.

32. Cermets – Ketac Silver:
Powder:
glass particles sintered to 40 wt. % of 3.5 m silver particles
Liquid:
37 wt% of 1:1 copolymer of acrylic and maleic acids
9% tartaric acid
54 wt.% water

33. Cermets – Ketac Silver - properties
silver in the powder
working time
final set
compressive strength
diametral tensile str.
flexural strength
40 wt.%
1.5 min
5.0 min
190 MPa (24 hr.)
14 MPa (24 hr)
32 MPa (24 hr)

34. Cermets – Ketac Silver – toothbrush wear
amalgam
microfilled resin comp.
resin composite
glass-ionomer restor.
cermet
0.2 mm3
0.4 mm3
6.0 mm3
0.3 mm3

35. Resin-Modified Glass-Ionomer Cements

36. Resin-modified glass-ionomer restorative materials
3M Vitremer Tri-cure Core Buildup / Restorative (3M / Espe)
Photo-fil Quick (3M / ESPE)
Fuji Filling LC (GC America)
Ketac Nano (3M / Espe)

37. Resin-modified glass-ionomer bonded-base materials
3M Vitrebond Light Cure Glass Ionomer Liner/Base (3M Dental Products)
Fuji Bond LC (GC America)
Viva Glass Liner (Vivadent)

38. Conventional
glass-ionomer
Conventional
Resin-composite
Polyacid-modified
resin composite
Resin-modified GI

39. Conventional
glass-ionomer
Conventional
Resin-composite
Polyacid-modified
resin composite
Resin-modified GI
The consensus is that these are composites NOT ionomers!
Ketac-Fil
Dyract
Compoglass
Fuji Filling LC
Vitremer
Ketac Nano

40. Resin-modified G-Is: liquid composition simple systems
Polyacid - PAA, polymaleic, etc.
polyHEMA
water
light cured activation system

41. Resin-modified G-Is: liquid composition more complicated systems
Polyacid modified with methacrylate groups replacing some (-COOH) groups
HEMA or polyHEMA
water
light-cured activation system

42. PAA with methacrylate graftO C O C O C O C O C O O H O H O H O H O H O R C C H 2 C H 3
PAA with methacrylate graft

43. O O _ _ M O C C O O O _ _ O C C O O H H O C R C H C C H C R C C H H H
setting due to precipitation of metallic polysalt O O _ _ +2 M O C C O O O _ _ O C C O O H H O C R C H C C H C R C C H H H C H 3 3
Cross-link formed by
addition polymerization

44. Resin-modified G-Is: liquid composition more complicated systems
Polyacid modified with methacrylate groups replacing some (-COOH) groups
HEMA or polyHEMA
water
light-cured activation system

45. hydroxyethylmethacrylate
hydrophobic
methacrylate group C O H 3
HEMA
hydroxyethylmethacrylate
hydrophilic
hydroxyl group

46. polyHEMA
(poly) hydroxyethylmethacrylate O C H

47. glass-ionomer lining cement:
Application:
Lining composite or amalgam restoration when the preparation is close to the pulp.
Temporary restorations

48. glass-ionomer lining cement:
current product:
GC Fuji
Lining LC
GC America

49. glass-ionomer lining cement:
Shake bottle to fluff
up powder
level scoop against edge
of the half-diaphragm at
mouth of bottle.

50. glass-ionomer lining cement:
Glass powder – contains
fluoride
Liquid polymeric acid

51. glass-ionomer lining cement:
Mixing:
One scoop powder + one drop liquid
Divide powder into two parts
Add ½ powder to liquid – mix 5 – 10 s
Add remaining powder complete mix in s

52. Direct Restorative materials - setting shrinkage

53. Fluoride release over time (mean of 4 Gis)
From Fortsen, Biomaterials 1998;19:

54. Fluoride release - restorative materials

55. Flexural strength - restorative materials

56. Elastic modulus - restorative materials

57. RMGI restorative materials – Uses*
In general: restoration under low stress
Restoration of cervical lesions (Cl. 5) – larger lesions than GI restorative materials
Interproximal anterior restoration (Cl. 3)
Small Cl. 1 restorations in deciduous teeth
Bases under resin composite restoration, especially where recurrent caries is a concern (“sandwich” technique)
Notice that these uses are not too different from those for GI restorative materials.

58. Resin-modified glass-ionomer restorative materials – sandwich restorations

59. RMGI restorative materials – Class V Survival
After five years more RMGI than GI Class V restorations are surviving in non-carious lesions:
% Failed
Time since Placement (months)
amal GI
RMGI
Comp RC
Flowable
GI – 60%
RMGI – 85%
Stewardson et al. Brit Dent J (9) 1-9.

60. RMGI restorative materials – Class V Survival
After five years, more RMGI than GI Class V restorations are surviving in carious lesions:
% Failed
Time since Placement (months)
amal GI
RMGI
Comp RC
Flowable
GI – 44%
RMGI – 78%
Stewardson et al. Brit Dent J (9) 1-9.

61. Resin-modified GIs: advantages
Immediate cure with visible light
fluoride release
stronger than GIs
moderate bond to enamel & dentin
low solubility immediately
fewer steps that GIs; less technique sensitive

62. Resin-modified GIs: disadvantages
polymerization shrinkage
stronger, but still weaker than RCs
subject to wear & erosion
bond to dentin better, but still lower than DBSs
poor esthetics
less biocompatible than GIs

63. Polyacid - Modified Resin Composites

64. Conventional
glass-ionomer
Conventional
Resin-composite
Polyacid-modified
resin composite
Resin-modified GI

65. Conventional
glass-ionomer
Conventional
Resin-composite
Polyacid-modified
resin composite
Resin-modified GI
Ketac-Fil
Dyract
Compoglass
Fuji Filling LC
Vitremer
Ketac Nano

66. Polyacid-modified Resin Composites Restorative materials
3M F-2000 Compomer Restor Syst (3M)
Compoglass F (Vivadent)
Compoglass Flow (Vivadent)
Dyract (Dentsply/Caulk)
Dyract AP (Dentsply/Caulk)
Dyract Flow (Dentsply/Caulk)

67. Polyacid-modified Resin Composites Restorative materials
elan Compomer Restorative System (Kerr)
Hytac Aplitip (ESPE)

68. TCB oligomer - Dyract (Caulk)H O O C H 3 3 C C H C C C O H C H C O O C H C H O C C C H 2 2 2 2 2 2 H C C H 2 2 C H C H 2 2 O O C C O H O H
TCB oligomer - Dyract (Caulk)

69. Fluoride release - restorative materials

70. Flexural strength - restorative materials

71. Elastic modulus - restorative materials

72. End