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Lecture Outline. What is glass inomer?Classification of glass inomer.Advantages
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1. Fluoride-Releasing Materials IGlass Inomer & Resin Modified Glass Inomer Dr.Ghada Maghaireh
BDS, MS, ABOD
3. Dental Cements
4. Ionomer
Acrylic acid
Maleic acid
Itaconic acid
Butene dicarboxylic acid
Vinyl phosphonic acid
5. Acid Base Reaction
Liquid acid attacks glass.
Glass decomposition, metal ion release (Calcium, Aluminum, Fluoride).
Migration of metal ions into liquid.
Gelation of matrix by metal ions.
Post-set hardening by continued binding of metal ions.
Slow maturation (cross-linking, hydration, silica matrix).
6. Simplified Diagram of Setting Reaction Polyacrylic Acid
7. Transport media for fluoride.
Stabilizes the set matrix (25 - 50% water).
Solvation of ionomers/polymers and metal ions. Role of Water
8. Glass Inomer Cement loses and gains water easily:
Early moisture contamination leads to increased solubility and poor esthetics,(protect for first 7 minutes).
Later desiccation causes shrinkage and crazing, (maybe even months later).
9. How fluoride works:
Inhibits demineralization.
Enhances remineralization.
Improves enamel crystal structure (fluorapatite).
More readily taken up in demineralized enamel.
Inhibits the process by which cariogenic bacteria metabolize carbohydrates (inhibits acid production).
Interferes with ionic bonding during pellicle and plaque formation on tooth surface. Fluoride
10. halo effect around restoration ~ 3 mm.
Level around restoration ~ 10 ppm.
Level in saliva of average patient ~ 0.08 ppm.
Fluorine release from GIC does not lead to restoration breakdown.
11. Fluoride Release Rates Show burst for 1 to 2 days followed by a rapid decline to steady-state.
Recharging.
12. ADA Classification
Type I: luting agents (Ketac-Cem, Fuji I)
Type II: restorative material
a = tooth-colored (Ketac-Fil, Fuji IX)
b = reinforced (Ketac-Silver, Miracle Mix)
Type III:
fast-set liners and bases (Ketac-Bond)
13. Classification Usage Classification
Restorative material
Traditional (Fuji II, Ketac-Fil)
Highly viscous (Fuji IX, Ketac-Molar)
Metal reinforced (Miracle Mix, Ketac-Silver)
Base/liner
GC lining cement, Ketac-Bond
Root surface sealing
Cervical Cement
Root canal sealing
Ketac-Endo
14. Strengths:
Ionic exchange leads to adhesion to tooth structure (chemical bond).
Fluoride release and rechargeable.
15. GIC Physical Properties Weaknesses
Moisture sensitivity.
Lack of command cure, i.e. doesnt cure with light.
Esthetics.
Not recommended for stress-bearing areas.
Difficult handling.
16. High caries risk patient
Atrumatic Restorative Treatment (ART)
Pediatric dentistry
Class V lesions
Liners & bases & sandwich technique
Luting agents
Core buildups ??? Maybe if > 2/3 of tooth structure remains
Orthopedics (bone substitute material)
17. Steps of Clinical Use of Glass Inomer 1. Mechanical retention in preparation advised (no bevels).
18. Steps of Clinical Use of Glass Inomer 2. Dentin conditioning (10 % polyacrylic acid for 10-20 seconds).
3. Inject into preparation. Overfill the preparation.
19. Steps of Clinical Use of Glass Inomer 4. Trim excess with finishing bur (wet, with very light pressure as the cement material cuts easily!) and polish (if necessary). Be cautious not to over-reduce, the material is softer than composite resin.
5. Dry the surface and paint on a thin layer of light-cured unfilled resin (smoothes the surface and prevents desiccation but lowers fluoride release. (optional)
20. References Chapter 13 Fundamentals of Operative Dentistry.