Glass Ionomer Cement Long Essays
Question 1. Describe the merits and demerits of GIC. Write about its application.°
Answer:
Merits:
- Chemical bonding to tooth structure
- Bio-compatible
- Good marginal seal
- Anticarcinogenic
- Translucent
- Conservative
- Less technique sensitive
Demerits:
- Low fracture resistance
- Low wear resistance
- Opaque
- Require moisture control
Applications:
Isolate the tooth
↓
Tooth preparation
Conservative preparation
Minimal depth
No need for a retentive feature
↓
Conditioning of tooth with 20% polyacrylic acid
↓
Manipulation Of Cement:
Use of cool, dry glass slab/paper pad along with a plastic spatula
Dispense and divide the cement powder into 2 parts
Mix individuality for 20 sec.
Total mixing time 40-60 sec.
↓
Restoration:
Carrying cement with a cement carrier
Placement into the preparation
↓
Carving
↓
Surface protection by petroleum jelly
↓
Finishing and polishing after 24 hours
Glass Ionomer Cement Short Essays
Question 1. Clinical Indications and Contraindications for GIC.
Answer:
Clinical Indications and Contraindications for GIC:
Indications:
- Restoration of Class 3, 5, and small Class 1
- Noncarious lesions
- Root caries
- Deciduous teeth
- As luting
- As liner
- Preventive restoration
- Core build-up
- Splinting
- Endodontic failure
Contraindications:
- Stress bearing areas
- Xerostomia
- Mouth breathers
- Cuspal replacement
- Areas that require aesthetics
Question 2. Uses of Glass monomers and add a note on biocompatibility.
Answer:
Uses of Glass monomers:
1. As pit and fissure sealants
- Due to anticariogenicity and adhesive properties
2. As liners and Bases – Beneath composite and amalgam
3. As luting agents
- For cementation of crowns, bridges, veneers, and orthodontic bands
4. As orthodontic brackets adhesive
5. For restorations of class 3 and class 5 lesions
6. Fissure sealing
- Use of high-viscosity GIC
Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers
7. Restoration of root caries
- Due to adhesion to dentin
- Anticariogenicity
- Ease of use
8. High caries Risk patients
- Because of their adhesion
- Abrasion resistance
- Anticariogenicity
9. Temporary restoration
10. Core build-up
11. ART (Atraumatic Restorative Treatment)
- Used in children with poor families
- Small to moderate pit and fissure caries
Biocompatibility:
- GIC is biocompatible due to
- Polyacrylic acid is a weak acid
- Dissociated hydrogen ions present in GIC bound to the polymer chains
- The formation of long polymer chains prevents their penetration into dentinal tubules
- Postoperative sensibility due to
- Low viscosity
- Low initial pH of the cement
Question 3. Bilayered restoration / Sandwich technique / Laminated technology.
Answer:
Bilayered restoration:
- Developed by McLean et. al in 1985
- Refers to a laminated restoration using glass ionomer to replace dentin and composite to replace enamel
- Composite bonds micromechanically to set GIC and chemically to the HEMA.
Steps:
Isolate the tooth
↓
Tooth preparation
Butt joint
Bevelling of enamel margin
↓
Pulp protection using Calcium hydroxide
↓
Tooth conditioning using polyacrylic acid
↓
Placement of GIC
↓
Etching of GIC surface
↓
Coating with a dentin bonding agent
↓
Placement of composite and curing
↓
Finishing and polishing
Advantages:
- Resistance to microleakage
- Esthetics
- Flouride release
- Less polymerization shrinkage
- Biocompatible
Disadvantages:
- Technique sensitive
- Time-consuming
Question 4. Cermet Cement.
Answer:
Cermet Cement:
- Introduced by McLean and Gasser
- It is a fusion of glass ionomer to powder like silver or gold.
Manufactured:
- Sinter compressed pellets made from fine metal powder and glass ionomers powder at 800oC
- Ground it into fine form
↓ - Addition of titanium dioxide
Advantages:
- Better abrasion resistance
- Higher flexure strength.
Disadvantages
- Poor aesthetics
Question 5. Resin-modified glass ionomer.
Answer:
Resin-modified glass ionomer:
- Introduced as Vitreband (3M)
- Incorporate the best properties of both GIC and composite resin
Composition:
- Powder:
- Fluorosilicate glass
- Initiator
- Liquid:
- 15-25% resin component (HEMA)
- Polyacrylic acid
- Water
Advantages:
- Long working time
- Good adaptation
- Chemical adhesion
- Flouride release
- Improved aesthetics
- Good strength
Disadvantages:
- Polymerization shrinkage
- Limited depth of cure.
Question 6. Type 2 GIC.
Answer:
- It is restorative glass ionomer cement
- It is further divided into
Type 2 – 1 – Restorative Esthetic:
- Used for esthetic purposes
- For classes 3, 5
- Tunnel Restoration
- The powder/liquid ratio is 3:1 or greater
- They can either be authored or resin-modified
- Has superior physical properties
- Good translucency
Type 2-2 – Restorative Reinforced Gic:
- These have metallic inclusion
- Have superior strength
- Lack esthetics
Uses:
- Core build-up
- Root caries
- Tunnel restorations
- Deciduous restorations
- Powder/liquid ratio – 3:1 or greater
Question 7. Advantages and disadvantages of Glass Ionomer cement.
Answer:
Advantages:
- Chemical bonding to tooth structure
- Bio-compatible
- Good marginal seal
- Anticarcinogenic
- Translucent
- Conservative
- Less technique sensitive
Disadvantages:
- Low fracture resistance
- Low wear resistance
- Opaque
- Require moisture control
Glass Ionomer Cement Short Answers
Question 1. Tunnel Preparation.
Answer:
Tunnel Preparation:
- Isolate the tooth
- Place wedge below proximal portion
- Penetrate occlusal surface – 2mm inside marginal ridge at 45° angulation
- Removal of caries
- Widen the preparation
- Placement of band
- Placement of restorative material and its condensation
- Removal of wedge and matrix
- Finishing and polishing
Question 2. Modifications of GIC.
Answer:
Modifications of GIC:
Fiber Reinforced Glasses:
- Alumina fibers, glass fiber, silica fiber, and carbon fiber added to cement
- Improves flexure strength
- Low abrasion resistance
Metal Reinforced GIC:
- A mixture of amalgam alloy to GIC powder
- Poor esthetics
- Poor abrasion resistance
Cermet Cement:
- Sintering metal and glass powders
- Improved abrasion resistance
- Higher flexural strength
Resin Modified Glass Ionomer:
- Incorporate the best properties of both glass ionomer Cement and composite resin
- Good adaptation
- Flouride release
- Improved aesthetics
Question 3. Composition of GIC.
Answer:
Composition of GIC:
Powder:
- Silica-41.9%
- Alumina-28.6%
- Aluminium fluoride-1.6%
- Calcium fluoride-15.7%
- Sodium fluoride- 9.3%
- Aluminum phosphate- 3.8%
Liquid:
- Polyacrylic acid with copolymers with itaconic acid, maleic acid, and tricarballylic acid
- Tartaric acid
- Water
Glass Ionomer Cement Viva Voce
- Varnishes or sealers should not be used to coat dentin if GIC is to be used as a restorative material
- GIC adhesion is achieved partly by mechanical adhesion and partly by chemical chelation
- To increase mechanical strength, GIC used as restoration is mixed at a higher powder-liquid ratio
- After 24 hours the pH of GIC is 5.3
- To increase the pH of GIC, zinc oxide is incorporated into the powder
- Glass ionomers bond best to enamel than dentin and cementum
- GIC shows decreasing levels of fluoride release with time
- Powder of GIC is referred to as “ion-leachable glass”