Clinical application of GIC and Class V cavity Flashcards
Class V cavity: What are the requirements in treating a class V cavity in terms of:
- White spot lesions
- ECC
• The carious lesion usually starts as a white or chalky line at the gingival 1/3 of the labial or buccal surfaces
• Preventive treatment should be prescribed for ‘white spot lesion’. Eg. Duraphat
* Early Childhood Caries ( ECC): Never restored without prior counselling in diet and oral hygiene for future prevention
What are some considerations when designing a class V?
• Close to gingival margin • Plaque accumulation • Gingival inflammation, easy to bleed • Difficult to isolate from moisture because of crevicular fluid • Subgingival root caries * Choice of restorative materials
What are acids that dissolve the smear layer?
Smear layers are soluble in hydrogen peroxide, chlorhexidine, sodium hypochlorite, EDTA and other organic substances
Explain GIC bonding and mild acids
• GIC’s bonding is higher with enamel than dentine because of the higher mineral content
• While strong acids like phosphoric acid remove smear layer, they also demineralise intratubular dentine by removing calcium. This exposes the collagen
• GIC cannot bond to collagen
* Hence, mild acids such as 10% polyacrylic acids are used to remove smear layer
Describe cavity conditioners in terms of components and application time
Components:
- 20% polyacrylic acid
- 77% distilled water
- 3% AL CL hydrate
Application time:
* 10 secs
List the indications for GIC use (6)
- Caries control/ temporisation
- Fissure protection
- Lining
- Base
- Luting
- Restoration
Describe caries control/ temporisation as a GIC indication
HINT: mention ART technique
Atraumatic Restorative Treatment (ART) technique: Hand instruments are used to remove only softened dentine, condition and GIC
• Some may use high fluoride release GIC with its pink colour. It helps identify that it is a temporary filling. The ion exchange layer acts as an effective seal against continuous bacteria insult. Any remaining bacteria will become inactive once the cavity is sealed properly
* Fluoride/ strontium/ calcium ions will also aid in remineralisation and faster healing
Describe fissure protection as a GIC indication
• Newly erupted teeth strengthen with time, as saliva provides it with calcium and phosphate, as well as fluoride from toothpastes/ water
* GIC cannot penetrate fissures, but it provides fissures with direct fluoride = makes more resistant to caries in the future and protects from bacteria
Describe linings as a GIC indication
- Occludes dentine tubules
- Protects pulp
- Lower powder to liquid ratio
- Smaller silicate glass particles
- Hand mixed RMGIC
- Thinner
Describe bases as a GIC indication
- Occludes dentine tubules
- Protects pulp
- Replaces lost dentine
- Thicker
- Higher powder to liquid ratio
- Encapsulated GIC
- Bigger silicate glass particles
Describe lutings as a GIC indication
• Cement stainless steel crowns
* Cement orthodontic bands and brackets. GIC will help prevent demin seen as white spot lesions
Describe restorations as a GIC indication; considerations
• For permanent teeth, it is only used on non-occlusal bearing surfaces. When choosing GIC/ amalgam, the longevity of the material and aesthetics should be considered
* For primary teeth, the patients dental age, chronological age and benefits of GIC should be considered
Discuss critically the advantages and disadvantage of use of Glass Ionomer Cement
Advantages: • Chemically bonds to tooth structure • Fluoride reservoir • Bonds to base metals • Adequate tooth- coloured aesthetics • Does not need to be applied incrementally • Similar co-efficient of thermal expansion to tooth structure • Can be used for many things
Disadvantages:
• Composite Resin has better aesthetics
• Water balance becomes an issue
• Pro-longed setting time for autocure GIC
• When it sets, it kind of contracts when light cured
• It’s soluble and can disintegrate
• Weak physical properties
• Prone to fracture with heavy occlusal loading
• Not as strong as amalgam and composite resin
Describe the process of hand-mixing and applying GIC (4 steps)
Dispensing:
• Dispense powder and liquid carefully onto a mixing surface/ glass slab that has a cool surface
• One level scoop of “ fluffed” powder with no excess on the back of the spoon
• One vertical drop of liquid (place the bottle horizontal and then vertical to prevent air bubbles)
• Mix two materials together briskly to achieve a thin mix within 25 secs
• Only dispense material just prior to mixing. If the powder is exposed early, it can also take up water; so always dispense immediately prior to mixing
Mix powder into liquid:
• Divide the powder in half so it can be mixed in two parts
• Incorporate first half by gently, but rapidly rolling the powder into the liquid with 10 sec
• Include the second part entirely, leaving no residue and mixing within a further 15 sec
Apply to dentine :
• Cavity should be conditioned
• Use ball applicator to deliver lining to cavity
• Cover all exposed dentine to seal tubules
Glass Ionomer Finishing:
• Cure for 5 seconds, removing excess from walls/ margins with excavator
• Complete curing for a further 20 secs
State and describe the coats used on GIC
Cocoa butter:
- Prevents water and saliva contamination to GIC during first 24 hours of treatment
- Fuji VII only
GC Fuji Coat LC: • Methyl methacrylate 30% • Dimethacrylate ester 30- 40% • Urethane acrylate 30% * Light cure for 10 seconds
Protects GIC against humidity and dehydration, and gives it a smooth glossy surface
G-Coat Plus:
- Contains homogenously dispersed wear resistance to GIC, composite and acrylic restorations
- Light cure for 20 seconds
Self etching, enabling strong adhesion to tooth surfaces surrounding restorations
