Using Glass Ionomers Flashcards
What are Glass Ionomers?
- Contain fluoro-alumino-silicate (contains fluride, aluminium and silica)
- Adheres directly to enamel and dentine
- Cariostatic properties from fluoride release
- Brittle and relatively poor resistance to abrasion
What is the Glass Ionomer Setting rection?
- Acid from liquid component attacks glass
- Surface of glass reacts releasin cations (e.g. calcium and aluminium) and fluoride ions
- Cations cross-link polyacid molecules giving salt matric and undreacted glass cores
What are the advantages of Glass ionomer cements?
- Tooth coloured and translucent (glass cores)
- Bonds directly to enamel and dentine – no adhesion system required
- Easy to mix and easy to manipulate
- Fluoride release and uptake
- Can be ‘resin-modified’ to increase strength of the material
What are the disadvantages of Glass ionomer cements?
- Wear resistance and compressive strength significantly lower than that of composite
- Poorer aesthetic results for anterior teeth
- Finite working time (not command set)
When do we use Glass Ionomer Cement?
- Abrasion and erosion cavities (no carious)
- Restoration of deciduous teeth
- Class III and V restorations
- Tunnel preparations
- Temporary restorations
- ART
- Root caries
- Luting cement
When do we avoid using Glass Ionomer Cement?
- Class I, II cavities (permanent dentition) – wear resistance and strength a problem
- Class III and IV (permanent dentition) unless no other alternative
What do we use our resin modified glass ionomer cement?
Mainly as Lining (over Calcium Hydroxide or moderately deep cavities)
What do we want when Restoration of deciduous teeth?
- Finite tooth longevity
- Ease of use
- Direct bonding
- fluoride release
- GIC no longer indicated for definitively restored class II cavities in the primary dentition
In primary dentitions where do we not want to use Glass Ionomer Cement?
Class III and IV restorations Avoid Glass Ionomer unless no other option
- Composite material of choice – better wear resistance and mechanical strength
- GIC tooth coloured material – used where composite is not a viable option
What is a Tunnel Preparation? and how is glass ionomer placed?
Technique for restoring aproximal lession on poterior tooth without having to break through marginal ridge.
- Material is syringed into cavity to ensure that the base of the cavity is filled
- Then composite at top
- Advantage – fluoride, no ‘packing’ required (e.g. amalgam), direct bonding, depth of cure of composite no problem
Glass is the Ideal temporary restoration … why?
- Strength to withstand some time in the mouth
- Direct bond
- Tooth coloured
- Ease of use
- Biocompatible
- Will not fail in the early stages
When is Atraumatic Restorative Treatment (ART)?
- Used where conventional restorative techniques are not appropriate or available i.e. underdeveloped countries, treatment of anxious children
- Caries is excavated by hand, restored with GIC
Is Glass Ionomer sutiable to use in Root Caries?
YES
- Non-load bearing area
- Fluoride release may be beneficial
- Direct bonding to dentine
- GIC (glass ionomer cement) ideal
When can resin modified glass ionomer be used?
- Can be placed as a lining in moderately deep cavities
- Has the strength to withstand placement of permanent material and condensing (e.g. under amalgam)
- Therefore, can be placed over other medicaments e.g. calcium hydroxide
- Temporary restorations/dressings
What are some clinical considerations when using glass ionomer?
- Remember that the material is not fully set for a full 24 hours – final polishing after 24 hours
- The material is particularly sensitive to moisture for first 24 hours – varnish or petroleum jelly can be placed over it
