Glass Ionomers Flashcards
what are the challenges of glass ionomers
- esthetics
- proximity to pulp
- bonding to dentin
- isolation
- control of sulcular fluids effecting bond/seal
- micro leakage at margin
what is the chemical composition of glass ionomer
- polycarboxylic acid
- FAS glass
- water
- tartaric acid
what is the mechanism of glass ionomer adhesion
- chelation of carboxyl groups of the polyacrylic acids with the calcium in the apatite of the enamel and dentin
- polyacrylic acid (weak acid) primer may be provided by manufacturer
- smear layer is removed. however weak acid leaves dentinal tubules plugged. do not use phosphoric acid to etch!
what is the bond strength of glass ionomer
3Mpa higher with new materials
what are the 2 types of glass ionomers
- reinforced glass ionomers
- resin modified glass ionomers
what are the the reinforced glass ionomers
- expand use of materials beyond cementing/luting
- miracle mix and ketac silver (amalgam particles)
- ketac molar and fuji IX
- equia forte
- chem-fil rock
what are the resin modified glass ionomers and what do they do
- improved esthetics and handling characteristics
- complex setting reactions- class GI acid based reaction as well as light activation resin polymerizaion. some have an additional chemical cure reaction and can set in the absence of light
- fuji II LC, vitremer restorative material, ketac nano, geristore
what is compomer
- polyacid modified composite resin (Dyract)
- light polymerized composite resin restoratives, modified to contain ion- leachable glass particles and anhydrous polyalkenoic acid
- have decreased in use due to development of type II GI/RMGI that have more favorable characteristic
what is Giomer
- relatively new resin with pre-reacted glass ionomer particles
- the particles are made of fluorosilicate glass that has been reacted with polyacrylic acid prior to being incorporated into the resin
- shofu beautifil
what is cavity liner
used at a thickness of no more than 0.5mm under either an amalgam or composite restorative material
- seals deep dentin exposed during caries removal
- vitrebond plus
- fuji liner
what are type 1 glass ionomer cements used for
luting crowns, FPP, orthodontic brackets
what are type 2 glass ionomer cements used for
esthetic restorative cements GI and RMGI
what are type IIb glass ionomer cements used for
reinforced restorative cements
what are type III lining cements used for
lining cements
what are the advantages and disadvatntages of type II reinforced restorative cements
- advantages: radiopaque, adhesion, fluoride release, quick set for finishing
- disadvantages: weaker than resin, no significant improvement in characteristics or longevity over other RMGIC
what are the advantages and disadvantages of esthetic restorative cements
- advantages: useful in high caries risk patients due to fluoride release, adequate esthetics, low polymerization shrinkage, excellent retention
- disadvantages: shade matching not equal to composite resin, low compressive strength
what are the indications for type II esthetic restorative cements
- non carious cervical lesions and root caries
- base to replace dentin
- block out undercut or void- not recommended for core build up
- primary dentition small class I or class II
- permanent dentition- open sandwhich or closed sandwhich
- interim therapeutic restoration or sedative filling
what are the contraindications for type II esthetic restorative cements
load bearing areas- class IV, II, large class I
- areas where esthetics is extremely important
what are the advantages of newer formulas
- improved handling
- decreased viscosity
- lengthens shelf life before gelation
- increased working time
- shortened setting time
- R and D expensive to replace amaglam
how is caries control performed with glass ionomer
- SDF for cavitated lesions or partial caries removal and interim restoration of all cavitated caries leisons in 1-2 apointments and restoring with glass ionomer
- this is sufficient to removal the bacterial load and prevent further progression on the lesion
- then perform definitive restorative care once caries control phase is complete
describe GI materials and fluoride release
GI materials must be recharged with fluoride which can then be re-released in order to provide protection
describe GC equia forte
- bulk fill
- non sticky, packable
- optimal marginal seal for resistance to micro leakage/discoloration
- high fluoride release
- high resistance to wear/erosion
- 8 shades- I recoemmend choosing one shade darker if using on the gingival third.
- if tooth is A2 choose A3-5
what is the sandwhich technique
the placing of glass ionomer cement as an intermediate layer between the tooth structure and a resin based composite restorative material; this restoration design combines the adhesion and fluoride releasing nature of a glass ionomer cement with the esthetic quality and durability of a resin based composite
what are the indications for open sandwhich technique
when any part of the gingival margin of the class II or class V prep has been extended past the CEJ and no longer has a cavo surface of enamel
what are the steps in the open sandwich technique for the class II restoration
- prepare class II prep
- place appropriate matrix
- scrub dentin at gingival floor with manufacture provided primer
- place GI at the dentin/cementum margin to fill until the height of the material is approximately at the level of the CEJ, light cure if using RMGI
- etch remaining dentin/enamel keepin etchant clear of GI/RMGI
- place bonding resin and composite, light cure
- finish and polish
what are the advantages to the sandwich technique
- minimize gap formation at margin due to shrinkage of the composite resin
- less technqiue sensitive than composite resin systems
- fluoride release provides anti cariogenic environment
- usefull for class II and class V restorations
- use in moderate and high risk for caries
what is the treatment of choice in the high caries risk patient
open sandwich technique with RMGIC with resin
what are the steps in root caries preparation
- tooth prep with infected caries and dentin removed
-retention grooves placed
what are the advantages of GI
- minimal cavity prep required
- adhesion to enamel and dentin
- fluoride release, recahrging, possible caries inhibition
- minimal shrinkage
- excellent marginal seal
- low solubility
- good esthetics
- excellent tissue compatibility
what are the disadvantages to GI
- lower resistance to wear compared to amalgam/resin
- lower bond strengths compared to resin
- shades sometimes not ideal for highly esthetic areas
