Glass Ionomer Materials Flashcards
_____ are water-base materials that adhere directly to the tooth via acid-base set reaction.
Glass Ionomers
______ are polymer based materials that require adhesives and set via a free radical reaction.
composites
Ionomers attach by ______ with HA surfaces.
chelating
Adhesives need a ______ dentin surface with exposed _____.
demineralized
collagen
True or False: Conditioners are used with composite materials.
False, Glass Ionomers use conditioners
What is a conditioner?
MILD organic acid (use with Glass Ionomer)
- solublizes the smear layer
- leaves smear plugs in tact
- does NOT demineralize dentin or enamel
- cleans the surface
What is an etchant?
Inoranic acid (use with composite)
- completely removes smear layer and plugs
- demineralizes surface dentin (2-10micrograms)
- leaves collagen-rich surface with many pores
Which acid is inorganic, that used for etching or conditioning?
etchant = inorganic
Which acid is used as an etchant?
35% phosphoric acid
Glass Ionomer and RMGI consist of what two components?
powder (glass usually)
liquid (water and acid)
The powder component of GI contains ______ glass. Why is that important?
non-silanated, acid soluble glass
- the liquid portion contains polyacid copolymers that will dissolve the periphery of the glass
- the glass will then release ions: calcium, aluminum, and fluoride
- the calcium ions are divalent and will quickly chelate with acid polymer chains
The glass ionomer reaction continues to act over the next 24-72 hours. During that time, _____ replaces calcium ions and _______ in strength.
aluminum
increases
What are the disadvantages to using Glass Ionomer?
- slow setting
- early dissolution
- optical properties are not as good (opacity)
- stain resistance is meh
- poor strength
True or False: RMGI and GI contain the same powder component.
True, its the liquid component that is modified
Do you remember what type of glass the powder contains?
GI contains ____% water and ____% polyacid copolymers. RMGI contains _____% water, 35% _______ modified polyacid copolymers, and ____% HEMA.
GI = 50:50 RMGI = 35% water 35% METHACRYLATE modified polyacid copolymers 30% HEMA
What type of reaction occurs with GI? What type of reaction occurs with RMGI?
GI: ionic (IONomer = IONic)
RMGI: ionic and free radical (R for Radical)
Free radical reactions (such as that with RMGI and composites) will produce some degree of _______.
polymerization shrinkage
True or False: During a resin ionomer reaction (such as that with RMGI), there is a net dimensional change due to shrinkage.
False, there is a ZERO net dimensional change because polymerization shrinkage is balanced by swelling due to water absorption.
(Think: RMGI contains only 35%water; whereas, GI contains 50% water. RMGI is therefore a little thirsty and is going to want to absorb some water)
True or False: GI sets by an acid-base reaction.
True, acid base (aka: ionic)
RMGI sets by a ______ cure.
Triple
- light cure
- self cure
- acid-base reaction
Which reaction occurs more quickly: free radical or acid-base?
Free radical is RAPID
acid base is SLOW
The rapid free radical reaction of RMGI protects the matrix from early ______.
solubility
The slow acid-base reaction of RMGI causes the properties to ______ over time.
improve
Compare composite, compomer, RMGI, and GI:
Which OSU product has the lowest %opacity?
Fuji II LC (RMGI material type)
Compare composite, compomer, RMGI, and GI:
Which OSU product has the smallest marginal gap?
Fuji II LC (RMGI material type)
What are the advantages to using RMGI and GI?
- Provide a good seal between dentin and material
2. Recurrent caries inhibition potential
What are the advantages to using RMGI instead of GI?
- Improved solubility resistance
- Improved strength (less stiffness though)
- Improved optical properties
RMGI material is used for high risk patients for restoration of _____ or ______ areas.
cervical
deep proximal
Where is the “open sandwich” technique used?
deep proximal margins
- area most susceptible to recurrent decay
- area where no enamel is present at the margin
- area with poor composite bonding
What are the four steps to caries removal?
- Slow speed with a large round bur (+/- spoon excav.)
- Clear DEJ first (most aggressive)
- Clear area over the pulp (less aggressive)
- Use tactile sense to detect unsound tissue (tugback)
“The seal is the deal” means…..what?
if you seal the site, caries remain dormant and does not progress. Therefore, you can leave some affected dentin in order to avoid exposing the pulp!
What are the three preparation designs for Class 3 and Class 5?
- Conventional (GV Black/amalgam principles)
- Beveled Conventional (composite only)
- Modified (minimal prep, for any adhesive materials)
The beveled conventional preparation design is only used when preparation walls are in _____.
enamel (remember, composite bonds best to enamel)
The “conventional” preparation design has a _____ degree cavosurface enamel margin, uniform ______mm depth into dentin, and ______ retention.
90
0.5mm
mechanical
True or False: Both the conventional and modified-conventional prep designs will have a uniform 0.5mm depth into dentin.
False,
Conventional and BEVELED conventional = 0.5mm in
MODIFIED conventional = removal of defective tooth structure only
What are the five selection criteria that must be considered when choosing a restoration material?
- esthetics
- location
- expected prognosis (long/short term)
- Etiology of lesion (carious?)
- Caries Risk of patient
What are four examples of non-carious lesions that would be restored?
attrition (tooth to tooth)
abrasion (mechanical/toothbrushing)
erosion (chemical)
abfraction (bruxism/forces)
Carious lesions are more visible when _____.
dried
Incipient carious lesions of enamel appear as ______.
white spots
The mesiodistal walls of a Class V preparation will ____ slightly and the gingival floor will follow the _____.
diverge (following the enamel rods)
curvature of the FGM (0.5mm above)
A conventional Class V preparation is deeper _____ than _____.
deeper incisal than gingival
True or False: Using a bevel with GI or RMGI will increase the bonding strength.
False, bevels are only used for composites because they bond best to enamel. RMGI and GI are weaker in thin areas
What are the advantages to composites?
- use of conservative prep (adhere to tooth/enamel)
- esthetic
The mesial and distal length of a Class V preparation will extend to ______.
the mesial and distal line angles of the tooth
The axial depth of a Class V preparation is ______ at the incisal portion and _____ at the gingival.
1.2 mm incisal
1 mm gingival
True or False: Composite, RMGI, and Amalgam can all be used for Class III restorations.
True
What is the most common technique for Class III preparation/restoration?
Lingual Approach
For a conventional Class III preparation, the incisal wall is left in contact and the gingival wall ______.
has clearance
What is the minimal facial depth for a class III prep?
typically 1.0 to 1.5mm to minimally break facial contact
For a conventional Class III preparation design, it is okay to undermine ______ but not okay to undermine _____.
dentin = okay enamel = not okay
How does the beveled preparation differ from the conventional Class III preparation?
lingual bevel =45 degrees
no retention grooves (conventional has Incisal and Gingival grooves)
The axial walls of a Class III prep should extend 0.2 mm into dentin and should be deeper incisally than gingivally. What is the axial depth on a lateral? Central?
lateral = 1.0 mm central = 1.2 to 1.5 mm
After filling a prep with one increment of composite, use a _____ to shape the material and cure.
mylar matrix
After curing, use a ____ blade to remove proximal flash and use a _____ to contour the restoration.
#12 fluted finishing bur
After using the finishing bur, use _____ and then ______ (if needed).
sand disks sand strips (if needed)
