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robbypowell's version from 2016-12-12 13:40

Glass Ionomer

Question Answer
aluminosilicate - polycarboxylic acid products (ASPA) is more commonly referred to _____ ____Glass Ionomer
This material was one of the first direct, esthetic restorative materials. Initially, the restorations appeared very good. However, over time, they tended to dissolve.. despite this dissolution there was little to no recurrent decay around the marginsSilicate Cement (predecessor to glass ionomer)
This material was the first restorative product to actually obtain chemical bonding to tooth tissue and metal surfaces. Although low in value, the presence of this bond tended to draw clinicians toward use of this product over others that relied solely upon mechanical retention.Polycarboxylate cements
This material is a combination of an acid etchable glass which releases fluoride with a polyacid molecule able to chelate bond to tooth and metal surfaces.Glass Ionomer (was developed to combine chemical bonding to tooth structure seen with polycarboxylates and fluoride release of the fluoroaluminosilicate glass powder of the silicates.)
Glass Ionomer was developed to combine chemical bonding to tooth structure seen with _____ cements and fluoride release of the ______ cementsPolycarboxylate; Silicate
Two components of silicate cements: _______ ______ powder (an acid etchable glass) + _____ _____ liquidfluoroaluminosilicate glass powder + phosphoric acid liquid
What was the major advantage of Silicate cement as a restorative material (even if it was only the perceived benefit)? Disadvantage?Advantage: Leached Fluoride; Disadvantage: Soluble, no chemical bond
What was the major advantage of Polycarboxylate cement as a restorative material (even if it was only the perceived benefit)? Disadvantage?Advantage: chemical bonding to tooth and metal; Disadvantages: no fluoride leaching, unesthetic
____ _____ is one of the only esthetic dental materials displaying true adhesion to dental tooth structuresGlass Ionomer (Polycarboxylate cement bonds, but is unesthetic)
What restorative material has a CTE most similar to tooth structure?Glass Ionomer
Rank Tooth, Gold, Porcelain, Glass Ionomer and Amalgam low to high for coefficient of thermal expansion (why is it hard to rank composites for CTE)Glass Ionomer (10.2-11.4) < Tooth (11.4) < Porcelain (12) < Gold (14.4) < Amalgam (26) (It is difficult to rank composites bc their CTE varies widely from 14-50)
What are two main advantages of Glass Ionomer over earlier silicate cements? over polycarboxylate cements?GI has F- release of Silicate, but also has Chemical bonding and doesn't washout like silicate; GI has chemical bonding of Polycarboxylate, but also has F- release and is esthetic (neither of which polycarboxylate has)
Which ADA Type of GI is useful as a luting agent (Useful in cases which have to be remade as a result of recurrent caries in an attempt to lower the possibility of this occurrence)Type 1
Which ADA Type of GI is used as a restorative material (esthetic, or reinforced)Type 2
Which ADA Type of GI is used as lining material or sealant?Type 3
The most beneficial uses of glass ionomers are in Class _________ and Class _________ lesions.Class 3 & 5
Use as a Class ____ restorative material in the adult is not advocated as a result of poor wear resistance and low values of flexural strength compared to composite and amalgamClass 2 (contraindicated) bc of low wear resistance and flex strength
How should a sealant prep that you'll use GI sealant for differ in design from one using a flowable composite?Wider for GI; (bc it doesn't have flow characteristics of Flowable composite)
T/F: The bond strength of composite to glass ionomer is sufficient for clinical applicationsTrue (sandwich technique)
T/F: The bond strength of composite to glass ionomer is insufficient for clinical applicationsFalse (bond is "very good"; sandwich technique)
Using glass ionomer at which interface in what class of restoration permits a more durable bond and an enhanced potential for long-term clinical success of the restoration.Gingival margin of Class 2 restoration (GI will chemically bond to the underlying tooth structure and the composite will bond to the GI resulting in a more microleakage - resistant margin)
______ technique does not remove the marginal ridge when restoring Class 2 lesionsTunnel technique
What property of glass ionomer allows the tunnel technique to leave "unsupported enamel"Chemical bond of glass ionomer (restorative material chemically bonds to and strengthens it)
What is the downside of Tunnel Technique for restoring class 2 lesions?lack of certainty that all peripheral demineralized enamel has been removed from the inter proximal caries
3 properties of GI that make it an ideal long-term temporary restorative materialchemical bond, F- release & similar CTE to tooth (retentive to tooth structure, releases fluoride, and expands and contracts at a similar rate as tooth structure)
What is the main advantage that GI has over most other luting cements? and disadvantage?AdvantageL Chemical bond to tooth and to metal; Disadvantage: Sensitivity that worsens with time (attributed to desiccation of the tooth)
Radiopacity of Glass Ionomer is attained by adding one or more of what 5 metals?Silver (Ag), strontium (Sr), barium (Ba), lanthanum (La), or zinc (Zn) (the glass also already contains aluminum) (zirconia can be added also)
products blend powdered glass with an elemental metal (silver, silver alloy, gold, platinum, palladium) or amalgam shavings in an attempt to provide greater wear resistance ... an example product of this type is ____ ____Miracle Mix
A ______ is made through metal incorporation by the sintering of glass and metal together, and then the crushing of this mass into particulate form. When in this form, the metal cannot separate from the glass powder particle.CERMET
The average particle size of CERMET GI's is ___ to ___ microns (although it can vary widely)5-10 microns
The proportion of ____ to _____ controls the basicity of the glass particle and thus the reaction properties, as the overall reaction is an acid-base type processalumina (Al2O3) to silica
SiO2-AlO3-CaF2-AlPO2-Na3AlF6 is a typical formulation of what component of GI?Glass (powder)
The liquid component of Glass Ionomer consists of Acids that are high in ______ ____ contentcarboxylate group
Addition of ______ species to the liquid component of GI greatly decreases the tendency of the acids to react with themselves ("gelation rxn")Polycarboxylic
T/F: Liquids component of Glass Ionomer should be refrigerated to preserve shelf lifeFALSE (the opposite, cooling of these acids actually increases spontaneous reactions)
This specific polyacrylic acid, _______ acid, increases attack of polyacrylic acid on glass and lowers viscosity; Helps decrease possibility of gelation in the liquid upon storageItaconic Acid
This specific polyacrylic acid, _______ acid, allows less reactive and more translucent aluminosilicate glasses to be used.Maleic Acid (In 3M / ESPE products - tends to leave very few unreacted acid sites)
This specific polyacrylic acid, _______ acid, helps to initially release metal ions from the glass and then form complexes with them, controlling their ability to enter into the final reaction process. Thus, this material extends working time and extends the time of setting.Tartaric Acid (Later in the reaction, it acts to sharpen the setting reaction process by enhancing the rate at which the aluminum polyacrylate species is formed.)
This SPECIFIC type of Glass Ionomer glass powder has been mixed with freeze-dried polyacrylic acids in the solid form. Thus, all the material needs to start reaction is water“anhydrous” glass ionomers (Water-hardened)
The ______ strength of glass ionomers is acceptable, but the _______ strength and wear resistance were poor.Compressive (acceptable); Transverse (poor) (this accounts for poor wear resistance)
Glass ionomers are _______ materials, meaning that they will not deform much prior to fractureBrittle
The first attempt to enhance the physical properties introduced amalgam alloy powder into the glass portion... this product was called ____ ____Miracle Mix
T/F: Because Miracle Mix has improved transverse it also showed to have improved wear resistanceFalse (did improve transverse, but not wear resistance)
T/F: Miracle Mix has improved transverse strength compared to traditional GI's but wear resistance was not improvedTrue
T/F: CERMET has improved wear resistance and transverse strength compared to other GI's and can stand up to occlusal stressesFalse (improved strength, but cannot stand up to occlusal stresses)
T/F: CERMET has improved wear resistance and transverse strength compared to other GI's but still cannot stand up to occlusal stressesTrue
Which type of GI has poor "optical" properties and appear metallic in colorCERMET
memorize

Setting Reaction

Question Answer
For a traditional GI setting reaction to occur, ________ MUST be presentWater
What type of reaction is GI setting reaction? Liquid acts as the _____; Glass acts as the _____Acid-base; Liquid=Acid; Glass=Base
early stage setting rxn of GI cross-linking occurs through the formation of chelation bonds between the net-_____ (negatively/positively) charged carboxylate ions and the ______ (negatively/positively) charged metal ions in solutionNEG=Acid; POS=Metal
First type of bond to form in GI setting is ____-valent (mono, di, tri?) _______ (metal) complexes; Second type of bond to form (much later) is ____-valent (mono, di, tri?) _______ (metal) complexes1st: DI-valent Calcium complexes; 2nd: Tri-valent Aluminum complexes
______ ______ is a product of the acid attack on the glass. This material is the jelly-like “hydrogel” envelope around the partially-dissolved glass particleSilicic acid
______ ions are the first leached metal ions to form an initial matrix that holds the material together. However, this early reaction network results in a weak material and the restoration should not be immediately trimmed.Calcium
Much later, trivalent _____ ions enter into the chelation reaction and greatly increase strength values. This reaction requires a long time to initiate and complete, however (up to 1 to 7 days)Aluminum
T/F: As a result of GI's slow maturation, the final analysis of color match in glass ionomers should be postponed until the dentist is sure the reaction is completeTrue (1-7 days)
T/F: It is theorized that the reaction process of glass ionomers never really completesTrue ( ...and undergoes a continuous, dynamic internal ion-exchange process for the lifetime of the restoration.)
______ serves as the reaction medium in which all the various processes of GI setting are occurring.Water
Water is present in the set GI material in two forms: _______ and _______.Bound & Unbound
What was used to prevent early loss or gain of water by "locking water in"varnishes and/or light-cured resins (both designed specifically for this purpose)
_____ (Bound/Unbound) water is present with each acid group-metal ion chelation bond, acting to stabilize the bond. It is very difficult to remove. The proportion of ______ (bound/unbound) water increases as the material ages.Bound; Bound
memorize

Physical properties

Question Answer
recall that 1 MPa is equivalent to ___ psi145 psi (= 1 MPa)
What is the typical composite resin bond-strength to enamel?20 MPa (greater bond strength of resin to enamel than GI to enamel, however GI bonds better to dentin)
T/F: GI tend to break at the GI-tooth interfaceFalse (tends to break within the GI material itself)
T/F: GI tends to break within the GI material and not at the GI-tooth interfaceTrue (Therefore, bond strength values of glass ionomers to different substrates may not be very relevant or a good predictor of clinical success)
bond strength values of glass ionomers to different substrates are not relevant predictors of clinical successTrue (because they dont fail at this interface, but by fracture within the material itself)
How long does it take for fluoride release from GI to reach levels that are ineffective in preventing decalcification of tooth structure?Within a few days
T/F: Only conventional "true" Glass Ionomers can have their fluoride rechargedTrue
What are 2 ways that Fluoride release of conventional "true" glass ionomers can be recharged?topical fluoride application and fluoride-containing toothpaste
T/F: GI's shrink less than Composite upon curingFalse (shrink same amount, 4-5% by volume, however bc setting time is slower, material can flow from unbonded free surface causing less stress at the tooth-material interface)
T/F: GI's shrink more than Composite upon curingFalse (shrink same amount, 4-5% by volume, however bc setting time is slower, material can flow from unbonded free surface causing less stress at the tooth-material interface)
T/F: GI's shrink about the same as Composite upon curingTrue (shrink same amount, 4-5% by volume, however bc setting time is slower, material can flow from unbonded free surface causing less stress at the tooth-material interface)
T/F: GI's shrink about the same as composite upon curing, but have less potential for gap formation and micro leakage.True (due to slower setting time and ability of unbonded material to "flow")
T/F: Post-operative pain with GI luting cements decreases over timeFalse (Zinc Phosphate decreases over time)
T/F: The ADA recommends removing the smear layer prior to bonding with GI luting cementsFalse (recommends not to remove for GI luting cements, Type 1 GI's)
T/F: The ADA recommends not removing the smear layer prior to bonding with GI luting cementsTrue (recommends not to remove for GI luting cements, Type 1 GI's)
T/F: The ADA recommends removing the smear layer prior to bonding with GI Type 2 restorative materialsTrue, no complications like seen with Luting Cements (recommends not to remove for GI luting cements, Type 1 GI's)
The ADA recommends not removing the smear layer prior to bonding with GI luting cementsTrue (recommends not to remove for GI luting cements, Type 1 GI's)(no complications associated with removing smear layer from Type 2 restorative GI's)
T/F: Glass Ionomers are used for direct and indirect pulp capsFalse (do not use, place dycal first, then GI over top of dycal)
T/F: Glass Ionomers are not to be used for direct and indirect pulp capsTrue (place dycal first)
When should glass ionomer not be used directly over dentin?Deep restorations aka direct and indirect pulp caps (can be used after calcium hydroxide is placed first)
memorize

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