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Dental Materials
Composites
| Question | Answer |
|---|---|
| What is the definition of a directly placed restoration? | restoration placed directly into cavity preparation without being first made in a lab |
| What is the definition of a restorations that is indirectly placed? | restoration fabricated in a lab and then placed in the mouth |
| What does esthetic mean in terms of dentistry? | pleasing to the eye. In dentistry esthetic restorations are tooth colored. |
| What are some examples of restorations that are directly placed? | composite resin, amalgam |
| What are some examples of restorations that are indirectly placed? | crowns, bridges, inlays, onlays |
| Which material is used to make a direct placement composite resin material stronger? | inorganic silica particles. |
| What material is responsible for adhering particles to the resin matrix? | silane coupling agent |
| During polymerization, an activator causes an initiator molecule to form which highly charged molecules that have unpaired electrons? | free radical |
| What is the purpose of a tertiary amine in chemical cure composite resin? | Activates the catalyst for polymerization. |
| When placing composite in layers in large restorations, what is the maximum amount that should be placed at any one time? | 2 mm |
| Between a microfill and a nanohybrid composite, which has the higher wear rate? | Microfill |
| What do the nano sized particles used in nanohybrid resins do? | reduces the amount of resin matrix allowing the material to be used for both anterior and posterior restorations. |
| What size particles do microhybrid composite resins contain? | a combination of small particles and microfine particles. |
| Which composite resins retain their highly polished appearance longest? | nanohybrids |
| How much has the shrinkage been reduced from earlier composites as compared to some of the new nanohybrids? | from 3% with earlier composites to less than 1% with some nanohybrids |
| What are the characteristics of nanohybrid composites? | strong, high polishability, less shrinkage |
| Between flowable and condensable composites, which is more useful as a liner? | flowable |
| Between flowable and condensable composites, which is more heavily filled? | condensable |
| Between flowable and condensable composites, which has a lower viscosity? | flowable |
| What does the low elastic modulus allow a flowable composite to do? | it allows them to cushion stresses created by polymerization shrinkage or heavy occlusal loads |
| Between bulk-fill composite resins and conventional composite resins, which allows placing increments of 4 mm or more? | bulk fill |
| Between bulk-fill composite resins and conventional composite resins, which is less translucent? | conventional |
| Between bulk-fill composite resins and conventional composite resins, which works better for class II restorations because of the depth of the proximal box? | conventional |
| Between bulk-fill composite resins and conventional composite resins, which has less polymerization shrinkage? | bulk fill |
| When composite is placed and cured in a preparation that has two opposing walls, what will the composite do? | the shrinking composite will stress the bonds to the two walls and may end up pulling away from one of the walls |
| What type of composites shrink less than hybrids and packables? | Microfills and flowables |
| For composite restorative materials, the greater the filler content, what happens to the coefficient of thermal expansion (CTE)? | it is lower |
| For composite restorative materials, and the greater the resin content, what happens to the coefficient of thermal expansion CTE? | it is greater |
| Why does it take longer to cure darker shades of composite resin than lighter shades? | Light is not transmitted through dark material as it does through lighter material. |
| During incremental addition of composite resin, how will each additional increment bond to the previously placed increment of composite? | If good isolation is maintained and no contaminants are introduced |
| What is recommended to reduce sticking of the composite material to the placement instrument? | use a specially coated instrument |
| What are the characteristics of the Light-emitting diode (LED) curing light? | It is the most popular, lasts as long as 5000 hours, and has rechargeable batteries that make for portability and convenience. |
| What makes composite resin restorations fail? | tooth fracture, poor diet, poor oral hygiene, microleakage, excessive wear |
| What is the average lifespan of a composite resin? | 5.7 years |
| What is the high-viscosity glass ionomer composite used for? | the atraumatic restorative treatment (ART) of caries |
| What are advantages of laboratory-processed composite restorations over directly placed composites? | denser restoration, and the restoration polymerizes more completely |
| What procedures can glass ionomers be used for? | sealants, luting cements, ART, lamination, and restorations |
| Which filler materials are radiopaque? | lithium, barium, and strontium |
| Which filler materials are radiolucent? | quartz |
| To avoid shrinkage, how should composite resins be placed into a preparation? | in small increments |
| How are glass ionomer cements supplied for use? | Bulk container or individual capsule of powder and liquid, or a two paste system |
| Why are glass ionomer cements (GICs) sometimes used for pit and fissure sealants? | because of their fluoride content |
| Why do glass ionomer cements (GICs) not always work very well for pit and fissure sealants? | because they are fairly thick and do not penetrate pits and fissures well |
| What are hybrid ionomers? | a blend of resin and glass ionomer |
| Between hybrid ionomers and glass ionomers, which is made stronger by resin ? | hybrid ionomer |
| Between hybrid ionomers and glass ionomers, which is more polishable? | hybrid ionomer |
| Between hybrid ionomers and glass ionomers, which is more opaque? | glass ionomer |
| What is the organic matrix of composite resins made up of? | BIS-GMA |
| How should a patient’s color/shade be taken? | With clean, moist teeth, a shade guide, and cure a small quantity before you begin to ensure the shade is a match |
| The use of two different restorative materials in the same restoration is referred to as what? | lamination or sandwich technique |
| What are compomers? | they are essentially composite resins that have been modified with polyacid |
| What does the resin component in a compomer contain? | polycarboxylic acid and methacrylates together. |
| How does properly etched enamel appear? | chalky |
| What is a combination of a pit and fissure sealant and a composite resin restoration called? | preventative resin restoration |
| What is it called when bonding is what holds the composite restoration in place? | chemical retention |
| What precautions should be taken with the acid etch solution? | proper PPE, timing, and isolation of the tooth |
| What are fillers made of that are used in dental composites? | sand, glass, quartz |
| What is the correct way to take a shade? | have moist tooth and natural lighting |
| What are some acceptable polishing materials? | rubber cup, rubber wheel, diamond bur, stones, other burs |
| When composite resins are light cured, what may contribute to a longer curing time? | the product, the shade, type of curing light used |
| What criteria needs to be present for a dental sealant to be recommended? | deep pits and fissures, xerostomia, orthodontics, other restored teeth, other teeth with carious lesions |
| What were acrylic resins first used as? | denture bases |
| Dental acrylic resin is the same polymer as what household object? | Plexiglass |
| Why are silicates no longer used for restorative materials? | they are water soluble and irritating to the pulp |
| Between permanent and primary teeth, which need to be etched longer and why? | primary teeth need to be etched longer because the enamel rods in primary teeth are less regularly arranged |
| Which dental materials are acceptable for use as pit and fissure sealant material? | unfilled (normal sealant material) or lightly filled resins |
| When composite resins are light cured, what may contribute to a longer curing time? | Shade of composite resin, product being used, type of curing light used |
| What are some potential issues when working with composite resin? | Thermal expansion, polymerization shrinkage, strength and abrasion resistance |
Created by:
BrendaAlberts