Direct and indirect restorative materials (Ch 6) Flashcards
what is aesthetic
- meaning to replace or bring something back to a pleasing appearance
what are aesthetic materials
- materials that replace lost tooth structure
what are direct-placement aesthetic materials
- tooth coloured materials that can be placed directly into the cavity preparation without being constructed outside of the oral cavity first
- restorative materials are applied to the tooth while the material is pliable and one is able to carve and finish the material
what are indirect-placement aesthetic materials
- tooth coloured materials that are used to construct restorations outside of the oral cavity in the dental lab or at chair side on replicas of the prepared teeth. they are cemented or bonded to the teeth after tooth preparation
what are some examples of direct restorative materials
- composite resins
- glass ionomers
- hybrid (resin-modified) ionomers
- compomers
what are composite resins
- becoming the most widely accepted material of choice by dentists and patients because of their aesthetic qualities and new advances in strength
what are the 2 main characteristics of composite resins
- tooth coloured
2. general usage
what are some indications for using composite resins
- withstand the environments of the oral cavity
- be easily shape to the anatomy of a tooth
- match the natural tooth colour
- be bonded directly to the tooth surface
what is the composition of composite resins
- resin matrix: BidGMA = monomer used to make synthetic resins = Bis-phenol A = BPA
- polymerization additives: allow the material to take form through a chemical process. made of initiator, accelerator, retarder, UV stabilizers
- fillers: add the strength, increase wear resistance
what is Bis-phenol A (BPA)
- a plasticizer used in many products
- plastic food storage containers (plastic bottles)
- plastic lining in autoclavable food and beverage cans
what are monomers used for in dentistry (like BPAs)
- composite resins
- pit and fissure sealants
when using BPAs…
- use light-cure materials
- BPA monomer leaches out of cured resin after light-curing (20-40 seconds)
- to remove residual monomer: polish the surface with a mild abrasive (pumice); wash with air-water spray for 30 seconds using HVS
what do fillers do in composite resins
- control the handling characteristics and reduce shrinkage
- inorganic fillers: colourants = pigments in varying amounts to approximate tooth colours
what are macrofilled composites
- contains the largest size of filler particles
- provides greater strength
- duller rougher surface
what are microfilled surfaces
- filler particles are much smaller
- highly polished finished restoration
- primarily used for anteriors because of lack of strength
what are hybrid composites
- contains both macrofilled and microfilled particles
what are microhybrids
- contains a mix of small particles and microfine particles
- can contain high filler content because microfine particles fill in spaces between small particles
what are nanohybrids
- increase numbers of filler particles which reduces amount of resin. less resin means less shrinkage
- strong and highly polishable
what are flowables
- low viscosity with 40-70% fill
- nano-sized fillers being used today
- PRR = preventative resin restoration, being used as sealants because more wear resistant due to higher filled content
- class V restoration due to toothbrush abrasion, acid erosion, occlusal stress (bruxism) leading to abfraction
what are pit and fissure sealants
- no filler to more heavily filled (flowable)
what are packables
- condensable
- highly viscous with a high volume filler
- stiff consistency and shrink less
- substitues for amalgams, used in high function areas of post teeth, are stronger and more wear resistant
what are ‘smart’ restorations
- not confirmed in clinical studies
- release fluoride, calcium, hydroxyl ions when acidity is around restoration increases
what is core buildup
- heavily filled, used in teeth needing crowns
what is provisional restoratives
- used instead of acrylic resins for temporary crowns and bridges or onlays
what is polymerization of composite resins
- the process in which the resin material is changed from a plastic state into a hardened restoration
- monomers = low molecular weight resin molecules
- polymers = high chain high molecular weight molecules
what is the process for direct application of composite resins
- select the shade of the tooth
- express the needed amount of material onto the treated pad or the light-protected well
- material transferred in increments
- material is light-cured in increments
- last increment is adapted to tooth anatomy
- material is finished and polished
what are glass ionomer cements
- very versatile with chemical properties which allow it to be used for:
- restorations
- liners
- bonding agents
- permanent cements
what are indications for using glass ionomers as a restoration
- primary teeth
- core material for a buildup
- final restorations in non-stress areas
- long-term temporary restorations
what are some qualities of glass ionomer restorations
- ability to chemically bind to teeth
- less extensive preparation of tooth structure as compared to what is necessary for amalgam or composite
- release of fluoride after the final set
what are hybrids (resin modified) ionomers
- combination of glass ionomer and resin
- popular for primary dentition due to fluoride release and exfoliate before excessive wear becomes a problems
- resin makes this material:
- stronger
- more wear resistant
- more pliable
- protects it from moisture
what are compomers
- composite resins and glass ionomers
- polyacid composite resin containing fluoride-releasing silicate glass
- fluoride is not well released and takes months to occur
- designed for lower stress areas for patients at risk for caries
- are similar to microfilm composite resins, but weaker
what are surface sealers
- unfilled resin can be added to the surface of the composite after finishing
- reseals the margins and fills in any porosity created by finishing
- obtains a smoother glossier surface
- does wear off in about a year leaving an improperly polished surface
what are the 4 types of light curing units
- QTH = quartz-tungsten halogen
- PAC = plasma arc
- laser = argon laser
- LED = light emitting diode
how do you care for the light curing units
- cover with disposable covers
- wear uncontaminated gloves when handling
- wipe light area to maintain intensity of light
light curing-unit precautions
- inadequate light output: lightbulbs deteriorate over time - check monthly, hardened composite on light unit will impede output
- premature set of composite: operator light can cause initial surface set interfering with manipulation of material, move operators light away from composite
- eye protection: light shielding device for patient and clinician
what are castings
- cannot be reshaped and carved one they are in their shape; indirect restorations
indirect placement aesthetic restorative materials
- inlays
- onlays
- veneers of porcelain or composite resins
- porcelain-bonded to metal crowns
- ceramic crowns
casting alloys
- partial crowns: 3/4 crowns, 7/8 crowns
- full crowns: PFM: strength gained from the metal under the porcelain
- ceramic crowns: not very strong, easily fracture
what are veneers
- thin layers of porcelain or composite that are bonded to the facial surfaces of teeth. mostly anterior teeth 5-5
what are veneers used for
- lighten colour
- covers defects
- close diastemmas
- reshape crooked teeth, so they look as if they were in proper alignment
characteristics of porcelain veneers
- excellent aesthetics
- biocompatible
- low wear rate
- stain resistant
- great risk of fracture
- wear opposing dentition
characteristics of resin veneers compared to porcelain veneers
- less wear
- less fracture
- stain more easily
- not as good aesthetics
