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What was the first tooth colored filing material
Silicate Cements
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What are some properties of silicate cements
- shrinkage left less than ideal margins that leaked excessively
- Very acidic, highly irritating to the pulp, and highly soluble
- anticariogenic
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What is the composition of silicate cement
a glass powder that contains fluoride mixed with a liquid of phosphoric acid
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When did the first dental acrylic resin appear
In 1948
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Who is responsible for major advancements in dental composites
Ray Bowen
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What were the three major advancement made to dental composites in 1960
- 1. Incorporated a strong ceramic filler particle into the acrylic polymer to form a much stronger dental restorative material
- 2. Developed a polymer for dental composites by combining several monomers to form an oligomer - called Bis-GMA which has more cross linking. It’s stronger and has less shrinkage. Bis-GMA is made using bisphenol A (see next slide) as a starting ingredient
- 3. Silane coupling agents – he incorporated a gluing agent that coats the filler particles and binds them chemically to the resin
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______ is not a _______ of dental materials but it is a _____ of restoratives and sealants
- BPA
- direct ingredient
- by-product
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Release of Bisphenol A after sealant or restoration placement is higher for first
30-60 minutes
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What are the two phases of dental composites
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Explain the matrix phase of the dental composite
a polymer, typically bis-GMA and a diluent (both comprised of C=C) which is added to control the viscosity. Remember, the matrix polymerizes by addition polymerization activated by chemical or light. It is the weakest phase of a dental composite
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Explain the filler particles of dental composites
- Filler particles (inorganic filler) - made up of ground glass (silicone dioxide) which:
- reduces the amount of resin and therefore the amount of bad features (i.e. shrinkage, poor thermal expansion, wear, poor marginal integrity).
- confers positive physical and mechanical properties to the restorative material (ex: strength, hardness, optics)
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What is a composite
a compound of two or more distinctly different materials with properties that are superior to those of the individual components
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What is composite composed of
- 1. Bis-GMA resin
- 2.Filler particles (glass)
- 3. Silane coupling agent
- 4. Activator/initiator (tertiary amine) 5.Hydroquinone - inhibitor
- 6.Color pigments
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What is the initiator and activator for self cure composite
- Initiator Benzoyl Peroxide
- Activator Tertiary Amine
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What is the initiator and activator for light cure composite
- Initiator-Camphoroquinone
- Activator-Light
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Self cure is what kind of system
paste-paste system
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Light cure composites penetrate to a depth of
1.5 to 2.0 mm
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Dual cure composites is used for _______ ad beneath other restorations where _________
- core build-ups
- light penetration is uncertain
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What are some characteristics of the fillers in the past
- ground up pieces of quartz ranging in size from 10-25microns
- Rough feel to the surface
- Radiolucent on radiographs
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The original fillers have been replaced with those containing _____ which provide ______
- barium and strontium glass particles
- radiopacity
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What are some characteristics of macrofilled composites
- Contain large (10 -25 microns), irregularly shaped quartz particles
- Filler content makes up 70-80% by weight
- Better physical properties than unfilled resins, but there still are difficulties with shrinkage and thermal expansion
- difficult to polish
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What are some characteristics of microfilled composites
- contain small (.03-0.5 microns) particles of fused silica
- Only 40-50% filler by weight
- Smooth surface/easy to polish yielding excellent esthetics
- easily chipped
- prepolymerized resin fillers – these help to decreases polymerization shrinkage
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What are some characteristics of hybrid composites
- 75 to 80% filler percentage by weight
- Less curing shrinkage and good color matching
- Thermal expansion and wear very similar to natural tooth
- Very popular and widely used today
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Nanofilled composites
hybrid composite that contain particle size down to 75nm. Allows more filler particles to be mixed in giving 80%+ fill percentage
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when working with flowable composites Lower percentage of filler equals lower _____ and also used as ______
- viscosity- creating a more fluid material
- the initial increment of a composite restoration which is then covered with a hybrid composite
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composite shrinks in _______ that is ______
- the direction of light
- away from the cavity walls
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__________are the key reason to pulpal death and sensitivity
Uncured composites
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Clinical challenges of posterior composites include
- Wear
- Integrity of the margin
- Contour
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_______ technique was developed in 1955 by _______ which allowed _________
- Acid etch
- Michael Buoncore
- bonding of composite to enamel
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Enamel bonding provides a _______ between restoration and tooth enamel
mechanically bonded connection
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In the enamel acid etch technique one would clean the tooth with _______ to remove the biofilm
pumice / or a microetcher
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During the acid etch technique one would Etch with ____ phosphoric acid for ______
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Raises surface energy ______ the surface wettability
increases
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unfilled resin is
hydrophobic
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Dentin bonding as compared to enamel bonding is
- Not as predictable as enamel bonding
- Not as strong of a bond
- Much more technique sensitive
- Requires education and care
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The composition of dentin is
- 50% inorganic minerals
- 30% organics (collagen fibers)
- and 20% water
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The smear layer of dentin bonding is produced by
the activity of caries causing bacteria and, by the cutting action of dental burs and instruments in cleaning and preparing the tooth for the restoration
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The first step to dentin bonding procedure is applying ______ which is an _______ agent that _____ and ____
- conditioner
- acid-etch
- cleans the smear layer and opens the dental tubules
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The acid etch agent in dentin bonding could be a
- weaker mix of phosphoric acid
- or a mild organic acid (maleic acid)
- or EDTA (ethylenediaminetetraacetic acid).
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The second step to the dentin bonding procedure is the _____ which is a _____ that has a ______ side to react with dentin and a _____ side to react with the adhesive
- primer
- bi-functional monomer
- hydrophilic side
- hydrophobic
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The third/last step to dentin bonding is to apply an ______ that forms a _____ that is a mix of _______
- adhesive
- hybrid layer
- collagen mesh, decalcified dentin, and resin
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Two step or one step uses the concept of ______ which is _____
- of self-etching
- using a very mild acid etch solution (conditioner) that doesn't have to be washed off before the application of primer and the adhesive agent
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glass ionomers are used as a
cement, liner, build-up, and restorative
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All types of glass ionomers release
fluoride to provide anticariogenic nature of material
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What are some characteristics of glass ionomers
- Used in class V restorations in patients with high risk for caries
- Good marginal integrity
- excellent thermal properties
- anticariogenic
- very poor wear resistance
- Rechargable nature of fluoride release
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