Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
|
Adhesion Requirements
|
1. HIGH wettability
2. HIGH surface energy 3. HIGH contact area 4. LOW contact angle |
|
|
Smear Layer
|
Hydroxyapatite, collagen, water, oil and bacteria
Lowers the dentin permeability in 86% 0.5-5.0 micrometers |
|
|
Acid Etchant
|
- Phosphoric Acid (30-40%)
- Gel, semi-gel or liquid |
|
|
Etchant Effect
|
- Increase the contact area
- Increase the surface energy - Lower the contact angle - Leaves a porous surface - Removes the smear layer - Demineralized dentin (7.5 um) - Expose collagen fibers - Lowers the surface energy |
|
|
Primer
|
- Monomers (hema) + solvents (water, acetone, alcohol)
- Bi-functional molecules - Displace water and leave a layer of hema on surface of collagen - Turn the surface compatible for the adhesive - Hydrophobic (bis-gma) and hydrophilic (hema) monomers - Infiltrates the surface microporosities and creates micro-mechanical interlocking after polymerization |
|
|
Tooth colored restoratives
|
1. Dental resin
a. Composite resin b. Sealants c. PMMA (polymethylmethacrylate) 2. Glass ionomer 3. Ceramic |
|
|
Resin matrix
|
- bis-GMA
Additives: - UDMA - TEG-DMA |
|
|
Resin Filler particles
|
1. Glass
a. Barium glass b. Borosilicate glass c. Strontium glasses, etc 2. Silicon dioxide (fumed silica) - Same as thickening agent used in toothpaste *The greater the % of filler, the better the physical properties of resin |
|
|
Resin Coupling agent
|
Glass and resin matrix are chemically incompatible
Coupling agent chemically interacts with glass and resin matrix “coupling” the filler particle to the resin matrix (adhesion between two components) Coupling agent is an organosilane (ceramic primer) |
|
|
Resin Chemical Initiators
|
Activates the polymerization reaction of the composite resin
Types of reactions: - Autocure (self-cure) - Light cure - Dual cure |
|
|
Initiators self-cure resins
|
- Generally use a tertiary amine
- Poor color stability (color changes over time - Applications- dental cements for laboratory fabricated restorations; large core buildups for crowns |
|
|
Initiators-light curing resins
|
1. Photopolymerization
- Visible light - Blue light wavelength (460-480 nm) 2. Photoinitiators - Camphoroquinone - Proprietary (usually 420-460 nm) |
|
|
Tri cure
|
Combination of light cure, self-cure and usually heat curing
|
|
|
Types of composite resin
|
1. Microfill
2. Hybrid 3. Micromatrix or nanofill or microfill hybrid 4. Flowable 5. Packable |
|
|
Microfill clinical indications
|
- Class 5
- Esthetic veneering - Not indicated for Class 3 or posterior because x-ray transparent (radiolucent) - Not indicated for Class 4- brittle will fracture |
|
|
Microfill Resin
|
- Average filler particle size = 0.04 microns
- Filler is prepolymer - Most polishable - Most brittle - Radiolucent (not radiopaque on x-rays) |
|
|
Hybrid Resin
|
- Average filler particle size = 1-4 microns
- Filler is combined radiopaque glass and fumed silica (0.04 microns) - Polishable - Best physical properties |
|
|
Hybrid resin clinical indications
|
- All classes of anterior restorations
- All classes of posterior restorations - Direct esthetic veneers |
|
|
Micromatrix or nanofill or microfill hybrid composite
|
- Average filler particle size = 0.4 microns
- Filler is combined radiopaque glass and fumed silica (0.04 microns) - Very polishable - Best physical properties (comparable to hybrid) |
|
|
Clinical indications Micromatrix or nanofill or microfill composite
|
- All classes of anterior restorations
- All classes of posterior restorations - Direct esthetic veneers |
|
|
Flowable resin
|
- Least filled
- Filler particle size averages 1-4 microns - Specialized applications |
|
|
Clinical indications Flowable resin
|
- Small occlusal preparations (preventive resin restorations- PRR)
- Repairing composite resin margins - Where needle tip placement is desired due to limited access of size of preparation - Can be used for cementing porcelain veneers |
|
|
Packable composite resin
|
- Average filler particle size = 5 microns
- Least polishable - Most opaque (least translucency) - Limited applications (posterior restorations) - A hybrid by definition - Most viscous composite |
|
|
Clinical indications Packable
|
- Class 1 or 2 restorations
- May need modified technique for optimal adaptation (use of flowable composite in a proximal box before placement of packable) |
|
|
Applications of composite resins
|
- Microfill: Class V, direct veneers
- Hybrid: all classes; direct veneers - Micromatrix hybrid: all classes; direct veneers - Flowable: preventive resin restorations (PRR); other uses - Packable: posterior restorations |
|
|
Light energy is measured in...
|
mW/cm^2
|
|
|
How much energy do you need to cure a composite resin?
|
Irradiance x Time = Energy Density
400 mW/cm2 x 20s 1000 mW/cm2 x 10s |
|
|
Basis for light selection
|
- Blue light- polyphase curing light
- Energy density: greater than 600 mW/cm2 - Type of light source: QHL, LED, PAC - Light probe-tip access to all areas of mouth/teeth - Diameter of light tip compatible with size of restorations - Rechargeable or plug-in |
|
|
dental resin composites have an average replacement time of...
|
5.7 years
|
|
|
Keys to the Class 5 preparation
|
- Size of preparation determined by caries or defective restoration
- Select shade of composite before isolation - Bevel enamel cavosurface margins - No bevel on root surface margins |
|
|
Enamel and dentin surfaces are etched for how long?
|
15-30 seconds
|
|
|
Purpose of adhesive
|
- Seal tooth/restorative interface
- Decrease leakage at tooth/restorative interface - Enhance restoration retention by mechanical locking of adhesive to roughened surface |
|
|
Keys to the Class 3 prep
|
- Size of preparation determined by caries or defective restoration
- Select shade of composite before isolation - Preparation should break gingival contact but does not need to break facial or incisal contact - Lingual approach preferred to maintain esthetic facial wall - Bevel non-stressing bearing cavosurface margins - No bevel in stress bearing cavosurfaces |
|
|
Keys to the Class IV prep
|
- Size of preparation determined by caries, defective restoration or traumatic fracture
- Select shade of composite before isolation - Preparation of facial and lingual surfaces with diamond - Facial surface 1-2 mm bevel or chamfer - Lingual surface either no preparation or chamfer to have bulk of composite to avoid fracture (stress bearing surface - Bevel non-stressing bearing cavosurface margins - No bevel in stress bearing cavosurfaces |
