Composite Flashcards
Tooth-colored materials, such as composite, are
used in almost all types and sizes of restorations.
Composite
What are the causes of esthetic restoration failures?
*Trauma
*Improper tooth preparation
*Inferior materials
*Misuse of dental materials
What are the two types of Esthetic restorative materials?
Inlays and Onlays
An indirect restoration, fabricated in dental laboratories. These are fabricated using sophisticated computer-aided design/computer-assisted machining (CAD/CAM).
Inlays and Onlays
*It is the first translucent filling material
*Introduced in 1871
*Alumina-silica glass & phosphoric acid
*Very soluble
*Poor mechanical properties
Silicate Cement
True or False: Failed silicate cement restorations display loss of contour of tooth.
True
It is an early acrylic material characterized having poor activator systems, high polymerization shrinkage, high coefficient of thermal expansion, and lack of abrasion resistance.
Acrylic Resin
It is introduced commercially in 1962 by Boen of the National Bureau of Standards. It is the most popular tooth-colored material.
Composite
What are the composition of Composite?
*Organic Resin
*Inorganic Resin
*Coupling Agent (Silane)
*Initiator system
*Stabilizers / Inhibitors
Composition of Composite:
* It forms the matrix.
* Typically consists of a resin-based oligomer matrix, such as a bisphenol-A glycidyl methacrylate (Bis-GMA) or urethane dimethacrylate (UDMA).
Organic Resin
Composition of Composite:
* Inhibits deformation of the matrix.
* Reduces the coefficient of thermal expansion of the resin matrix.
* Gives the composite wear resistance and translucency.
e.g. fused silica, crystalline quartz, lithium aluminum silicate, borosilicate glass
Inorganic Resin
Composition of Composite:
* Unite the resin with the filler
* Stress absorber of the filler and resin
Coupling agent
Composition of Composite:
* Activate the setting mechanism
* Begins the polymerization reaction of the
resins when external energy (light/heat,
etc.) is applied.
Initiator system
Composition of Composite:
* Resins require stabilizers to avoid spontaneous polymerization.
* Stabilizers are also used to control the reaction of activators and resin mixtures.
* Hydroquinone is most commonly used as
a stabilizer.
Stabilizer / Inhibitors
What are the 4 classification of composites based on filler particle size?
Macrofill, Microfill, Hybrid, Nanofill
What are the 2 classification of composite based on viscosity?
Packable and Flowable
What are the 6 properties of composite?
1.Linear Coefficient of Thermal Expansion
2.Water Sorption
3.Wear Resistance
4.Surface Texture
5.Radiopacity
6.Modulus Elasticity
Classification of Composite based on filler particle size:
* Contains 75-80% inorganic filler by weight.
* Average particle size 8µm.
* Large size particle and extremely hard filler.
* Rough surface structure strontium and barium glass (radiopaque).
* Due to large particle size, macrofills are not very polishable.
* Prone to staining.
Macrofill
Classification of Composite based on filler particle size:
* Introduced in the late 1970
* Polishable
* Smooth lustrous surface similar to tooth enamel
* Particle size is 0.01 – 0.04µm
* Contains 35-60% inorganic filler by weight
* Wear resistant
* Low modulus of elasticity (allow restoration to flex)
* High resin content results in an increased coefficient of thermal expansion and lower strength.
MIcrofill
Classification of Composite based on filler particle size:
* Combines the properties of conventional and microfilled
* Contains 75-85% inorganic filler by weight
* Particle size is 0.4 – 1µm
* Physical properties is superior to conventional
* Predominant direct esthetic resin
* Have universal clinical applicability
Hybrid
Classification of Composite based on filler particle size:
* Materials that are created by introducing
* nanoparticulates (often referred to as filler) into a macroscopic sample material (often referred to as the matrix).
* Nanofill composites contain filler particles that are extremely small (0.005–0.01 µm).
Nanofill
Classification of Composite based on viscosity:
* More viscous, “thicker, stiffer feel”
* Have filler particle feature that prevents sliding of the filler particle by one another
* Easier restoration of proximal contact
* Similar to the handling of amalgam
Packable
Classification of Composite based on viscosity:
* Flows into cavity due to lower viscosity
* Have lower filler content
* Inferior physical properties (lower wear resistance, lower strength)
* Used in small class I, pit and fissure sealant, marginal repair, liner
* Easy to use
* Good wettability
* Favorable handling properties
Flowable
Property of Composite:
It is the Change in length of a solid material when heated or cooled.
Linear Coefficient of Thermal expansion
