Lecture 2 - Composite Restoration 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 Aglycidyl 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 (Silane)
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.
Stabilizers / 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?
- Linear Coefficient of Thermal Expansion
- Water Sorption
- Wear Resistance
- Surface Texture
- Radiopacity
- 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