Biomaterials
man-made materials that are used to replace tissues or that function in intimate contact with living tissues.
Dental Materials
Biomaterials used in the oral cavity
Biocompatibility
The lack of harmful effects to the patient
Class 1 ada
Least regulated
Class 2 ada
II devices gain approval from the FDA after being shown to be equivalent to products currently in use.
Class 3 ada
Most regulated
When does a product get ADA seal?
If it does what it's says it's going to do
Who can approve implants?
FDA
3 classifications of dental materials
Use
Location of fabrication
Longevity of use
Esthetic Materials
Tooth colored
Abutement
a mass that supports each end of a bridge, the actual tooth
Pontic
False tooth that replaces a missing tooth
prosthesis
artificial body part
Cast
When a restoration is constructed on the replica
Diagnostic cast
When replica is used to study the size and position of oral tissue
Luting
Gluing
Luting agents
dental cements
Base
Used as strength and insulation. Bulkier
liner
Painted on to protect dentin from chemicals
Direct restoration
Create the restoration in the mouth
Indirect restorations
Take a picture or impression and send off to lab
What is the only dental materials that can be direct and indirect
Veneers
Cements are classified as what
Base or liner
temporary restoration
Short term
Interim restoration
A long term temporary restoration, ex for an addict
G.V. Black's Classification
Review
Preventative materials
Sealants
Mouth guards
Fluoride trays
Polishing
Use of a rubber cup with an abrasive agent
Dental implants
screws or posts that are anchored into alveolar bone and protrude through the gingiva
Indirect restorations include
Crowns, inlays, polymers
Direct Restoration examples
Amalgam
Composite resin
Glass ionomers
Intermediate restorative materials/IRM
Tooth whitening products
Materials science
the study of the characteristics and uses of materials in science and technology
Gases type of bond
Weak bonds
Liquids order
Short range order
Solids: Crystalline
Long range order, spatial consistency
Solids: Amorphous
Short range, random
bond length
the distance between the nuclei of two bonded atoms
secondary bonds
Permanent dipoles
Hydrogen bonds ( strongest of secondary)
Fluctuation- bugs around a light
Metals characteristics
Metallic bonds
Electron cloud
Ductile
Amorphous
Ceramics characteristics
Ionic bonds
Strong and brittle
Crystalline
Porcelain
Polymers
Long chains, covalently bonded
Composites
2 or more materials
Commonly polymer and ceramic
Colloids
2 phase materials
Example is emulsion
Algenite
secondary bonds
Partial charges from an uneven distribution of electrons around an atom or molecule
4 types of properties
Physical
Mechanical
Chemical
Biological
Density
mass/volume
Depends on atoms present, packing of atoms and voids in material
Boiling and melting points
Temperature range and specific tempuratures
vapor pressure
Measure of liquids tendency to evaporate and become a gas
Thermal conductivity
the rate at which a substance conducts thermal energy
heat capacity
The amount of heat something can hoard
Heat of fusion
Amount of energy required to melt a material
Heat of vaporaization
Amount of energy required to boil a material
coefficient of thermal expansion
Measure of change in volume in relation to change in temperature
Ex) inner tube
Percolation
Opening and closing of the gap between tooth structure and a restoration due to differences in coefficients of thermal expansion
Results of percolation
Microleakage
Tooth sensitivity
Recurrent decay
electrical conductivity
Good- metal
Poor-polymers and ceramics
Viscosity
Ability of liquid to flow
high viscosity
High contact angle, poor wetting
Ex);lotion
low viscosity
Low contact angle, good wetting
Ex) alcohol
Knoop Hardness scale
Higher the number= harder the material
Knoop hardness of dental structures
Enamel 350
Dentin 70
Porcelain 400-500
Acrylic 20
Durometer measurements
used to determine hardness of impression materials and other elastic polymers
abrasion resistance
Goldilocks principle
Solubility
Amount of material that dissolves in liquid
water sorption
Amount of water a material can absorb
Ex) milk and cookie
Color
Phsycological response to physical stimulus(light)
Radiolucent materials
Ceramic, acrylic
Radiopaque materials
Most things.
Metals
Elasticity
A material's ability to recover its initial shape after undergoing a force
Strain
Change in length that occurs when stress(force) is placed on a material
Stress
Force that develops in a loaded object
3 types of stress
compression, tension, shearing
Relationship of stress and strain
Always occur together
High MOE
Enamel
Low MOE
Rubber band
Failure
Ultimate strength
yield point
point at which elasticity is almost exceeded
Bending is what 2 forces
Compression and tension
Poisson's Ratio
Elephant and a marshmellow
Resilience
Material has the ability to absorb energy without becoming deteriorated
Ex) mouth guard
Toughness
How much energy a material can absorb before failure
Ex) bike helmet
Low fracture toughness
Glass
Dental porcelain
high fracture toughness
metals
fracture toughness
The measure of a material's resistance to fracture when a crack is present.
Fatigue
Material failure due to being stressed repetitively for a long time
creep
Amalgams
Small change in shape when an object is under continuous compression
stress relaxation
Slow decrease in force over time
Ex) hair types and braces
stress concentration
stress increases around defects