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DENTAL MATERIALS (Part 1) - Coggle Diagram
DENTAL MATERIALS (Part 1)
Definition
ENGINEERING SCIENCE
Application of
science an maths
to solve world problems
Scientists come up with innovations,
engineers apply the discoveries
MATERIAL SCIENCE
Study of
solid-state properties
Composition and structure
of material
Importance
Improve life quality
through
replacement or
tooth structure
alteration
FACTORS
Safety
— handling, disposal, patient safety, environmental safety
Maintenance
— cleaning, polishing, instrumentation
Application
— material behaviors, manipulation, assistance in delivering materials
Patient knowledge
— options of materials, maintenance
Classification Based on PROPERTIES
Thermal Properties
Thermal conductivity
— thermal energy transfer in watt-second through a specimen (1 cm thick, 1 cm^2 cross sectional area)
Thermal diffusivity
— rate at which heated object undergoes temperature changes
Rheology
Viscosity
— a fluid's resistance to flow
Pseudoplastic
— rate of flow reduces as strain rate increases until a constant value is reached (flows easier when driven quickly through a syringe)
Dilatant
— rate of deformation increases along with resistance to flow (fluid grows viscous and resistive to flow as pumped rapidly through syringe)
Thixotropic
— fluids that become less viscous and more flowable as a result of repeated applied pressure
Color and Optical Effects
Absorption
— amount of light absorbed by substance
Color
— reflection of light wavelengths reaching the eye
Hue
— dominant color
Opacity
— the amount of light that doesn't flow through a material
Chroma
— unit of saturation measurement
Metamerism
— phenomenon where color of item lit by one form of light changes when illuminated by another
Reflection
— amount of light reflected n a surface
Refraction
— light refracts when passing from one medium to another
Transparency
— how much light can pass through a substance
Translucency
— light passes through a material in a diffused manner
Transmittance
— amount of light that passes through an object
Value
— lightness or darkness of a color
Electrochemical Properties
Galvanic corrosion
— electrical contact between electrochemically different metals inside corrosive liquid result in attack on less noble metal
Corrosion
— chemical or electrochemical process that occurs when an contaminant attacks a solid causing partial or full disintegration
Cervice corrosion
— caused localized electrochemical processes and chemistry changes in confined places (tooth restoration microleakage)
Pitting corrosion
— occurs at metal surface defects, oxygen deprived bottom becomes anode; surrounding surface becomes cathode
Elastic Properties
Elastic Modulus
— ratio of elastic stress to elastic strain, used to calculate a materials stiffness
Elastic Strain
— amount of deformation recovers instantly when an externally imposed force is abolished
Strength Properties
Strength
— maximum stress a structure can bear before suffering plastic strain
Compressive strength
— amount of stress applied to a fracture
Shear strength
— percentage of initial cross-sectional area in parallel direction to applied force
Yield strength
— stress under which a test specimen demonstrates a degree of plastic strain
Tensile strength
— tensile stress experienced at time of fracture
Flexural strength
— force per unit area of test specimen subjected to flexural stress at time of fracture
Stress and Strain Properties
Stress
— force per unit are within a structure subjected to a force or pressure
Tensile stress
— ratio of tensile force to the original cross-sectional area perpendicular to the direction of applied force
Strain
— change in dimension per unit initial dimension
Strain rate
— change in strain per unit time during loading of a structure.
Plastic strain
— irreversible deformation that remains when the externally applied force is reduced or eliminated
Elastic strain
— amount of deformation that is recovered instantaneously when an externally applied force or pressure is reduced or eliminated
Classification Based on FUNCTION
Restorative
Repair or replace
defected tooth structure
TYPES
Direct
— used intraorally, fabricate restoration directly on teeth or tissue
Indirect
— used extra orally, formed indirectly over a cast or model
Ex:
amalgam, bonding agent, resin based composites, compomers, ceramics, liners, cement bases, dental polymers
Auxiliary
Used in the process of
fabricating prosthesis
Does not
become part of the tooth structure
Ex:
impression materials, dental waxes, gypsum casts, acrylic resins, acid etching solutions
Preventive
Also serve as
restorative
material
Ex:
fluoride gels, pit and fissure sealants
Prevent
disease and injury
Classification Based On COMPOSITION
METAL
Used for
dental restoration, implants and instruments in preparing teeth
Has
strength, stiffness and long durability
Ductile and malleable
Good
electrical and thermal conductors
Fairly
high density
Good
toughness
Opaque
or transparent
and can be dipole to glitter
CERAMICS
Used for
dental restorations, dentures, and as fillers to fill mixtures of composites and resins
Have
hard
properties, but are inferior to metals
Stiff
and are
poor conductors of electricity and thermal conductivity
Can be used as
dental restorations
with a molded process
Transparent
and
opaque
and
slightly brittle
POLYMER
Used in dental
restorative applications, orthodontics, temporary restorations, root canal filling materials, denture bases,
and others
Easy to form, can be made translucent or opaque,
low density, low hardness
, are
poor conductors
of temperature and electricity
Have the
lowest stiffness,
functional stability and melting or glass transition points
COMPOSITE
Combination
of two or more material classes
Have the desired
handling
properties
and cannot be achieved with one material alone
Formed to
improve
mechanical properties such as stiffness, toughness, ambient, and high temperature strength.