1. Introduction to Dental Materials Flashcards
St. Apollonia
St Apollonia with a tooth grasping forceps in hand
A source of comfort to ____ sufferers
tooth ache
Historical Perspectives
1728 ____ – Father of Dentistry
Published report on dental restorations
1756 ____
Wax impressions and POP casts
1792 ____
Construction of porcelain teeth
1915 Discovery! ____ reduced caries rates in Colorado
1935 - Polymerized ____ resin
1919 - US NBS/NIST - ____
- Specifications for amalgam
1928 - ____
Fauchard Pfaff de Chamant Fluoride Acrylic Wilmer Souder ADA Standards
Relevant Standards Organizations
• ____
- Food and Drug Administration (FDA)
- American Dental Association (ADA)
• ____
- Int. Dental Federation (FDI)
- Int. Standards Organization (ISO)
Control which materials are sold and which materials are released to consumers
Each organization has their own ____ that products must meet
National
International
standard
Federal Regulations
1976 Medical Devices Amendment
- FDA regulation of medical devices
- Class I devices - ____ risk
- – General controls - good manufacturing practices
- Class II devices -
- – FDA Performance standards
- Class III devices
- –Approval for safety and efficacy
- — Premarket Approvals - Dental Implants
Class I > ____
Class II > dental ____
Class II > most ____ > implants; evidence of meeting certification standards, and that they are safe
low
burs
composites
invasive
Scope of Subject
General classification of dental materials
Metals
Gold ____, Base metal ____, dental ____, direct filling gold, stainless steel wrought ____
Classify dental materials into ____ major groups
alloys
alloys
amalgam
alloys
three
Maryland Bridge
A type of ____ material > replacing a missing tooth, cemented to the adjacent teeth
metallic
Polymer Materials
\_\_\_\_ Composite \_\_\_\_ \_\_\_\_ base impression materials \_\_\_\_ impression materials \_\_\_\_
Composite resin (combination of a polymer ____ + inorganic filler)
Acrylic is used for making ____ (PMMA)
polymethylmethacrylate (PMMA) resin rubber hydrocolloid waxes
Bis-GMA
dentures
Metals/Polymers
Maxillofacial Prosthodontists > ____ body parts attached via implants
silicone
Waxes
Wax is made from a mixture of ____ resins
Used as an ____ step for restorations
polymeric
intermediate
Ceramic Materials
- ____ veneers and crowns
- ____ materials
- ____ products
- Dental ____
porcelain
investment
gypsum
cements
Ceramic Veneers
____ veneer for correcting discolored canine
Ceramic
Ceramics and Color
____ Fused-to -____ restorations tinted to give appearance of aging
porcelain
metal
Effects of Oral Environment
Physical Considerations
____
____ changes
____ changes
biting forces/stresses
temperature
pH
Stresses on Restorations
Stresses in ____ of dental restorations
selected regions
Effects of Oral Environment
Biological Considerations
- ____
- ____ effects on dental pulp
- ____
- ____
Microleakage > leakage of fluids and oral bacteria through a filling
Thermal effect > using a ____ restoration > high thermal conductivity > can potentially kill the pulp
Galvanism > saliva and tissue fluids are ____; there can be electrical currents generated in the mouth (esp common between two metals and the saliva)
microleakage
thermal
galvanism
toxicity
metallic
conductive
Biological Consequences
____ along tooth/restoration interface
____ products from amalgam reduce microleakage
Patient may experience pain initially, but eventually the sensitivity wanes because the ____ corrodes and seals the margin; advise to take a tylenol
microleakage
corrosion
amalgam
Other Properties
Electrical - Galvanic cell formation
- Opposing metallic restorations
- Saliva as ____
- Current Flow
Assume one filling is gold and the other is amalgam, different ____, whenever they come into contact they generate a current
Avoid placing two ____ metals in contact with each other; not always homogenous, some patients experience ____
electrolyte
conductivities
different
no effect
Structure of Matter
Primary (chemical) bonds a. \_\_\_\_ b. covalent c. \_\_\_\_ d. combination of ionic and covalent bond
ionic
metallic
Ionic Bonds
- Electron ____
- Electrons are ____ for charge neutrality
- ____ Materials
transfer
fixed
ceramic
Covalent Bonds
- Electron ____
- ____ bond orientation
- ____ and ____
sharing
precise
polymers
ceramics
Metallic Bonds
- Electron ____
- Electron ____ around ____ charged ions
sharing
gas
positively
Structure of Matter
Secondary (Physical) bonds
- ____ forces eg. Hydrogen bonding
- ____
polar
van der waals
Secondary Interatomic Bonds
Hydrogen Bonding
____ dipoles exemplified by ____ molecules
permanent
water
Secondary Interatomic Bonds
van der Waals forces
____ dipoles of ____ gas molecules
____ electron field
Typically they are ____
instantaneous
inert
fluctuating
symmetrical
Crystal Structure
- Regular arrangement of atoms in space for ____ internal energy
- – every atom is situated ____ to every other atom
- – ____
____ Possible lattice forms
Ordered arrangement (space lattices)
minimal
similarly
space lattice
14
Crystal Structures
A. Simple Cubic
B. Body Centered Cubic
C. Face Centered Cubic
____ > atoms at corners and one atom located at the center of the cube
____ > in addition to corners, there are also atoms located on the faces of the cube
body centered
face centered
Crystal Structures
Body centered cubic (BCC) eg. ____
Face centered cubic (FCC) eg. ____
Hexagonal close packed (HCP) eg. ____
Important in the formation of alloys (mixing two metals); same ____ > more likely to mix (into an alloy)
Fe
Au, Ag, Pd
Ti
crystal structure
14 Bravais Lattices
Each point has
____
surroundings in
three dimensions
identical
Non Crystalline Structure
____ materials
Random arrangement of atoms (____ & some ____)
____ are an example of a crystalline structure (ordered)
amorphous
polymers
ceramics
metals
Noncrystalline and Crystalline Network of Atoms (SiO2)
Some materials can exist in a crystalline and non-crystalline >
____
in glass (\_\_\_\_ form of silica), it can exist in a relatively \_\_\_\_ structure. OR it can exist in an \_\_\_\_ structure in materials like quartz (\_\_\_\_ form of silica)
silica amorphous disordered ordered crystalline
Non-crystalline Structure
- Effect of solvent
on chain
____ in a
Polymer molecule
Typical noncrystalline polymers would have
a ____ arrangement of polymer chains. If
you have a polymer chain entangled like
this, if you add a ____ to it you can have
it open up. The idea is that the structure is
random and noncrystalline.
Better solvent and higher temp > less entangled
entanglements
random
solvent
Tg vs Tm
Arrangement of atoms leads to certain properties in materials; for metals (crystalline) > heat it > you see the plot on the right: volume increases ____ as metal expands (upon heating), and as you continue you approach melting temperature and the temp remains ____ as it changes to liquid, and once it is completely liquified the ____ begins increasing again
Amorphous/non-crystalline (wax, polymer; left plot) > as you heat, ____ expands > reach ____ temperature > rapid change in volume ____
Amorphous materials have a
____,
while crystalline materials have a
____.*
slowly
constant
temperature
slowly
glass-transition
immediately
glass-transition temperature (Tg)
fixed melting temperature (Tm)
Surface Energy
Density and nature of unsatisfied bonds at ____ of a material
High surface energy promotes ____
Solid material with ordered arrangement; ____ atoms in a state of high energy > surface energy (interior atoms are satisfied)
Important because of ____ materials; if high surface energy material, it promotes “wetting”
surface
wetting
unsatisfied
adhering
Wetting/Contact Angles
Low contact angle = ____ wetting
High contact angle = ____ wetting
Solid material, drop of liquid > the liquid appears to spread over the surface; place a ____ and measure angle between liquid and solid > wetting/contact angle
good
poor
tangent
Wetting
The degree of spreading of a liquid on a ____ surface
Contact angles - Measure of degree of wetting
< 90o - ____ wetting
> 90o - ____ wetting
0o - ____ wetting
solid
good
poor
complete
Wetting in Dentistry
- ____ materials on teeth
- ____ layer removal
○ Tooth dust collects on surface of tooth that you are restoring; the surface is now covered by debris; if this is present and trying to bond it can prevent proper ____ of surface - ____ and ____ bonding
○ Similar to smear layer mechanism; want a high surface energy in order to optimize bonding and the spread of bonding material to spread (wetting)
impression smear bonding/wetting enamel dentin
