Dental Material Flashcards

Terms Definitions
yield strength
plastic strain
Abnormal clinical reaction or exaggerated immune response to a foreign substance that is manifested by one or more of the following signs and symptoms (among others): breathing difficulty, erythema, itching, sneezing, swelling, and vesicles. The most relevant dental situations are Type I hypersensitivity (immediate reaction) and Type IV hypersensitivity (delayed reaction) according to the Gell and Coombs classification of immune responses.
Class I, II, III devices
productivity increases _______ with the use of one assistant
the act of absorbing moisture
T of F:
Eugenol Containing dressings aren't used much anymore because of its negative affects
Particulate matter
Extremely small particles, gypsum, alginate, microblasting materials, acrylic resins from finishing and polishing.
a cloudlike mist containing microbes such as bacteria, viruses, mold, fungi, and yeast.
The process through which sufficient energy is provided to induce an initiator to generate free radicals and cause polymerization to begin. The three sources of energy commonly used with dental resins include heat, chemicals, and light.
Process of removing the investment from a casting or hot-pressed ceramic.
Metallic bond.
Primary bond between metal atoms
A crystalline substance with metallic properties that is composed of two or more chemical elements, at least one of which is a metal.
Pitting corrosion
Highly localized corrosion occurring on base metals, such as iron, nickel, and chromium, which are protected by a naturally forming, thin film of an oxide. In the presence of chlorides in the environment, the film locally breaks down and rapid dissolution of the underlying metal occurs in the form of pits.
displays a linear relationship between force and velocity
total energy absorbed prior to rupture
________________ has the same chemical formula as plaster, but is much denser and has a more regular shape
liquid state in which colloidal particles are suspended. by cooling or chemical reaction it can change into a gel
the process when the hemihydrate is produced as a result of heating gypsum and driving off the water of crystalization
An element or alloy whose atomic structure readily loses electrons to form positively charged ions, and which exhibits metallic bonding (through a spatial extension of valence electrons), opacity, good light reflectance from a polished surface, and high electrical and thermal conductivity.
Light-cured composite
A particle-filled resin consisting of a single paste that becomes polymerized through the use of a photosensitive initiator system (CQ and an amine initiator) and a light source activator (visible blue light).
In materials and science, a solid formed from two or more distinct phases (e.g., particles in a metal matrix) that have been combined to produce properties superior to or intermediate to those of the individual constituents; also a term used in dentistry to describe a dental composite.
Precipitation hardening
Process of strengthening and hardening a metal by precipitating a phase or constituent from a saturated solid solution.
Proptional limit
Basically the ability to deform something and for it to come back to shape. (Mechanical Properties)
Maximum stress that a structure can withstand without sustaining a specific amount of plastic strain (yield strength) or stress at the point of fracture (ultimate strength).
Which has a higher proportional limit, dentin or enamel
Thixotropic behavior
when viscosity changes over time, under stress(similar to pseudoplastic, but with element of time)
failure of a material undergoing load and unload cycles
when components are completely soluble in liquid state, but have limited solubility in solid state
eutectic alloy
when mixing non eugenol dressings you should use _________ per sextant
and DO NOT let then to come in contact with each other until you are ready to begin mixing
An assistants _________ hand is used to retract soft tissue, retrieve instruments, operate the air/water syringe, and wipe the working end.
What branch of dentistry comprises the prevention, diagnosis and treatment of diseases of the surrounding and supporting structures of the teeth.
things placed over gingival /surgical wounds to protect, to control post operative bleeding, and to prevent further pain and injury
periodontal dressings
an impression of the occulusal relationship of opposing teeth in centric occlusion
bite registration
Hardness is the measure of the resistance of a metal to indentation or scratching. It is an indication of the strength and wearability of an alloy or metal.
low speed
The ___-speed handpiece (6000rpm) is used for buffing, refining cavity preps and prophylaxis.
Process of brazing or soldering two or more metal components of a prosthesis after the metal substructure has been veneered with a ceramic.
Force per unit area acting on the external surface of a material.
Process of joining two components of a fixed partial denture by means of casting molten metal into an interlocking region between the invested components. This procedure is sometimes preferred for base metal alloys because of the technique sensitivity associated with brazing or soldering these alloys.
Hygroscopic expansion
The amount of setting expansion that occurs when a gypsum-bonded casting investment is immersed in water (usually heated to approximately 38° C [100° F]).
Side notes:We do this with casting to increase the number of grains to increase metal strength.
van der Waals forces
Short-range force of physical attraction that promotes adhesion between molecules of liquids or molecular crystals.
Galvanic shock
Pain sensation caused by the electric current generated when two dissimilar metals are brought into contact in the oral environment.
Phenomenon in which the color of an object under one type of light appears to change when illuminated by a different light source.
:Process by which a metal surface is dulled or discolored when a reaction with a sulfide, oxide, chloride, or other chemical causes a thin film to form.
Green state
A term referring to an as-pressed condition before sintering.
Glass-infiltrated ceramic
A minimally sintered core ceramic with a porous structure that has been densified by the capillary inflow of a molten glass.
Process of fusing two or more metal parts through the application of heat, pressure, or both, with or without a filler metal, to produce a localized union across an interface between the parts.
Process of brazing or soldering two or more metal components of a prosthesis before a ceramic veneer is fired or hot-pressed on the structure.
Lost-wax technique
Process in which a wax pattern, prepared in the shape of missing tooth structure, is embedded in a casting investment and burned out to produce a mold cavity into which molten metal is cast.
Lining Efficiency
Thickness over (sq. root of) Thermal Diffusivity
Amount of stress for first measurable permanent deformation
Elastic Limit
This type of material has a glass transition temperature
stress corresponding to maximum value of load, before rupture occurs
ultimate (tensile) strength
used to maintain stability of the matrix band during condensation of the material
matrix retainers
Part of the instrument that is used for stabilization, grip, and leverage
what is the name of the instrument used to extract teeth?
the most widely used impression material
but it is the least accurate
ALGINATE (irreversible hydrocolloid)
primarily an infection, the result of gram negative anaerobic microorganisms in the gingival pocket stimulating an inflammatory response in the patient (host).
periodontal disease
Father of Dental Hygiene who instructed Irene Newman
Dr. Alfred Fones
the prevention and controlling dental disease and promoting oral health through organized community efforts
dental public health
Who is the patron saint of dentistry?
St. Appolonia
Thermal Conductivity
Thermal conductivity is defined as the ability of a material to transmit heat or cold. A low thermal conductivity is desired in restorative materials used on the tooth whereas a high thermal conductivity is desirable where the material covers soft tissue.
____ are mounting devices with a screw and threaded end of snap on attachment with prongs to hold on to the disc or wheel. It is used for polishing/finishing cavity preps/restoration.
The rheostat was first used in ____ with a 10000 rpm rotary instrument.
Elastic memory
Tendency of a solid wax form to partially return to its original shape when it is stored at a temperature higher than that to which it was cooled.
Shear strength
Maximum shear stress at the point of fracture of a test specimen.
Chemically activated resin
A resin system consisting of two pastes (one containing a benzoyl peroxide [BP] initiator and the other an aromatic tertiary amine activator) which, when mixed together, release free radicals that initiate polymerization.
Heat of vaporization
Thermal energy required to convert a solid to a vapor.
Stain ceramic
A mixture of one or more pigmented metal oxides and a low-fusing glass that can modify the shade of the ceramic-based restoration when it is dispersed in an aqueous slurry or monomer medium, applied to the surface of porcelain or other dental ceramic, and heated to its vitrification temperature for a specific time.
some physical considerations of the oral environment
biting forces/stressestemp changespH changes
amount of energy recovered during an elastic deformation
modulus of resilience
a hard and brittle impression material used in complete denture procedures
zinc oxide eugenol
T or F:
Periodontal dressing has curative powers
False - does NOT
- people used to bond teeth with gold wire for the afterlife.
- rubber based impression materials have almost emilinated the use of this paste
- it came as two pastes
- inexpensive 
zinc oxide - eugenol
History of Amalgam
Dr. G. V. Black investigated the properties of amalgams and their possible use for dentistry about 1895. His studies showed the effects of chemical composition and physical structure on the properties of amalgam restorations. Due largely to the work done by Dr. Black and the National Bureau of Standards, and other researchers, amalgam is now used more than any other filling material for the restoration of posterior teeth.
Flexibility and Elasticity
These terms differ in their technical definition but they are very closely related. Flexibility is the characteristic of a metal, which allows it to deform temporarily. The elasticity of a metal is used when it returns to its original shape when the load or force is removed.
indications: permanent teeth, deep pit/fissures, good oral hygiene; contra: detection of clinical caries on tooth (exc. max molars), radiographic detection of interproximal caries, presence of existing restoration (exc. max molars)
List three indications and contraindications for p/f sealants.
A ___ is a thicker than a liner, relatively strong and usually a mm or more in thickness. Traditionally used to build up internal form of prep to ideal depth.
Supercooled liquid.
A liquid that has been cooled at a sufficiently rapid rate to a point below the temperature at which an equilibrium phase change can occur.
Linear coefficient of expansion
Relative linear change in length per unit of initial length during heating of a solid per °K within a specified temperature range.
Bite wax
A wax form used to record the occlusal surfaces of teeth as an aid to establish maxillomandibular relationships.
Face Centered Cubic:Body Centered Cubic:Hexagonal Close Packed:
change in length over change in temperture
coefficient of thermal expansion
amounts of each metal in an alloy are usually presented as...
weight percent
when mixing a gypsum product, when do you put the water in the rubber bowl?
before the powder
Grain size
The size of the grains in a solidified metal depends upon the number of nuclei of crystallization present and the rate of crystal growth. In the practical sense, the faster a molten is cooled to solidification, the greater will be the number of nuclei and the smaller will be the grain size. Generally speaking, small grains arranged in an orderly fashion give the most desirable properties.
distal, central incisor, canine
Rubber dam extends from clamped tooth (which is usually ____ to the tooth being worked on) to the _____ or ____ on opposite side.
nasal obstructions, allergies, asthma, phobias, anatomical interference
Name some contraindications for using a rubber dam. (5)
Direct wax technique
Method by which a wax pattern is made directly on the prepared tooth in the mouth.
Fatigue occurs below or above the UTS?
Below (fracture would occur above...)
what are the three components of visoelastic deformation?
elastic deformation, retarded elastic deformation, and viscons deformation
Whcih of the following is NOT a component of dental inpression compounds?
- resins
- wax
- coloring agents
- all of the above are components
- none of the above are components
all of the above
thin, medium, heavy, extra heavy
___ rubber dams are used for endodontics, ___ for pedodontics, ___ are tear-resistant, and ____ are class V.
type I PRR
type ___ PRR is for a suspicious p/f, requires minimal cavity prep, caries removal limited to enamel and has not invaded dentin, no local anesthesia required.
Body porcelain (also dentin or gingival porcelain)
A veneering ceramic for ceramic or metal-ceramic prostheses.
a contact angle of less than 90 degrees is...
goooood wetting(poor wetting, greater than 90, think of a large droplet on surface)
Non-eugenol perio dressings should not extend beyond the ________________
height of contour - the greatest distance from the axial plane of a tooth when you divide it in half
Composition and Effects of Amalgam: Composition of the alloy
The ADA specification states that the composition of the alloy must include a minimum of 65 percent silver, a maximum of 29 percent tin, a maximum of 6 to 13 percent copper, and a maximum of two percent zinc by weight.
1. Isolate 2. cleanse/debride w/pumice 3. etch 4. Rinse 5. Dry 6. Apply sealant 7. finish, examine
Describe the procedure for placing P/F sealants. (7 steps)
What are the five types of gypsum products?
Impression Plaster, Lab or Model Plaster, Lab Stone, Die Stone, High Strength/High Expansion Die Stone
palladium used for PFC and bridges, platinum used in alloying and foil.
___ is a metallurgical whitener used for poercelain fused to metal crowns and bridges. ___ is used for alloying and foil.
compared to an alloy, a metal has more or less melting temperatures
metals only have one melting temperature(the fusion temperature)
zinc oxide, 80% zinc oxide, 20% resin
____ ____ ____ is used for temporary cementation, temporary and intermediate restorations and bases. Powder contains ___% zinc oxide and ___% acrylic resin. liquid is eugenol.
base metals = amalgams, noble metals = cast alloys
___ metals are used in amalgams, cast removable partial dentures, and implants. ___ metals are used in cast alloys.
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