Term Test 1 Flashcards
When were synthetic resins introduced?
1932
When were cements introduced?
1855
Know the classification of dental materials.
- Preventive
- Therapeutic
- Restorative
When was fluoride first mentioned?
1874
What year was fluorosis first noted?
1901
Compressive force:
force applied to compress or squeeze object; crushing biting forces; posterior teeth are ideally suited for this type of force.
Tensile force:
force applied to an object in opposite directions to pull object apart; biting forces used to stretch a material; imagine chewing a caramel.
Shearing force:
force applied when two surfaces slide against each other in opposite directions. This occurs when max and mand incisors are used for cutting, and when anterior teeth are used to bite into food, mand teeth slide forward or to the side, and max teeth in the opposite direction to shear it off.
Torsion or Torque:
twisting force that is a combination of tensile and compressive forces. This force is more descriptive of normal mastication.
Solubility:
Susceptible to being dissolved.
Water sorption:
The ability to absorb moisture.
Corrosion:
Deterioration of a metal caused by a chemical attack or electrochemical reaction with dissimilar metals in the presence of a solution containing electrolytes (such as saliva).
Tarnish:
Discoloration that results from oxidation of a thin layer of metal at its surface. It is not as destructive as corrosion.
Dimensional change:
a change in the size of matter (expansion of dental materials due to heat or contraction due to cold temperature).
Coefficient of thermal expansion (CTE):
the measurement of change of volume or length in relationship to change in temperature.
Percolation:
movement of fluid within the microscopic gap of the restoration margin as a result of differences in the expansion and contraction rates of the tooth and the restoration with temperature changes associated with ingestion of cold or hot liquids or foods.
Thermal conductivity:
The rate in which heat flows through a material.
Insulator:
materials that have a low thermal conductivity.
Retention:
A materials ability to maintain its position without displacement under stress.
Adhesion:
The act of sticking two things together. Described as bonding or cementing in dentistry.
Bonding:
to connect or fasten; to bind.
Wetting:
The ability of a liquid to wet or intimately contact a solid surface (water beading on a waxed surfaces of a car is an example of poor wetting).
Viscosity:
The ability of a liquid material to flow.
Film thickness:
The minimum thickness obtainable by a layer of a material. This is particularly important to dental cements.
Surface energy:
The electrical charge that attracts atoms to a surface.
What is micro leakage and what causes it?
Leakage of fluid and bacteria caused by microscopic gaps that occur at the interface of the tooth and the restoration margins.
What is galvanism?
An electrical current transmitted between two dissimilar metals.
Review primary versus secondary bonds.
- Primary bonds: hold atoms together by the exchanging or sharing of electrons.
- Secondary bonds: no transfer or sharing of electrons; weaker.
Which bonds are the strongest?
Primary bonds are the strongest.
What are the three primary bonds known as?
The three types of primary bonds are known as ionic, covalent, and metallic bonds.
Define Preventive materials:
chemicals, devices, or procedures that reduce or eliminate disease or tooth destruction in the oral cavity.
Define Therapeutic Materials:
materials used to treat disease.
Define Restorative Materials:
Materials used to reconstruct tooth structure.
Define direct restorations:
fabricated directly in the mouth
Define indirect restorations:
fabricated outside of the mouth (commonly in a lab) and then placed in the patient’s mouth.
Permanent restorations:
expected to be long lasting replacement or missing, discoloured or damaged teeth.
Temporary restorations:
used for short periods of time (several days to weeks).
Intermediate restorations:
placed for a limited time, however, the time may extend from several weeks to months. Often used when there is other ongoing treatment such as orthodontics or implant therapy that is needed before a permanent restoration is required.
Mixing time:
the amount of time allotted to bring the components of a material together in a homogenous mix.
Working time:
the time permitted to manipulate the material within the mouth.
Initial set time:
The time at which the material can no longer be manipulated within the mouth.
Final set time:
The time at which a material has reached its ultimate state.
Chemical set materials:
materials that set through a timed chemical reaction with the combination of a catalyst and a base.
Light-activated materials:
materials that require a blue light source to initiate a reaction.
Dual set materials:
materials that polymerize by a chemical reaction that occurs when the material is mixed with a catalyst or that is initiated by exposure to blue light (or a combination of chemical and light reaction).
Define bio-aerosol.
A cloud-like mist that contains droplets, tooth dust, materials dust, and bacteria of a particle size smaller than 5um in diameter.
Acute chemical toxicity:
results from high levels of exposure over a short time. Effects are felt right away.
Chronic chemical toxicity:
repeated exposures to lower doses over a much longer time such as months or years. Effects include cancer.
Know the ways in which chemical can enter the body.
???Through the skin, eyes, ears, mouth, nose.???
Review proper PPE and safe handling of dental materials.
…
Self-cure:
two paste system; catalyst and base.
Light-cure:
operator controls working time; needs to be cured with blue light.
Dual-cure:
two paste system; contain both chemically and light activated materials; ensures material is set in areas of the tooth that cannot be reached by the light.
Which curing system is most common for resins?
Light cure is the most common.
