difference between stress and strain

Stress - the reaction within the material that can cause distortion Strain - the change produced within the material that occurs as the result of stress

Meaning of Polymerization

the process by which the resin material is changed from pliable state then into a hardened restoration

Meaning of Poly

Pliable state

What are 3 kinds of stress and how are they applied to materials

Tensile - Pull and stretch of the material Compressive - When two forces directed towards one another ( Occurs in mastication ) Shear - when two forces of material are parallel from one another moving in opposite directions (bruxism)

two types of curing

auto-curing - hardens by the result of chemical reaction of a material once mixed together light-cure - material does not harden until it has been exposed to UV light

Meaning of Malleability

The measure of materials ability to be extended in all directions by compressive force

Meaning of Ductility

The ability of a material to have its shaped changed by being stretched or by a pulling or tensile force without losing strength or breaking.

Meaning of Galvanic Action

the coming together of all conditions also another term for shock

Meaning of Solubility

The degree in which a substance will dissolve in a given amount of another substance

Meaning of Flow

when decay is removed and healthy tooth structure is prepared to receive permanent filling material

Meaning of Adhere

When two things come together

Characteristics of dental materials that can affect the adesion process

- wetting - viscosity - surface characteristics - film thickness

Meaning of wetting

ability to flow over surface

Meaning of Viscosity

Property of a liquid that causes it not to flow easily

Meaning of surface characteristics

influence the wetting ability

Meaning of film thickness

thinner means a stronger adhesive junction

Meaning of Retention

Ability of holding two things firmly together when they will not adhere to each other naturally

Indications for using Amalgam

- primary and permanent teeth - stress bearing areas of the mouth - small to moderate sized cavities in the posterior teeth - severe destruction of tooth structure - a foundation for cast metal, metal ceramic and ceramic restorations - when a patient commitment to personal oral hygiene is poor - moisture control is problematic - cost if overriding patients concern

Contradictions of using Amalgam

- when esthetics is particularly important - when patients who have a history of allergy to mercury or other amalgam components

Metals in Amalgam

- silver - zinc - copper - tin

Meaning of Trituration

also referred to as amalgamation, is the process by which mercury and alloy powders are mixed together to form the mass of amalgam needed to restore the tooth.

What is a Pestle

Aids in the mixing process of alloy and mercury

Eames Technique

1:1 mercury to alloy ratio

Some controversial issues regarding Mercury

- toxicity level of mercury vapors affecting dental personnel whom are exposed for a long period - potential harm to patients from mercury within the amalgam that is placed in their teeth

What is the purpose of condensation

to pack the amalgam tightly into all areas of the prepped cavity and to aid in removing any excess mercury from the amalgam mix

what smooths amalgam fillings?

Burnishers

what tools are used to put anatomy back into Amalgam fillings?

T3 and Discoid cleoid carver

what classifications do composite resin's restore

Class I, II, III, IV, and V

what is diestima

Gaps/spacing between teeth

What are some contradictions for using Composite Resins

- not good for people with poor oral hygiene habits - the cost of restorative materials - esthetics

what is another word for Dimethacrylate

BIS-GMA

3 different types of Composites

Macrofilled Composites Microfilled Composites Hybrid Composites

what is coupling agent

Strengthens the resin by chemically bonding the filler to the resin matrix

what are the three components to consider when curing ?

- Thickness and size of restoration - Composite manufacturer's instructions - shade of the restorative material being used

what is a unique feature of glass ionomers

releases fluoride after the final setting which then provides the added advantage of inhabiting decay.

What stage of teeth are glass ionomers used on?

primary teeth