Dental Materials Flashcards
The chemical attraction between like molecules?
Cohesion
An index which indicates how one material reacts to temperature extremes in relation to another is called?
Coefficient of thermal expansion
The force at which a material breaks under pressure is called?
Compressive strength
Slow dimensional change caused by compression is called?
Creep
The ability to undergo change of form without breaking is called?
Ductility
A materials ability to recover its initial shape after undergoing a force is called?
Elasticity
An electrical current generated by dissimilar metals in an acidic environment is called?
Galvanism
The process of gelling (solidification by cold) is called?
Gelatin
Absorption of a solvent by a gel is called?
Imbibition
A materials capacity to be shaped by force or pressure is called?
Malleability
The passage of oral fluids/bacteria into and out of tooth structure due to a marginal gap or failure of the marginal seal is called?
Micro leakage (percolation)
The linking, branching, or cross linking of smaller molecules to generate a larger molecule is called?
Polymerization
The force at which a material cannot return to its original shape is called?
Proportional limit
Contraction of a gel due to the loss of a solvent is called?
Syneresis
The force needed to stretch a material to the point of fracture is called?
Tensile strength
Resistance to flow?
Viscosity
An alloy of mercury with silver, copper, tin and zinc is called?
Amalgam
Is silver susceptible to corrosion?
Yes
Why is copper added to amalgam?
To minimize corrosion (gamma II phase eliminated)
What bonding agent establishes micromechanical retention with enamel and dentin by adapting to relief areas created by conditioning with phosphoric acid?
Dental resins (BIS-GMA or urethane dimethacrylate)
Name the barrier used to protect the occlusal surfaces of teeth from bacterial assault by sealing anatomically unprotected tooth structure with resin?
Pit and fissure sealants
Name the 3 most common filler particles for composites:
- Silicates
- Quartz
- Glass
What 2 ingredients are usually added to composites for radiopacity?
- Barium
2. Strontium
What are generally used to seal Dentin or medicate the dental pulp (seal/medicate)?
Liners
What liner stimulates reparative dentin formation/pulp exposure?
Calcium hydroxide
Which liner soothes the pulp, is oily, and is contraindicated with composites?
Zinc-oxide/eugenol
Which liner seals tubules and releases fluoride?
Resin-modified glass ionomer
What are generally used to provide thermal insulation or mechanical protection for the dental pulp (insulate/protect)?
Bases
Name the cement that has an exothermic reaction on mixing (use a cool glass slab) and creates a mechanical interlock between tooth and casting
Zinc phosphate
Which cement has a high chemical affinity for enamel and its powder is mixed with polyacrylic acid?
Polycarboxylate cement
Which cement is :
Resin-modified glass ionomer
Seals dentin effectively to minimize sensitivity
Releases fluoride
Hybrid cements
Which cement is commonly used for temporary cementation?
Zinc-oxide/eugenol cement
Name a reversible hydrocolloid that undergoes a physical reaction only
Agar
Name a irreversible hydrocolloid that undergoes a chemical reaction
Alginate
Which elastomeric material is messy, smelly and must be poured the same day?
Polysulfide rubber
Which elastomeric material is relatively rigid, has good tissue detail, and is unstable in presence of moisture( will distort if left wet)?
Polyether rubber
Which elastomeric material is putty-like and rarely used?
Silicone rubber
Beta-calcium sulfate hemihydrate is which gypsum product?
Plaster
Alpha-calcium sulfate hemi-hydrate is which gypsum product?
Stone
Inorder to modify your working time with gypsum products you:
Add ___________ to accelerate set
Mix with _________water to accelerate set
Add __________ to slow set
Add potassium sulfate to accelerate
Mix with warm water to accelerate
Add borax to slow set
Which type of wax is used for cast restorative patterns?
Inlay and casting wax
Which type of wax is useful in removable prosthetic procedures?
Baseplate wax
Which type of wax is useful to obtain occlusal records?
Bite registration wax
Which type of wax is used in pouring models (vertical wall around impression)?
Boxing wax
Which type of wax becomes sticky when heated, used to attach models?
Sticky wax
Which type of wax is used to modify the shape of impression trays and cushion braces?
Utility wax
List 3 noble metals used in dentistry
- Gold
- Platinum
- Palladium
List 5 base metals used in dentistry:
- Silver
- copper
- Zinc
- Tin
- Nickel
What is the leading cause of failure for implants?
Mobility
The chemical attraction between unlike molecules?
Adhesion
