Dental Materials (NBDHE)-from Dental Hygiene Seminars Board
Review 2026/2027 textbook | Actual Questions and Answers
Latest Updated 2026/2027 (Graded A+)
•
Adhesion
- ✔✔the chemical attraction between *unlike* molecules
•
Cohesion
- ✔✔the chemical attraction between *like* molecules
•
Coefficient of thermal expansion
- ✔✔An index which indicates how one material reacts to temperature extremes in relation
to another
•
Compressive strength
- ✔✔the force at which a material breaks under pressure
•
Creep
- ✔✔slow dimensional change caused by compression
•
Ductility
- ✔✔the ability to undergo change of form without breaking
•
Elasticity
- ✔✔a material's ability to recover its initial shape after undergoing a force
•
Galvanism
- ✔✔An electrical current generated by dissimilar metals in an acidic environment
•
Gelation
- ✔✔The process of gelling (solidification by cold)
•
Imbibition
- ✔✔Absorption of a solvent by a gel
,•
Malleability
- ✔✔A material's capacity to be shaped by force or pressure
•
Microleakage (percolation)
- ✔✔passage of oral fluids/bacteria into and out of tooth structure due to a marginal gap or
failure of the marginal (restorative) seal
•
Polymerization
- ✔✔the linking, branching, or cross-linking of smaller molecules to generate a larger
molecule, as seen with composite bonding and impression setting
•
Proportional limit
- ✔✔the force at which a material cannot return to its original shape
•
Syneresis
- ✔✔Contraction of a gel due to the loss of a solvent
•
Tensile strength
- ✔✔The force needed to stretch a material to the point of fracture
•
Viscosity
- ✔✔resistance to flow (the higher it is, the lower the flow)
•
*mouthwash has lower than toothpaste
•
amalgam
- ✔✔an alloy of mercury with silver, copper, tin, and zinc
•
silver
- ✔✔a base metal that is susceptible to corrosion
•
Why is copper added to an amalgam?
- ✔✔to minimize corrosion (gamma II phase eliminated)
•
Desirable features of amalgams:
, i. - ✔✔(a) durable
ii. (b) compressive strength is similar to enamel
iii. (c) relatively inexpensive
•
undesirable features of amalgams:
i. - ✔✔(a) unattractive
ii. (b) high thermal conductivity
iii. (c) dimensionally unstable (creep)
iv. (d) delayed expansion if contaminated (e) requires tooth support
v. (f) fracturable by excessive occlusion
vi. (g) susceptible to galvanism when new
•
Polishing amalgams:
i. - ✔✔-*Can reduce the rate of corrosion (because of less surface area)*
ii. -Move from coarse to fine agents when polishing to remove surface tarnish, stains, flash,
roughness
iii. -Final polish in the mouth is *tin oxide*
iv. -Use a light tough with water and short bursts when power polishing with a rubber cup to
avoid odontoblast-damaging heat
•
Avoid overhang formation by:
i. - ✔✔-Using a properly placed band and wedge(s)
ii. -Detect overhang with explorer
•
Bonding agents
- ✔✔unfilled organic resins which establish micro-mechanical retention with enamel and
dentin by adapting to relief areas created by conditioning with phosphoric acid
•
Steps for a bonding agent?
i. - ✔✔1. 15-20 seconds etch
ii. 2. Rinse
iii. 3. Dry
iv. 4. Apply
v. 5. air-thin
vi. 5. Polymerize (light cure)
•
Phorphoric acid application increases:
- ✔✔enamel and dentin surface area
Review 2026/2027 textbook | Actual Questions and Answers
Latest Updated 2026/2027 (Graded A+)
•
Adhesion
- ✔✔the chemical attraction between *unlike* molecules
•
Cohesion
- ✔✔the chemical attraction between *like* molecules
•
Coefficient of thermal expansion
- ✔✔An index which indicates how one material reacts to temperature extremes in relation
to another
•
Compressive strength
- ✔✔the force at which a material breaks under pressure
•
Creep
- ✔✔slow dimensional change caused by compression
•
Ductility
- ✔✔the ability to undergo change of form without breaking
•
Elasticity
- ✔✔a material's ability to recover its initial shape after undergoing a force
•
Galvanism
- ✔✔An electrical current generated by dissimilar metals in an acidic environment
•
Gelation
- ✔✔The process of gelling (solidification by cold)
•
Imbibition
- ✔✔Absorption of a solvent by a gel
,•
Malleability
- ✔✔A material's capacity to be shaped by force or pressure
•
Microleakage (percolation)
- ✔✔passage of oral fluids/bacteria into and out of tooth structure due to a marginal gap or
failure of the marginal (restorative) seal
•
Polymerization
- ✔✔the linking, branching, or cross-linking of smaller molecules to generate a larger
molecule, as seen with composite bonding and impression setting
•
Proportional limit
- ✔✔the force at which a material cannot return to its original shape
•
Syneresis
- ✔✔Contraction of a gel due to the loss of a solvent
•
Tensile strength
- ✔✔The force needed to stretch a material to the point of fracture
•
Viscosity
- ✔✔resistance to flow (the higher it is, the lower the flow)
•
*mouthwash has lower than toothpaste
•
amalgam
- ✔✔an alloy of mercury with silver, copper, tin, and zinc
•
silver
- ✔✔a base metal that is susceptible to corrosion
•
Why is copper added to an amalgam?
- ✔✔to minimize corrosion (gamma II phase eliminated)
•
Desirable features of amalgams:
, i. - ✔✔(a) durable
ii. (b) compressive strength is similar to enamel
iii. (c) relatively inexpensive
•
undesirable features of amalgams:
i. - ✔✔(a) unattractive
ii. (b) high thermal conductivity
iii. (c) dimensionally unstable (creep)
iv. (d) delayed expansion if contaminated (e) requires tooth support
v. (f) fracturable by excessive occlusion
vi. (g) susceptible to galvanism when new
•
Polishing amalgams:
i. - ✔✔-*Can reduce the rate of corrosion (because of less surface area)*
ii. -Move from coarse to fine agents when polishing to remove surface tarnish, stains, flash,
roughness
iii. -Final polish in the mouth is *tin oxide*
iv. -Use a light tough with water and short bursts when power polishing with a rubber cup to
avoid odontoblast-damaging heat
•
Avoid overhang formation by:
i. - ✔✔-Using a properly placed band and wedge(s)
ii. -Detect overhang with explorer
•
Bonding agents
- ✔✔unfilled organic resins which establish micro-mechanical retention with enamel and
dentin by adapting to relief areas created by conditioning with phosphoric acid
•
Steps for a bonding agent?
i. - ✔✔1. 15-20 seconds etch
ii. 2. Rinse
iii. 3. Dry
iv. 4. Apply
v. 5. air-thin
vi. 5. Polymerize (light cure)
•
Phorphoric acid application increases:
- ✔✔enamel and dentin surface area
