DES 2100 DENTAL MATERIALS EXAM QUESTIONS WITH
SOLUTIONS 2025 GRADED A+
✔✔they are a unique group of materials in that both a maximum and a minimum
strength are required - ✔✔temporary cement
(must be strong enough to hold but not so strong that they cannot be removed)
✔✔an important sign that working time has ended? - ✔✔loss of gloss
✔✔what is used as an etchant - ✔✔orthophosphoric acid 37%
✔✔how are dental materials classified? - ✔✔by
- use
- location of fabrication
✔✔you want to take an impression of the prepared tooth, a bite registration, and an
impression of the opposite arch all at the same time. what type of tray are you using? -
✔✔triple tray
✔✔this stress occurs when parts of an object slide past each other (like incisors) -
✔✔shear
✔✔the tendency of a material to dissolve in a fluid - ✔✔solubility
✔✔when measuring proper water to powder ratio for gypsum, which product has the
highest water to powder ratio? 45-50ml/100gm - ✔✔plaster
✔✔which impression material is known for being inexpensive and easy to use but it is
not stable over a long term? - ✔✔alginate
✔✔a pulling stress - ✔✔tension
✔✔the seepage of harmful products, such as bacteria, into the interface between a
restoration and the tooth - ✔✔microleakage
✔✔what is gypsum powder? - ✔✔calcium sulfate hemihydrate
✔✔name the two hydrocolloids. what is the main difference between the two? - ✔✔-
alginate - irreversible less accurate
- agar - reversible, needs special equipment; very accurate
✔✔bending is a combination of which two stresses? - ✔✔tenstion and compression
, ✔✔a temperature dependent property. measured in grams/meter-second. the measure
of a products ability to flow - ✔✔viscosity
✔✔how do you fill an impression tray with gypsum?
what special tool is needed and why? - ✔✔let it flow ahead of itself using a dental
vibrator to prevent trapping air
✔✔give an example of each:
inelastic
aqueous elastomeric
non-aqueous elastomeric - ✔✔- wax/impression compound - ZOE, plaster
- alginate - agar
- polysulfides - condensation silicones- polyethers - addition silicones
✔✔discoloration from the oxidation of a thin surface layer of a metal - ✔✔tarnish
✔✔movement of fluid in and out at the interface of a restoration and tooth due to
expansion and contraction - ✔✔percolation
✔✔die - ✔✔an exact replica of a single tooth
✔✔which impression material has the longest working time and the longest set time? -
✔✔polysulfide
✔✔a hydrocolloid will absorb water, swell, and distort - ✔✔imbibition
✔✔a gradual change in shape due to compressive forces - ✔✔creep
✔✔what is given off during the setting of gypsum? - ✔✔heat
✔✔agar can be used for final impressions - ✔✔true
✔✔hydrocolloid materials contract slightly after setting and exude water - ✔✔syneresis
✔✔occurs within an amalgam due to interaction with components - ✔✔corrosion
✔✔gypsum product used for diagnosis treatment planning - ✔✔study model
✔✔protects against thermal irritation - ✔✔base
✔✔protects against chemical irritation - ✔✔liner
SOLUTIONS 2025 GRADED A+
✔✔they are a unique group of materials in that both a maximum and a minimum
strength are required - ✔✔temporary cement
(must be strong enough to hold but not so strong that they cannot be removed)
✔✔an important sign that working time has ended? - ✔✔loss of gloss
✔✔what is used as an etchant - ✔✔orthophosphoric acid 37%
✔✔how are dental materials classified? - ✔✔by
- use
- location of fabrication
✔✔you want to take an impression of the prepared tooth, a bite registration, and an
impression of the opposite arch all at the same time. what type of tray are you using? -
✔✔triple tray
✔✔this stress occurs when parts of an object slide past each other (like incisors) -
✔✔shear
✔✔the tendency of a material to dissolve in a fluid - ✔✔solubility
✔✔when measuring proper water to powder ratio for gypsum, which product has the
highest water to powder ratio? 45-50ml/100gm - ✔✔plaster
✔✔which impression material is known for being inexpensive and easy to use but it is
not stable over a long term? - ✔✔alginate
✔✔a pulling stress - ✔✔tension
✔✔the seepage of harmful products, such as bacteria, into the interface between a
restoration and the tooth - ✔✔microleakage
✔✔what is gypsum powder? - ✔✔calcium sulfate hemihydrate
✔✔name the two hydrocolloids. what is the main difference between the two? - ✔✔-
alginate - irreversible less accurate
- agar - reversible, needs special equipment; very accurate
✔✔bending is a combination of which two stresses? - ✔✔tenstion and compression
, ✔✔a temperature dependent property. measured in grams/meter-second. the measure
of a products ability to flow - ✔✔viscosity
✔✔how do you fill an impression tray with gypsum?
what special tool is needed and why? - ✔✔let it flow ahead of itself using a dental
vibrator to prevent trapping air
✔✔give an example of each:
inelastic
aqueous elastomeric
non-aqueous elastomeric - ✔✔- wax/impression compound - ZOE, plaster
- alginate - agar
- polysulfides - condensation silicones- polyethers - addition silicones
✔✔discoloration from the oxidation of a thin surface layer of a metal - ✔✔tarnish
✔✔movement of fluid in and out at the interface of a restoration and tooth due to
expansion and contraction - ✔✔percolation
✔✔die - ✔✔an exact replica of a single tooth
✔✔which impression material has the longest working time and the longest set time? -
✔✔polysulfide
✔✔a hydrocolloid will absorb water, swell, and distort - ✔✔imbibition
✔✔a gradual change in shape due to compressive forces - ✔✔creep
✔✔what is given off during the setting of gypsum? - ✔✔heat
✔✔agar can be used for final impressions - ✔✔true
✔✔hydrocolloid materials contract slightly after setting and exude water - ✔✔syneresis
✔✔occurs within an amalgam due to interaction with components - ✔✔corrosion
✔✔gypsum product used for diagnosis treatment planning - ✔✔study model
✔✔protects against thermal irritation - ✔✔base
✔✔protects against chemical irritation - ✔✔liner
