Biomaterials Exam Questions and answers with complete solutions Latest
Updated 2025 | Verified
Dental Ceramics - ✔✔The general term ceramics is used to describe porcelain and a variety of materials
that are similar in appearance, but vary in their composition, mode of fabrication, and physical and
mechanical properties.
Dental Ceramics used for? - ✔✔Used for crowns, fixed bridges, inlays, onlays, and veneers
-inlays: fillings on occlusal
-onlays: fillings on cusps
Type of material for dental ceramics to be used depends on.. - ✔✔1) (in part) on the extent of damage
to the tooth
2)the stresses that will be placed on the restoration
3)the esthetic requirements of the patient.
Dental ceramics can be classified based on... - ✔✔their composition
processing method
fusing temperature
microstructure
translucency
fracture resistance
abrasiveness
2 broad categories of ceramics (according to their composition) - ✔✔1)glass based
2)non-glass based
Glass-based ceramics - ✔✔Have silica as a main component and have a *glassy matrix (not dull/matte)*
-Include feldspathic porcelains, leucite-reinforced ceramics, and lithium disilicate ceramics
,-*More esthetic than the non-glass-based ceramics*
Non-glass-based ceramics - ✔✔Are crystalline in nature
-*No glassy matrix (dull/matte looking)*
-Include *alumina and zirconia*
*Strongest of the ceramics* (not as esthetic)
-composed of oxides of alumina and/or zirconia with minor amounts of other components to improve
their properties
Advantages of ceramics - ✔✔- Esthetics
- Biocompatibility
- Wear resistance under function
- Stain resistance
- Ability to precisely place contacts and contours of the restorations
-Esthetic restorations can be made from composite resin, ceramics with a metal substructure (core), or
entirely ceramics.
-Primary advantage of all-ceramic restorations is their esthetics, no metal substructure to hide.
-Other advantages over direct-placement restorations include biocompatibility, wear resistance under
function, color stability, stain resistance, and the ability to precisely place contacts and contours of the
restorations
Disadvantages of ceramics - ✔✔difficult to fabricate, low strength in tension, torsion, bending, or impact
-Disadvantages compared with direct-placement restorations include their brittleness (can lead to
fracture),wear of the opposing enamel or restorations, difficulty or inability to repair them in the mouth,
the need for two appointments (except CAD/CAM restoration), and the difficulty of polishing them in
the mouth
Porcelain - ✔✔describes a glass-like tooth-colored dental materials.
-Some use the term interchangeably with ceramics, but *porcelain is actually a subgroup of ceramic
materials*
-Porcelain becomes more fracture resistant once it is bonded to a substrate
, Feldspathic Porcelain - ✔✔Until advances in ceramic materials were made, *was* the most common
ceramic material used
Alumina Porcelain - ✔✔developed in 1965
-enhanced the fracture resistance (doubled) when compared to feldspathic porcelain
-glassy type of porcelain
Uses of Porcelain - ✔✔Manufactured in a variety of colors, called shades.
Presently, the feldspathic porcelains have a variety of uses.
-They are used to cover (or veneer) a metal core to fabricate PFM crowns and to veneer high-strength
ceramic cores such as zirconia
-Zirconia is opaque and lacks the vitality of natural tooth structure, so it is not very esthetic, but it is very
strong
-Porcelain becomes more fracture resistant once it is bonded to a substrate
Reinforced Ceramics - ✔✔Because porcelains were prone to fracture, stronger ceramic materials were
developed.
-2 types:
1) leucite-reinforced ceramics (Empress)
2) lithium disilicate ceramics (Emax).
Lithium disilicate ceramic: - ✔✔Has high strength, good marginal integrity, and biocompatibility
-Used in both anterior and posterior teeth
-Very esthetic material because of its high translucency (more natural looking)
-Popular for veneers and crowns
-Comes in a variety of shades
Alumina - ✔✔Was developed as an alternative to the PFM crown
-First all-ceramic material that could be used for both anterior & posterior crowns
Updated 2025 | Verified
Dental Ceramics - ✔✔The general term ceramics is used to describe porcelain and a variety of materials
that are similar in appearance, but vary in their composition, mode of fabrication, and physical and
mechanical properties.
Dental Ceramics used for? - ✔✔Used for crowns, fixed bridges, inlays, onlays, and veneers
-inlays: fillings on occlusal
-onlays: fillings on cusps
Type of material for dental ceramics to be used depends on.. - ✔✔1) (in part) on the extent of damage
to the tooth
2)the stresses that will be placed on the restoration
3)the esthetic requirements of the patient.
Dental ceramics can be classified based on... - ✔✔their composition
processing method
fusing temperature
microstructure
translucency
fracture resistance
abrasiveness
2 broad categories of ceramics (according to their composition) - ✔✔1)glass based
2)non-glass based
Glass-based ceramics - ✔✔Have silica as a main component and have a *glassy matrix (not dull/matte)*
-Include feldspathic porcelains, leucite-reinforced ceramics, and lithium disilicate ceramics
,-*More esthetic than the non-glass-based ceramics*
Non-glass-based ceramics - ✔✔Are crystalline in nature
-*No glassy matrix (dull/matte looking)*
-Include *alumina and zirconia*
*Strongest of the ceramics* (not as esthetic)
-composed of oxides of alumina and/or zirconia with minor amounts of other components to improve
their properties
Advantages of ceramics - ✔✔- Esthetics
- Biocompatibility
- Wear resistance under function
- Stain resistance
- Ability to precisely place contacts and contours of the restorations
-Esthetic restorations can be made from composite resin, ceramics with a metal substructure (core), or
entirely ceramics.
-Primary advantage of all-ceramic restorations is their esthetics, no metal substructure to hide.
-Other advantages over direct-placement restorations include biocompatibility, wear resistance under
function, color stability, stain resistance, and the ability to precisely place contacts and contours of the
restorations
Disadvantages of ceramics - ✔✔difficult to fabricate, low strength in tension, torsion, bending, or impact
-Disadvantages compared with direct-placement restorations include their brittleness (can lead to
fracture),wear of the opposing enamel or restorations, difficulty or inability to repair them in the mouth,
the need for two appointments (except CAD/CAM restoration), and the difficulty of polishing them in
the mouth
Porcelain - ✔✔describes a glass-like tooth-colored dental materials.
-Some use the term interchangeably with ceramics, but *porcelain is actually a subgroup of ceramic
materials*
-Porcelain becomes more fracture resistant once it is bonded to a substrate
, Feldspathic Porcelain - ✔✔Until advances in ceramic materials were made, *was* the most common
ceramic material used
Alumina Porcelain - ✔✔developed in 1965
-enhanced the fracture resistance (doubled) when compared to feldspathic porcelain
-glassy type of porcelain
Uses of Porcelain - ✔✔Manufactured in a variety of colors, called shades.
Presently, the feldspathic porcelains have a variety of uses.
-They are used to cover (or veneer) a metal core to fabricate PFM crowns and to veneer high-strength
ceramic cores such as zirconia
-Zirconia is opaque and lacks the vitality of natural tooth structure, so it is not very esthetic, but it is very
strong
-Porcelain becomes more fracture resistant once it is bonded to a substrate
Reinforced Ceramics - ✔✔Because porcelains were prone to fracture, stronger ceramic materials were
developed.
-2 types:
1) leucite-reinforced ceramics (Empress)
2) lithium disilicate ceramics (Emax).
Lithium disilicate ceramic: - ✔✔Has high strength, good marginal integrity, and biocompatibility
-Used in both anterior and posterior teeth
-Very esthetic material because of its high translucency (more natural looking)
-Popular for veneers and crowns
-Comes in a variety of shades
Alumina - ✔✔Was developed as an alternative to the PFM crown
-First all-ceramic material that could be used for both anterior & posterior crowns
