Introduction To Dental Materials

Question 1

Dental Prosthesis:

Answer 1

Dental Prosthesis: An artificial replacement (prosthesis) of one or
more teeth (up to the entire dentition in either arch) and
associated structures (fixed or removable).

Question 2

Rdp is

Answer 2

• Removable Dental Prosthesis: Any dental prosthesis that replaces
some or all teeth in a partially dentate arch (PRDP) or edentulous
arch (CRDP). It can be removed from the mouth and replaced at
will.

Question 3

Fixed Dental Prosthesis

Answer 3

Fixed Dental Prosthesis (Crowns and Bridges): Any prosthesis
that is securely fixed to a natural tooth or teeth, or to one or
more dental implants/implant abutments; it cannot be removed
by the patient.

Question 4

•crown

Answer 4

• Crown: An artificial replacement that restores missing tooth
structure by surrounding part or all of the remaining structure
with a material such as cast metal, porcelain, or a combination of
materials such as metal and porcelain.

Question 5

Inlay:
• Onlay:
• Ceramic Inlay:

Answer 5

Inlay: An intracoronal restoration
• Onlay: If one or more cusps are restored (covered)
• Ceramic Inlay: a ceramic intracoronal restoration

Question 6

What is Science of Dental materials?

Answer 6

What is Science of Dental materials?
“Is the study of the composition and properties of dental materials
and the way in which they interact with the environment in which
they are placed (vivo and vitro)”

Question 7

Gypsum products are used to construct

Answer 7

Gypsum products are used to construct models and dies (casts)
which should be accurate replicas of the patient’s hard and soft
tissues.

Question 8

• Gypsum rproducts used in dentistry are based on
• When mixed with water it reacts to form

Answer 8

• Gypsum products used in dentistry are based on calcium sulphate
  hemihydrate CaSO4·0.5H2O.
• When mixed with water it reacts to form the calcium sulphate
  dihydrate CaSO4·2H2O.
  CaSO 4·0.5 H 2 O + 1.5H 2 O CaSO 4·2H 2 O

Question 9

Types of Dental Gypsum Products

Answer 9

Types of Dental Gypsum Products
- Type 1 Dental plaster, impression
- Type 2 Dental plaster, model
- Type 3 Dental stone, die, model
- Type 4 Dental stone, die, high strength, low expansion
- Type 5 Dental stone, die, high strength, high expansion

Question 10

Waxes

Answer 10

Waxes
- Waxes are thermoplastic materials which are normally solids at
room temperature but can change into the soft or liquid state by
heating.

Question 11

• Investing:
• Casting investment materials:

Answer 11

• Investing: The process of covering or enveloping, wholly or
  partially, wax patterns with a suitable investment material before
  processing, soldering, or casting
• Casting investment materials: Material consisting principally of
  silica and a bonding agent (binder).

Question 12

• According to the nature of the binder, casting investment
  materials can be categorized into three groups:

Answer 12

• According to the nature of the binder, casting investment
  materials can be categorized into there groups:
  . Gypsum-bonded (for use in lower casting temperatures)
  . Silica-bonded
  . Phosphate-bonded (for use in higher casting temperatures)

Question 13

In the case of acrylic denture production the baseplate wax is
invested in a

Answer 13

In the case of acrylic denture production the baseplate wax is
invested in a two-part split mold using dental plaster or stone as
the investment (Flasking). Following removal of the wax the
resulting mold is filled with acrylic resin.

Question 14

• Metal:

Answer 14

• Metal: Any strong and relatively ductile substance that provides
  electropositive ions to a corrosive environment and that can be
  polished to a high luster. Metals are characterized by metallic
  atomic bonding.

Question 15

• Alloy:

Answer 15

• Alloy: A mixture of two or more metals or metalloids* that are
  mutually soluble in the molten state.

Alloying elements** are
added to alter the hardness, strength, and toughness of a metallic
element, thus obtaining properties not found in a pure metal

Question 16

• A metalloid (semimetal) is any

Answer 16

• A metalloid (semimetal) is any chemical element which has properties in between those of metals and
  nonmetals, or that has a mixture of them (boron, silicon, germanium, arsenic, antimony, and tellurium)

Question 17

• Steel alloys are commonly used for the construction of
• Gold alloys and alloys containing chromium or cobalt are used for making
• Dental amalgam, an alloy containing

Answer 17

• Steel alloys are commonly used for the construction of
  instruments and of wires for orthodontics.
• Gold alloys and alloys containing chromium or cobalt are used for
  making crowns, inlays, onlays and denture bases.
• Dental amalgam, an alloy containing mercury, is the most widely
  used dental filling material

Question 18

• Ceramic:

Answer 18

• Ceramic: Refers to any product made from a nonmetallic
  inorganic material usually processed by firing at a high
  temperature to achieve desirable properties.

Question 19

• Porcelain:
• Dental Porcelains:

Answer 19

• Porcelain: Refers to a specific compositional range of ceramic
  materials originally made by mixing kaolin = Clay (hydrated
  aluminosilicate: Al2O3·2SiO2·2H2O), quartz (silica), and
  feldspar (potassium and sodium aluminosilicates/
  K2O·Al2O3·6SiO2 and Na2O·Al2O3·6SiO2), and firing at high
  temperature.
• Dental Porcelains: Contain little or no clay and, therefore, would
  be more described as dental glasses.

Question 20

• Dental ceramics can be classified according to their crystalline
  phase, fabrication method, or applications.

Answer 20

• Dental ceramics can be classified according to their crystalline
  phase, fabrication method, or applications.
  1. Classification by Crystalline Phase (microstructure):
  I- Glass
  II- Crystalline
  III- Crystalline-containing glass
  2. Classification by Application:
  I - ceramics for metal-ceramic crowns and fixed dental
  prostheses
  II - all-ceramic crowns, inlays, onlays, veneers, and fixed
  dental prostheses.
  III- Denture teeth

Question 21

Monomer:
- Polymer:

Answer 21

Monomer: A chemical compound that can undergo
polymerization; any molecule that can be bound to a similar
molecule to form a polymer
- Polymer: A chemical compound consisting of large organic
molecules built by repetition (joining together) of smaller
monomeric units.

Question 22

PMMA acrylic resins have been often applied in

Answer 22

PMMA acrylic resins have been often applied in prosthetic
dentistry such as
fabricating of artificial teeth,
dentures,
impression trays,
record bases,
temporary crowns and
maxillofacial prostheses.

Question 23

Acrylic resins are, commonly, supplied in a powder-liquid form.
- Curing (Polymerization) of acrylic resins can take place at

Answer 23

Acrylic resins are, commonly, supplied in a powder-liquid form.
- Curing (Polymerization) of acrylic resins can take place at room
temperature (Cold-cured),
or activated by applying heat
(Heat-cured),
microwave energy (Microwave-cured)
or light
(Light-cured).

Question 24

Dental impression:
- Impression materials:

Answer 24

Dental impression: A negative imprint of an oral structure used to
produce a positive replica of the structure to be used as a
permanent record or in the production of a dental restoration or
prosthesis.
- Impression materials: Are materials used to make an accurate
replica or mold of the hard and soft oral tissues.

Question 25

Direct Filling materials - Direct filling materials are used for chairside restoration of teeth. They replace - Tooth substance loss can be because of:

Answer 25

Direct Filling materials - Direct filling materials are used for chairside restoration of teeth. They replace missing/lost tooth substance. - Tooth substance loss can be because of: 1. Caries 2. Trauma 3. Wear (Abrasion, Attrition, Erosion)

Question 26

Amalgam

Answer 26

Amalgam: is an alloy of mercury, silver, copper, and tin, which may also contain palladium, zinc, and other elements.

Question 27

- Composite resin:

Answer 27

- Composite resin: a highly cross-linked polymeric material reinforced by a dispersion of amorphous silica, glass, or organic resin filler particles and/or short fibers bonded to the matrix by a coupling agent (Silane).

Question 28

Gic

Answer 28

- Glass ionomer cement: A cement, luting or restorative agent composed of an acid-soluble glass, polyacrylic acid, and water. Setting is by an acid-base reaction.

Question 29

Classification (structure) MetallicFilling materials : 1. Alloy: 2. Pure Metal: Non-Metallic Filling materials : 1. Polymeric: 2. Non-Polymeric:

Answer 29

Classification (structure) MetallicFilling materials : 1. Alloy: - Amalgam 2. Pure Metal: - Direct gold filling Non-Metallic Filling materials : 1. Polymeric: - Filled resin (Composite resin) - Unfilled resin (acrylic) 2. Non-Polymeric: - Glass ionomer cement (GIC) - Silicate cement

Question 30

Cement :

Answer 30

Cement : (1): A binding element or agent used as a substance to make objects adhere to each other, or something serving to firmly unite. 2): A material that, on hardening, will fill a space or bind adjacent objects- syn: luting agent.

Question 31

- Cementation:

Answer 31

- Cementation: (1): The process of attaching parts by means of cement. (2): Attaching a restoration to natural teeth by means of a cement Classification (Application) - Cavity Lining (cavity base) - Luting - Filling materials - Sealing root canals

Question 32

Preventive dental materials

Answer 32

- Cement, coating, or restorative material that either seals pits and fissures or releases a therapeutic agent such as fluoride to prevent or arrest the demineralization of tooth structure. - These include: a) Chemotherapeutic agents like Dentifrices, Mouthwashes and cavity varnishes. b) Pit and fissure sealants. c) Fluoride releasing cements.

Question 33

Restorative materials

Answer 33

Restorative materials (direct or indirect) are used to restore function and/or aesthetics in mouths containing damaged, decayed, or missing teeth - These include: 1. Amalgam. 2. Bonding agents. 3. Resin-based composites. 4. Compomers. 5. Ceramics. 6. Liners. 7. Cement bases. 8. Dental polymers.

Question 34

Direct restorative materials: Indirect restorative materials:

Answer 34

Direct restorative materials: - A cement, metal, or resin-based composite that is placed and formed intraorally to restore teeth and/or to enhance esthetics. Indirect restorative materials: - A ceramic, metal, metal alloys, metal-ceramic, denture base resins, or dental implants used to produce prostheses in a dental laboratory, which replace missing teeth, enhance esthetics, and/or restore damaged teeth.

Question 35

Auxiliary material

Answer 35

- (1) Materials used in the process of fabricating dental prosthesis, (2) Substance that is used in the construction of a dental prosthesis but that does not become a part of the structure. - These include: 1. Impression materials. 2. Dental waxes. 3. Gypsum casts and model materials. 4. Finishing and polishing abrasives. 5. Acrylic resins for impressions. 6. Acid etching solutions.

Question 36

Temporary restorative dental materials

Answer 36

- These are products used for dental restorations and appliances that are not intended for moderate- or long-term applications, i.e. used for a period of a few days to several months to restore or replace missing teeth or tooth structure until a more long- lasting prosthesis or restoration can be placed. - These include: 1. Temporary cements for luting. 2. Cements used as temporary filling materials. 3. Acrylic resins used for inlays, onlays, crowns and fixed dental prosthesis.