Dental Biomaterial: Structure of Matter and Atomic Structure
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Questions and Answers

What is the basic unit of internal structure for materials?

  • Electron
  • Atom (correct)
  • Neutron
  • Proton

    • Which particles are found in the nucleus of an atom?

  • Neutrons and electrons
  • Protons and neutrons (correct)
  • Protons and electrons
  • Protons and neutrons only

    • What is the role of valence electrons in determining physical and chemical properties?

  • They are responsible for energetic interaction with other atoms (correct)
  • They determine the atomic weight
  • They affect the density and specific heat
  • They have very little effect on the mechanical properties

    • What does the atomic weight of an atom depend on?

    <p>The weight of protons and neutrons</p> Signup and view all the answers

    Which particles in the atom have a positive charge?

    <p>Protons only</p> Signup and view all the answers

    What determines the different lattice systems in crystalline structures?

    <p>Interatomic bonds</p> Signup and view all the answers

    How do the physical and chemical properties of an atom depend on the electrons furthermost from the nucleus?

    <p>They affect energetic interaction with other atoms</p> Signup and view all the answers

    What are the properties affected by atomic weight?

    <p>Density and specific heat</p> Signup and view all the answers

    What is the role of neutrons in the nucleus of an atom?

    <p>They are unchanged particles</p> Signup and view all the answers

    What determines the atomic number of an element?

    <p>The number of protons.</p> Signup and view all the answers

    What is the primary reason for the formation of ionic bonds?

    <p>Obtaining extra electrons to complete the outer shell and becoming negatively charged</p> Signup and view all the answers

    Which type of bond leads to a high electrical and thermal conductivity?

    <p>Metallic bond</p> Signup and view all the answers

    What is the primary characteristic of covalent bonds?

    <p>Strong and highly directional</p> Signup and view all the answers

    Which type of bond is responsible for the attraction between positive and negative ions?

    <p>Ionic bond</p> Signup and view all the answers

    What is the reason for the formation of secondary bonds (Van der Waals forces)?

    <p>Polarization of molecules leading to weak attraction</p> Signup and view all the answers

    Which characteristic is associated with metallic bonds?

    <p>High electrical and thermal conductivity</p> Signup and view all the answers

    What is the primary characteristic of amorphous solids?

    <p>Without shape and having random arrangement of atoms</p> Signup and view all the answers

    In which type of solid are the atoms regularly arranged in a space lattice?

    <p>Crystalline solids</p> Signup and view all the answers

    What is the primary classification criterion for unit cells in space lattices?

    <p>The length of their axes and interfacial angles</p> Signup and view all the answers

    What is the main reason for the formation of a covalent bond?

    <p>Sharing electrons so that the outer shell of two or more atoms is complete</p> Signup and view all the answers

    What is the primary role of valence electrons in the formation of primary bonds?

    <p>Completing the outer electron shell</p> Signup and view all the answers

    Which type of bond arises when atoms share their electrons to achieve an inert gas structure?

    <p>Covalent bond</p> Signup and view all the answers

    What is the primary characteristic of amorphous solids?

    <p>Random arrangement of atoms</p> Signup and view all the answers

    What is the main factor responsible for the high electrical and thermal conductivity in metallic bonds?

    <p>Free movement of electrons through the metal</p> Signup and view all the answers

    Which type of bond arises from the attraction between positive and negative ions?

    <p>Ionic bond</p> Signup and view all the answers

    What determines the atomic number of an element?

    <p>The number of protons in the nucleus</p> Signup and view all the answers

    What is the primary classification criterion for unit cells in space lattices?

    <p>The length of their axes (a, b, c)</p> Signup and view all the answers

    What is the primary reason for the formation of secondary bonds (Van der Waals forces)?

    <p>Polarization of molecules leading to weak forces</p> Signup and view all the answers

    What is the role of neutrons in the nucleus of an atom?

    <p>Balancing the charge inside the nucleus</p> Signup and view all the answers

    What is the primary classification criterion for unit cells in space lattices?

    <p>Arrangement of atoms</p> Signup and view all the answers

    What determines the different lattice systems in crystalline structures?

    <p>Arrangement of atoms</p> Signup and view all the answers

    Which type of bond is responsible for the attraction between positive and negative ions?

    <p>Ionic bonds</p> Signup and view all the answers

    In which type of solid are the atoms regularly arranged in a space lattice?

    <p>Crystalline solid</p> Signup and view all the answers

    What is the basic unit of internal structure for materials?

    <p>Atom</p> Signup and view all the answers

    What is the primary characteristic of metallic bonds?

    <p>Delocalized electrons</p> Signup and view all the answers

    What determines the atomic number of an element?

    <p>Number of protons</p> Signup and view all the answers

    What is the primary characteristic of covalent bonds?

    <p>Sharing of electrons</p> Signup and view all the answers

    How do the physical and chemical properties of an atom depend on the electrons furthermost from the nucleus?

    <p>They affect both physical and chemical properties</p> Signup and view all the answers

    What is the role of valence electrons in determining physical and chemical properties?

    <p>They determine both physical and chemical properties</p> Signup and view all the answers

    Which dental material has the highest thermal conductivity?

    <p>Gold alloys</p> Signup and view all the answers

    What is the specific heat of dentin compared to that of water?

    <p>Lower</p> Signup and view all the answers

    What does the rate at which a body approaches thermal equilibrium describe?

    <p>Thermal diffusivity</p> Signup and view all the answers

    What is the primary factor causing marginal percolation in composite restorations?

    <p>Thermal expansion</p> Signup and view all the answers

    What is the role of viscoelastic materials in dental practice?

    <p>To resist flow under external force</p> Signup and view all the answers

    What is the significance of heat of fusion in the context of dental materials?

    <p>Accompanying state transitions</p> Signup and view all the answers

    What is the primary effect of thermal cycling on restorations with different expansion coefficients from tooth structure?

    <p>Bond degradation between restoration and tooth</p> Signup and view all the answers

    What determines the rate at which the interior surface under a dental crown is heated?

    <p>Thermal diffusivity</p> Signup and view all the answers

    What are the units for density?

    <p>gm/cm3 and pound/inch3</p> Signup and view all the answers

    What is the specific gravity of a material with a density of 2.5 gm/cm3?

    <p>2.5</p> Signup and view all the answers

    Which dental material has the highest density?

    <p>Gold alloys</p> Signup and view all the answers

    Why must upper dentures be made up of low-density materials?

    <p>To enhance the retention of the denture</p> Signup and view all the answers

    What is thermal conductivity?

    <p>The quantity of heat per second passing through a body</p> Signup and view all the answers

    Why are thermal properties of dental materials important?

    <p>To protect the pulp from extreme temperature differences</p> Signup and view all the answers

    What happens when a patient drinks a hot beverage without dental protection?

    <p>The pulp reacts severely to the temperature difference</p> Signup and view all the answers

    Which type of material would require higher pressure to fill mold cavities during casting procedures?

    <p>Materials with low density</p> Signup and view all the answers

    What defines specific gravity, in terms of density?

    <p>Specific gravity is numerically equal to density, with units</p> Signup and view all the answers

    'A low specific gravity material requires ___________ pressure to fill mold cavities.' Fill in the blank.

    <p><code>Higher</code></p> Signup and view all the answers

    What is the unit for density of dental materials?

    <p>gm/cm3 and pound/inch3</p> Signup and view all the answers

    Which material would require higher pressure to fill mold cavities during casting procedures?

    <p>Gold alloys</p> Signup and view all the answers

    What is the specific gravity of a material with a density of 2.5 gm/cm3?

    <p>2.5</p> Signup and view all the answers

    What is the primary factor to consider for protecting the pulp of the tooth from temperature differences?

    <p>Thermal conductivity</p> Signup and view all the answers

    Which dental material has the highest density?

    <p>Gold alloys</p> Signup and view all the answers

    What is the unit for thermal conductivity of a material?

    <p>watts per meter per degree Kelvin</p> Signup and view all the answers

    'A low specific gravity material requires ___________ pressure to fill mold cavities.' Fill in the blank.

    <p>higher</p> Signup and view all the answers

    'Density of equal volume of HO2' is used to calculate what property?

    <p>Specific gravity</p> Signup and view all the answers

    What property is affected by atomic weight?

    <p>Density</p> Signup and view all the answers

    Why must upper dentures be made up of low-density materials?

    <p>To aid retention</p> Signup and view all the answers

    What is the thermal conductivity of zinc oxide Eugenol cement?

    <p>0.0011 cal/sec/cm2/(0C/cm)</p> Signup and view all the answers

    What is the primary advantage of high thermal conductivity in metallic denture base materials?

    <p>It causes tissue stimulation through vasodilatation</p> Signup and view all the answers

    What does the rate at which a body with non-uniform temperature approaches thermal equilibrium describe?

    <p>Thermal diffusivity</p> Signup and view all the answers

    What does the heat of fusion of a material indicate?

    <p>The absorption or liberation of heat during state transitions</p> Signup and view all the answers

    What is the primary characteristic of viscoelastic materials?

    <p>They exhibit time-dependent strain due to a combination of viscous and elastic behavior</p> Signup and view all the answers

    What does the exterior thermal expansion (α) help to avoid in porcelain fused to metal (PFM) restorations?

    <p>Marginal percolation</p> Signup and view all the answers

    What is the specific heat of gold compared to that of water?

    <p>$0.03 cal/gm-10C$</p> Signup and view all the answers

    What is the importance of the specific heat of a metal or alloy during the melting process?

    <p>It indicates the amount of heat required to raise the temperature to the melting point.</p> Signup and view all the answers

    What is most accurate about the rate at which heat flows through a material?

    <p>It determines the thermal conductivity.</p> Signup and view all the answers

    What characteristic does dentin possess in terms of its thermal conductivity?

    <p>Poor conductor of heat.</p> Signup and view all the answers

    Study Notes

    Atomic Structure

    • The basic unit of internal structure for materials is the atom.
    • The nucleus of an atom consists of protons and neutrons.
    • Valence electrons determine physical and chemical properties of an atom.
    • Atomic weight depends on the number of protons and neutrons in the nucleus.
    • Protons have a positive charge in the nucleus.

    Bonding

    • Ionic bonds form between positive and negative ions.
    • Ionic bonds lead to a high electrical and thermal conductivity.
    • Covalent bonds form when atoms share electrons to achieve an inert gas structure.
    • Covalent bonds are primary bonds.
    • Metallic bonds arise from the attraction between positive and negative ions.
    • Metallic bonds lead to high electrical and thermal conductivity.
    • Secondary bonds (Van der Waals forces) form due to the attraction between positive and negative ions.
    • Valence electrons play a primary role in the formation of primary bonds.

    Crystalline Structures

    • The arrangement of atoms in a space lattice determines the lattice system in crystalline structures.
    • Unit cells in space lattices are classified based on the arrangement of atoms.
    • Crystalline structures have atoms regularly arranged in a space lattice.

    Physical Properties

    • Atomic weight affects physical properties such as density and thermal conductivity.
    • Thermal conductivity is the ability of a material to conduct heat.
    • Specific heat is the amount of heat energy required to raise the temperature of a material by 1°C.
    • Density is the mass per unit volume of a material, measured in gm/cm³.
    • Specific gravity is the ratio of the density of a material to that of water.

    Dental Materials

    • The primary factor to consider for protecting the pulp of the tooth from temperature differences is thermal conductivity.
    • Upper dentures must be made up of low-density materials to reduce weight.
    • The thermal conductivity of zinc oxide Eugenol cement is low.
    • High thermal conductivity in metallic denture base materials is an advantage.
    • Viscoelastic materials are used in dental practice due to their ability to deform and recover.
    • The specific heat of dentin is lower than that of water.
    • The heat of fusion of a material indicates the energy required to change its state from solid to liquid.
    • The exterior thermal expansion (α) helps to avoid mismatch between porcelain and metal in PFM restorations.

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    Description

    Test your knowledge about the structure of matter, atomic structure, interatomic bonds, amorphous and crystalline structures, and crystalline lattices as related to dental biomaterial in the Faculty of Oral and Dental Medicine at Sinai University.

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