Chemistry and Light Quiz

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Questions and Answers

What type of bonding occurs in hydrocarbons such as methane (CH4)?

Metallic bonding

Covalent bonding (correct)

Ionic bonding

Hydrogen bonding

Which of the following best describes metallic bonding?

Attraction between oppositely charged ions

Attraction between neutral atoms

Sharing of electrons between atoms

Attraction between positively charged cores and free electrons (correct)

Which of the following compounds represents covalent bonding?

NaCl

CH4 (correct)

MgO

What characteristic is typically associated with metallic bonds?

Malleability and ductility Signup and view all the answers

Which of the following statements is true regarding covalent bonds?

They involve the sharing of electron pairs Signup and view all the answers

What does polychromatic light mean?

A mixture of various wavelengths Signup and view all the answers

What range of wavelengths can the human eye detect as visible light?

400-700 nanometers Signup and view all the answers

Which of the following statements is true regarding visible light?

It is a mixture of different wavelengths. Signup and view all the answers

How does visible light differ from other forms of electromagnetic radiation?

It can be detected by the human eye. Signup and view all the answers

What would NOT be considered visible light?

Ultraviolet radiation Signup and view all the answers

What happens to temporary strain when the external force is removed?

It disappears. Signup and view all the answers

Which type of strain remains in a material after the external force is removed?

Permanent strain Signup and view all the answers

Which characteristic defines permanent strain?

It results in a change in shape that lasts indefinitely. Signup and view all the answers

In material science, what is another term for elastic strain?

Temporary strain Signup and view all the answers

What occurs to a material exhibiting plastic strain once the external force is removed?

It retains a deformed shape. Signup and view all the answers

What is the primary function of molecules in a body under shear stress?

To resist sliding past one another Signup and view all the answers

Why is it difficult to induce a single type of stress in a structure?

Multiple stress types often interact in materials Signup and view all the answers

Which of the following accurately describes shear stress?

It results in tearing or sliding between molecules Signup and view all the answers

What happens to molecules in a body under shear stress?

They experience tearing or sliding Signup and view all the answers

In the context of complex stresses, what is often required to analyze the behavior of structures?

Recognition of interactions among various stress types Signup and view all the answers

What physical state do dental polymers exhibit at room temperature?

Either as rubbers or hard materials Signup and view all the answers

What characterizes the molecular structure of rubbers found in dental polymers?

They consist of long chain molecules that are coiled Signup and view all the answers

Which of the following best describes elastomers in dental polymers?

They possess elastic properties due to their molecular structure Signup and view all the answers

What happens to the molecular chains in rubbers when force is applied?

They can stretch and return to their original shape Signup and view all the answers

Which aspect of polymers makes them suitable for dental applications?

Their mechanical strength and resilience Signup and view all the answers

What is meant by flexibility in the context of alloys used in dental clasps?

The amount of bending an alloy will withstand and still return to its original shape Signup and view all the answers

Why is high flexibility important for alloys used in dental clasps?

It prevents the clasps from breaking during normal chewing Signup and view all the answers

Which property is essential for an alloy used in dental clasps that undergoes flexing during mastication?

High flexibility Signup and view all the answers

How does flexibility in dental clasps impact a patient's chewing experience?

It enables the clasps to resist deformation from daily use Signup and view all the answers

What may happen if an alloy used for clasps is too rigid?

The clasp may break during mastication due to lack of flexibility Signup and view all the answers

Study Notes

Bio Materials PRS 101 First Year (2024-2025)

Course title: Bio Materials
Course code: PRS 101
Year: First Year
Academic Year: 2024-2025

Faculty of Oral and Dental Medicine

Vision: The Faculty of Oral and Dental Medicine aspires to be a recognised educational institution, regionally and internationally, by providing advanced educational programs, innovative applied research, and sustainable community development.
Mission: The mission of the Faculty of Oral and Dental Medicine is to prepare knowledgeable and well-trained dentists committed to human values and professional ethics, by developing advanced educational programs that correspond to the actual needs of the local and global labor market. The Faculty is also committed to preparing applied research in line with national strategies, as well as providing sustainable community service following international quality standards.

Basic Biomaterials Fall 2024

Structure of Matter ILOs: Explain the atomic relations and space lattices of different types of dental materials. Recognize the physical properties of dental materials.
Physical Properties ILOs: Discuss the mechanical behaviour of materials used in the dental laboratory or clinic. Outline the basic principles of adhesion to oral soft and hard structures.
Adhesion ILOs: List the properties of metals and alloys; estimate their uses in the dental field. Outline the basic types and causes of tarnish and corrosion of metallic restorations in the oral cavity.
Metallurgy ILOs: Describe polymeric materials and report their specific properties. Recite types and properties of noble and base metal alloys used as metallic denture bases. Introduction to Nanotechnology [Define Nanotechnology, classify the materials at nanoscale and list the fabrication techniques of nanostructures].
Appendix: Chapter topics and page references for chapters 1 to 10.
Intended Learning Outcomes (ILOs): a1- Explain properties of dental materials with reference to the atomic relations and energy levels; a2- Recognize physical/thermal/optical properties of dental materials; a3- Discuss mechanical behavior of dental materials used in the lab/clinic; a4- Give description about polymeric materials and their properties;a5- Outline the basic principles of adhesion to oral tissues and artificial structures; a6- Report the properties of metals and alloys with estimation of their uses in the dental field; a7- Outline the types and causes of tarnish and corrosion for noble/base metals.
Academic Departments:
- Biomaterials (Dental Materials)
- Oral Biology
  - Human Dentition
  - Oral Histology
- Oral Pathology
Clinical Departments:
- Diagnosis, Oral Medicine & Periodontology
- X-ray
- Operative Dentistry
- Endodontics
- Oral Surgery
- Crown & Bridge
- Prosthesis
- Pedodontics
- Orthodontics
Oral Biology Subtopics: Human dentition (Dental Anatomy), Oral Histology.
Oral Pathology Subtopics: Deals with soft and hard oral and dental tissues in diseased conditions.
Operative Dentistry: Deals with the treatment of dental caries (the irreversible bacterial disease of hard tissue).
Endodontics: Deals with pulp and periapical diseases.
Oral Surgery: Deals with tooth extraction, tumors, and fractures.
- Prosthodontics: May be fixed (Crown and Bridge) or Removable (Prosthesis)
  - Crowns, Bridges, and dentures.
Dental implants: Made from Titanium (Ti) or Titanium alloys because they are biocompatible.
Pedodontics: Dentistry that deals with children's teeth.
Orthodontics: Specialty of dentistry concerned with the study and treatment of malocclusions.

Structure of Matter

Introduction: All materials are built up of atoms and molecules which relate to their properties.
Structure of Atoms & Atomic Bonding: The basic unit of the internal structure of any material.

Physical Properties

Mass Related Properties: Density and Specific Gravity. (Density figures for Gold alloy, Chromium cobalt alloy, Acrylic Resin).
Thermal Properties: Heat of fusion, thermal conductivity, coefficient of thermal expansion and contraction, melting/freezing temperatures, specific heat, and thermal diffusivity.
Electrical Properties: Electrical conductivity, resistivity, electromotive force, and electrochemical corrosion.
Less Specific Properties: Water sorption and shelf life.
Optical Properties: Transparency, Translucency, Opacity. Light has wavelengths which can be identified by the human eye (400-700 nanometers).
Reflection, Refraction, Scattering, Luminescence. (Fluorescence, Phosphorescence).

Mechanical Properties

Force: Result of an applied force on a body (displacement, acceleration, and deformation).
Stress (σ): Internal reaction to external force (Force/Area). Types (normal tensile, compressive, and tangential shear). Units (Ib/in², Kg/cm², MN/m²).
Strain (ε): Change in length (Deformation/Length). Types (temporary elastic, permanent plastic).
Stress-Strain Curves: Elastic portion (obeys Hooke's law with proportional limit and elastic limit), plastic portion.
Yield Strength (Y.S.) and Ultimate Strength (U.S.).
Modulus of Elasticity (Young's Modulus): Measures stiffness (slope of elastic straight line).
Fracture Stress: Stress at which a material fractures.
BENDING, Stress-strain properties (e.g. stiffness, ductility, toughness), impact test.
Toughness and fracture toughness.

Surface Phenomena and Adhesion

Outline the basic principles of adhesion to oral soft and hard structures.
Define adhesion;
- Adhesion: Bonding between dissimilar materials resulting from chemical reaction of atoms and molecules.
- Cohesion: Bonding between similar materials.
- Adhesive: Liquid material used for adhesion
- Adherend: Solid substance to which adhesive is applied.
Types of adhesion (True Adhesion, Mechanical Attachment)
Wetting / Wettability: Ability of adhesive to wet the surface of a solid. (Measured by Contact Angle).
Factors affecting Wetting.

Metallurgy

Outline properties of metals and alloys, and their use in the dental field.
Types of Metal Alloys: Solid Solution Alloys, Eutectic Alloys, Intermetallic Compounds.
Formation of Metallic Alloys: Methods of altering mechanical properties (Work Hardening, Aging treatment, solution hardening, and precipitation hardening).
Processes of shaping metals:
- Casting
- Cold Working
- Powder Metallurgy (sintering)
- Electroforming

Tarnish and Corrosion

Outline types and causes of tarnish and corrosion of metallic materials in the oral cavity, including examples.
Types of corrosion (Dry/Chemical corrosion, Electrolytic/Electrochemical corrosion).
Types of Corrosion (Galvanic Corrosion, Compositional Cell Corrosion, Stress Corrosion).

Introduction to Nanotechnology

Define the concept.
Classify materials at the nanoscale according to dimensionality.
Provide a list of fabrication techniques for nanostructures.

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Description

Test your knowledge on chemical bonding types in hydrocarbons, metallic and covalent bonds, and properties of visible light. This quiz covers the fundamental concepts of material science, including strain types and the electromagnetic spectrum. Perfect for students studying chemistry and physics.