Orthodontics Lab Procedures Question And Answers

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Orthodontics Lab Procedures Definitions

  • Soldering
    • It is a process of joining metals by the use of a filler metal that has a lower fusion temperature than that of the metals being joined.
  • Welding
    • Involves the joining of two metals without introducing a third metal.

The Records Through The Reviewing Process

Orthodontics Lab Procedures Important Notes

  • Types of solders
    • Investment soldering
    • Freehand soldering
  • Composition of flux
    • Borax glass – 55%
    • Boric acid – 35%
    • Silica – 10%
  • Gases used for soldering.
    • Gas air/oxygen torch flame
    • Hydrogen
    • Natural gas
    • Acetylene
    • Propane

Orthodontics Lab Procedures Short Essays

Question 1. Soldering and Welding.
Answer.

Soldering: It is a process of joining metals by the use of a filler metal that has a lower fusion temperature than that of the metals being joined.

Types of soldering:

Investment soldering:

Indication: Presence of large contact area between metals

  • In need of precision
    Procedure: By embedding metals in investment

Freehand soldering:

  • Indication: Common orthodontic procedures
  • Procedures: Soldering by holding metals precisely

Steps of freehand soldering:

  • Clean the surfaces
  • Assemble the parts
  • Select proper solder and flux
  • Select proper joint
  • Flux application
  • Application of solder
  • Quenching

Read And Learn More: Orthodontics Short And Long Essay Question And Answers

Indications of freehand soldering:

  • Join parts of appliances
  • Fastens attachments to bands

 

Orthodontics Lab Procedures Soldering In Procedures

Welding: Involves joining of two metals without introducing a third metal

Welding Procedure:

  • Selection of electrode
  • Placement of metals between 2 electrodes
  • Maintain pressure on it
  • Switch on electrode
  • Keep it for sometime

Indications of welding:

  • For banding
  • For brackets and molars tubes

Question 2. Shape Memory Alloy – Nickel titanium alloy is a shape memory alloy.
Answer.

Synonym: Nitinol (Nickel Titanium Naval Ordinance Laboratory)

Inventor: William R. Buchler

Introduced by: Andersen in 1971

Properties of shape memory alloy:

  • Super elasticity
  • Shape memory
  • High working range
  • Low stiffness

Advantages of shape memory alloy: Procedure low and more constant force on teeth

Disadvantages of shape memory alloy:

  • Cannot be bent
  • Cannot be soldered/welded

Orthodontics Lab Procedures Short Questions And Answers

Question 1. Solder and Flux.
Answer.

Solder: Alloys used as filler metal between two metals

Properties of solder:

  • Resist tarnish and corrosion
  • Low fusion temperature
  • Free-flowing
  • Similar strength as the metals to be joined
  • Colour similar to metals to be joined
  • Ex – Gold, silver, copper, zinc, tin and nickel

Flux: means flowing

  • Important for good solder joint

Uses of flux:

  • Removal of oxide coating of solder
  • Dissolves impurities
  • Prevents oxidation
  • Reduces melting point

Flux Composition:

  • Borax glass – 55%
  • Boric acid – 35%
  • Silica – 10%

Question 2. Antiflux.
Answer.

Flux:

  • Means flowing
  • Important for good solder joint

Uses of Flux:

  • Removal of oxide coating of solder
  • Dissolves impurities
  • Prevents oxidation
  • Reduces melting point

 Composition of Flux:

  • Borax glass – 55%
  • Boric acid – 35%
  • Silica – 10%

Antiflux:

  • Confines flow of molten solder
  • Ex. Lead pencil markings
    • Graphite lines
    • Iron rouge

Question 3. Gases used for soldering.
Answer.

  • Gas air/oxygen torch flame
  • Hydrogen
  • Natural gas
  • Acetylene
  • Propane

Question 4. Sensitization and stabilization of stainless steel.
Answer.

Sensitization: At 400-900 c, stainless steel resists corrosion and tarnish

  • At lower temperatures, carbon reacts with the surface granules and forms chromium iron carbide causing tarnish and corrosion
  • This can be prevented by decreasing carbon content or by cold working of stainless steel

Stabilization:

  • The process to prevent sensitization
  • For it, two/more metals are added, for example, titanium, niobium

Question 5. Irreversible Hydrocolloids (Alginate).
Answer.

Advantages of Irreversible Hydrocolloids:

  • Easy to manipulate
  • Comfortable
  • Inexpensive
  • Pleasant taste
  • Hydrophilic
  • Biocompatible

Disadvantages of Irreversible Hydrocolloids:

  • Tears easily, and require immediate pouring
  • Incompatible with epoxy resin

Composition of Irreversible Hydrocollids:

  • Potassium Alginate
  • Calcium sulfate dehydrate
  • Potassium sulfate
  • Diatomaceous earth
  • Sodium phosphate
  • Glycol
  • Pigments
  • Sodium silicofluoride

Orthodontics Lab Procedures Viva Voce

  • Gold foil filling is the best example of cold welding
  • Welding is a process of joining two metals directly under pressure
  • The space provided between the metals to be joined is 0.5 mm
  • Borax glass is the main component of dental flux
  • The oxidized layer in the metallic surfaces to be joined is removed by antireflux
  • Nickel in dental solder gives a white color to the solder
  • The copper component in solder gives the yellow color
  • Fusion temperature exceeding 150 degrees is used for brazing

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