Expansion In Orthodontics Question And Answers

Expansion

• Types of expansion appliances

• Rapid maxillary expansion [RME]
  • Should be initiated prior to ossification of the mid-palatal suture
  • Time of ossification of mid-palatal suture
    • 16 years – in girls
    • 18 years – in boys
• Contraindication of RME
  • Single tooth crossbites
  • In adults with severe anteroposterior skeletal discrepancies
  • Vertical growers
  • Periodontally weak condition
• Schedule of activation of expansion screw
  • For patients upto 15 years – 90° rotation in morning and evening
  • For patients over 15 years – 45° rotation 4 times a day
• Quad helix
  • Uses:
    • Expand a narrow arch
    • Rotation of molars
    • Brings
      • Orthopaedic movement in children
      • Orthodontic movement in adults

Expansion Long Essays

Question 1. Explain slow and rapid expansion, their indications, contraindications, and appliances used.
Answer.

Effects Of Rapid Maxillary Expansion:

• Open mid-palatal suture:
  • By compresses PDL
  • Bends buccal alveolar process and slowly opens the suture
• Triangular opening:
  • Maximum opening at incisor region
  • Reduces over posterior part of palate

• • Maximum opening towards oral cavity
  • Less opening towards nasal aspect
• Midline diastema
• Buccal tipping of maxillary posteriors

• Downward and backward mandibular rotation
• Increase in mandibular plane angle
• Displacement adjacent cranial bones
• Increase in intra-nasal space
• Reduction in airway resistance

Expansion Short Essays

Question 1. Expansion screws.
Answer.

• A typical expansion screw consists of an oblong body with two halves, each half consisting of threaded inner side that receives one end of a double-ended screw
• The screw has a central basing with four holes, which receive a key used to turn the screw
• The turning of screw to 90 degrees brings about linear movement of 0.18mm

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

• Various types of expansion used in removable and fixed appliances are
  • Jackscrew
  • Coffin springs
  • Qual helix
  • Isacson
  • Hyrax
  • Derischweiler
• Activation schedules

According to Timms:

• In patient upto 15 years of age – 90 degrees rotation in the morning and evening
• In patient over 15 years old – 45 degrees activation 4 times a day

According to Zimring and Isacson:

• In growing individuals
  • Two turns each day for 4-5 days and later one turn per day till the desired expansion is achieved
• In non-growing adults
  • Two turns each day for first 2 days and later one turn per day for next 5-7 days and one turn every alternate day till the desired expansion is achieved

Question 2. Quad Helix Appliance.
Answer.

Example of slow maxillary expansion appliance

Introduced by Walter coffin

• Wired used: 0.038 inch
  • Parts
• Bands: Over first molar
• Helices: 2 anteriors helices
  • 2 posterior helices
• Bridge: Anterior bridge – Connencts anterior helices
• Palatal bridge: Connects anterior and posterior helices
• Outer arms: Free ends adjacent to posterior helices
  • Soldered on lingual aspect of molar bands
• Uses: Expansion of narrow arch
  • Rotation of molars
• Skeletal expansion: During mixed dentition periods
• Activation: Pre-stretching of molar bands before cemenstation.

Question 3. Rapid v/s slow expansion.
Answer.

Expansion Short Questions And Answers

Question 1. Hyrax Appliance.
Answer.

Tooth bone fixed appliances used for rapid maxillary expansion

Hyrax – Hygienic rapid expander

Designs Of Hyrax Appliance:

• Wire used – Heavy guage wire
• Extensions of screw wire are adapted over palatal contour and soldered to molar bonds

Question 2. Coffin Spring.
Answer.

• Removable slow expansion appliance by Walter Coffin
• Wire used: 1.25 mm thick
• Design: Omega shaped wire – Over mid-palatal region
• Free ends of wire: Embedded in acrylic
• Activation: Pulling two sides apart
• Use: Dento-alveolar expansion in adults
• Skeletal expansion in younger patients

Question 3. Expansion Appliance.
Answer.

• Appliance for RME
  • Removable – Split acrylic plate
  • Fixed
• Tooth and tissue borne
  • Derichsweiler type
  • Hass type
• Tooth borne
  • Issacson type
  • Hyrax type
• Appliances for Slow Expansion
  • Jack screw
  • Coffin spring
  • Quad helix
  • Fixed appliance

Question 4. Slow Expansion Appliance.
Answer.

• Jack screw:
  • It is incorporated in the appliances
  • Have more spread out activation schedule
  • Have smaller pitch
• Coffin spring:
  • Removable slow expansion appliance by Walter Coffin
  • Wire used – 1.25 mm thick
  • Design – Omega shaped wire – Ove mid-palatal region
  • Free ends of wire – Embedded in acrylic
  • Activation – Pulling two sides apart
  • Use – Dento-alveolar expansion in adults
  • Skeletal expansion in younger patients
• Quad helix:
  • Introduced by Walter coffin
  • Wire used – 0.038 inch
    • Parts
• Bands – Anterior bridge – Connects anterior helices
• Palatal bridge – Connects anterior and posterior helices
• Outer arms – Free ends adjacent to posterior helices
  • Soldered on lingual aspect of molar bands
• Uses: Expansion of narrow arch
  • Rotation of molars

Question 5. Types of Expansion Screws.
Answer.

• 3D screws
• Split midline screw
• Jack screw

Expansion Viva Voce

• Coffin spring and quad helix are used for palatal expansion
• Rapid palatal expansion should be carried out prior to ossification of midpalatal suture
• In rapid expansion two turns daily of 0.5mm is done
• In slow expansion the rate is 0.5 mm per week
• In rapid expansion, the ratio of skeletal to dental expansions is 4:1
• In slow expansion, the ratio of skeletal to dental expansions is 1:1
• In rapid expansion, force generated – 2-4 pounds
• In slow expansion, force generated – 10-20 pounds
• Treatment completed in rapid expansion – 1-2 weeks
• Treatment completed in slow expansion – 2-5 months