Orthodontic Tooth Movement Question And Answers

Types Of Tooth Movement Important Notes

• Couple
  • It is a pair of parallel forces having equal magnitude acting in opposite direction
  • Brings about pure rotation
• Center of resistance

• Center of rotation in different movement

• Types of tipping

• Types of forces

Types Of Tooth Movement Long Essays

Question 1. Define optimum force. Classify and discuss Orthodontic forces.
Answer.

Optimum Orthodontic Force

• It is a force that rapidly moves teeth in the desired position with minimum damage to adjacent tissues and with less discomfort to the patients
• Value – According to Oppenheim and Schwarz, it is equal to capillary pressure i.e. 20-26gm/cm2

Orthopaedic Force.

• It is defined as an act upon a body that changes/tends to change the state of rest or uniform motion of that body
• It has definite magnitude, specific direction, and point of application.

Value – In grams

Generated by – Orthodontic appliances

Significance – Orthodontic treatment depends on it

Types Of Optimum Forces:

Continuous Force:

• Active force
• Decreases little in magnitude between appointment periods
• Example Light wire appliance
• Requirement:
  • Components must be highly flexible
  • Activation must be of low force level
• Results:
  • Direct resorption of root socket
  • No occlusion of blood vessels
  • No sacrifice of nutritional supply
  • No rest period
  • Soft tissue tolerance

Intermittent Force:

• Active force
• Declines to zero magnitudes before next appointment
• Example Removable active plates
• Requirements:
  • High stiffness of components
  • Initial activation – twice the expected
• Results:
  • Greater force on teeth
  • Undermining resorption
  • Repair of necrosed soft tissue
  • Resumption of blood supply

Interrupted Force:

• Inactive between appointment intervals
• Has cyclic, long-term magnitude time pattern

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

• Ex. Extra oral appliance
• Requirements:
  • Should exert heavy forces
  • No decay
  • Have specific magnitude – time pattern
  • Have sufficient inactive period

Types Of Tooth Movement Short Essays

Question 1. Tooth Movement.
Answer.

It is a unique process in which a tooth is made to move through bone.

Types Of Tooth Movement:

Tipping:

• It is a type of tooth movement where a single force is applied to the crown resulting in the movement of the crown in the direction of force and the root in the opposite direction.
• Controlled Tipping:
  • Tooth tips about the center of rotation at its apex.
• Uncontrolled Tipping:
  • The Centre of rotation occurs apical to & very close to the center of resistance.

Types Of Tooth Movement Short Questions And Answers

Question 1. Force and Couple.
Answer.

Force: It is defined as an act upon a body that changes/tends to change the state of rest or uniform motion of that body

• Expressed in grams

Couple: It is a pair of concentrated forces having equal magnitude and opposite direction with parallel but non-collinear lines of action

• Example. Pure rotation

Question 2. Intrusion.
Answer.

• Intrusion is defined as the axial movement of the tooth along the long axis toward the apex of the root
• This tooth movement requires minimum force and the center of rotation passes through the center of resistance
• 10-20g of force is required the periodontal ligament at the apex is compressed over a small area and no area of tension exists

Question 3. Tipping movement.
Answer.

It is a type of tooth movement where a single force is applied to the crown resulting in the movement of the crown in the direction of force and root in the opposite direction.

• Controlled Tipping
  • Tooth tips about the center of rotation at its apex.
• Uncontrolled Tipping
  • The Centre of rotation occurs apical to & very close to the center of resistance.

Question 4. Moment of force.
Answer.

Definition Of Moment of force

• It is defined as the measure of rotational potential of a force concerning a specific axis
• It is a tendency for a force to produce rotation

Calculated by

• Moment = Magnitude of force x distance
• Unit
• Gram millimeters
• Factors determining it
• Magnitude of force
• Distance from the center of resistance

Types Of Tooth Movement Viva Voce

• The center of rotation is the variable point
• The center of resistance is a fixed point
• Tipping is tooth movement around the mesiodistal axis
• Torqueing is tooth movement around fac-io-lingual axis
• Rotation is tooth movement around the long axis of the tooth
• Couple brings about pure rotation
• The unit of measurement of moment of force is gram millimeters
• The center of rotation during intrusion and extrusion is outside the tooth
• The center of resistance in the multi rooted tooth is located at 1-2mm apical to furcation