MCQs in Orthodontics

Chapter 4: Biomechanics and Mechanics

 

1- How much force is required to tip an incisor:

  1. 20-30gms
  2. 50-75gms
  3. 40-50gms
  4. 10-20 gms

 

 

 

 

 

The answer is: B

 

2- Wires also called shape memory are:

  1. stainless steel
  2. multiflex round wire
  3. nickel titanium wire
  4. stainless steel edgewise wire

 

 

 

 

 

The answer is: C

 

3- When the diameter of wire is doubled the force exerted on teeth is:

  1. 4 times
  2. 1/2 times
  3. 8 times
  4. 16 times

 

 

 

 

 

The answer is: D

 

4- Which contemparay orthodontic wire has maximum surface tension:

 

  1. Stainless steel
  2. Ajw wires
  3. TMA wires
  4. Niti wires

 

 

 

 

 

 

The answer is: C

 

5- The pitch of hyrax expansion is:

 

  1. 25mm
  2. 1mm
  3. 5mm
  4. 5mm

 

 

 

 

 

The answer is: B

 

6-Cement used for cementation of orthodontics bracket is:

 

  1. Composite
  2. Resins
  3. Gic
  4. None of the above

 

 

 

 

 

The answer is: A

 

7-Active component of fixed appliance is:

 

  1. Bracket
  2. Buccal tube
  3. Ligature
  4. Seperator

 

 

 

 

 

The answer is: D

 

8- Uprighting spring is used to:

 

  1. Derotate a tooth
  2. Move the root in mesiodistal direction
  3. Move the root in palatal direction
  4. Closure of space

 

 

 

 

 

 

The answer is: B

 

9- Reinforced anchorage example is:

 

  1. Bite plane anterior
  2. Posterior bite plan
  3. Inclined plane
  4. All of above

 

 

 

 

 

 

The answer is: C

 

10- Moment to force ratio for bodily movement is:

 

  1. 6
  2. 8
  3. 10
  4. >10

 

 

 

 

 

The answer is: D

 

11- 1st  order bends are:

 

  1. Tipping bends.
  2. Toquing bends.
  3. In and out bends.
  4. Anchorage bends.
  5. Up and down bends.

 

 

 

 

 

The answer is: C

 

12- When the gold wires were replaced by steel arch wires the reduction in the slot in the edgewise system was found to be:

 

  1. 22 mil bracket
  2. 28 mil bracket
  3. 24 mil bracket
  4. 18 mil bracket

 

 

 

 

 

The answer is: D

 

13- The artistic positioning bends are:

 

  1. First order bend
  2. Second order bend
  3. Third order
  4. None

 

 

 

 

 

The answer is: B

 

14- Whip spring is:

 

  1. Fixed
  2. Semifixed
  3. Removable
  4. Functional

 

 

 

 

 

The answer is: C

 

15- Amount of force required to protact maxilla is:

 

  1. 12oz
  2. 12-16oz
  3. 16-20oz
  4. 24 oz

 

 

 

 

 

The answer is: D

 

16- Example of fixed functional appliance is:

 

  1. Churro jumper
  2. Mandibular anterior reposition applianace ( MARA)
  3. Sabbagh universal spring( sus)
  4. All of above

 

 

 

 

 

The answer is: D

 

17- Amount of force required to applied by chin cap to stop mandibular growth:

 

  1. 1200-1600gms
  2. 1000-1200gms
  3. 400-800gms
  4. 1600-2000gms

 

 

 

 

 

 

The answer is: B

 

18-Orthodontic appliances should not be reactivated more frequently than at:

 

  1. 1 week interval                   
  2. 2 week interval
  3. 3 week interval    
  4. 4 week interval

 

 

 

 

 

The answer is: C

 

19- The most efficient orthodontic tooth movement is produced by:

 

  1. Light & intermittent forces   
  2. Light & continuous forces
  3. Heavy & intermittent forces  
  4. Heavy & continuous forces

 

 

 

 

 

 

The answer is: B

 

20- Physiological tooth movements is which of the following:

 

  1. Drifting of teeth
  2. Changes in tooth position during mastication
  3. Tooth eruption
  4. All of the above

 

 

 

 

 

The answer is: D

 

21- Extreme forces applied to teeth, this can cause:

  1. Undermining resorption
  2. Frontal Resorption
  3. Rearward resorption
  4. Secondary resorption

 

 

 

 

 

 

The answer is: A

 

22- The optimum orthodontic force is:

  1. 10 gm/sq cm
  2. 20-26 gm/sq cm
  3. 15 gm/sq cm
  4. 30-40 gm/sq cm

 

 

 

 

 

 

The answer is: B

 

23- The presence of hyalinised zone as a result of extreme forces indicates that:

 

  1. More force needs to be applied to move the tooth
  2. Further treatment is not possible till the local damaged tissue is removed
  3. Tooth movement is not affected
  4. None of the above

 

 

 

 

 

 

The answer is: B

 

24- The amount of force necessary to tip an incisor is:

 

  1. 20-30 gm
  2. 10-15 gm
  3. 1-5 gm
  4. 10-50 gm

 

 

 

 

 

 

The answer is: A

 

25- The amount of force necessary to tip a canine is:

  1. 1-10 gm
  2. 20-30 gm
  3. 50-75 gm
  4. 100-150gm

 

 

 

 

 

 

The answer is: C

 

26- The amount of force needed for an intrusion is:

 

  1. 1-10 gm
  2. 100 gm
  3. 150-175 gm
  4. 15-50gm

 

 

 

 

 

 

The answer is: D

 

27-  Which of the following is the simplest tooth movement with a removable appliance:

 

  1. Tipping
  2. Rotation
  3. Torquing
  4. Translation

 

 

 

 

 

 

The answer is: A

 

28- Removable active plates apply:

 

  1. Zero force
  2. Intermittent force
  3. Continuous force
  4. interupted force

 

 

 

 

 

 

The answer is: B

 

29- Translation of a small tooth requires how much force:

 

  1. 10 – 15 gm
  2. 100-150 gm
  3. 40-50 gm
  4. 20-30 gm

 

 

 

 

 

 

The answer is: C

 

30- Tooth movements difficult to achieve are:

 

  1. Intrusion and extrusion
  2. Intrusion and translation
  3. Tipping and rotation
  4. Tipping and extrusion

 

 

 

 

 

 

The answer is: B

 

31- Continuous heavy orthodontic forces used in moving teeth can cause all of the following EXCEPT:

 

  1. Resorption of cementum
  2. Resorption of dentin
  3. Resorption of enamel
  4. Devitilise teeth

 

 

 

 

 

The answer is: C