MCQs in Orthodontics - Biomechanics of Tooth Movement

# 'Torque' in orthodontics refers to:
A. The change in mesiodistal inclination of teeth
B. The change in labiolingual inclination of teeth
C. The rotation of teeth
D. None of the above

# Resorption in case of ideal orthodontic tooth movement should be:
A. Undermining
B. Frontal
C. Indirect
D. Necrotic

# In orthodontic tooth movement which is involved:
A. Osteoblast
B. Osteoclast
C. Both A and B
D. None

# Torquing movement in orthodontics:
A. Is movement of the root without moving the crown
B. Cannot be accomplished in clinical practice
C. Is always deleterious to the tooth
D. None of the above

# For a bodily movement of a small tooth the force required is:
A. 25 - 30g
B. 40 - 75g
C. 120 - 150g
D. More than 150g

# Tooth movement easily accompanied by use of removable orthodontic appliance is:
A. Translation
B. Tipping
C. Rotation
D. Extrusion

# Heavy forces on periodontal ligament causes:
A. Hyalinization
B. Osteoclastic activity around tooth
C. Osteoblastic activity around tooth
D. Crest bone resorption

# In orthodontic treatment, rapid tooth movement will cause all except:
A. Devitalisation of teeth
B. Resorption of roots
C. Diffuse calcification of pulp
D. Ankylosis

# A single force is applied to the crowns of the upper incisors. Tipping is around the point of rotation present at:
A. Infinity
B. Apical 1/3rd
C. Middle 1/3rd
D. Coronal 1/3rd

# A 300 gm force is applied through a canine retractor, the following change will be noticed:
A. Hyalinization
B. Rapid tooth movement
C. Frontal root resorption
D. None of the above

# The tooth movement most difficult to accomplish is:
A. Tipping
B. Bodily movement
C. Intrusion
D. B and C

# Optimum orthodontic force should not exceed the:
A. Arterial blood pressure
B. Venous blood pressure
C. Capillary blood pressure
D. Masticatory pressure

# The tipping of a tooth results in the fibers of the PDL to be:
A. ALL compressed
B. All stretched
C. Half compressed half stretched
D. No effect

# The appropriate force required to tip a tooth is:
A. 10 - 20mg
B. 20 - 25mg
C. 50 - 70mg
D. 70 - 100mg

# Which of the following enzymes decreases the orthodontic movement?
A. Cyclo-oxygenase
B. Metalloprotein
C. Alkaline phosphatase
D. Protein kinase

# The force applied to cause root movement should be:
A. Positive intermittent force
B. Torque or moment
C. Extra - oral
D. Gentle action

# The first tissue to react when orthodontic forces are applied is:
A. PDL
B. Cementum
C. Dentine
D. Alveolar bone

# During orthodontic tooth movement, periodontal ligament provides:
A. Osteoblasts
B. Osteoclasts
C. Both A and B
D. None of the above

# If during an application of an orthodontic force, the level declines to zero between activations then the force duration is classified as:
A. Continuous force
B. Interrupted force
C. Intermittent force
D. Differential force

# Frontal resorption is caused due to:
A. Light continuous force
B. Heavy continuous force
C. Heavy interrupted force
D. Light interrupted force

# Most easiest movement during orthodontic treatment is:
A. Intrusion
B. Tipping
C. Extrusion
D. Bodily movement

# Resorption of cementum as compared to bone occurs:
A. Less readily
B. More readily
C. Same
D. Undermining resorption

# Which of the following statements concerning the wires used in tooth movement is most accurate?
A. The larger the diameter of the wire, the greater the force and the faster the movement of the tooth
B. The longer the wire, the greater the fo rce and the faster the movement of the tooth.
C. The more rectangular the shape of the wire, the greater the force and the faster the movement of the tooth
D. The longer the wire, the more gentle the force and the faster the movement of the tooth.

# In which orthodontic movement utmost control is required:
A. Intrusion
B. Extrusion
C. Tipping
D. Rotation

# Dominant movement of root with relatively less movement of the crown is called:
A. Couple
B. Torque
C. Intrusion
D. Extrusion

# The relative mesial or distal angulations of the crown and the root along the line of occlusion is called:
A. Torque
B. Tip
C. Offset
D. Inclination of teeth

# In translation, center of rotation is at:
A. Apical 1/3rd
B. Coronal 1/3rd
C. Infinity
D. Apex

# Hyalinisation of the periodontal ligament, due to excessive orthodontic forces results in:
A. Frontal resorption
B. Undermining resorption
C. Cementum remaining intact
D. Dentine remaining intact

# Which of the following is an intramatrix procedure?
A. Rotation of mandibular base in relation to cranium
B. Rotation of mandibular plane in relation to cranium
C. Rotation of mandibular plane relative to core of mandible
D. Rotation of mandibular base in relation to maxilla

# The incisor over-jet is increased for a class II case that is undergoing treatment. The reason is:
A. Loss of anchorage
B. Arch collapse
C. Crowding in the lower arch
D. None of the above

# In Stationary anchorage, anchorage is obtained from:
A. More stable teeth
B. Extra - oral
C. Teeth from the opposite arch
D. Stationary teeth

# Which of the following is related to occipital anchorage?
A. Intraoral force
B. Tipping a tooth
C. Extraoral force
D. Bodily movement of anchor

# Closing of midline diastema by using a removable appliance:
A. Reciprocal single simple anchorage
B. Reciprocal simple compound anchorage
C. Reciprocal stationary single anchorage
D. Reciprocal stationary compound anchorage

# Stationary anchorage refers to the anchor teeth which are:
A. Are banded
B. Cannot move
C. Are not free to tilt
D. Are supported by extra oral forces

# Reinforced anchorage. Example is:
A. Bite plane anterior
B. Posterior bite plane
C. Inclined plane
D. All of the above

# Anchorage is better provided by:
A. Single rooted teeth
B. Multi rooted
C. Narrow rooted
D. Small rooted teeth

# Which of the following is not inter maxillary anchorage?
A. Max incisors to maxillary molars
B. Maxillary incisors to mandibular molars
C. Bakers anchorage
D. All of the above

# When anchor unit is allowed to tip, it is called _____________ anchorage.
A. Simple
B. Compound
C. Complex
D. Reciprocal

# Simple anchorage refers to:
A. Closure by tipping
B. Closure by bodily movement
C. Closure by rotation
D. Closure by intrusion

# Reciprocal anchorage is exhibited by:
A. Split expansion appliance
B. Inter maxillary elastics
C. A and B
D. Intra arch elastics

# The type of anchorage in which two groups of teeth move in equal and opposite direction is called as:
A. Stationary
B. Reciprocal
C. Simple
D. Compound

# Bakers anchorage is a type of:
A. Intra maxillary anchorage
B. Inter maxillary anchorage
C. Extra oral anchorage
D. Muscular anchorage

# Reciprocal anchorage is offered by:
A. Activator
B. Inter maxillary elastics
C. Maxillary expansion appliance
D. Catalan's appliance

# The greatest advantage of using extra oral anchorage is that:
A. More force can be applied
B. It has a direct reciprocal action on opposing arch
C. It permits posterior movement of teeth in one arch without disturbing the opposing arch adversely
D. Any of the above

# It is normal response to orthodontic treatment for periodontal space to:
A. Widen
B. Narrow
C. Shorten
D. Elongate

# The type of resorption seen when light continuous orthodontic forces are applied:
A. Apical
B. Frontal or direct
C. Indirect or undermining
D. No resorption is seen

# Extrusive movements ideally would produce no areas of compression within PDL, but will produce:
A. Only contusion
B. Only tension
C. Only retraction
D. Only extraction

# A single force applied at which point of a tooth will allow complete translation of the tooth:
A. At the apex
B. At the incisal stage
C. At the center of resistance
D. At the center of rotation

# During which orthodontic tooth movement center of rotation is at the bracket slot:
A. Controlled movement
B. Torque
C. Rotation
D. Translation

# The first reaction that takes place when an orthodontist attempts active tooth movement with a removable appliance is:
A. Pressure and tension zones form in the periodontal ligament
B. Force is applied on the tooth
C. Osteoclasts create undermining resorption
D. Tooth moves by direct resorption

# The histological section of tooth under orthodontic force representing an avascular area in the periodontal ligament is often referred as:
A. Frontal zone
B. Hyalanized zone
C. Undermining zone
D. Clear zone

# Anchorage obtained from the nape of the neck represents:
A. Occipital anchorage
B. Cervical anchorage
C. Facial anchorage
D. Parietal anchorage

# Most efficient orthodontic tooth movement is obtained by:
A. Light continuous force
B. Large intermittent force
C. Light interrupted force
D. Heavy continuous force

# The centre of rotation for bodily movement of tooth is located at:
A. apical 1/3rd of root
B. at infinity
C. apical 2/3rd of root
D. middle 1/3rd of root

# The optimal orthodontic force per square centimeter of the root surface area is held to be:
A. 18-22 gms
B. 18-26 gms
C. 20-26 gms
D. 26-30 gms

# Optimum force for orthodontic bodily movement (translation) is:
A. 50 - 75 gms
B. 100 - 150 gms
C. 200 - 250 gms
D. 300 - 400 gms

# The first bone formed in response to orthodontic loading is:
A. Bundle bone
B. Composite bone
C. Lamellar bone
D. Woven bone

# During orthodontic movement of maxillary central incisor, centre of rotation is applied to apex then it shows:
A. Controlled tipping
B. Uncontrolled tipping
C. Translation
D. Intrusion

# Band and loop space maintainer is:
A. Unilateral fixed non functional
B. Unilateral removable functional
C. Bilateral fixed non functional
D. Bilateral removable functional

# A distinctive clinical manifestation of a successful rapid maxillary expansion is:
A. Anterior crossbite
B. Posterior crossbite
C. Midline diastema
D. Open bite

# What is the effect of doubling the diameter of a cantilever spring?
A. Strength increases by 4 times, Springiness increases by 8 times
B. Strength decreases by 4 times, Springiness decreases by 8 times
C. Strength decreases by 8 times, Springiness increases by 16 times
D. Strength increases by 8 times, Springiness decreases by 16 times

# Simple retraction of maxillary incisors using maxillary molars as anchorage is an example of:
A. Simple anchorage
B. Reciprocal anchorage
C. Stationary anchorage
D. Intermaxillary anchorage

# Moment: Force Ratio for bodily movement of tooth is:
A. 6
B. 10
C. 14
D. Zero

# Type of force in a patient activated appliance is:
A. Interrupted
B. Intermittent
C. Continuous Interrupted
D. Continuous Intermittent

# Intrusion is best produced by:
A. Light intermittent forces
B. Heavy intermittent forces
C. Light continuous forces
D. Heavy continuous forces

# During orthodontic movement of maxillary Central incisor, centre of rotation is present at apex, it shows:
A. Controlled tipping
B. Uncontrolled tipping
C. Translation
D. Intrusion

# In Orthodontic treatment, placing the tooth into its normal position results in:
A. Esthetics
B. Esthetics, Function and Tooth placement
C. Esthetics and Occlusion
D. Esthetics, Occlusion and Stability

# Light orthodontic forces produce:
A. Light forces will not have any effect
B. Brings up osteoclasts with 10 seconds
C. Compression of blood vessel within 3-5 seconds on the pressure side
D. Compression of blood vessel in 2 hours on the tension side

# Hyalinization in orthodontic movement means:
A. A cell free zone histologically similar to hyaline appearance
B. Change to hyaline cartilage
C. Lamina dura converts into hyaline cartilage
D. Periodontal ligament changes to hyaline cartilage

# The lag phase of tooth movement usually lasts for:
A. 2-3 mins
B. 2-3 hrs
C. 2-3 day
D. 2-3 weeks

# Which characteristic of orthodontic wire describe energy storage capacity?
A. Range
B. Resiliency
C. Formability
D. Proportional limit

# Centre of rotation during intrusion is at:
A. Infinity
B. Middle third of tooth
C. CEJ
D. Outside the tooth

# Which of the following material used in orthodontics, commonly causes sensitivity?
A. Steel
B. Ceramic
C. Nickel
D. Plastic

# According to the type of movement of the anchorage unit, it can be classified as all except:
A. Simple
B. Compound
C. Reciprocal
D. Stationary

# Which of the following orthodontic wire has Least modulus of elasticity?
A. NiTi
B. Beta titanium
C. Stainless steel
D. Co-Cr-Ni

# Following metal alloy held in reducing hardness of orthodontic wires?
A. Chromium
B. Cobalt
C. Silicon
D. Carbon

# Which of the following chrome cobalt wire is highly ductile and become resilient on heating?
A. Yellow elgiloy
B. Blue elgiloy
C. Green elgiloy
D. Red elgiloy

# The play (degrees) for 21.5 x 28 wire size used in 22- slot bracket is?
A. 2.5
B. 0.5
C. 1
D. 1.8

# Tooth movement is primarily a phenomenon involving:
A. Pulp
B. Periodontal ligament
C. Dentin
D. Cementum

# Center of resistance of six maxillary anterior teeth is?
A. Midline between two central incisors
B. Between central and lateral incisor
C. Between first and second premolar
D. Between canine and premolar

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