MDS PREP
Bone tissue grows by
1) Apposition
2) Interstitial growth
3) Osteoclastic growth
4) Mesenchymal tissue growth
Orthodontics Answer: 1
SOLUTION
Interstitial growth, simply means that it occurs at all points within the tissue. When mineralization takes place so that hard tissue is formed, interstitial growth becomes impossible.
Activation of a reverse labial bow is done by?
1) Opening the loop
2) Compressing the loop
3) Reversing the loop
4) Bending the loop
Orthodontics Answer: 1
Reverse labial bow is so called as activation of the bow is done by opening the U-loop, instead of compressing as is seen in the conventional labial bows.
In orthodontic treatment, the forces applied should not exceed the ________________ in order to avoid injuries to the tissues.
1) Arterial blood pressure
2) Muscular forces of facial muscles
3) Masticatory retrusion
4) Capillary blood pressure
Orthodontics Answer: 4
SOLUTION
Optimum orthodontic force is one, which moves teeth most rapidly in the desired direction, with the least possible damage to tissue and with minimum patient discomfort.
Oppenheim and Schwarz following extensive studies stated that the optimum force is equivalent to the capillary pulse pressure, which is 20-26 gm/sq. cm of root surface area.
From a clinical point of view, optimum orthodontic force has the following characteristics:
1) Products rapid tooth movement
2) Minimal patient discomfort
3) The lag phase of tooth movement is minimal
4) No marked mobility of the teeth being moved
From a histologic point of view the use of optimum orthodontic force has the following characteristics:
1) The vitality of the tooth and supporting periodontal ligament is maintained
2) Initiates maximum cellular response
3) Produces direct or frontal resorption
Which of the following forces best accomplish orthodontic tooth movement?
1) Heavy and continuous
2) Heavy and intermittent
3) Light and continuous
4) Light and intermittent
Orthodontics Answer: 3
SOLUTION
Light and continuous
Use of continuous light force is recommended to be applied for adult group of patient rather than intermittent force as applied by removable appliance. This is because continuous forces are expected to bring about direct resorption of the root socket. They should hence not occlude more than a small percentage of blood vessels with in the periodontal ligament, not substantially interfere with their nutritional supply and little interference
with normal biologic functioning. In adult due to heavy force teeth may devitalize because the opening into the tooth (apical foramen) is smaller and blood vessels can be easily disrupted.
If maxillary canines are placed forward to orbital plane, they are said to be in
1) Protraction
2) Retraction
3) Abstraction
4) Contraction
Orthodontics Answer: 1
SOLUTION
Simon used the orbital plane (a plane perpendicular to the F-H plane at the margin of the bony orbit directly under the pupil of the eye).
According to Simon, in normal arch relationship, the orbital plane passes through the distal axial aspect of the maxillary canine
Malocclusions described as anteropostenor deviations based on their distance from the orbital plane are as follows:
1. Protraction: The teeth, one or both, dental arches, andYor jaws are too far forward, i.e. placed forward or anterior to the plane as compared to the normal where the plane passes through the distal incline of the canine.
2. Retraction: The teeth, one or both dental arches and/or jaws are too far backward, i.e. placed posterior to the plane than normal
Servo system theory of Grown was given by
1) Scott
2) Petrovic
3) Limborgh
4) Vander Kaauw
Orthodontics
Answer: 2
The servo system theory, which relates to the control mechanisms in orthodontics, was proposed by Petrov ic (option 2). This theory helps in understanding how forces applied to teeth can be controlled and adjusted to achieve desired tooth movements during orthodontic treatment.
Which of the following cannot be used for incisor retraction
1) Roberts retractor
2) Split labial-bow
3) High labial-bow
4) Apron spring
Orthodontics
Answer: 3
The high labial-bow is typically used for molar retraction and is not designed for incisor retraction. In contrast, Roberts retractors, split labial-bows, and apron springs are all instruments that can be used effectively for retracting incisors during orthodontic treatment.
If the tooth has not erupted to the line of occlusion it is called
1) Supraversion
2) Torsiversion
3) Rotated
4) Infraversion
Orthodontics Answer: 4
Terms used to describe the position of teeth.
Mesioversion - A tooth in the arch located more mesial than normal
Distoversion - A tooth in the arch located more distal than normal
Labioversion - An incisor or canine outside of arch towards the lips
Buccoversion - A posterior tooth outside the arch toward the cheek
Linguoversion - A tooth inside the arch form toward the tongue
Infraversion - A tooth that has not erupted to the occlusal plane
Supraversion - A tooth the has over-erupted
Torsiversion - A tooth rotated on its axis
Transversion (Transposition) - Teeth that are in the wrong sequential order.