MDS PREP
Slow progression in molar uprighting in an adult patient is due to
1) Occlusion not being relieved
2) Overcontoured spring
3) Back of anchorage control
4) All of the above
Orthodontics
Answer: 1
Slow progression in molar uprighting can occur if the occlusion is not
adequately relieved. If the opposing teeth are still in
contact, it can hinder the movement of the molar being
uprighted.
What dental relationship is present in an Angle Class I occlusion?
Orthodontics Answer: 3
1. The buccal cusp of the maxillary second premolar aligns with the mesiobuccal groove of the mandibular first molar.
2. The cusp of the maxillary canine aligns with the cusp of the mandibular canine.
3. The mesiobuccal cusp of the maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar.
4. The mesiobuccal cusp of the maxillary first molar aligns with the embrasure between the mandibular first molar and second premolar.
The mesiobuccal cusp of the maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar.
The iron carbide in orthodontic wire is in the form of
1) Martensite
2) Ferrite
3) Carbide
4) Austenite
Orthodontics
Answer: 4
Orthodontic wires are often made from stainless steel, which contains iron, carbon, and other alloying elements. The term "iron carbide" refers to a compound of iron and carbon, typically represented as Fe₃C. In the context of orthodontic wires, the microstructure can exist in different phases depending on the temperature and composition. Austenite is a face-centered cubic (FCC) structure that is stable at high temperatures and is known for its ductility and strength. When orthodontic wires are heated during the manufacturing process, they can be formed into austenite, which can then be transformed into martensite upon cooling, providing the wire with desirable properties for orthodontic applications.
What is force applied per unit area?
1) Strain
2) Stress
3) Couple
4) Center of resistance
Orthodontics Answer: 2
SOLUTION
Stress is the force applied per unit area while strain can be defined as the internal distortion per unit area.
Stress and strain are inter-related terms as stress is an external force acting upon a body while strain is the resultant of stress on that body.
Strain can be expressed in the form of a change in either the external dimension or internal energy of the body.
How much force is usually used to move a tooth with an orthodontic appliance?
- extremely light force, less than 1 gram
- moderate force, in the range of 50 to 150 grams
- very heavy force, greater than 500 grams
- whatever the patient can tolerate
moderate force, in the range of 50 to 150 grams
Analysis which is similar to Pont’s analysis is_______?
1) Linder Harth index
2) Korkhaus analysis
3) Bolton’s analysis
4) (A) and (B)
Orthodontics Answer: 4
SOLUTION
· Pont’s in 1905 presented a system whereby the measurement of the four maxillary incisors automatically established the width of the arch in the premolar and molar region. If measured value is less than calculated value, it indicates the need for expansion.
· Linder Harth index: This analysis is very similar to Pont’s analysis except that a new formula has been proposed to determine the calculated premolar and molar value.
· Korkhaus analysis: This analysis is also very similar to Pont’s analysis it makes use of Linder Harth’s formula to determine the ideal arch width in the premolar and molar region.
In addition this analysis utilizes a measurement made from the midpoint of the inter-premolar line to a point in between the two maxillary incisors.
· Bolton’s analysis: The Bolton’s analysis helps in determining disproportion in size between maxillary and mandibular teeth.
Which of the following is a noninvasive method of gaining the space
1) Slenderisation and extraction
2) Expansion and extraction
3) Expansion and distalization
4) All of the above
Orthodontics
Answer: 3
Expansion and distalization are considered noninvasive methods for
gaining space in orthodontic treatment.
Which of the following are included in the Orthodontic camouflage methods for treating class II malocclusion?
1) Retraction of upper teeth and forward movement of lower teeth
2) Retraction of maxillary incisors into pre-molar extraction space
3) Distal movement of maxillary molars
4) All of the above
Orthodontics Answer: 4
SOLUTION
The following three patterns of tooth movement can be used to correct a Class II malocclusion:
· A combination of retraction of the upper teeth and forward movement of the lower teeth, without tooth extractions
· Retraction of maxillary incisors into a premolar extraction space
· Distal movement of maxillary molars and eventually the entire upper dental arch