MDS PREP
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.
What is the relation of the lower first molar to the upper first molar in an
Angle Class III malocclusion?
1. distal
2. lateral
3. mesial
4. normal
Orthodontics Answer: 3
Angle Class III Malocclusion:
Angle Classification:
The Angle classification system, developed by Edward Angle, is a
widely used method for categorizing malocclusions based on the
relationship of the first molars and the canines.
Class III Malocclusion:
In Angle Class III malocclusion, the lower first molar is positioned
more mesially (toward the midline) relative to the upper first molar.
This means that when the first molars are in occlusion, the lower first
molar is ahead of the upper first molar.
Clinical Implications:
Class III malocclusion is often associated with a prognathic
mandible (where the lower jaw is positioned forward) or a retruded
maxilla (where the upper jaw is positioned backward). This can lead to
various functional and aesthetic concerns, including difficulties with
biting and chewing, as well as facial profile changes.
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 basic principle of Orthodontic spot welder lies on the concept of :-
1 Heat technique
2) Quenching
3) Diodelasers
4) Electrode Technique
Orthodontics Answer: 4
SOLUTION
The type of welding used to join Orthodontic components is called Spot welding. The heat source usually a high amperage electricity. Orthodontic spot welders employ the electrode technique, in which current is conducted through two copper electrodes. The copper electrode in a welding unit serve the following purposes :
1. Transmit current to the metals to be joined so as to cause a rapid increase in temperature.
2. The electrodes help in conducting the heat produced away from the area so as to preserve the properties of stainless steel around the weld spot.
3. The electrode also help in holding together the two metals to be joined.
4. The electrodes are designed to apply pressure on the metals being joined. As soon as the temperature increases, the pressure exerted by the electrodes helps in squeezing metal into each other.
What is Sunday bite related to?
1) Angle’s class I with anterior open bite
2) Angle’s class I with anterior deep bite and posterior cross bite (unilateral)
3) Angle’s class II
4) Angle’s class III
Orthodontics Answer: 3
SOLUTION
Children and adults with a skeletal Class II relationship and an underlying skeletal Class II jaw relationship position the mandible forward in a “Sunday bite,” making the occlusion look better than it really is.
The part of the removable appliance which provides the anchorage is
1) Adams clasp
2) Base plate
3) Active labial bow
4) Guided springs
Orthodontics Answer: 2
SOLUTION
Baseplate: The hard plastic part of some retainers that covers the gum and has the wire components of the retainers attached to it.
The first ossification center of the mandible in six weeks old human embryo is found in which of the following locations
1) Future coronoid process
2) Future condylar process
3) Future mental foramen
4) Future mandibular foramen
Orthodontics Answer: 3
SOLUTION
The mandible is ossified in the fibrous membrane covering the outer surfaces of Meckel’s cartilages.
These cartilages form the cartilaginous bar of the mandibular arch, and are two in number, a right and a left.
Ossification takes place in the membrane covering the outer surface of the ventral end of Meckel’s cartilage , and each half of the bone is formed from a single center which appears, near the mental foramen, about the sixth week of fetal life.
By the tenth week the portion of Meckel’s cartilage which lies below and behind the incisor teeth is surrounded and invaded by the membrane bone
Facial profile of a typical mouth breather is
1) Long and wide
2) Short and wide
3) Long and narrow
4) Short and narrow
Orthodontics Answer: 3
SOLUTION
Altered respiratory pattern, such as breathing through the mouth rather than the nose, could change the posture of the
head, jaw, and tongue. This in turn could alter the equilibrium of pressures on the jaws and teeth and affect both jaw growth and tooth position.
In order to breathe through the mouth, it is necessary to lower the mandible and tongue, and extend (tip back) the head.
If these postural changes were maintained, face height would increase, and posterior teeth would super-erupt;
unless there was unusual vertical growth of the ramus, the mandible would rotate down and back, opening the bite
anteriorly and increasing overjet; and increased pressure from the stretched cheeks might cause a narrower maxillary dental arch.