MDS PREP
How/where should the wire be bent to activate a correctly made palatal canine retraction?
1) Between the coil and tooth, but close to the coil
2) Between the coil and tooth, but close to the tooth
3) Between the coil and its insertion into the base of the plate
4) By opening out the coil
Orthodontics
Answer: 1
Bending the wire between the coil and the tooth, but closer to the coil, allows for effective activation of the retraction mechanism, providing the necessary force for movement.
Considering the 3D growth of the face, it ceases last in which direction?
1. A-P
2. sagittal
3. transverse
4. vertical
Orthodontics
Answer: 4
for facial growth order of growth is
width > depth > height
Relative to a heterogenous population the incidence of malocclusion in a homogenous population is
1. lower
2. slightly higher
3. significantly higher
4. about the same
Orthodontics
Answer: 1
In a homogeneous population, the genetic variation is less compared to a heterogeneous population. Malocclusion is influenced by both genetic and environmental factors. A homogenous population, which is more genetically similar, would be expected to have a more uniform expression of dental traits, including a lower incidence of malocclusion, assuming that the specific genetic factors for malocclusion are not prevalent in that particular population. In a heterogeneous population, the greater genetic diversity can lead to a higher incidence of malocclusion due to a wider range of genetic combinations contributing to dental misalignments.
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.
The most common permanent tooth found to be ankylosed is
1) 1st molars
2) 2nd molars
3) Canines
4) Premolars
Orthodontics Answer: 4
ankylosed teeth are also known as submerged teeth.
submerged teeth are decidous teeth most commonly mandibular second molars
Most common permanant tooth found to be ankylosed is premolars.
All of the following factors interfere with statural growth on long-term basis except
1) Cleft palate
2) Poor nutrition
3) Chronic diseases
4) Cardiac diseases
Orthodontics
Answer: 1
A cleft palate is a congenital condition that does not inherently affect statural growth. The other factors listed—poor nutrition, chronic diseases, and cardiac diseases—can all have long-term negative impacts on a person's growth and development. Poor nutrition can lead to stunted growth due to insufficient nutrients for bone and tissue development, while chronic diseases and cardiac diseases can impair the body's ability to regulate growth hormones and overall health, potentially leading to growth delays or abnormalities.
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
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.