MDS PREP
In Angle’s class III malocclusion, mandibular anterior teeth will be
1) Proclined
2) Retroclined
3) Inclined
4) Any of the above
Orthodontics Answer: 2
SOLUTION
The reason is found in the concept of "dental compensation for skeletal discrepancy. This can occur naturally as well as being created by orthodontic camouflage treatment.
In mandibular prognathism, for instance, as the individual grows the upper incisors tend to protrude while the lower incisors incline lingually.
By the time growth is completed, the dental discrepancy usually is smaller than the jaw discrepancy.
Tooth position has compensated at least partially for the jaw discrepancy.
Supracrestal fibrotomy is done after correction of:
1) Crowding
2) Proclined incisors
3) Severely rotated teeth
4) Space closure
Orthodontics Answer: 3
Solution
Circumferential supracrestal fibrotomy (CSF) eliminates the pull of the stretched supracrestal gingival fibres which are the major cause of orthodontic relapse.
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
Transitional phase of dentition is
1) During eruption of permanent and exfoliation of deciduous teeth
2) After all permanent teeth have erupted
3) Phase during correction of malocclusion
4) None of the above
Orthodontics
Answer: 1
The transitional phase of dentition refers to the period when the primary (deciduous) teeth are being replaced by permanent teeth. This phase is characterized by the simultaneous eruption of permanent teeth and the exfoliation (loss) of primary teeth. It typically occurs between the ages of 6 and 12 years. The other options do not accurately describe this transitional phase; option 2 refers to a post-transitional phase, while option 3 pertains to orthodontic treatment rather than a specific phase of dentition.
The diameter of labial-bow of the maxillary plate
1) 0.5-0.6 mm
2) 0.6-0.8 mm
3) 0.7-0.8 mm
4) 0.8-1.0 mm
Orthodontics
Answer: 3
The labial bow is a component of the maxillary denture framework that helps in stabilizing the denture and providing support. The diameter of the labial bow is typically measured to ensure proper fit and function. The standard range for the diameter of the labial bow is generally accepted to be between 0.7 mm and 0.8 mm
Which of the following shows 200 % of its adult growth by age 9-10 years
1) Lymphoid
2) General
3) Genital
4) Neural
Orthodontics
Answer: 1
The lymphoid system, which includes lymph nodes, spleen, and other lymphatic tissues, undergoes significant growth during childhood. By the age of 9-10 years, the lymphoid tissue can reach approximately 200% of its adult size due to the increased demand for immune function during this period. This growth is part of the body's preparation for increased exposure to pathogens as children interact more with their environment.
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.
Flaccid lip, digit sucking, high frenum attachment & poor muscle tone are the etiology of :
1) Anterior cross bite
2) Diastema
3) Anterior bite
4) Posterior cross bite
Orthodontics Answer: 2
Midline diastema Etiology
Normal developing dentition - (Ugly Ducking Stage)
Parafunctional habits
- Flaccid lips along with poor muscle tone
- Simple Tongue thrust can cause anterior open bite as well as diastema
- Thumb sucking or digit sucking for a prolonged time period
Retrognathic mandible/ Prognathic mandible
Frenum attachments
Mesio-distal angulation of teeth
Tooth anomalies (eg. supernumerary teeth, peg laterals, absence of laterals)
Pathological (Juvenile periodontitis)