MDS PREP
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.
Which one of these is the etiological factors of tongue thrust?
1) Hyposensitive palate
2) Hypertonic orbicularis oris activity
3) Macroglossia
4) All of these
Orthodontics Answer: 4
Etiology of Tongue thrust
Fletcher has proposed the following factors as being the cause for tongue thrusting.
Genetic factors : They are specific anatomic or neuromuscular variations in the oro-facial region that can precipitate tongue thrust. e.g. Hypertonic orbicularies oris activity.
Learned behaviour (habit) : Tongue thrust can be acquired as a habit.
The following are some of the predisposing factors that can lead to tongue thrusting:
a. Improper bottle feeding
b. Prolonged thumb sucking
c. Prolonged tonsillar and upper respiratory tract infections
d. Prolonged duration of tenderness of gum or teeth can result in a change in swallowing pattern to avoid pressure on the tender zone.
Maturational : Tongue thrust can present as part of a normal childhood behaviour that is gradually modified as the age advances. The infantile swallow changes to a mature swallow once the posterior deciduous teeth start erupting.
Sometimes the maturation is delayed and thus infantile swallow persists for a longer duration of time.
Mechanical restrictions : The presence of certain conditions such as macroglossia, constricted dental arches and enlarged adenoids predispose to tongue thrust habit.
Neurological disturbance: Neurological disturbances affecting the oro-facial region such as hyposensitive palate and moderate motor disability can cause tongue thrust habit.
Psychogenic factors : Tongue thrust can sometimes occur as a result of forced discontinuation of other habits like thumb sucking. It is often seen that children who are forced to leave thumb sucking habit often take up tongue thrusting.
An increase or decrease in the Y axis is related to:
1) The growth pattern
2) Extrusion of molars
3) Intrusion of molars
4) All of the above
Orthodontics Answer: 1
SOLUTION
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.
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.
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.
If the edgewise bracket is not pressed completely on to a tooth on the mesial side while bonding, the side effect would be
1. intrusion
2. extrusion
3. rotation
4. breakage of bracket
Orthodontics
Answer: 3
we are applying force distally only..force vector will rotate the tooth distally
Heat hardening is done in which orthodontic wire
1) Elgiloy
2) Stainless steel
3) TMA
4) NiTi
Orthodontics Answer: 1
SOLUTION
Elgiloy (Cobalt-Chromium) alloy is supplied in a softer state and can be heat hardened.
After hardening heat treatment, the softest elgiloy becomes equivalent to regular stainless steel.