MDS PREP
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.
Bone tissue grows by
1) Apposition
2) Interstitial growth
3) Osteoclastic growth
4) Mesenchymal tissue growth
Orthodontics Answer: 1
SOLUTION
Interstitial growth, simply means that it occurs at all points within the tissue. When mineralization takes place so that hard tissue is formed, interstitial growth becomes impossible.
A single force applied at which point of a tooth will allow complete translation of the tooth.
1) At the apex
2) At the incisal edge
3) At the center of resistance
4) At the center of rotation
Orthodontics Answer: 3
SOLUTION
Center of resistance- Point analogous to the centers of gravity.
Generally it is constant.In single root it lies between one third and one half of the root apical to alveolar crest.
In multi rooted tooth it lies 1-2 mm apical to furcation
Earnest Klein has classified habits into
1) Compulsive and non-compulsive habits
2) Intentional and non-intentional habits
3) Primary and secondary habits
4) Pressure and non-pressure habits
Orthodontics
Answer: 2
Earnest Klein's classification of habits distinguishes between intentional habits (those that are consciously performed) and non-intentional habits (those that occur unconsciously or without deliberate intention). This classification helps in understanding the nature of habits, particularly in the context of dental and orthodontic practices.
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.
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.
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.
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.