MDS PREP
The philtrum of the upper lip is formed largely by the
1) Lateral nasal processes
2) Globular process
3) Maxillary processes
4) Mandibular processes
Orthodontics
Answer: 2
Explanation: The philtrum is the vertical groove located in the middle of the upper lip. It is primarily formed by the fusion of the medial nasal processes, which include the globular process. The globular process is a key structure in the embryonic development of the face, contributing to the formation of the upper lip and the philtrum.
Which of the following is not one of the consequences of using Herbst appliance in treatment of Class II malocclusion?
1) Increase in mandibular growth
2) Over corrected Class I molar relation
3) Increase in SNB angle
4) Increase in overjet
Orthodontics Answer: 4
Solution
The following are the effects when Herbst appliance used for treatment of Class II malocclusion:
1. Class I molar relation or over-corrected Class I molar relation.
2. Increased mandibular growth
3. Distal driving of maxillary molars which helps to achieve molar relation.
4. Reduction of overjet by increasing mandibular length and proclination of mandibular incisors.
5. Inhibitory effect on sagittal maxillary growth
6. Weislander suggested double contour of glenoid fossa which indicates anterior transformation of glenoid fossa
7. Increased SNB angle and decreased SNA angle.
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.
Crowding that occurs after age of 18 is the result of
1) Impacted third molar
2) Physiological maturational change
3) Orthodontic relapse
4) Periodontal disease
Orthodontics
Answer: 2
Crowding that occurs after age 18 is typically the result of physiological maturational changes.
Explanation: Dental crowding is a common malocclusion where teeth do not have enough space to align properly in the dental arch. After the age of 18, most of the facial growth has concluded, and the teeth are fully erupted. If crowding occurs at this stage, it is most likely due to physiological maturational changes, such as the natural movement of teeth or the eruption of third molars (wisdom teeth). Impacted third molars are another potential cause of late crowding, but the question specifies that the crowding is not due to them. Orthodontic relapse is a possibility if the individual had prior orthodontic treatment, but without that context, the most likely cause for new crowding in adulthood is the natural shifting of teeth over time or the late eruption of wisdom teeth. Periodontal disease can affect tooth positioning, but it does not directly cause crowding.
If a coil and tag of a palatal canine retractor are placed too far distally
1) Base plate is weakend
2) Tooth movement will be slowed
3) Tooth will tend to be moved buccally
4) Tooth will tend to be moved palatally
Orthodontics
Answer: 3
If the coil and tag of a palatal canine retractor are placed too far distally,
the force applied will tend to move the tooth buccally
(toward the cheek) rather than palatally (toward the
palate), which can hinder the intended movement.
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.
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)