MDS PREP
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.
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.
Baker anchorage utilizes
1) Intermaxillary anchorage with screws
2) Intramaxillary anchorage with screws
3) Intermaxillary anchorage with elastics
4) Intramaxillary anchorage with elastics
Orthodontics Answer: 3
SOLUTION
Intermaxillary anchorage or Baker's Anchorage. This type of anchorage involves using elastics from one jaw to the other, in the form of either Class 2 elastics (moving upper teeth back) where lower molar teeth serve as anchors, or Class 3 elastics (moving lower teeth back) where upper molars serve as anchors.
Intramaxillary anchorage is also used in the form of E-chain, when elastics are used from the back molar teeth to the front teeth in the same jaw to move teeth back of the mouth.
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
Ashley-Howe model analysis is used to predict
1) Tooth material excess
2) Maxillo - mandibular relationships
3) Basal bone-transverse relationship
4) Growth prediction
Orthodontics
Answer: 3
Ashley-Howe Model Analysis
The Ashley-Howe model analysis is a method used in
orthodontics to assess the relationship of the dental arches and the position of
the teeth, particularly in the context of planning orthodontic treatment. This
analysis is particularly useful for evaluating the transverse dimension of the
dental arches and understanding how the maxilla (upper jaw) and mandible (lower
jaw) relate to each other.
Measurement Parameters:
The analysis involves measuring specific distances and angles on dental
casts or models. Key measurements may include:
Intercanine Width: The distance between the cusp
tips of the canines.
Interpremolar Width: The distance between the cusp
tips of the first premolars.
Intermolar Width: The distance between the cusp
tips of the first molars.
These measurements help in determining the transverse relationships of
the dental arches.
Classification:
The results of the Ashley-Howe analysis can help classify the dental
arch relationships into different categories, such as:
Normal: Where the measurements fall within the
expected range.
Narrowed: Indicating a constricted arch that may
require expansion.
Widened: Indicating a broader arch that may need to
be reduced or managed differently.
Clinical Application:
The Ashley-Howe model analysis is particularly useful in treatment
planning for orthodontic cases involving:
Crossbites: Where the upper teeth are positioned
inside the lower teeth.
Crowding: Where there is insufficient space for
teeth to erupt properly.
Expansion Needs: Determining if a patient requires
arch expansion to correct transverse discrepancies.
Treatment Implications:
Based on the analysis, orthodontists can decide on appropriate treatment
modalities, which may include:
Orthodontic Appliances: Such as expanders to widen
the arch.
Extraction: In cases of severe crowding or when
space needs to be created.
Comprehensive Orthodontic Treatment: To align the
teeth and improve occlusion.
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.
Supervision of child"s dentition is critical at or in
1) 3-6 years primary dentition
2) 7-10 years mixed dentition
3) 11-14 years permanent dentition
4) 14-17 years post permanent
Orthodontics
Answer: 2
Supervision of a child's dentition is critical during all developmental stages, but the 7-10 years age range, which is the mixed dentition stage, is a particularly important time for monitoring. This is because it is the period when both primary (baby) and permanent (adult) teeth are present in the mouth. During this stage, children are at risk for various dental problems such as crowding, malocclusion, and the loss of primary teeth that can affect the eruption of permanent teeth.
Relapse of orthodontic tooth rotation is due to periodontal traction. This is mainly caused by action of which periodontal fibers
1) Supracrestal fibres and oblique fibres
2) Supracrestal fibres and horizontal fibres
3) Supracrestal fibres and transeptal fibres
4) Transeptal fibres and oblique fibres
Orthodontics Answer: 3
PDL traction is mainly due to supracrestal fibres, transeptal fibres of gingival fibers.
It needs at least 232 days for readaptation, e.g. rotations.
To avoid relapse either circumferential supracrestal fibrotomy is done OR a prolonged retention is given.