MDS PREP
According to Angle, the key to normal occlusion in adults is the anteroposterior relationship. His description of teeth relationships in normal occlusion remains a fundamental observation. Angles observations are based on which teeth that are most reliable to understand occlusion
1) First molars and canines
2) First molars and first Premolars
3) Canines and first Premolars
4) First molars and central incisors
Orthodontics Answer: 1
SOLUTION
The mesial incline of the upper canine occludes with the distal incline of the lower [canine];
the distal incline of the upper canine occludes with the mesial incline of the buccal cusp of the lower first premolar.
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.
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.
Analysis which is similar to Pont’s analysis is_______?
1) Linder Harth index
2) Korkhaus analysis
3) Bolton’s analysis
4) (A) and (B)
Orthodontics Answer: 4
SOLUTION
· Pont’s in 1905 presented a system whereby the measurement of the four maxillary incisors automatically established the width of the arch in the premolar and molar region. If measured value is less than calculated value, it indicates the need for expansion.
· Linder Harth index: This analysis is very similar to Pont’s analysis except that a new formula has been proposed to determine the calculated premolar and molar value.
· Korkhaus analysis: This analysis is also very similar to Pont’s analysis it makes use of Linder Harth’s formula to determine the ideal arch width in the premolar and molar region.
In addition this analysis utilizes a measurement made from the midpoint of the inter-premolar line to a point in between the two maxillary incisors.
· Bolton’s analysis: The Bolton’s analysis helps in determining disproportion in size between maxillary and mandibular teeth.
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.
Ideally, Orthodontic traction to pull an impacted tooth to line of arch should begin at
1) 2-3 months post surgically
2) As soon as possible after surgery
3) After a waiting period of at least1.5 months
4) Only the method of traction is critical, not the time
Orthodontics Answer: 2
SOLUTION
Mechanical approaches for aligning unerupted teeth. Orthodontic traction to pull an unerupted tooth toward the line of the arch should begin as soon as possible after surgery
Ideally a fixed orthodontic appliance should already be in place before the unerupted tooth is exposed, so that orthodontic force can be applied immediately.
If this is not practical, active orthodontic movement should being no later than 2 or 3 weeks post-surgically.
What dental relationship is present in an Angle Class I occlusion?
Orthodontics Answer: 3
1. The buccal cusp of the maxillary second premolar aligns with the mesiobuccal groove of the mandibular first molar.
2. The cusp of the maxillary canine aligns with the cusp of the mandibular canine.
3. The mesiobuccal cusp of the maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar.
4. The mesiobuccal cusp of the maxillary first molar aligns with the embrasure between the mandibular first molar and second premolar.
The mesiobuccal cusp of the maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar.
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.