MDS PREP
The angle of convexity
1) SNA
2) NAPog.
3) ANB
4) SNB
Orthodontics Answer: 2
SOLUTION
Angle of Convexity The angle of convexity is formed by the intersection of line from N to point A, to point A to pogonion.
Premature exfoliation of primary mandibular canine is most often the sequelae of:
1) Caries
2) Trauma
3) Serial tooth extraction
4) Arch length inadequacy
Orthodontics Answer: 4
SOLUTION
The two major symptoms of severe crowding in the early mixed dentition are severe irregularity of the erupting permanent incisors and early loss of primary canines caused by eruption of the permanent lateral incisors. The children with the largest arch length discrepancies often have reasonably well aligned incisors in the early mixed dentition, because both primary canines were lost when the lateral incisors erupted
After a definitive analysis of the profile and incisor position, these patients face the same decision as those with moderate crowding; whether to expand the arches or extract permanent teeth. In the presence of severe crowding, limited treatment of the problem will not be sufficient and permanent tooth extraction is most likely the best alternative.
In Angle’s class III malocclusion, mandibular anterior teeth will be
1) Proclined
2) Retroclined
3) Inclined
4) Any of the above
Orthodontics Answer: 2
SOLUTION
The reason is found in the concept of "dental compensation for skeletal discrepancy. This can occur naturally as well as being created by orthodontic camouflage treatment.
In mandibular prognathism, for instance, as the individual grows the upper incisors tend to protrude while the lower incisors incline lingually.
By the time growth is completed, the dental discrepancy usually is smaller than the jaw discrepancy.
Tooth position has compensated at least partially for the jaw discrepancy.
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)
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.
Orthodontic tooth movement is inhibited by which of the following drugs
1) NSAIDS, such as Brufen
2) OPIOIDS, such as CORTISONE
3) Antibiotics such as tetracycline
4) Vasoconstrictors such as adrenaline
Orthodontics Answer: 1
SOLUTION
NSAIDS, i.e. Brufen, etc. inhibit tooth movement as they interfere with production of prostaglandins.
• Nimesulide does not interfere with PG production and so can be safely given during tooth movements.
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.
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.