MDS PREP
The first ossification center of the mandible in six weeks old human embryo is found in which of the following locations
1) Future coronoid process
2) Future condylar process
3) Future mental foramen
4) Future mandibular foramen
Orthodontics Answer: 3
SOLUTION
The mandible is ossified in the fibrous membrane covering the outer surfaces of Meckel’s cartilages.
These cartilages form the cartilaginous bar of the mandibular arch, and are two in number, a right and a left.
Ossification takes place in the membrane covering the outer surface of the ventral end of Meckel’s cartilage , and each half of the bone is formed from a single center which appears, near the mental foramen, about the sixth week of fetal life.
By the tenth week the portion of Meckel’s cartilage which lies below and behind the incisor teeth is surrounded and invaded by the membrane bone
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.
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.
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.
Considering the 3D growth of the face, it ceases last in which direction?
1. A-P
2. sagittal
3. transverse
4. vertical
Orthodontics
Answer: 4
for facial growth order of growth is
width > depth > height
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.
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.