ORTHO MCQ

Question 1

Which of the following is not included in the 6 keys that Andrews determined were required to produce ideal occlusion :

a. Correct mesio-distal tip
b. Correct molar relationship
c. Presence of a Curve of Spee
d. No spaces
e. No rotations

Answer 1

c. Presence of a Curve of Spee

Question 2

Which of the following best describes the most reproducible patient positioning when carrying out an extra-oral A-P or vertical orthodontic assessment?
Select one:

a. Patient standing looking straight ahead
b. Frankfort plane parallel to the floor
c. Mandibular plane parallel to the Frankfort plane
d. Patient sitting in the dental chair looking straight ahead
e. Go-Me plane parallel to the floor

Answer 2

b. Frankfort plane parallel to the floor

Question 3

The BSI definition “The lower incisor edges lie posterior to the cingulum plateau of the upper incisors. The upper central incisors are retroclined. The overjet is usually minimal or may be increased” refers to which malocclusion type:
Select one:

a. Class I
b. Class II Division II
c. Class II Division 1
d. Class II
e. Class III

Answer 3

b. Class II Division II

Question 4

Which of the following statements defines a Class I molar relationship?

a. The mesio-buccal cusp of the upper first molar occludes with the distal cusp of the lower second premolar
b. The mesio-buccal cusp of the upper first molar occludes with the disto-buccal cusp of the lower first molar
c. The mesio-buccal cusp of the upper first molar occludes with the mesio-buccal groove of the lower first molar
d. The disto-buccal cusp of the upper first molar occludes with the mesio-buccal cusp of the lower first molar
e. The disto-buccal cusp of the upper first molar occludes with the mesio-buccal cusp of the upper second molar

Answer 4

c. The mesio-buccal cusp of the upper first molar occludes with the mesio-buccal groove of the lower first molar

Question 5

Which of the following statements describes a normal (or average) complete overbite?
Select one:

a. The upper incisor crown overlaps two thirds to three quarters of the lower incisor crown and both tooth crowns are in contact with each other
b. The upper incisor crown overlaps one third to one half of the lower incisor crown but the crowns of these teeth do not make contact with tooth or soft tissue.
c. The upper incisor crown overlaps one third to one half of lower incisor crown and the lower incisor crown is in contact with the upper incisor crown
d. The upper incisor crown at its incisal edge occludes with the lower incisor crown
e. The upper incisor crown overlaps the full height of the lower incisor crown and the lower incisor is in contact with the palatal tissue.

Answer 5

c. The upper incisor crown overlaps one third to one half of lower incisor crown and the lower incisor crown is in contact with the upper incisor crown

Question 6

Class II skeletal jaw relationship is most commonly associated with which of the following?
Select one:

a. An increased lower anterior face height.
b. Mandibular prognathism.
c. Bimaxillary retrusion.
d. A prognathic maxilla.
e. A retrognathic mandible.

Answer 6

e. A retrognathic mandible.

Yes! A small or retrusive mandible is the most common cause.

Question 7

Which of the following is most commonly associated with a Class III jaw relationship?

Select one:

a. Anterior open bite.
b. Mandibular prognathism.
c. Vertical maxillary excess.
d. Anteroposterior maxillary deficiency.
e. True mandibular asymmetry.

Answer 7

d. Anteroposterior maxillary deficiency.

Question 8

Which of the following would you expect to find in a patient with long face syndrome?

Select one:

a. Backward growth rotation of the mandible.
b. Increased maxillary posterior dentoalveolar height.
c. An increased lower anterior face height percentage.
d. Ante-gonial notching of the mandible.
e. All of the above.

Answer 8

e. All of the above.

Question 9

What is the likely cause of a left-sided unilateral posterior crossbite that is not associated with a lateral displacement of the mandible on closure?

Select one:

a. A narrow maxillary dental arch.
b. Vertical maxillary deficiency.
c. A true asymmetry of the mandible with the chin point shifted to the left.
d. An anterior open bite.
e. Mandibular prognathism.

Answer 9

c. A true asymmetry of the mandible with the chin point shifted to the left.

Correct. The asymmetry causes the teeth to occlude straight into the crossbite position with no need for the mandible to slide into ICP.

Question 10

What is the correct term used to describe a mismatch between the size of a patient’s teeth and jaws?

Select one:

a. Dento-skeletal discrepancy.
b. Dento-alveolar disproportion.
c. Severe crowding.
d. Odonto-alveolar disproportion.
e. Microdontia.

Answer 10

b. Dento-alveolar disproportion.

Question 11

When performing an intra-oral examination of a 9.5 year-old patient which of the following would not be considered a relevant feature to indicate the possibility of an unerupted ectopic canine?
Select one:

a. Mobility of the deciduous canine
b. Discolouration of the deciduous canine
c. A palpable palatal elevation of the alveolar mucosa
d. Inclination/Angulation of the upper lateral incisor
e. Presence of an upper midline diastema

Answer 11

e. Presence of an upper midline diastema

Question 12

Which of the following can be caused by early loss of primary teeth?
Select one:

a. Crowding and dental centreline shifts
b. Ankylosis of permanent teeth and loss of alveolar bone
c. Dental centreline shifts and loss of alveolar bone
d. Space loss and ankylosis of permanent successor
e. Drifting of adjacent teeth and caries in the permanent dentition

Answer 12

a. Crowding and dental centreline shifts

Question 13

Which of the following is not a recognised effect of a digit-sucking habit on the developing dentition?
Select one:

a. Retroclination of the lower incisors
b. Unilateral posterior cross-bite
c. Proclination of the upper incisors
d. Anterior crossbite
e. Anterior open bite

Answer 13

d. Anterior crossbite

Question 14

Which two the following categories of supernumerary teeth are the most likely to erupt into the oral cavity?
Select one:

a. Compound odontome and tuberculate
b. Mesiodens and complex odontome
c. Supplemental and conical
d. Conical and tuberculate
e. Tuberculate and Supplemental

Answer 14

c. Supplemental and conical

Question 15

Your child patient presents with a single grossly carious first permanent molar. The condition of the other three first permanent molars is reasonably good. Which of the following are the main factors that influence any decisions that need to be made regarding whether or not to balance or compensate the extraction of this grossly carious tooth?
Select one:

a. Early loss of primary teeth, malocclusion type, age of patient
b. Age of patient, presence of bilateral crossbite, degree of crowding
c. Age of patient, degree of crowding, malocclusion type
d. Presence of carious deciduous teeth, age of patient, Crowding
e. Presence of crowding, malocclusion type, presence of carious deciduous teeth

Answer 15

c. Age of patient, degree of crowding, malocclusion type

Question 16

Which of the following histological features is thought to play the biggest role in tooth eruption:
Select one:

a. Gubernacular cord
b. Reduced enamel Epithelium
c. Epithelial root sheath ( Hertwig’s root sheath )
d. Dental Follicle
e. Epithelial cell rests (of Malassez)

Answer 16

d. Dental Follicle

Question 17

In order to promote eruption of an upper second premolar we are considering extracting the deciduous second molar. What would be the ideal stage of root development of the unerupted second premolar to produce an optimal result?
Select one:

a. Less than one half root formed
b. Less than one third root formed
c. More than two thirds root formed
d. One half to two thirds root formed
e. Root formation not started but crown formation complete

Answer 17

d. One half to two thirds root formed

Question 18

Which of the following force ranges would be most appropriate to apply when trying to intrude teeth with a fixed appliance?
Select one:

a. 100-150g
b. 10-20g
c. 35g -60g
d. 150-200g
e. 50-100g

Answer 18

b. 10-20g

Question 19

Which of the following is NOT a factor which can influence the rate of tooth movement?
Select one:

a. Magnitude of force
b. Anatomy of bone in the area
c. Direction of force
d. Age of the patient
e. Duration of force

Answer 19

c. Direction of force

Question 20

With regards to the mechanism by which bodily orthodontic tooth movement takes place during fixed appliance treatment, which of the following statements is true:

Select one:

a. Bone is removed in response to tension of the periodontal ligament on the same side of the tooth as the direction of intended tooth movement
b. Bone is removed in response to compression of the periodontal ligament on the opposite side of the tooth to the direction of intended tooth movement
c. Bone is laid down in response to compression of the periodontal ligament on the same side of the tooth as the direction of intended tooth movement
d. Bone is laid down in response to tension of the periodontal ligament on the opposite side of the tooth to the direction of intended tooth movement
e. Bone is laid down in response to compression of the periodontal ligament on the same side of the tooth as the direction of intended tooth movement

Answer 20

d. Bone is laid down in response to tension of the periodontal ligament on the opposite side of the tooth to the direction of intended tooth movement

Question 21

The study of facial growth is important to Orthodontists because…?

Select one:

a. the position and function of the soft tissues will depend on facial maturity.
b. the size and shape of the jaws is genetically determined and will be responsible for the malocclusion observed.
c. the eruption of teeth can be timed to facial growth.
d. it is necessary to know when facial growth stops so that orthodontic treatment can begin.
e. orthodontists can increase or reduce the rate of facial growth to treat a malocclusion.

Answer 21

b. the size and shape of the jaws is genetically determined and will be responsible for the malocclusion observed.

Question 22

All the limbs and organs including the face have developed during the embryonic period. How long in weeks is the embryonic period?

Select one:

a. 1-6
b. 1-8
c. 1-10
d. 1-12
e. 1-14

Answer 22

b. 1-8

Question 23

Which embryological cells are responsible for the branchial arches, cartilage, bone, connective tissue, including the dental tissues such as dental pulp, dentine, cementum and PDL?

Select one:

a. Endoderm Cells
b. Neuroepithelial Cells
c. Neural Crest Cells
d. Ectoderm Cells
e. Mesoderm Cells

Answer 23

c. Neural Crest Cells

Question 24

Fetal Alcohol Syndrome can present in 1 in 300 live births and has the following features; microcephaly, short palpebral fissures, low nasal bridge, flat mid-face, indistinct philtrum, micrognathia. At what stage during embryological development, in days, is it thought that these defects originate?

Select one:

a. 17
b. 27
c. 37
d. 47
e. 57

Answer 24

a. 17

Question 25

Clefts of the lip and clefts of the palate have different embryological origins but can occur together. What stage, in days, during embryological development is it believed that the palatal shelves must elevate?

Select one:

a. 28-38
b. 32-45
c. 37-47
d. 42-55
e. 45-52

Answer 25

d. 42-55

Question 26

To utilise growth potential when expanding the maxilla with an orthodontic appliance treatment should be carried out:

Select one:

a. Before the age of 7 years
b. Before the age of 16 years
c. Before the age of 12 years
d. Before the age of 20 years
e. At any age (there is always scope to expand the maxilla due to continued growth throughout life)

Answer 26

b. Before the age of 16 years

Question 27

Which of the following cartilages has the greatest contribution to the post-natal development of the mandible?

Select one:

a. Symphyseal cartilage
b. Septal cartilage
c. Meckel’s cartilage
d. Condylar cartilage
e. Coronoid cartilage

Answer 27

d. Condylar cartilage

Question 28

The synchondrosis which remains active for the longest period of time during facial growth is :
Select one:

a. Spheno-ethmoidal synchondrosis
b. Spheno-palatine synchondrosis
c. Inter-sphenoidal synchondrosis
d. Spheno-occipital synchondrosis
e. Fronto-ethmoidal synchondrosis

Answer 28

d. Spheno-occipital synchondrosis

Question 29

Which of the following statements best describes a forward growth rotation of the mandible:
Select one:

a. The increase in the anterior face height is greater than the increase in the posterior face height and a “ short face “ type results.
b. The increase in the posterior face height is greater than the anterior face height and the mandible rotates clockwise
c. The increase in the anterior face height is greater than the posterior face height and a “long face” type is produced
d. The increase in the posterior face height is greater than the anterior face height and a “short face” type is produced
e. The increase in the anterior face height is greater than the posterior face height and a “deep bite” is produced.

Answer 29

d. The increase in the posterior face height is greater than the anterior face height and a “short face” type is produced

Question 30

In relation to growth of the cranial vault: Which of the following statements best describes the growth mechanisms by which the cranial vault increases in size?

Select one:

a. Growth at the Spheno-ethmoidal synchondrosis, with deposition of bone on the outer surface of the calvarium and resorption of bone in the middle of the sutures
b. Deposition of bone at the periphery of the sutures, resorption of bone on the inner surface of the calvarium and deposition of bone on the outer surface of the calvarium
c. Deposition of bone within the sutures, resorption of bone on the outer surface of the calvarium and deposition of bone on the inner surface of the calvarium
d. Deposition of bone in the middle of the sutures, resorption of bone at the periphery of the sutures and deposition of bone on the outer surface of the calvarium
e. Growth at the Spheno-ethmoidal synchondrosis, deposition of bone at the sutures and resorption of bone on the inner surface of the calvarium

Answer 30

b. Deposition of bone at the periphery of the sutures, resorption of bone on the inner surface of the calvarium and deposition of bone on the outer surface of the calvarium