1. Orthodontics
2011 NDEB Questions
Pages 27-53

2. Page- 47
Question 6. In cephalometry, the most stable in growing skull is the
A. Sella Turcica
B. Nasion
C. Broadbent’s Point
D. Bolton point
 Answer: A. SELLA TURCICA
 Explanation: Sella Turcica is the center or
pituitary fossa in cranial base.
 Ref. Orthodontics Dental Decks
Page 23

3. Page- 47
#. 7. Which of the foloiwng patient should be referred for orthodontic
treatment to close a diastema between maxillary central incisor.
1.An 8 yrs old with no abnormal oral habits
2. A 3 yrs old with no abnormal oral habits
3. A 3 yrs old with a 4mm over jet
4. An 8 yrs old with previous thum habit.
A. 1,2,3
B. 1 and 3
C. 2 and 4
D. 4 only
E. All of the above
 Answer: D- 4 only
 Explanation: About 98 % of children at ages 6 yrs old have
median maxillary diastema. Spaces tend to close as
permanent canine erupts. The permanent canine erupts at
age 11. However if oral habits such as thumbsucking is
involved, its better to refer patient to orthodontist for
consultation to minimize further damage as the child is at the
age that its crucial to get rid of the bad oral habits.

4. Page- 46
1. An 8 yrs old boy has lost tooth 11. The lateral incisor have partially erupted. You would expect that
the tooth 12 will erupt
A. without encrouching upon the space,
B. ecrouching upon the central incisor space.
C. and the left central incisor will encrouch upon the space.
D. B and C.
 Answer: A – without encrouching upon
the space.
 Explanation: There should be no change
on the space because it is only applies to
permanent molars – Mesial drifting.

5. Page-49
1. If there is insufficient arch space for a permanent tooth to erupt, the tooth may
A. cause resorption of the root of another tooth
B. erupt out of position
C. not erupt
D. All of the above
 Answer: B. erupt out of position
 Explanation: It is a usual observation with
primary dentition that if the existing
decidous tooth is still in place and the
adult tooth is coming in, it usually erupt
out of position – usually lingually or labially.

6. Page 49
3. Following very early loss of a primary tooth, the eruption time of the permanent
successor could be
A.unaltered
B. accelerated
C. delayed
D. None of the above
 Answer: C. delayed
 Explanation: Usually when the primary
tooth loss prematurely, the successor
tooth takes longer to erupt, this is because
the adult teeth has no more guiding path
for eruption. The decidous tooth is a
guidline for the the permanent dentition
path of eruption by resorbing the root
apex slowly.

7. Page 49
5. In a normally developing occlusion, spaces between decidous or permanent
incisor are called.
A. physiological spaces
B. primate space
C. Leeway space
D. Freeway space
 Answer: B. Primate space
 Explanation: Primate space is the gap between the primary
teeth of a child. These are normal. They are the result of the
jaws growing to accommodate the larger adult teeth.
In the mandibular arch, the primate space is between the canine
and the 1st molar (or 1st premolar in adults).
Whereas, in the maxillary arch, it is between the lateral incisors
and canines.
Leeway Space -Difference between the combined mesiodistal
widths of the deciduous cuspids and molars and their successors.
Freeway space-the interocclusal distance or separation between
the occlusal surfaces of the teeth when the mandible is in its
physiologic rest position.

8. Page 49
6. The principal growth sites of the maxilla in a downward and forward direction
include the
1. frontomaxillary suture A. 1,2,3 E. All of the above.
2. zygomaticomaxillary suture B. 1 and 3
3. pterygopalatine suture C. 2 and 4
4. median palatine suture D 4 only
 Answer: A – 1,2,3
 Explanation: The maxilla develops entirely by intra
membranous ossification. Sutural connective tissue
proliferation; ossifications, surface
apposition, resorption, and translation are
mechanism for maxillary growth. The maxilla is
related to the cranium at least partially by the
frontomaxillary suture, the zygomaticomaxillary
suture, zygomaticotemporal suture and
pterygopalatine suture.

9. Page 50
1. If a patient loses a maxillary first permanent molar before the age of 10 the
A premolar drifts distally
B maxillary second molar erupts and moves forward
C. opposing tooth erupts into the space created
D. overbite increases
 Answer: B- maxillary second molar erupts
and moves forward.
 Explanation : The contemporary view is that mesial
drift is a phenomenon of the permanent molars
only. The major reason these teeth move mesially
when a space opens up is their mesial
inclination, so that they erupt mesially as well as
occlusally.

10. s. The frankfort plane
1. Extends from the Porion to the Orbitale A. 1 only
2. is parallel with the maxillary plane. B. 1,2,3
3. describes the cranial base dimensions C. 1 and 3
D. 1 and 2
 Answer : A – 1 only
 Explanation : a plane used in craniometry that
is determined the highest point on the upper
margin of the opening of each external
auditory canal and the low point on the lower
margin of the left orbit and that is used to
orient a human skull or head usually so that
the plane is horizontal.

11. 3. The facial profile associated with a Class III malocclusion is
A. Concave
B. Convex
C. either concave or convex
D. Straight
 Answer: B- convex
 Explanation: This is a profile
Facial view of class III
Malocclusion
http://www.columbia.edu/itc/hs/dental/D5300/Classificati
on%20of%20Malocclusion%20GALLOIS%2006%20final_BW.p
df

12. 4. An 11 year old child has an open bite caused by active thumbsucking. You would
A. insert a habit-breaking appliance
B. refer to psychologist for evaluation
c. encourage the child to accept help in discontinuing the habit and observe periodically.
D. refer to an orthodontist.
 Answer: D- refer to an orthodontist.
 Explanation: Because of the patients age
It is best for Orthodontist to evaluate the
child if the open bite so correction can be
made earlier.
A habit breaking appliance might not
correct the open bite created by the active
thumbsucking.

13. 5. Spacemaintainer in the posterior segment will:
A. Prevent extrusion of opposing teeth
B. Prevent the eruption of the permanent teeth
C. Retard eruption of the permanent teeth
D. maintain arch length
 Answer: D. Maintains arch length
 Explanation: Spacemaintainers are define
as the appliance that prevents loss of
arch length and which in turn guide the
permanent tooth into a correct position in
the dental arch.

14. 6. Occipital and / or cervical extra-oral anchorage is used to
1. restrict anterior tooth movement A. 1 and 3
2. enhance maxillary forward growth B. 2 and 4
3. enhance mandibular forward growth c. 3 and 5
4. encourage anterior tooth movement D. 1 and 5
5. restrict maxillary forward growth E. 2 and 3
 Answer: C – 3 an 5
 Explanation:
Uses of cervical extra oral anchorage :
-Restrict maxillary growth
-Retract maxillary dentition
- Camouflage by extraction of upper premolars
-Advance the mandible
-Advance mandibular dentition

15. 7. The root of the first permanent molar should be completely formed by the age of
A. 6 years
B. 7 years
C. 9 years
D. 11 years
E. 13 years
 Answer: D. – 11 years old
 Explanation: For Max. and Mand. the year
t he root is completely form for the
permanent first molar is
10 ½- 10 ¾years this is then closer to 11 yrs
old.

16. 8. As the mandible grows down ward and forward, bone deposition takes place
A. on all surfaces of the mandible
B. on the posterior border of the ramus
C. on the anterior border of the ramus
D. on the alveolar margins
E. B and D
 Answer: B- on the posterior border of the
ramus
 Explanation: The body of the mandible
grows longer as the ramus moves away
from the chin, this occurs by removal of
bone from the anterior surface of the
ramus and depostion of bone on the
posterior surface.

17. Page 51
3. The roots of primary molars in the absence of their permanent succesors
1. sometimes partially resorbed and ankylosed
2. may remains for years with out significant resorption
3. may remain for years partially resorbed
4. are always resorbed
A. 1,2,3
B. 1 and 3
C. 2 and 4
D. 4 only
E. all of the above
 Answer: E – all of the above
 Explanation: Although there is no permanent succesor , the
root of the primary molars eventually resorbed and sometimes
can stay for many years partially resorbed , but its unknown
why the resorption process happens. Most of the time when
there is no succesor the primary tooth is submerge into the
gums and ankylosed.
 Akylosis – is a hard tissue union between the bone and tooth.

18. 6. Which of the following factors is related to a malocclusion caused by
thumbsucking?
A. Duration
B. Frequency
C. Intensity
D. All of the above
 Answer: D- all of the above
 Explanation- if the habits persist beyond the time that the
permanent teeth begin to erupt, however, malocclusion
characterized by flared and spaced maxillary incisors, lingually
positioned lower incisors, anterior open bite, and a narrow
upper arch is likely result. The characteristic malocclusion
associated with sucking arises from a combination of direct
pressure on the teeth and an alteration in the pattern of resting
cheek and lip pressure.
 How much the teeth are displaced should correlate better with
the hours per day of sucking than with the magnitude of the
pressure.

19. Page 52
1 Alveolar bone is undergoing remodeling
A. through the primary dentition
B. until the end of mixed dentition
C. until the complete eruption of permanent teeth
D. throughout life
 Answer: D. throughout life
 Explanation: With out a tooth there is no
Alveolar bone. Alveolar bone holds the
tooth in place. Through out life it continues
to remodels as it needed. When
orthodontic force is applied the alveolar
bone goes through a process of remodeling
to compensate for the movement of the
tooth being moved by the appliance.

20. 5. During orthodontic treatment, poor oral hygiene may result in
1. marginal gingivitis A. 1 and 2
2. gingival fibrosis B. 1,2,3
3. ulcerative gingivitis C. 1 and 3
4. acute periodontitis D. 1,3,5
5. juvenile periodontitis E. all of the above
 Answer: A 1 and 2
 Explanation:
 Marginal Gingivitis an inflammation of the gingivae localized to the marginal gingivae and
interdental papillae – Right answer.
 Gingival fibrosis -Gingival enlargement may be caused by a multitude of causes. The most
common is chronic inflammatory gingival enlargement, when the gingivae are soft and
discolored. This is caused by tissue edema and infective cellular infiltration caused by
prolonged exposure to bacterial plaque, and is treated with
conventional periodontal treatment, such as scaling and root planing –right answer .
 Juvenile periodontitis occurs in children and young adults and can be classified into:
periodontitis which occurs in otherwise healthy individuals, and periodontitis which occurs in
juveniles with systemic disease. – NOT the right answer
 Acute periodontitis is a sharply localized, acute inflammatory process involving the
interproximal and marginal areas of two or more adjacent teeth, characterized by severe
pain, purulent exudate from edematous inflamed gingivae, general malaise, fever, and
sequestration of the crestal aspects of the alveolar process. It is now considered a stage of
periodontal disease. – Not the right answer
 Necrotizing ulcerative gingivitis (NUG) is a condition affecting the gums that is caused by a
bacterial infection. It is a form of periodontal (gum) disease. But unlike other forms, it
typically develops quickly and causes moderate to severe pain.- Not the right answer.

21. 7. The term “ Dental Age” refers to the
A. State of dental maturation
B. Eruption time of given tooth
C. number of year elapse since a given tooth erupted
D. None of the above.
 Answer: B. Eruption time of given tooth
 Explanation: Dental age is determined
from three characteristics. The first is which
teeth have erupted. The second and
third, which are closely related , are the
amount of resorption of the roots of
primary teeth and the amount of
development of the permanent teeth.

22. Page 53
3. The most frequent cause malocclusion is
A.Thumbsucking
B. Mouth breathing
C. Heredity
D. Ectopic Eruption
 Answer: A. and C
 Explanation:
The most frequent cause of malocclusion is -
Hereditary causes related with the development of
jaws and teeth
Tooth loss related with non hereditary factors such
as diseases or trauma
Oral habits that affect the teeth and jaws health-
like thumbsucking.

23. 5. Orthodontic tooth movement in an adolescent Is easier than an adult because of
A. difference in tissue/bone reaction
B. difference in growth
C. difference in cooperation
D. all of the above
 Answer: D – all of the above
 Explanation: Various factors must be given considerations, which
demand special consideration for adults.
 Psychosocial factors-adults demand best treatment results in a short
Period of time.
 Perio-restorative problems
 Age related considerations
Lack of growth potential
Aging of tissues
Vulnerability to Root resorption
Vulnerability to TMD

24. 6. Labioversion of maxillary incisor teeth is associated with
A. thumbsucking
B. spaced maxillary incisor teeth.
C. lack of normal tonicity of the labial musculature
D.All of the above
Answer: A. Thumbsucking
Explanation: Angle Class II Division 1 is an example of labioversion
of maxillary incisor.
Prolonged oral habits is a clear cause of some malocclusion.

25. 7. Premature loss of mandibular decidous cuspids in Class 1 and class II cases result in
increased
1. Overjet A. 1,2,3 E. all of the above
2. arch width B. 1 and 3
3. overbite c. 2 and 4
4. leeway space D. 4 only
 Answer: Not sure
Needs help with this one

26. 8. The maxillary incisor in Angle’s class II Division 2 malocclusion are in
A. linguoversion
B. labioversion
C. infraversion
D. supreversion
 Answer: A- linguoversion
 Explanation: The incisors are inclined
lingually.

27. Othodontics
2012 NDEB Question
Pages 27- 53

28. Page 27
6. In treatment of an Angle Class II Div 2 the Frankel functional regulator is designed
to perform all the following except
A . Increase vertical dimension
B. reposition the mandible
C. retract the maxillary molars
D. expand the dental arches
 Answer: B- reposition the mandible
 Explanation: Frankel's Functional Regulator is an
activator particularly suitable in malocclusions of
Class II at the age of growth. The Frankel use the
natural growth spurt and shields from
unwanted forces, to encourage the top and bottom
jaw to develop a more natural position. Its has shields
to remove unwanted forces from the cheeks and
labial shields to relieve pressure from the lips.

29. Page 35
5. The optimal time for orthodontic treatment involving growth manipulation for
skeletal class II malocclusions is during
A. late primary dentition
B. after the eruption of third molars.
C. after skeletal growth is complete
D. during the period of greatest growth velocity
 Answer: D. during the period of greatest growth
velocity
 Explanation : The concept of two-phase treatment:
early use of functional appliances in the mixed
dentition, followed by a period of retention and then
a second phase of treatment, usually involving the
use of fixed appliances. The advocates of early
treatment fee lthat starting early will maximize the
chances of growth modification (especially in female
patients who tend to reach their skeletal maturity
earlier), allow for two chances to correct the
malocclusion and avoid problems of compliance
often encountered in adolescents.

30. Page 36
7. An anterior cross-bite of a permanent maxillary incisor in a mixed dentition is often
associated with
A. a functional shift
B. unexplainable genetic factors
C. lingually situated supernumerary teeth
D. prolonged retention of a primary incisor.
E. premature eruption of a maxillary incisor
 Answer: D. prolonged retention of a
primary incisor.
 Explanation: Most of the time if the
decidous maxillary incisors still in place the
succeding tooth will erupt out of position
and usually it lingually, this is why
sometimes there is an evident of crossbite
with maxillary incisor and this gets better
as soon as the decidous tooth exfoliate or
extracted.

31. Page 37
1. The principal growth sites of the maxilla in a down ward and forward direction
include the
1. frontomaxillary suture A. 1,2,3 E. all of the above
2. zygomaticomaxillary suture B. 1 and 3
3. pterygopalatine suture C. 2 and 4
4. median palatine suture D. 4 only
 Answer: A – 1,2,3
 Explanation: Everything but Median
palatine suture. Growth sutures are the
following for the maxilla:
1. Frontonasal suture
2. Frontomaxillary suture
3. Zygomatico Temporal suture
4. Zygomatico maxillary suture
5. Pterygopalatine suture
This sutures are oblique and more or less parallel with each other. The
growth in these areas would serve to move maxilla downward and forward.

32. Page 38
1. if a flush terminal plane convers to a mesial step terminal plane (Class I occlusion) without
orthodontic intervention, it is primarily a result of
A. the absence of mandibular primate space.
B. maxillary forward growth exceeding mandibular forward growth
C. mesial movement of the mandibular first permanent molars following exfoliation of the mandibular
second primary molars.
D. distal movement of the maxillary first permanent molars following eruption of the maxillary second
bicuspids.
 Answer: C. Mesial movement of the
mandibular first molars following
exfoliation of the mandibular second
primary molars.
Explanation: When the second primary molars are
lost, the first permanent molars move forward( mesially)
relatively rapidly using the leeway space. This decreases
both arch length and arch circumference , which are
related and commonly confused terms. The leeway space
is normally used by mesial movement of the permanent
molars.

33. Page 43
7. The occlusal parameter most likely associated with maxillary anterior spacing is
a/an
A. Class II Div 2 dental malocclusion
B. Class III skeletal malocclusion
C. Accentuated maxillary curve of Wilson
D. reverse maxillary curve of Wilson
 Answer: C
 Explanation: Curve of wilson is the
curvature of the cusps, as seen from the
front view. The curve in the mandibular
arch is concave, whereas the one in the
maxillary arch is convex.

34. Page 42
5. Which of the following conditions is usually present in an Angle Class II Division
2 malocclusion?
A. Openbite
B. Retroclined maxillary lateral incisor
C. Retroclined maxillary central incisor
D. Distoclusion of permanent maxillary first molars
 Answer: C- retroclined maxillary central
incisors.
 Explanation: occlusal view of ClassII Div 2

35. Page 34
7 Which occlusal parameter is the most useful to determine if a posterior crossbite is
of skeletal of dental origin?
A. Anterior overbite
B. Sagittal molar relationship
C. Lack of space in the maxillary anterior area
D. Lack of space in the mandibular arch.
E. Buccolingual angulation of affected teeth
 Answer: E. Buccolingual angulation of
affected teeth
 Explanation: From occlusal view , the
actual position of the tooth involve is a big
indication of posterior crossbite is of
skeletal dental origin.

36. Page33
5. The most appropriate treatment following the extraction of a first primary molar in 4
years old child is
A. regular assessment of arch development
B. to perform space analysis
C. insertion of a space maintainer
D. extraction of the contra-lateral molar
E. extraction of the opposing molar
 Answer: C – insertion of spacemaintainer
 Explanation : Because of the age of the
patient, it is important to preserve the
space by inserting a band and loop
spacemaintainer in order to preserve the
space for the succedaneous tooth.
 According to the eruption table its not
until 9-11 years old when the primary
molar is ready to exfoliate.

37. 7. Closure of a 2 mm maxillary midline diastema by orthodontic treatment is best accomplished
A. Prior to complete eruption of the maxillary central incisors
B. Prior to eruption of the maxillary lateral incisors
C. after complete eruption of the maxillary lateral incisors
D. during intra-oral emergence of the maxillary canines
C. After complete eruption of the maxillary canines
 Answer: C – after complete eruption of
the maxillary canines
 Explanation:

38. Page 49
8. A Bolton relationship has determined a
- maxillary “12” excess of 3.5mm
- maxillary “6” excess of 3.0mm
What effect could this Bolton relationship have on a Class I malocclusion?
1. Deeper overbite
2. Maxillary crowding
3. Reduced overjet
4. Increased overjet
A. 1,2,3
B. 1 and 3
C. 2 and 4
D. 4 only
E. all of the above
 Answer:
 Explanation:

39. Page 51
8. An overjet of 8mm is usually associated with
A. Class I cuspid relationship
B. Class II cuspid relationship
C. Class III cuspid relationship
D. Class I molar relationship
 Answer:
 Explanation:

40. Page 52
6. Which of the following maxillary incisor angulations complicates a functional
appliance contrustion bite?
A Retroclined central incisor
B. Proclined lateral incisors
C. Retroclined lateral incisors
D. Proclined central incisors
 Answer:
 Explanation:

41. Orthodontics
2013 NDEB Questions
Page 27-53

42. Page 51
1. The primary stimulus for growth of the mandible is
A. Genetic
B. Epigenetic
C. Environmental
D. Functional
E. A and D
 Answer:
 Explanation

43. 3. In patient with an Angle Class ! Malocclusion arch length in the mandible changes
between 5 and 18 years of age . It is usually
A increases 0-1 mm
B. increases 3-4 mm
C. decreases 0-1 mm
D. decreases 3-4 mm
 Answer:
 Explanation:

44. Page 53
6. The eruption of which of the following permanent teeth signals the beginning of
the mixed dentition stage?
A. Maxillary central incisor
B. Maxillary canine
C. Mandibular first molar
D. Mandibular central incisor
 Answer:
 Explanation:

45. 7. The interocclusal relationship of the primary second molars
1. The interocclusal relationship of the primary second molars
h