INBDE Practice Questions exam Questions and Answers
Question 1.
1. If a tooth is ankylosed, which of the following types of resorption are most likely to have
occurred? A. Cervical resorption B. Replacement resorption C. Inflammatory root
re-sorption D. Internal resorption
Correct Answer: B. Replacement resorption * Ankylosis of a tooth refers to the
fusion of two mineralized surfaces together, usually cementum and alveolar
bone. Replace-ment resorption refers to the phenomenon where osteoclasts
mistake dental tissue for bone leading to the eventual fusion of the two. This
happens most commonly during luxation injuries.
Question 2.
2. Early childhood caries pri-marily affects which teeth? A. Primary maxillary incisors and
molars B. Primary maxillary canines and molars C. Primary maxillary and mandibular
incisors D. Permanent maxillary in-cisors and canines E. Per-manent mandibular incisors
and molars ECC occurs in patients typically ages 3 to 5. It is defined as having one or more
cavitated, miss-ing (owed to caries), or filled smooth surface in any pri-mary tooth. The
most com-mon presentation involves the primary maxillary in-cisors and primary molars,
so the correct answer is A.
Correct Answer: A. Primary maxillary incisors and molars * ECC occurs in
patients typically ages 3 to 5. It is defined as having one or more cavitated,
missing (owed to caries), or filled smooth surface in any primary tooth. The
most common presen-tation involves the primary maxillary incisors and primary
molars, so the correct answer is A.
Question 3.
3. What muscle contracts in such a way that it shapes the distobuccal aspect of a
mandibular denture during border molding? A. Temporalis B. Masseter C. Medial pterygoid
D. Lateral pterygoid E. Ge-nioglossus
Correct Answer: B. Masseter * The masseter muscle originates from the
zygomatic arch and inserts into the mandible. This muscle contracts when the
mouth closes against resistance, like if you were to try to hold your mouth open
with your hand while trying to close your mouth with your jaw muscles. During
border molding, the masseter muscle will shape the distobuccal corner of the
impression and it is thus called the masseteric notch. The answer is B.
Question 4.
4. Which of the follow-ing ions of tooth structure does the fluoride ion replace during the
remineralization process? A. Calcium (Ca) B. Phosphate (PO4) C. Hydroxyl (OH) D. Sodium
(Na)
Correct Answer: C. Hydroxyl (OH) * First off, all of these are ions found in tooth
enamel! Calcium and Sodium are positively charged so it makes sense that a
Fluoride ion with a charge of -1 would not be replacing either of these. It turns
,out that the Phosphate ion with charge of -3 is not replaced, and instead the
Hydroxyl ion with charge of -1 is routinely replaced when enamel is
remineralized and converted from hydroxyapatite to fluorapatite, hence the
name change. The answer is C.
Question 5.
5. Which of the following is a common short-term side ef-fect of nitrous oxide as used in a
dental setting? A. Hives B. Seizure C. Nausea and vomiting D. Rapid heart rate
Correct Answer: C. Nausea and vomiting * This question may seem a bit tricky at
first, but this one is a classic example of applying the high yield facts. If we
picked this question apart, every answer choice could potentially relate to
ni-trous oxide. Hives could be a result of an allergic reaction. Seizure and rapid
heart rate could be due to an overdose. But nausea and vomiting is the classic
short-term side effect that should always be divulged to patients before
administering nitrous oxide sedation. The answer is C.
Question 6.
6. Which of the following dental indexes is not re-versible? A. Periodontal score B. Gingival
score C. DMFT D. OHI-S
Correct Answer: C. DMFT * These dental indexes are used in both clinical
practice and research literature. OHI-S is simplified oral hygiene index and
measures the amount of gross debris and calculus which can be 'reversed' if a
patient improves their oral hygiene. Gingival score (GI) designates amount of
gingival inflammation which can be reversed. Periodontal score (CPITN)
designates probing pocket depth, and while bone loss in periodontal disease is
irreversible, pocket depths can be reversed via reattachment and repair. DMFT
stands for decayed, missing, and filled teeth; and once a tooth becomes
decayed, missing, or filled, that damage/treatment is irreversible. Therefore,
the answer is C.
Question 7.
7. The initial lesion of syphilis is called a __________. A. bubo B. gumma C. chancre D.
pustule E. mucous patch
Correct Answer: C. chancre * Syphilis is caused by contact with the spirochete
bacterium Treponema pallidum. A primary lesion is called a chancre, a
sec-ondary lesion is called an oral mucous patch, condyloma latum, or
maculopapular rash, and a tertiary lesion is called a gumma. The answer is C.
Question 8.
8. When a fourth root canal exists in a maxillary first mo-lar, it is most likely locat-ed in
which of the following roots? A. Lingual B. Distofacial C. Distolingual D. Mesiofacial E.
Mesiolingual
Correct Answer: D. Mesiofacial * Maxillary first molars are a notoriously tricky
tooth to perform a root canal on! That's because the vast majority of them have
3 roots, which you think would mean 3 canals. However, the mesiobuccal root
,more often than not houses 2 canals of its own (MB1 and MB2), so the most
common anatomical layout is 4 canals. That's part of the reason why they are
very frequently referred out to an endodontist. Therefore, the answer is D.
Question 9.
9. Endochondral ossification occurs in the formation of _______________. A. all bones B. flat
bones C. long bones D. elastic cartilage E. mesenchymal sheets
Correct Answer: C. long bones * There are several different ways that bone can
form! Endochon-dral literally translates to "within cartilage" where bone
devel-ops from a pre-existing cartilage model. The cranial base, part of the
mandible, and most long bones of the body are devel-oped via endochondral
ossification. Other bones are formed via intramembranous ossification.
Intramembranous literally trans-lates to "within membrane" where bone
develops from mes-enchyme (fibrous connective tissue). The cranial vault,
maxilla, and the other part of the mandible are formed via intramembra-nous
ossification. The best answer for this question, therefore, is C.
Question 10.
10. Which of the following is the distal view of tooth #14? (Image) 1, 2, 3, 4
Correct Answer: This is a tricky one! Let's start first with the clear outlier,
number 2. Only two roots are visible, and also two cusps are visible. This is the
distal aspect of #5/mesial aspect of #12. Number 3 also looks unique from the
others in that it has a clear bifurcation between the two roots, cluing you in that
it is a mandibular molar. You can also notice that how the cusps are arranged, it
has to be a facial or lingual aspect which would make it incorrect as well. This
leaves us between number 1 and 4. Number 1 is showing the broad mesiobuccal
root (to the right) and the longer palatal root (to the left) making this a mesial
view of #14/distal view of #3. Number 4 on the other hand is showing the small
distobuccal root (to the left), a little glance of the broad mesiobuccal root
behind that, and the palatal root (to the right). And this makes number 4 the
distal view of #14! I hope you had fun with this different kind of dental anatomy
question. The answer is 4.
Question 11.
11. The free gingi-va extends from the _____________________. A. free gingival groove to the
gingival crest B. gingival crest to the inter-dental groove C. alveolar mucosa to the free
gingival groove D. mucogingival junction to the free gingival groove E. epithelial
attachment to the cementoenamel junc-tion
Correct Answer: A. free gingival groove to the gingival crest * The free gingiva is
the portion of gum tissue between the free gingival margin/gingival crest and
the free gingival groove. The attached gingiva is the portion of gum tissue from
the free gingival groove to the mucogingival junction. Apical to this junc-tion is
the mucosa. Since this question is asking to identify the boundaries of the free
gingiva, the answer is A.
Question 12.
, 12. Cracked tooth syn-drome most commonly af-fects which tooth? A. Maxillary first
premolar B. Maxillary second premo-lar C. Mandibular first molar D. Mandibular second
mo-lar E. Maxillary central incisor
Correct Answer: D. Mandibular second molar * The term cracked tooth syndrome
(CTS) refers to an "incom-plete fracture of a vital posterior tooth that involves
the dentin and occasionally extends into the pulp." According to a landmark
paper on the topic, the three most commonly affected teeth are mandibular
second molars, then mandibular first molars, then maxillary premolars. There
are many possible explanations. The proximity of lower second molars to the
center of rotation of the mandible means more occlusal force can be generated
in this region and the relatively high prevalence of large intracoronal
restorations on these teeth may also be a contributing factor. The answer is D.
Question 13.
13. The spacing nor-mally seen between the anterior teeth of a five-year-old child is
caused by ___________________. A. the presence of an exces-sive maxillary labial frenum B.
thumb sucking C. tongue thrusting D. growth of the dental arch-es
Correct Answer: D. growth of the dental arches * Some space in the primary
dentition (called interdental space) is actually a good thing, since it indicates
less likelihood of severe crowding during the transition to the permanent
dentition. This normal (key word is normal) amount of spacing, particularly
between the anterior teeth, is a result of normal growth and development of the
dental arches. The other three etiologies could result in excessive or abnormal
spacing in the anterior. The answer is D.
Question 14.
14. Which of the following speech sounds is NOT con-sidered a sibilant used for evaluating
closest speaking space during the denture fabrication process? A. /s/ B. /z/ C. /v/ D. /sh/ E.
/j/
Correct Answer: C. /v/ * Sibilant or linguoalveolar sounds involve contact
between the tip of the tongue and the anterior palate or lingual surfaces of the
anterior teeth. These include s, z, sh, ch, j (try it out!). These sounds help
determine the vertical length and overlap of anterior teeth during denture
fabrication. The /v/ sound is a fricative or labiodental sound which involves
contact between the maxillary incisors and wet/dry line of lower lip. The answer
is C.
Question 15.
15. The lingual cusp(s) on which of the following mandibular posterior teeth is (are)
approximately 2/3 the height of the respective facial cusp(s)? A. First premolar B. Second
premolar C. First molar D. Second molar E. Third molar
Correct Answer: A. First premolar * Mandibular second premolars have facial
cusps that are slightly taller than their respective lingual cusps, but they are
relatively even in height. All three types of molars also have relatively even
cusp heights, with the non-functional lingual cusps being pointed and maybe
even slightly taller than their respective facial cusps. The crown of mandibular
Question 1.
1. If a tooth is ankylosed, which of the following types of resorption are most likely to have
occurred? A. Cervical resorption B. Replacement resorption C. Inflammatory root
re-sorption D. Internal resorption
Correct Answer: B. Replacement resorption * Ankylosis of a tooth refers to the
fusion of two mineralized surfaces together, usually cementum and alveolar
bone. Replace-ment resorption refers to the phenomenon where osteoclasts
mistake dental tissue for bone leading to the eventual fusion of the two. This
happens most commonly during luxation injuries.
Question 2.
2. Early childhood caries pri-marily affects which teeth? A. Primary maxillary incisors and
molars B. Primary maxillary canines and molars C. Primary maxillary and mandibular
incisors D. Permanent maxillary in-cisors and canines E. Per-manent mandibular incisors
and molars ECC occurs in patients typically ages 3 to 5. It is defined as having one or more
cavitated, miss-ing (owed to caries), or filled smooth surface in any pri-mary tooth. The
most com-mon presentation involves the primary maxillary in-cisors and primary molars,
so the correct answer is A.
Correct Answer: A. Primary maxillary incisors and molars * ECC occurs in
patients typically ages 3 to 5. It is defined as having one or more cavitated,
missing (owed to caries), or filled smooth surface in any primary tooth. The
most common presen-tation involves the primary maxillary incisors and primary
molars, so the correct answer is A.
Question 3.
3. What muscle contracts in such a way that it shapes the distobuccal aspect of a
mandibular denture during border molding? A. Temporalis B. Masseter C. Medial pterygoid
D. Lateral pterygoid E. Ge-nioglossus
Correct Answer: B. Masseter * The masseter muscle originates from the
zygomatic arch and inserts into the mandible. This muscle contracts when the
mouth closes against resistance, like if you were to try to hold your mouth open
with your hand while trying to close your mouth with your jaw muscles. During
border molding, the masseter muscle will shape the distobuccal corner of the
impression and it is thus called the masseteric notch. The answer is B.
Question 4.
4. Which of the follow-ing ions of tooth structure does the fluoride ion replace during the
remineralization process? A. Calcium (Ca) B. Phosphate (PO4) C. Hydroxyl (OH) D. Sodium
(Na)
Correct Answer: C. Hydroxyl (OH) * First off, all of these are ions found in tooth
enamel! Calcium and Sodium are positively charged so it makes sense that a
Fluoride ion with a charge of -1 would not be replacing either of these. It turns
,out that the Phosphate ion with charge of -3 is not replaced, and instead the
Hydroxyl ion with charge of -1 is routinely replaced when enamel is
remineralized and converted from hydroxyapatite to fluorapatite, hence the
name change. The answer is C.
Question 5.
5. Which of the following is a common short-term side ef-fect of nitrous oxide as used in a
dental setting? A. Hives B. Seizure C. Nausea and vomiting D. Rapid heart rate
Correct Answer: C. Nausea and vomiting * This question may seem a bit tricky at
first, but this one is a classic example of applying the high yield facts. If we
picked this question apart, every answer choice could potentially relate to
ni-trous oxide. Hives could be a result of an allergic reaction. Seizure and rapid
heart rate could be due to an overdose. But nausea and vomiting is the classic
short-term side effect that should always be divulged to patients before
administering nitrous oxide sedation. The answer is C.
Question 6.
6. Which of the following dental indexes is not re-versible? A. Periodontal score B. Gingival
score C. DMFT D. OHI-S
Correct Answer: C. DMFT * These dental indexes are used in both clinical
practice and research literature. OHI-S is simplified oral hygiene index and
measures the amount of gross debris and calculus which can be 'reversed' if a
patient improves their oral hygiene. Gingival score (GI) designates amount of
gingival inflammation which can be reversed. Periodontal score (CPITN)
designates probing pocket depth, and while bone loss in periodontal disease is
irreversible, pocket depths can be reversed via reattachment and repair. DMFT
stands for decayed, missing, and filled teeth; and once a tooth becomes
decayed, missing, or filled, that damage/treatment is irreversible. Therefore,
the answer is C.
Question 7.
7. The initial lesion of syphilis is called a __________. A. bubo B. gumma C. chancre D.
pustule E. mucous patch
Correct Answer: C. chancre * Syphilis is caused by contact with the spirochete
bacterium Treponema pallidum. A primary lesion is called a chancre, a
sec-ondary lesion is called an oral mucous patch, condyloma latum, or
maculopapular rash, and a tertiary lesion is called a gumma. The answer is C.
Question 8.
8. When a fourth root canal exists in a maxillary first mo-lar, it is most likely locat-ed in
which of the following roots? A. Lingual B. Distofacial C. Distolingual D. Mesiofacial E.
Mesiolingual
Correct Answer: D. Mesiofacial * Maxillary first molars are a notoriously tricky
tooth to perform a root canal on! That's because the vast majority of them have
3 roots, which you think would mean 3 canals. However, the mesiobuccal root
,more often than not houses 2 canals of its own (MB1 and MB2), so the most
common anatomical layout is 4 canals. That's part of the reason why they are
very frequently referred out to an endodontist. Therefore, the answer is D.
Question 9.
9. Endochondral ossification occurs in the formation of _______________. A. all bones B. flat
bones C. long bones D. elastic cartilage E. mesenchymal sheets
Correct Answer: C. long bones * There are several different ways that bone can
form! Endochon-dral literally translates to "within cartilage" where bone
devel-ops from a pre-existing cartilage model. The cranial base, part of the
mandible, and most long bones of the body are devel-oped via endochondral
ossification. Other bones are formed via intramembranous ossification.
Intramembranous literally trans-lates to "within membrane" where bone
develops from mes-enchyme (fibrous connective tissue). The cranial vault,
maxilla, and the other part of the mandible are formed via intramembra-nous
ossification. The best answer for this question, therefore, is C.
Question 10.
10. Which of the following is the distal view of tooth #14? (Image) 1, 2, 3, 4
Correct Answer: This is a tricky one! Let's start first with the clear outlier,
number 2. Only two roots are visible, and also two cusps are visible. This is the
distal aspect of #5/mesial aspect of #12. Number 3 also looks unique from the
others in that it has a clear bifurcation between the two roots, cluing you in that
it is a mandibular molar. You can also notice that how the cusps are arranged, it
has to be a facial or lingual aspect which would make it incorrect as well. This
leaves us between number 1 and 4. Number 1 is showing the broad mesiobuccal
root (to the right) and the longer palatal root (to the left) making this a mesial
view of #14/distal view of #3. Number 4 on the other hand is showing the small
distobuccal root (to the left), a little glance of the broad mesiobuccal root
behind that, and the palatal root (to the right). And this makes number 4 the
distal view of #14! I hope you had fun with this different kind of dental anatomy
question. The answer is 4.
Question 11.
11. The free gingi-va extends from the _____________________. A. free gingival groove to the
gingival crest B. gingival crest to the inter-dental groove C. alveolar mucosa to the free
gingival groove D. mucogingival junction to the free gingival groove E. epithelial
attachment to the cementoenamel junc-tion
Correct Answer: A. free gingival groove to the gingival crest * The free gingiva is
the portion of gum tissue between the free gingival margin/gingival crest and
the free gingival groove. The attached gingiva is the portion of gum tissue from
the free gingival groove to the mucogingival junction. Apical to this junc-tion is
the mucosa. Since this question is asking to identify the boundaries of the free
gingiva, the answer is A.
Question 12.
, 12. Cracked tooth syn-drome most commonly af-fects which tooth? A. Maxillary first
premolar B. Maxillary second premo-lar C. Mandibular first molar D. Mandibular second
mo-lar E. Maxillary central incisor
Correct Answer: D. Mandibular second molar * The term cracked tooth syndrome
(CTS) refers to an "incom-plete fracture of a vital posterior tooth that involves
the dentin and occasionally extends into the pulp." According to a landmark
paper on the topic, the three most commonly affected teeth are mandibular
second molars, then mandibular first molars, then maxillary premolars. There
are many possible explanations. The proximity of lower second molars to the
center of rotation of the mandible means more occlusal force can be generated
in this region and the relatively high prevalence of large intracoronal
restorations on these teeth may also be a contributing factor. The answer is D.
Question 13.
13. The spacing nor-mally seen between the anterior teeth of a five-year-old child is
caused by ___________________. A. the presence of an exces-sive maxillary labial frenum B.
thumb sucking C. tongue thrusting D. growth of the dental arch-es
Correct Answer: D. growth of the dental arches * Some space in the primary
dentition (called interdental space) is actually a good thing, since it indicates
less likelihood of severe crowding during the transition to the permanent
dentition. This normal (key word is normal) amount of spacing, particularly
between the anterior teeth, is a result of normal growth and development of the
dental arches. The other three etiologies could result in excessive or abnormal
spacing in the anterior. The answer is D.
Question 14.
14. Which of the following speech sounds is NOT con-sidered a sibilant used for evaluating
closest speaking space during the denture fabrication process? A. /s/ B. /z/ C. /v/ D. /sh/ E.
/j/
Correct Answer: C. /v/ * Sibilant or linguoalveolar sounds involve contact
between the tip of the tongue and the anterior palate or lingual surfaces of the
anterior teeth. These include s, z, sh, ch, j (try it out!). These sounds help
determine the vertical length and overlap of anterior teeth during denture
fabrication. The /v/ sound is a fricative or labiodental sound which involves
contact between the maxillary incisors and wet/dry line of lower lip. The answer
is C.
Question 15.
15. The lingual cusp(s) on which of the following mandibular posterior teeth is (are)
approximately 2/3 the height of the respective facial cusp(s)? A. First premolar B. Second
premolar C. First molar D. Second molar E. Third molar
Correct Answer: A. First premolar * Mandibular second premolars have facial
cusps that are slightly taller than their respective lingual cusps, but they are
relatively even in height. All three types of molars also have relatively even
cusp heights, with the non-functional lingual cusps being pointed and maybe
even slightly taller than their respective facial cusps. The crown of mandibular
