Deck 12: Incisors

Question 1

Each of the following is true of the permanent central incisor EXCEPT one.Which one is the EXCEPTION?

A) Evidence of calcification occurs at three months.
B) This is the widest mesiodistally of any of the anterior teeth.
C) Root formation is completed by six years of age.
D) Gemination is an anomaly that sometimes occurs.
E) Development is usually normal.

Answer 1

C
Root formation of the permanent central incisors is not complete until ten years of age.The remaining selections accurately describe this tooth.While development is usually normal,gemination,an infrequent anomaly,is a process where the tooth shows evidence of attempting to divide itself.Other anomalies include a short root or an unusually long crown.

Question 2

Teeth most likely to be peg-shaped are the mandibular lateral incisors because the distal developmental lobe is large and located more lingually than its mesial lobe.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct,but the reason is NOT correct.
D) The statement is NOT correct,but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Answer 2

D
Teeth most likely to be peg-shaped are the maxillary lateral incisors,which vary greatly in form.The reasoning provided in the question accurately describes the mandibular lateral incisors.Note that the lingual location of the large developmental lobe is the reason the mandibular lateral incisors curve distally to fit into the mandibular arch.

Question 3

The maxillary lateral incisor usually has a straight,thick,cylindrically shaped root.The root length of the maxillary lateral incisor is about 1.5 times the length of the crown.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Answer 3

C
It is the root of the maxillary central incisor that usually is straight,thick,and cylindrically shaped.Conversely,the root of the maxillary lateral appears thinner and often curves distally.As a rule the root of the maxillary lateral incisor is about 1.5 times the length of the crown.

Question 4

When incisors first erupt the incisal ridge is smooth.After teeth have been in function for several months,mamelons,which aid in mastication,develop on the incisal ridge.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 5

The mandibular lateral incisors are wider mesiodistally than the mandibular central incisors because the mesial developmental lobe of the laterals is larger than that of the centrals.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct,but the reason is NOT correct.
D) The statement is NOT correct,but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 6

Maxillary central incisors usually develop normally.Two anomalies that sometimes occur are a longer root or a shorter crown.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 7

Mandibular lateral incisors are generally smaller than mandibular central incisors.Mandibular lateral incisors have greater facial curvature than the central incisors.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 8

Extracted mandibular central incisors are the easiest to identify as either right or left because they are located anteriorly and near the midline.

A) Both the statement and the reason are correct and related.
B) Both the statement and the reason are correct but are NOT related.
C) The statement is correct,but the reason is NOT correct.
D) The statement is NOT correct,but the reason is correct.
E) NEITHER the statement NOR the reason is correct.

Question 9

Each mamelon forms the incisal edge of one of the primary labial lobes of the incisors.With wear,the rounded incisal edge becomes flat and is then referred to the incisal ridge.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 10

Which anatomical landmark could make an incisor more prone to dental caries?

A) Cingulum
B) Lingual pit
C) Mamelons
D) Prominent marginal ridges

Question 11

The mandibular central incisor occludes with both the maxillary central incisor and the maxillary lateral incisor.Similar to other anterior teeth,a mandibular incisor is derived from five lobes,three facial lobes and two lingual lobes.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 12

All incisors have two marginal ridges,a cingulum,and a lingual fossa.The mandibular central incisor has the least distinct lingual anatomy.

A) Both statements are true.
B) The first statement is true;the second statement is false.
C) The first statement is false;the second statement is true.
D) Both statements are false.

Question 13

Which of the following are characteristic of one or both maxillary incisors (Select all that apply. )?

A) Slender roots
B) Linguoincisal attrition
C) Greater labiolingual than mesiodistal crown dimension
D) Most prominent teeth in the mouth

Question 14

The eruption time for both the maxillary central incisor and mandibular lateral incisor is

A) 6 to 7 years
B) 7 to 8 years
C) 8 to 9 years
D) None of the above

Question 15

Which of the following are commonly found on roots of maxillary incisors?

A) Proximal grooves
B) Evidence of division
C) Bifurcation
D) Indentation
E) None of the above

Question 16

Each of the following statements correctly describes maxillary lateral incisors EXCEPT one.Which one is the EXCEPTION?

A) The incisal aspect can resemble that of a central incisor or a canine.
B) Incisally,they exhibit more convexity both labially and lingually than maxillary centrals.
C) Of all incisors,the maxillary laterals vary the least in form.
D) The mesial aspect of a maxillary lateral incisor is similar to that of a small central incisor.
E) Frequently maxillary lateral incisors are peg-shaped.

Question 17

Which incisor has a lingual pit?

A) Maxillary central
B) Maxillary lateral
C) Mandibular central
D) Mandibular lateral

Question 18

In an anterior crossbite,the maxillary central incisors would exhibit wear in which location?

A) Labioincisal edge
B) Linguloincisal edge
C) Cervical region
D) Apex

Question 19

Which incisor is not derived from four primary lobes?

A) Maxillary central
B) Maxillary lateral
C) Mandibular central
D) Mandibular lateral
E) All of the above are derived from four lobes.

Question 20

Which of the following are characteristic of one or both mandibular incisors (Select all that apply. )?

A) All contact areas are in incisal third.
B) Rounded distoincisal angle
C) Smooth,shallow lingual surface
D) Slender roots

Question 21

Proximal grooves are commonly found on the roots of the maxillary incisors.

Question 22

Mandibular incisors do not have marginal ridges.

Question 23

All incisors can erupt with mamelons.

Question 24

Mandibular lateral incisors are distolingually inclined when viewed incisally.

Question 25

Gemination is an anomaly that most commonly occurs in mandibular incisors.

Question 26

Maxillary lateral incisors vary in form more than any other teeth in the mouth.