Question 1

Maxillary molars have three roots,a facial and two lingual.Mandibular molars have two roots,a facial and a lingual.

Accepted Answer

While it is true that maxillary molars have three roots,there are two facial roots and one lingual root.Mandibular molars have two roots,one buccal and one lingual.

Question 2

The crowns of the maxillary incisors are wider mesiodistally than labiolingually.The roots of maxillary incisors are oval in cross section.

Accepted Answer

The crowns of maxillary incisors are wider in mesiodistal dimension than in faciolingual dimension.The second statement is false because the roots of maxillary incisors are triangular in cross section.The roots of the mandibular incisors,however,are oval in cross section.These facts apply to both central and lateral incisors.

Question 3

Which of the following accurately describe mandibular molars (Select all that apply. )?

Accepted Answer

Crowns of mandibular molars are wider mesiodistally than faciolingually.Note that the opposite is true of maxillary molars.Mandibular molars have two roots: one buccal and one lingual.The cusp of Carabelli is not located on a mandibular molar;it is found on the maxillary first molar.It is true that the occlusal groove on the second molar is well established.Running in a mesial to distal direction,this groove forms a cross (+)with facial and lingual grooves.Finally,a strong oblique ridge is present on the maxillary first molar,not the mandibular.

Question 4

On anterior teeth,the curvature of the CEJ is the same on mesial and distal surfaces.

Accepted Answer

A general rule of tooth identification is that the curvature of the cementoenamel junction (CEJ)is usually about 1 mm less on the distal surface of the tooth than on the mesial.This rule applies to anterior as well as posterior teeth.

Question 5

Which has an oblique ridge (Select all that apply. )?

Accepted Answer

The maxillary first molar has a strong oblique ridge and the maxillary second molar has a smaller oblique ridge that is usually interrupted by a groove.The maxillary third molar does not have an oblique ridge.Note that the maxillary first and second premolars do not have an oblique ridge;instead the maxillary first premolar has a well-developed central groove and the maxillary second has a short central groove.

Question 6

Which molars have five (major and minor)cusps?

Accepted Answer

The maxillary first and mandibular first molars have five cusps.This count includes major as well as minor cusps.The fifth cusp of the maxillary first molar is located on the mesiolingual cusp and is called the cusp of Carabelli.The fifth cusp of the mandibular first molar is the distal cusp.

Question 7

Which premolar most frequently has three cusps?

Accepted Answer

The second mandibular premolar most frequently has three cusps.Both the first and second mandibular premolars always have at least two cusps,one a single facial cusp,with one or two lingual cusps.The second is more likely to have two lingual cusps.

Question 8

Roots of third molars are most often dilacerated because the more posterior the molars are positioned,the more variation of anatomy is evident.

Accepted Answer

Roots of third molars are often fused.In general,the roots of molars tend to be shorter and closer together the more posterior the molars are positioned.Often third molar roots fuse into one.Conversely,first molars have the widest and longest roots of all molars.A dilacerated root is one that has a sharp bend or curve.

Question 9

Root bifurcations may be present on maxillary premolars but not on mandibular premolars because maxillary premolars have two roots whereas mandibular premolars have only one root.

Accepted Answer

Both the statement and the reason are incorrect because only maxillary first premolars have two roots.The remaining premolars have only one root.This fact illustrates the importance of strong command of tooth anatomy as it applies to periodontal assessment.

Question 10

The cusp of Carabelli is located on the

Accepted Answer

The cusp of Carabelli is located on the maxillary first molar.It is considered the fifth lobe of this tooth and is situated at the tip of the mesiolingual cusp.

Question 11

Third molars are generally larger than first molars because a general rule of tooth identification states that permanent molars are generally taller in height and have more cusps the more posteriorly they are placed.

Accepted Answer

The general rule of tooth identification applicable to molars states that permanent molars are typically smaller in height and have fewer cusps the more posteriorly they are positioned.For example,the permanent first molar usually has five cusps and is larger than either a second or third molar.

Question 12

The mandibular second molar has

Accepted Answer

The mandibular second molar has four almost equal cusps.It is the mandibular first molar that has an additional smaller distal cusp.

Question 13

Which molar has two buccal grooves?

Accepted Answer

The mandibular first molar has two buccal/facial grooves.This tooth is also distinguished by its widely separate and relatively vertical roots.It also has a distal cusp,which is generally the smallest cusp.

Question 14

Crowns of which teeth are wider faciolingually than mesiodistally (Select all that apply. )?

Accepted Answer

Crowns of maxillary premolars and molars are wider faciolingually than mesiodistally.This difference is more prominent in maxillary premolars.Mandibular molars are wider in the mesiodistal dimension.Mandibular premolars are nearly equal in their mesiodistal vs.faciolingual dimension.

Question 15

Which are the smallest teeth?

Accepted Answer

Mandibular central incisors are the smallest teeth.The crown and root of the mandibular lateral incisor are slightly larger than those of the central incisor.Both the maxillary central and lateral incisors are larger than their mandibular counterparts.

Question 16

The lingual cusp of the maxillary first premolar is longer than the facial cusp.This tooth often has two roots,one mesial and one distal.

Accepted Answer

The lingual cusp of the maxillary first premolar is shorter than the facial cusp.While it is true that this tooth often has two roots,they are the buccal and lingual roots.For comparison,mandibular molars have a mesial and distal root.

Question 17

Secondary anatomy refers to anatomical features of second molars and premolars.Tertiary anatomy refers to unique anatomical features of third molars.

Accepted Answer

Secondary anatomy refers to extra grooves and pits in addition,or secondarily,to the main primary developmental anatomy in any tooth.Tertiary anatomy refers specifically to the extremely shallow and more numerous grooves,pits,and lines present in third molars.Tertiary features give third molars a more wrinkled appearance than first or second molars.

Question 18

Which premolar has a small lingual cusp and no central pit?

Accepted Answer

The mandibular first premolar has no central pit whereas the mandibular second premolar does have a central pit.Important to note,both the mandibular first and second premolars have a small lingual cusp.A distinction is that the mandibular second premolar frequently has two lingual cusps whereas the first typically has only one cusp.

Question 19

Which incisor exhibits a slight distolingual rotation?

Accepted Answer

The distal half of the incisal edge of the mandibular lateral incisor is rotated toward the lingual side.This can also be described as a slight distolingual rotation.This rotation is most apparent from the incisal view.

Question 20

Tooth roots do not always curve.If roots do curve,they typically curve distally.

Accepted Answer

Teeth exhibit extreme amounts of anatomical variation;however a general rule of identification is that tooth roots do not always curve,which implies that root curvature certainly exists.The rule further states that root curvature usually is in a distal direction.However,the rule further states that it is not uncommon for roots to curve mesially.

Quiz 10: Tooth Identification