Premolars

Question 1

Premolars func

Answer 1

o Work with the molars in mastication and maintaining the vertical dimension of the face
o Erupt in positions previously occupied by deciduous molars, thus they are known as succedaneous
teeth

Question 2

Maxillary First premolar

Answer 2

▪ Very brittle due to the presence of the mesial marginal groove, the mesial concavity, and two spindly roots
• It is protected/supported by the canine

Question 3

Facial View max 1

Answer 3

• Widest premolar
• Buccal cusp tip is slightly distal of the root axis line
• Buccal cusp has a longer mesial cusp ridge than distal cusp ridge
• It’s the most pointed cusp in the dentition

Question 4

Lingual View max 1

Answer 4

• Crown and root is narrower on the lingual side
• The lingual cusp is shorter and bends mesially
• The lingual root is shorter than the Buccal root

Question 5

Proximal View max 1

Answer 5

• Prominent mesial concavity cervical to the contact area
• Buccal cusp is longer than the lingual
• Mesial marginal groove is always present
• Has 2 roots 61% of the time
• Because of the mesial marginal groove, mesial concavity, and two spindly roots – it is very brittle - protected by the canine

Question 6

Occlusal View max 1

Answer 6

• Lingual cusp offset mesially
• Long central developmental groove runs mesiodistally, crosses the transverse ridge and ends in pits in the triangular fossae
• There are few supplementary grooves

Question 7

Facial View max 2

Answer 7

The Buccal cusp is not as long or as pointed
• The cusp tip is offset mesially (max 1st offset distally)
o Mesial cusp ridge shorter than the distal cusp ridge

Question 8

Lingual View max 2

Answer 8

• Lingual cusp is longer than the lingual cusp of the first max PM
• Lingual and Buccal cusps are nearly equal in size
• Lingual cusp offset mesially

Question 9

Proximal View max 2

Answer 9

• One root
• NO mesial concavity
• NO mesial marginal groove
• Distal root depression deeper than mesial root depression
• Cusps are nearly equal in size

Question 10

Occlusal View max 2

Answer 10

• Central groove is shorter and more irregular than the first max PM
• No mesial marginal groove
• Lingual cusp offset mesially, but not as much

Question 11

Mandibular premolars special characteristics

Answer 11

▪ The first man PM is smaller than the second (opposite of maxillary PMs)
▪ First PM resembles, and functions with the canine
▪ Second resembles, and functions with the molars
▪ The two mandibular PMs are less alike than the two max PMs
▪ Crowns are tilted lingually– greatest lingual inclination in the mandibular arch
▪ Buccal cusp larger than the lingual
▪ First PM develops from 4 lobes
▪ Second PM develops from 5 lobes in most instances

Question 12

Buccal View man 1

Answer 12

• Cusp tip pointed and slightly mesial to the midline of the tooth
• Mesial contact area is more cervical than the distal contact area
o Only tooth in permanent dentition that has this feature

Question 13

Lingual View Man 1

Answer 13

• Miniscule lingual cusp
• Entire occlusal surface, and most of the mesial and distal surfaces can be seen from this view
• Mesiolingual developmental groove and prominent transverse ridge
o Hallmark trait

Question 14

Mesial View man 1

Answer 14

• Rhomboidal outline (as are all mandibular posterior teeth)
• Tip of Buccal cusp is nearly centered over the root
• Tip of the lingual cusp is in line with the lingual border of the root
• Crest of curvature on lingual and buccal surfaces are in or near the middle third
• Mesiolingual groove is seen
• Short root but it often has a deep developmental groove

Question 15

Distal View man 1

Answer 15

• No developmental groove

* Distal marginal ridge is more occlusal than the mesial so you can’t see as much of the occlusal surface

Question 16

Occlusal View Man 1

Answer 16

• Outline is diamond shaped
• Middle labial lobe makes up the bulk of the tooth
• Distal portion is described as being a larger arc than the mesial side, with a broader contact
• Sharp lingual convergence

Question 17

Mandibular Second Premolar characteristic

Answer 17

▪ Larger than the first premolar and has a longer root
▪ Has two common forms
• three cusp type (more common)
• Two cusp type

Question 18

Buccal View man 2

Answer 18

• Buccal cusp is shorter (more blunt) than the first premolar

Question 19

Lingual View man 2

Answer 19

• Usually a ML and DL cusp present
• ML is larger and there is a lingual groove separating the cusps
• Lingual groove is centered over the root
• Very little convergence

Question 20

Mesial View Man 2

Answer 20

• Not similar to mandib first PM
• Marginal ridge at right angle to the long axis of the tooth
• No mesiolingual developmental groove

Question 21

Distal View man 2

Answer 21

• Two cusps are visable
• Crown is tipped distally so more of the occlusal surface is visible from the distal view than from the mesial view (characteristic of ALL posterior teeth)

Question 22

Occlusal View man 2

Answer 22

• 3 cusp type – square outline
o B > ML > DL in size
o Cusps separated by deep developmental grooves that form a “y” on the occlusal surface (mesial, distal, and lingual developmental grooves)
• 2 cusp type – round with some lingual convergence
o 1 lingual cusp
o Central developmental groove is often crescent shaped