Mandibular Molars

Question 1

What are the functions of molars?

Answer 1

1. Mastication (grinding)
2. Maintenance of vertical dimension of face
3. Support cheeks
4. Keep the tongue confined within the confines of the arch

Question 2

All molars….

Answer 2

1. Have a mesiodistal dimension that is greater than the occlusocervical dimension
2. Molars are the shortest teeth occlusocervically
3. Have 3 to 5 cusps
4. Generally larger in other directions when compared to other teeth except (occlusocervically)

Question 3

All molars…from the buccal or lingual view

Answer 3

1. Have a mesial to distal taper

2. Distal cusps are shorter than mesial cusps

Question 4

All molars…from the occlusal view

Answer 4

1. All molar crowns have a buccal to lingual taper (EXCEPT Maxillary first molars w/ large distolingual cusp)
2. All molar crowns have a mesial to distal taper

Question 5

All molars…from the proximal view

Answer 5

1. Buccal height of contour is in cervical third (as on all teeth)
2. Lingual height of contour is in the middle third (as on all posterior teeth)
3. Mesial and distal contact located in the middle third

Question 6

Is the mesiodistal dimension longer or shorter than buccolingual?

Answer 6

The mesiodistal dimension is much wider than buccolingual

Question 7

How many buccal cusps?

Answer 7

2 or 3 (1st molars have 3 buccal cusps, 2nd molars have 2 buccal cusps)

• mesiobuccal
• distobuccal
• distal

Question 8

How many lingual cusps?

Answer 8

2

• mesiolingual
• distolingual

Question 9

Are the mandibular molars the shortest teeth occlusocervically?

Answer 9

Yes

Question 10

How many roots do mandibular molars typically have?

Answer 10

2

• mesial
• distal

Question 11

Mandibular first molars

Answer 11

30 and 19

Question 12

Mandibular 1st molar buccal view

Answer 12

1. All five cusps are visible from this view since the lingual cusps are taller (non-functional)
2. The MB and DB cusp are shorter and more rounded
3. The MB cusp is the widest of the three buccal cusps
4. The DB cusp is almost as wide as the MB, and is more rounded
5. The distal cusp is very narrow and is more pointed

Question 13

Mandibular 1st molar buccal view

Answer 13

1. Mesiobuccal groove is the shorter of the two–depression or buccal pit
2. Cervical ridge gingival to the buccal depression
3. Distobuccal groove is somewhat longer and extends distal to the cervical ridge described above and does not typically end in a pit

Question 14

Mandibular 1st molar buccal view (roots)

Answer 14

1. Roots positioned mesially and distally
2. Roots are typically longer than 2nd and 3rd molars
3. Mesial root longer and more curved than distal root
4. Distal root is typically shorter, less curved and more pointed at apex

Question 15

Mandibular 1st molar lingual view

Answer 15

Three cusps visible from lingual view

• Mesiolingual
• Distolingual
• Distobuccal

Question 16

Mandibular 1st molar lingual view

Answer 16

1. The mesiolingual cusp is somewhat taller and a little wider than the distolingual cusp
2. cervical line 1.0 mm more occlusal on the lingual, means root trunk is longer in this view

Question 17

What is the anatomical crown?

Answer 17

The area of the tooth covered with enamel

Question 18

What is the clinical crown?

Answer 18

The amount of tooth exposed occlusal to the gingiva

Question 19

What is the anatomical root?

Answer 19

The area of the tooth covered with cementum

Question 20

What is the clinical root?

Answer 20

The amount of tooth embedded in the alveolar bone

Question 21

Mandibular 1st molars mesial view

Answer 21

1. The greatest curvature of the buccal outline is at the cervical third of the crown, termed the cervical ridge
2. The mesial cusps are taller than the distal cusps–only the MB and ML cusps are visible from this view

Question 22

Mandibular 1st molars mesial view

Answer 22

1. Only the mesial root is visible since it is wider buccolingually and usually a little longer
2. The mesial root has a wide developmental depression on both its mesial and distal surface
3. The tooth typically has two separate canal spaces in the mesial root
4. lingual tilt

Question 23

Where should your bur be aligned?

Answer 23

Bur should be aligned with the long axis of the crown or perpendicular to the occlusal surface

Question 24

Mandibular 1st molar distal view

Answer 24

The outline of the distal cusp will be superimposed on the distobuccal cusp

Question 25

Mandibular 1st molar distal view

Answer 25

1. Both roots visible from this view 2. Distal root shorter, narrower and more pointed than mesial 3. Longitudinal root depression but not as prominent as on the mesial 4. The distal root usually has one but can have two root canal spaces

Question 26

Mandibular 1st molar occlusal view

Answer 26

1. Occlusal crown is hexagonal 2. Buccal half much wider than the lingual half 3. Buccolingual measurement is greatest in the mesial half of the crown. The tooth converges toward the distal

Question 27

Cusp sizes in order from largest to smallest

Answer 27

Mesiobuccal, mesiolingual=distolingual, distobuccal, distal

Question 28

Mandibular 1st molars occlusal

Answer 28

1. Each cusp has a definite triangular ridge but none of them meet (no transverse ridges) 2. Central fossa (roughly circular) 3. Mesial triangular fossa 4. Distal triangular fossa

Question 29

Mandibular 1st molar- roots

Answer 29

1. Mesial root is dumbell shaped 2. Mesial and distal root depression 3. Usually two canals 4. Distal root is usually one large canal

Question 30

Mandibular 2nd molars

Answer 30

18 and 31

Question 31

Mandibular 2nd molars buccal view

Answer 31

1. Crown is narrower mesiodistally and shorter occlusocervically than that of the mandibular 1st 2. All 4 cusps visible since the lingual cusps are taller than the buccal cusps 3. Buccal cusps more rounded (functional)

Question 32

Mandibular 2nd molars buccal view

Answer 32

1. no distal cusp or distobuccal groove, just a single buccal groove 2. roots closer together and more parallel 3. Roots more distally inclined

Question 33

Mandibular 2nd molars mesial view

Answer 33

Root more narrow buccolingually, may have curved tip

Question 34

Mandibular 2nd molar occlusal view

Answer 34

1. crown tends to converge toward the distal 2. smaller in all dimensions compared to the mandibular 1st 3. The mesiobuccal prominence on the MB line angle contributes to the distal convergence 4. There are 4 cusps of nearly equal size - mesiobuccal - distobuccal - mesiolingual - distolingual 5. developmental grooves form a distinct cross (central, buccal, lingual)

Question 35

Mandibular 2nd molar occlusal view

Answer 35

1. Central pit 2. terminal ends of central pit contain mesial and distal triangular fossa 3. Each cusp has a triangular ridge and meet to form two transverse ridges

Question 36

Mandibular 3rd molars

Answer 36

32 and 17

Question 37

Mandibular 3rd occlusal

Answer 37

1. Varies considerably 2. Usually more rounded from any viewpoint 3. In most cases resembles mandibular second molar but 5 cusps is possible

Question 38

Mandibular 3rd molar roots

Answer 38

1. Shorter than on the mandibular 2nd or 1st 2. roots fused often 3. These teeth do not erupt on their own, may need to be surgically removed