MANDIBULAR Second Premolars

What are the main differences between first and second mandibular premolars

- 2nd is larger overall than the 1st

- 2nd has a longer root than the 1st

- 2nd functions more like a molar

- 2nd may have 3 cusps

When do mandibular second premolars initially calcify

2.5 years

When do mandibular second premolars erupt

11-12 years

When are roots completed for mandibular second premolars

13-14 years

What are the universal system numbers for mandibular second premolars

#20 and #29

What is the left mandibular second premolar number

#20

What is the right mandibular second premolar number

#29

Is the buccal cusp shorter or taller on the mandibular second premolar compared to the first premolar

shorter

How is the mandibular second premolar buccal cusp described as

- shorter compared to the first premolar

- slopes and tip more blunted than the first premolar

How is the buccal ridge described as for mandibular second premolars

not as well developed as the first

What is the crown root ratio for mandibular second premolars

1.81

What does the lingual surface on mandibular second premolars look like if one lingual cusp is present

- taller lingual cusp than the first premolar

- no groove present

- wider than the first premolar

What does the mandibular second premolar look like if it has 2 lingual cusps

- mesiolingual cusp is larger

- distolingual cusp is smaller

- cusps separated by lingual groove

- root is not as narrow as the first premolar

What separates the mesiolingual and distolingual cusps on mandibular second premolars

lingual groove

What does the mesial surface look like on mandibular second premolars

- no grooves present

- contact areas are occlusal to middle third

- root length longer

Where is the contact area on mandibular second premolars on the distal surface

occlusal to middle third

What are the 3 patterns of mandibular second premolars

U pattern and H pattern - for 2 cusps

Y pattern - for 3 cusps

What grooves are there for U patterned mandibular second premolars

- central

- mesiobuccal

- distobuccal

What grooves are there for H patterned mandibular second premolars

- central

- mesiobuccal

- mesiolingual

- distobuccal

- distolingual

What grooves are there for Y patterned mandibular second premolars

- buccal

- mesiolingual

- distolingual

How many triangular ridges are there on mandibular second premolars

3

What triangular ridges are present on mandibular second premolars

- buccal

- mesiolingual

- distolingual

What marginal ridges are present on mandibular second premolars

mesial marginal and distal marginal ridges

How many grooves are present on mandibular second premolars

4

What grooves are present on mandibular second premolars

- central

- mesiobuccal

- distobuccal

- lingual

How many fossae/pits are there on mandibular second premolars

3 pits and 3 fossae

What pits are present on mandibular second premolars

central pit

mesial pit

distal pit

What fossa are present on mandibular second premolars

central fossa

mesial fossa

distal fossa