13 - morphology of the upper molars

whats in it?

• main fucntion

• bucccal

• lingual

• proximal view of molars

• occlusal

• roots

buccal

• max. 1st molars have largest outline of all maxillary teeth (then 2nd max molars)

• crowns of 1st and 2nd max molar = broad mesiodistally, but 1st = widest tooth in upper arch

• 1st molar can have additional cusp of carabelli on lingual surface of ML cusp

• mesial/distal contact = as usual (m = betwn junction of middle and occlusal 3rd and vice versa for distal)

lingual

• lingual surface on both max molars = more narrow in cervical third than middle third, since crown tapers to join the single palatal root

• on max 1st molar = 2 LINGUAL cusps - larger ML and smaller DL cusp

types of 2ndary max molars based on cusps -

Tooth	Common Cusp Count	Cusp Arrangement
Max 1st Molar	4 (or 5 w/ Carabelli)	2 buccal (MB, DB), 2 lingual (ML, DL)
Max 2nd Molar	4 or 3	2 buccal + 2 lingual OR 2 buccal + 1 lingual

• lingual groove separates the ML and DL cusp - same as mand 2nd premolar

proximal

• max 1st molars are shorter occlusocervially but broader faciolingually from proximal view

• height of contour is in cervical third

• both first and second molar have a concave distal marginal ridge (ledge that seperates dist surface + occlusal surface except it has small depression bc its concave)

roots

• Are mostly 3 root teeth (trifurcation)

• Root	Position	Length & Shape	Applies to
  Lingual (Palatal)	Lingual side	Longest, largest root	1st & 2nd molars
  Mesiobuccal (MB)	Buccal, mesial	Longer than DB, often curved	1st & 2nd molars
  Distobuccal (DB)	Buccal, distal	Shorter, more pointed and tapered	1st & 2nd molars

occlusal surface

usually 4, sometimes 5

(MB (LARGEST),DB, ML (tallest) DL (smallest - absent on 2nd/3rd molars)

cusp of carrabelli on ML’s lingual surface

major grooves: buccal groove between MB/DB and distolingual grooves between ML and DL

oblique ridge = only max molars have it, runs diagonally from ML cusp to DB cusp