Permanent molars

Why this matters

Molars are where descriptive and measured dental anatomy disagree most. You will be taught that the upper six has four cusps; that the lower six has five cusps and two roots with three canals and that Carabelli's cusp is a European trait, and that the oblique ridge belongs to the maxillary first molar alone. Every one has a denominated series behind it saying something more complicated: four cusps in 838 of 1,249 people, four canals in 35.7% of 18,781 lower first molars, Carabelli present in 201 of 432 participants in Lahore.

The big picture

Two arches, three molars each, and one rule running through all six positions: what forms last varies most and disappears first. This lesson builds each molar from its cusps outward, then goes below the cervical line to the root trunk, furcation and pulp chamber - printing the denominator instead of the adjective.

The 15 cards in this lesson

1. 01The last cusp to form is the first one lost
2. 02Two vocabularies name the same cusps, and only one of them is derivable
3. 03The maxillary first molar: four cusps, two major fossae, one oblique ridge
4. 04Three things everyone gets wrong about the oblique ridge
5. 05Upper six, seven and eight: everything separates them except size
6. 06Carabelli: read the scoring threshold before you read the percentage
7. 07The mandibular first molar: five cusps, five grooves, and a groove that runs off the occlusal surface
8. 08Groove pattern is three contact states, and cusp count is a separate variable
9. 09Lower six, seven and eight: cusp count first, then everything else
10. 10Clinical alert — in the lesson
11. 11The pulp chamber sits at the cervical line and is under two millimetres tall
12. 12Roots and canals are two different counts, and the second one is not derived from the first
13. 13An extra lower molar root goes lingual, and how often depends on where you are
14. 14Root trunk and furcation: four published numbers, three different measurements
15. 15What to carry out of the molars, and what this lesson could not source

You have got it when

You can (1) name every molar cusp, groove, ridge and fossa in Y1-06.01's surface vocabulary and translate the anthropological names you meet in papers; (2) identify and side a molar from the whole morphological package rather than one cue; (3) state cusp number, groove pattern, root number and canal number as distributions with their denominator, population and method attached; and (4) locate the pulp chamber and…