Molar Teeth in Humans
- Molar teeth in humans have either four or five cusps.
- Adult humans have 12 molars, arranged in four groups of three at the back of the mouth.
- The third molar in each group is called a wisdom tooth.
- Wisdom teeth typically appear around the age of 20, but this can vary.
- Some individuals may have missing wisdom teeth.

Molar Evolution in Mammals
- In mammals, the crown of molars and premolars has complex shapes with cusps and valleys.
- Cusps contain dentine and enamel, while crenulations result from different enamel thickness.
- Mammalian cheek teeth likely evolved from single-cusped teeth in synapsids.
- Additional cusps may have arisen through budding or outgrowth from the crown.
- Therian mammals evolved from an ancestor with tribosphenic cheek teeth.

Morphology of Molars
- Upper molars have major cusps called cones, identified by prefixes like proto-, para-, meta-, hypo-, and ento-.
- Lower molars have cusps with the suffix -id, while minor cusps have the suffix -ule.
- A shelf-like ridge on the lower part of an upper molar is called a cingulum.
- A similar feature on a lower molar is called a cingulid.
- Minor cusps on the cingulid are referred to as cingular cuspules or conulids.

Tribosphenic Molars
- The tribosphenic molar is a key characteristic of therian mammals.
- The lower molar is divided into the trigonid (shearing end) and talonid (crushing heel).
- The trigonid has three large cusps: protoconid, anterior paraconid, and posterior metaconid.
- Upper molars have a mirrored structure with the protocone, anterior paracone, and posterior metacone.
- Tribosphenic molars likely developed independently in monotremes.

Different Types of Molar Morphologies
- Quadrate molars have a hypocone, an additional fourth cusp on the lingual side of the upper molar.
- Many mammals have additional smaller cusps called conules located between the larger cusps.
- Bunodont molars have low and rounded cusps, common among omnivores.
- Hypsodont dentition is characterised by high-crowned teeth with extended enamel.
- Brachydont dentition is characterised by low-crowned teeth, like human teeth.
- Zalambdodont molars have three cusps, one larger on the lingual side and two smaller on the labial side.
- Dilambdodont molars have a distinct ectoloph and are shaped like two lambdas or a W.
- Lophodont molars have enamel ridges called lophs that interconnect the cusps on the crowns.
- Selenodont molars have a major cusp elongated into a crescent-shaped ridge.
- Secodont teeth are adapted for slicing and chopping, commonly found in carnivorous mammals.