#ScienceWithGray — Learn About Your Teeth, Your "Bony Grinders"

✒️ - By Aan Gray
The teeth are collectively called the 'dentition'. They serve to masticate the food, breaking it into smaller pieces. This not only makes the food easier to swallow, but also exposes more surface area to the action of digestive enzymes and thus speeds up chemical digestion. Adults normally have 16 teeth in the mandible (lower jaw) and 16 in the maxilla (upper jaw), making it a total of 32 teeth. From the midline to the rear of each jaw, there are two incisors, a canine, two premolars, and up to three molars on each side.

The incisors are anterior, chisel-like cutting teeth used to bite off a piece of food. The canines are more pointed and act to puncture and shred it. They serve as weapons in many mammals but became reduced in the course of human evolution until they now project barely beyond the other teeth. The premolars and molars have relatively broad, lumpy surfaces adapted for crushing, shredding, and grinding; they are often informally called the 'grinders'. [0x1f628]

Teeth develop beneath the gums and erupt (emerge) in predictable order. Twenty deciduous teeth (milk teeth or baby teeth) erupt from the ages of 6 to 30 months, beginning with the incisors. Between 6 and 25 years of age, these are replaced by the 32 permanent teeth.
As a permanent tooth grows below a deciduous tooth, the root of the deciduous tooth dissolves and leaves little more than the crown by the time it falls out. The third molars (wisdom teeth) erupt around ages 17 to 25, if at all. Over the course of human evolution, the face became flatter and the jaws shorter, leaving little room for the third molars. Thus, they often remain below the gum and become impacted—so crowded against neighboring teeth and bone that they cannot erupt.
How spectacular! [0x1f62e]
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