Dental Anatomy of Humans

As omnivores, humans evolved specialized teeth to help them chew a mixture of meat and plants. Though small in relative size compared to some other animals, human teeth serve the purpose of processing our diet quite well. Humans are diphyodonts, meaning we posses two sets of teeth during our lifetime.

Primary/Deciduous Teeth

• Primary or deciduous teeth develop in young children during their first year of life and begin to fall out between age six and 11. In total, a child will develop 20 deciduous teeth, made up of four incisors, two canines and four molars per jaw. Incisors form at the very front of the mouth (two at the top, two at the bottom) and are used for tearing in to food. Canines, or eye teeth, form between incisors and molars and have a distinctive pointed shape. Molars form the back teeth and perform a grinding action within the mouth when chewing food. Deciduous teeth are much smaller than permanent teeth with a thinner enamel coating and rounded tops.

Mixed Dentition

• Deciduous teeth are only functional within the human mouth for around six percent of the average lifespan and begin to fall out around age six. Until the early teens, children will have a mixture of deciduous and permanent teeth, a period known as mixed dentition. Permanent teeth continue to form in the human mouth until around age 20. Humans have deciduous teeth until the jaw has developed to a size large enough to accommodate permanent teeth.

Permanent Teeth: Maxillary Arcade

• A full compliment of 32 permanent teeth consists of four incisors, two canines, four premolars (not present in deciduous dentition) and six molars in each jaw. The permanent maxillary arcade, the technical name for the upper teeth, features larger incisors, canines and molars than its deciduous predecessor. Newly present premolars are known as transition teeth which pass food torn by the incisors and eye teeth to the molars for chewing.

Permanent Teeth: Mandibular Arcade

• The mandibular arcade, or lower teeth, largely mirror the maxillary arcade in adulthood, consisting of the same number of incisors, canines, premolars and molars. Incisors of the mandibular arcade are noticeably thinner and contain "fossa," rounded depressions on the back of the tooth near the gum.

Wisdom Teeth

• Wisdom teeth are the last teeth to develop in the human mouth, sometimes causing crowding or discomfort in adults. Wisdom teeth are extra molars, usually developing between ages 18 and 23 and named for their late appearance. In some cases, the jaw is not large enough to accommodate wisdom teeth causing them to become impacted and stuck beneath the gum line.