The total number of permanent teeth in the human mouth is often confusing because the final set of teeth, known as third molars or wisdom teeth, is variable and frequently absent or removed. Determining the standard adult dentition requires setting aside these variable teeth to arrive at a consistent, functional number. This count provides a clear benchmark for a complete and healthy adult mouth.
The Permanent Teeth Without Third Molars
The typical adult human mouth, when excluding the third set of molars, is composed of 28 permanent teeth. This number represents a full and functional set of teeth that is commonly used as the measure for complete dentition in dental research. These 28 teeth are precisely divided between the upper and lower jaws, with 14 teeth situated in the maxilla, or upper jaw, and 14 teeth residing in the mandible, or lower jaw. This symmetrical arrangement ensures balanced biting and chewing across the dental arch.
Types and Roles of the 28 Teeth
The 28 teeth are organized into four distinct types, each performing a specialized role in the initial stages of digestion. The mouth is divided into four quadrants—two upper and two lower—with seven teeth in each section.
Types of Teeth
- Eight incisors, which are flat and sharp-edged teeth used primarily for biting and cutting food into manageable pieces.
- Four canines, which are pointed teeth positioned to tear and rip food materials, acting much like the fangs of a carnivore.
- Eight premolars, also known as bicuspids, which sit between the canines and the molars and feature two cusps to crush and shear food.
- Eight molars, which are the largest teeth located at the back of the mouth, with broad surfaces for the heavy grinding necessary before swallowing.
Why the Total Count Is Different
The maximum number of teeth an adult human can possess is 32, which is the count when all four third molars are included. These four additional teeth are the final molars to erupt, typically making their appearance between the ages of 17 and 25. The 28-tooth count is frequently cited because these third molars often cause complications. They may become impacted, meaning they are trapped beneath the gum line or jawbone, or simply fail to erupt properly. The modern human jaw often lacks the necessary space for these last molars, leading to crowding and pain. For this reason, the four wisdom teeth are routinely extracted, reducing the active dentition to 28.