The term “wisdom teeth” is the common name for the four third molars, the last teeth to develop in the human jaw. Dentists and oral surgeons rely on specific numerical codes to identify these and all other teeth consistently. This identification is achieved through a standardized approach, primarily the Universal Numbering System, which assigns a unique number to every tooth.
Understanding Dental Quadrants
To systematically number the 32 adult teeth, the mouth is conceptually divided into four sections called quadrants. This division uses an imaginary vertical line between the two central front teeth and a horizontal line separating the upper and lower jaws. The four resulting quadrants are the upper right, upper left, lower left, and lower right.
Each quadrant contains eight permanent teeth, ranging from the central incisor back to the third molar (wisdom tooth). This quadrant-based organization provides a map for dental professionals to accurately record the location of any specific tooth or issue.
The Universal Numbering System for Wisdom Teeth
The Universal Numbering System, the standard method used by dental practitioners in the United States, assigns a number from 1 to 32 to the permanent teeth. The counting sequence begins with the tooth farthest back on the upper right side of the mouth and proceeds clockwise. Starting with the upper jaw, the count moves across the front teeth to the last tooth on the upper left side, then drops down to the lower jaw, and moves back toward the starting point on the lower right.
The four numbers assigned to the third molars (wisdom teeth) are determined by their position at the starting and ending points of this sequence. The first number in the system, Number 1, identifies the upper right wisdom tooth. The last tooth on the upper arch, the upper left wisdom tooth, is designated as Number 16.
The numbering continues on the lower arch, beginning with the lower left wisdom tooth, which is assigned Number 17. The sequence progresses to the last tooth in the mouth, the lower right wisdom tooth, which is denoted as Number 32. Therefore, the four wisdom teeth are consistently labeled as 1, 16, 17, and 32 under the Universal Numbering System.
Timeline of Third Molar Development
The third molars earn the name “wisdom teeth” because of the late stage of life at which they emerge. Unlike the rest of the permanent teeth that erupt during childhood, the third molars usually begin to break through the gums between the ages of 17 and 21 years. This period corresponds to the time when an individual is thought to be reaching the age of maturity or gaining “wisdom.”
The root formation for these teeth may not be fully complete until the age of 19 to 23 years. The prolonged development period means that the jaw structure has largely finished growing before the third molars attempt to erupt. This often leads to a lack of sufficient space for them to fit properly in the dental arch.