When a dentist or hygienist calls out a series of numbers during an examination, they are using a standardized method of identifying each tooth. This precise identification is necessary for accurate dental charting, treatment planning, and seamless communication with specialists and insurance providers. While several numbering systems exist globally, the number 31 refers to a specific tooth within the system most commonly used by dental professionals in the United States.
Pinpointing Tooth 31
Tooth 31 is designated as the lower right second molar within the adult dentition, according to the Universal Numbering System (UNS). This tooth is situated in the lower jaw, or mandible, positioning it as the second tooth from the back of the mouth on the patient’s right side. It is located immediately in front of the wisdom tooth, which is tooth number 32, if present.
The second molar plays a significant role in the mechanics of eating, functioning primarily to grind and crush food. Its broad, flat chewing surface and multiple roots are designed to withstand the considerable forces exerted during mastication. This tooth typically erupts around the age of 12, earning it the alternative name of the “12-year molar.” Its physical location and powerful function define its importance to the overall stability of the dental arch.
Understanding the Universal Numbering System
The Universal Numbering System (UNS) provides a unique number for each of the 32 permanent teeth, starting with number 1 and ending with number 32. The sequence begins with the upper right third molar (wisdom tooth), assigned number 1. The count proceeds sequentially along the upper arch, moving toward the front and continuing to the upper left third molar, which is number 16.
After reaching the last tooth on the upper left, the sequence drops down to the lower jaw, starting with the lower left third molar, designated as number 17. The numbering continues across the lower arch, moving from the left side to the right side of the jaw. Tooth 31 falls within this lower right quadrant, which encompasses numbers 25 through 32. This clockwise pattern ensures every tooth has an unmistakable identifier.
Common Issues Associated with Tooth 31
The location of the second molar at the back of the jaw makes it susceptible to certain dental health problems. Due to its posterior position, tooth 31 is difficult to reach effectively with a toothbrush and floss, increasing the risk of plaque accumulation and decay. The deep grooves and pits on the chewing surface also tend to trap food particles and bacteria, making it a common site for cavities.
As a molar, this tooth absorbs intense pressure during chewing, making it vulnerable to fractures or cracks, especially if it has large existing fillings. The proximity of the third molar can also affect tooth 31; an impacted wisdom tooth may push against it, potentially causing damage or contributing to bone loss. If a deep cavity or fracture reaches the pulp, a root canal procedure may be necessary, though lower molars are known for complex internal anatomy.