Using the International Standards Organization system of tooth recording, which tooth is #25?

In the International Standards Organization (ISO) system, each tooth is assigned a two-digit number starting with a number that indicates the quadrant and a second number that indicates the specific tooth within that quadrant. The numbering system for the ISO begins with the maxillary right quadrant, moving from the central incisor to the second molar, followed by the maxillary left, mandibular left, and concludes with the mandibular right quadrant.

To understand why tooth #25 is designated as the maxillary left second premolar, we can break down the numbering. The first digit, 2, indicates that the tooth is in the maxillary quadrant, specifically in the upper jaw. The second digit, 5, refers to the position of the tooth in that quadrant, following the sequence of teeth. In this sequence, the central incisor is numbered as 1, the lateral incisor as 2, the canine as 3, the first premolar as 4, and the second premolar is therefore numbered as 5. This aligns tooth #25 with the maxillary left second premolar.

Understanding this system is crucial for dental professionals as it allows for clear communication regarding tooth identification in an efficient manner.