obsolete Universal tooth number true A label naming a type of secondary tooth canonically found in humans, adopted by the American Dental Association, and commonly used as labels on odontograms (toothcharts) and clinical notes. The Universal Numbering System uses No. 1 through 32 for the 32 teeth in the permanent dentition, starting with 1 for the maxillary right third molar, going around the arch to the maxillary left third molar as 16; dropping down on the same side, the left mandibular third molar becomes 17, and then the numbers increase around the lower arch to 32, which is the lower right third molar. Bill Duncan 4/12/2012: From the book: "The Universal Numbering System was first suggested by Parreidt in 1882, and officially adopted by the American Dental Association in 1975. It is accepted by third-party providers and is endorsed by the American Society of Forensic Odontology." Book:Scheid, Rickne. Woelfel's Dental Anatomy, 8th Edition. Lippincott Williams & Wilkins, 01/2011. pp. i - ii). Titus Schleyer 1/1/2014: slightly updated definition obsolete class