What method of identification is used in the universal national tooth numbering system for the primary dentition?

The universal national tooth numbering system for primary dentition assigns a unique number to each primary tooth, starting from 1 to 20. The numbering begins with the upper right second molar (tooth 1) and proceeds sequentially across the upper arch to the upper left second molar (tooth 10), then continues with the lower left second molar (tooth 11) and moves across the lower arch to the lower right second molar (tooth 20). This system enables clear communication and documentation of dental procedures and conditions.