Final answer:
The tooth numbering system where the first digit indicates the quadrant and the second number indicates the tooth is the FDI system, also known as the ISO system. This should not be confused with the Palmer Notation, which is less commonly used internationally.
Step-by-step explanation:
The numbering system in which the first digit indicates the quadrant, and the second number indicates the tooth is the FDI system. The four major tooth numbering systems globally are the Universal System, the Palmer Notation System, the ISO System, and the FDI World Dental Federation Notation. The FDI system, also known as the ISO system, uses a two-digit system where the first number represents the quadrant and the category of the tooth (permanent or primary) while the second digit indicates the specific tooth. For example, '13' would mean the first quadrant (upper right for permanent teeth) and the third tooth in that quadrant, which is the upper right canine for adults.
It's important to differentiate this from the Palmer Notation, often known as the Palmer-Notation, which uses a combination of number and bracket to indicate the quadrant and tooth position. This system is less widely utilized than the FDI, particularly in practice outside of the United Kingdom. The Universal System, mainly used in the United States, utilizes consecutive numbers for adult teeth and letters for deciduous (baby) teeth, which does not fit with the first digit representing the quadrant.