The Zsigmondy-Palmer method is a combination of systems developed by two separate dentists: Adolf Zsigmony and Coydon Palmer. Zsigmony developed his system in 1861, while Palmer developed his in 1870.
Hungarian dentist Adolf Zsigmondy developed a method of using a cross diagram to record teeth in quadrants identified by Roman numerals. Croydon Palmer, a dentist from Ohio, independently created a similar method using symbols and alphabetic letters to diagram baby and adult teeth. Elements of both systems evolved to become the Zsigmondy-Palmer system used by dentists today for numbering teeth.
The Fédération Dentaire Internationale system, developed in 1971, now called the ISO system, employs quadrants and two digit numbers to designate each tooth. The World Health Organization endorses this method. The American Dental Association officially adopted the Universal Numbering system, which uses uppercase letters for primary teeth and numbers for adult teeth, in 1975.