# Tooth Notation Systems > Tooth notation systems for BDS Oral Anatomy — Zsigmondy-Palmer, Universal and FDI systems with worked examples and exam-ready conversions in one page. - Canonical URL: https://prepelephant.com/topics/bds/oral-anatomy/tooth-notation-systems - Exam / course: BDS · Subject: Oral Anatomy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Tooth Notation Systems", PrepElephant, https://prepelephant.com/topics/bds/oral-anatomy/tooth-notation-systems ## Direct answer One tooth can carry three different names depending on the notation system in use, and the BDS student must translate between them instantly. The Zsigmondy–Palmer system places the number 1 to 8 (or the letter A to E for primary teeth) inside a bracket whose arm indicates the quadrant — simple on paper, clumsy on a keyboard. The Universal system numbers permanent teeth 1 to 32 clockwise from the maxillary right third molar, with primary teeth lettered A to T on the same path. The FDI two-digit system (ISO 3950) makes the first digit the quadrant — 1 to 4 permanent, 5 to 8 primary, starting at the upper right — and the second the tooth from the midline: 36 is the mandibular left first molar. ## What you must remember - Palmer (Zsigmondy): numbers 1 (central incisor) to 8 (third molar) or letters A to E in primary teeth, set in a right-angle bracket; the mirror-image brackets distinguish right from left quadrants. - Universal: 1 to 32 clockwise from the maxillary right third molar — 16 maxillary left third molar, 17 mandibular left third molar, 32 mandibular right third molar; primary letters A to T run the same circuit. - FDI: quadrant digit plus tooth digit; permanent quadrants 1 (upper right), 2 (upper left), 3 (lower left), 4 (lower right); primary quadrants 5, 6, 7, 8 on the same clockwise circuit. - Anchors: 11 maxillary right central incisor, 36 mandibular left first molar, 46 mandibular right first molar, 48 mandibular right third molar. - Primary anchors: FDI 55 maxillary right second primary molar and 75 mandibular left; Universal K is the mandibular left second primary molar. - The FDI system's advantages — self-describing quadrants, easy typing, no special symbols, unambiguous dictation — made it the ISO 3950 standard for records and research. - The Haderup system (Scandinavia) marks upper teeth with a plus and lower with a minus sign, placed left or right of the digit for side — a viva extra. ## Charting the same mouth three ways Chart one patient in all three languages. The maxillary left first molar with distal caries is Palmer 6 in the left-sided bracket, Universal 14, FDI 26 — quadrant 2, tooth 6. The mandibular right canine being extracted for orthodontic reasons is Palmer 3 with the right-sided bracket, Universal 27, FDI 43. Now a paediatric entry: a pulpotomy in the mandibular left second primary molar is Palmer E with the lower-left bracket, Universal K, FDI 75. Each system shows its weakness when read aloud: Palmer needs the bracket described, Universal "14" hides the quadrant, while FDI "two-six" decodes instantly — why FDI won internationally. The reverse conversion is the exam's sharper edge: given Universal 24, count along the circuit — 16 closes the maxillary sweep, 17 begins the mandibular LEFT arch at the third molar, then 18 second molar, 19 first molar, 20 second premolar, 21 first premolar, 22 canine, 23 lateral incisor, so 24 is the mandibular left central incisor: FDI 31, Palmer lower-left 1. ## Where notation questions steal marks The most punished error is direction: Universal starts at the maxillary RIGHT third molar, crosses to the left (16), drops to the mandibular left third molar (17) and crosses back (32) — start wrong and every answer mirrors, so write 1–16, 17–32 at the top of the answer sheet first. The second trap is FDI quadrant confusion between 4 and 3: quadrant 4 is the lower RIGHT and quadrant 3 the lower LEFT, and reversing them mirrors the entire mouth. Third, the letters: Palmer primary uses A to E, Universal primary A to T — writing "E" when the examiner wanted the Universal T is a classic half-mark loss. Fourth, "best for computerised records" is answered with FDI plus its ISO 3950 status — not merely "it is universal". ## Frequently asked questions ### What do the two digits mean in the FDI system? The first digit gives the quadrant — 1 upper right, 2 upper left, 3 lower left, 4 lower right for permanent teeth and 5 to 8 for the same clockwise circuit in primary teeth — and the second gives the tooth's position from the midline, 1 to 8 or 1 to 5. ### Convert FDI 36 and 46 into words. 36 is the mandibular left first molar, 46 the mandibular right — the pair that tests whether quadrants 3 and 4 are swapped. ### Which notation is the ISO standard? The FDI two-digit notation, standardised as ISO 3950, because each code is self-describing, unambiguous when spoken, and keyboard-friendly. ### What is the Haderup system? A Scandinavian notation using a plus sign for maxillary and a minus for mandibular teeth, placed to the right or left of the digit to indicate side.