Dental Notation Systems: FDI vs Palmer vs Universal (with Charts)

The three systems at a glance

Use our free Tooth Notation converter (linked below) to translate any tooth between all three systems instantly, and see our UK dental abbreviations guide for the surface codes and shorthand that sit alongside notation in a clinical note.

FDI two-digit system (the international standard)

The FDI World Dental Federation notation — also published as ISO 3950 — gives every tooth a two-digit number. There is no shorthand to draw and nothing ambiguous to mis-read, which is why it is the international standard and the system you will see in journals, specialist referrals and most dental software.

• First digit = quadrant. For permanent teeth: 1 = upper right, 2 = upper left, 3 = lower left, 4 = lower right.
• Second digit = tooth position, counting from the midline outwards: 1 = central incisor, 2 = lateral incisor, 3 = canine, 4 = first premolar, 5 = second premolar, 6 = first molar, 7 = second molar, 8 = third molar (wisdom tooth).

So FDI 26 is read "two-six" (not "twenty-six") and means upper-left first molar. FDI 48 is the lower-right third molar.

FDI permanent dentition chart (as the patient faces you):

Palmer notation (the UK clinic standard)

Palmer notation — historically the Zsigmondy–Palmer system, and sometimes called "grid" or "set-square" notation — is the one you will hear spoken across a UK surgery. Each tooth is identified by a quadrant symbol plus a digit 1–8, using the same 1–8 tooth-position key as FDI:

The quadrant is shown by a right-angle bracket (a "set square") drawn around the digit, indicating which corner of the mouth the tooth sits in. Because that bracket is hard to type, UK notes very commonly substitute the two-letter prefix — UR, UL, LR, LL — so "upper-right first molar" is written UR6 in everyday records, referral letters and clinical software.

Palmer permanent dentition chart (two-letter shorthand):

The strength of Palmer is that it is visual and intuitive at the chairside — the symbol literally points to the corner of the mouth. Its weakness is that the bracket does not survive typing cleanly, which is one reason FDI has spread in digital records.

Universal Numbering System (USA)

The Universal Numbering System is the convention used primarily in the United States and is associated with the American Dental Association. For permanent teeth it numbers all 32 teeth 1–32 in a single continuous sweep, starting at the upper-right third molar (1), running across the upper arch to the upper-left third molar (16), then dropping to the lower-left third molar (17) and continuing across to the lower-right third molar (32).

You will rarely write in Universal notation in the UK, but you will meet it in US textbooks, US-built software and international research — so being able to convert is the practical skill.

Universal permanent dentition chart:

Primary (deciduous) teeth in each system

The 20 primary teeth are handled differently in each system, and this is a common exam trap:

• Palmer: same quadrant symbol/prefix, but letters A–E instead of digits. A = central incisor, B = lateral incisor, C = canine, D = first primary molar, E = second primary molar. So URE = upper-right second primary molar.
• FDI: keeps the two-digit format but uses quadrants 5–8 for primary teeth (5 = upper right, 6 = upper left, 7 = lower left, 8 = lower right) and tooth digits 1–5. So 55 = upper-right second primary molar; 75 = lower-left second primary molar.
• Universal: uses letters A–T, sweeping in the same direction as the permanent numbers, starting at the upper-right second primary molar (A) and ending at the lower-right second primary molar (T).

Primary dentition three-system conversion table:

The three-system conversion table (permanent teeth)

This is the reference to bookmark. Every permanent tooth, in all three systems, by quadrant.

Why the UK uses Palmer and FDI — and what overseas grads must switch

Two practical points for working in the UK:

1. Spoken and handwritten clinic = Palmer. When a clinician calls out a tooth, demonstrates on a study model, or scribbles in paper notes, expect Palmer ("UR6"). It is the system most UK dental schools teach first and the convention in most general-practice records and referral letters.
2. Typed, academic and software = increasingly FDI. Many practice-management systems, BPE/perio charts, journal articles and specialist referrals use the unambiguous two-digit FDI format. ISO 3950 is the international standard, so FDI is the lingua franca for anything that crosses a border or a database.

For overseas-trained dentists, the most common adjustment is the reverse of what you might expect: many international curricula teach FDI as primary, so the new habit to build in UK practice is reading and speaking Palmer fluently — especially the UR/UL/LR/LL quadrant prefixes — while keeping FDI for written records. The systems map one-to-one (see the table above), so it is a translation habit rather than relearning anatomy. Our UK dental charting guide for overseas dentists (linked under Related guides below) walks through the wider conventions — surface codes, BPE and what a compliant UK note must contain.

Whichever system you write in, the medico-legal point is the same: a tooth reference must be unambiguous. Mixing notations within one record, or using a quadrant symbol that does not reproduce in your software, is exactly the kind of ambiguity that causes a wrong-tooth error or a record-keeping criticism. Pick the system your record demands and be consistent.

Free Tooth Notation converter tool

To take the guesswork out of conversion, we built a free Tooth Notation converter. Type a tooth in any one system and it returns the equivalent in the other two — useful when you are reading a US paper in FDI, a referral in Palmer, or revising for finals.

It sits alongside Nosht, a UK dental clinical-notes tool. Nosht’s core is a deterministic template engine, with optional, clinician-reviewed AI (powered by Anthropic’s Claude Haiku 4.5) that turns your shorthand into structured note fields — you review and confirm every field — plus an advisory completeness check on the finished note. The workflow does not record audio — you type shorthand — and there is no voice capture in this workflow; it is not trained on your notes, and the workflow is designed to exclude patient identifiers from any AI step. If you have used an ambient AI scribe that records and transcribes the appointment, the difference is that Nosht does not listen to your appointments — the workflow does not record audio, and nothing is finalised until you confirm it.

What notation does the UK use for teeth?

The UK uses two systems side by side. Palmer notation (quadrant symbol or UR/UL/LR/LL prefix plus a digit 1–8) is the most common in everyday clinical records and is usually taught first in UK dental schools. FDI (the two-digit ISO 3950 standard) is widely used in academic, specialist and practice-management-software contexts. The Universal Numbering System is a US convention and is not standard in UK practice.

What is the difference between FDI and Palmer notation?

Both identify a tooth by quadrant plus the same 1–8 position key (central incisor to third molar). The difference is how the quadrant is shown. Palmer uses a drawn right-angle ("set-square") symbol — or the UR/UL/LR/LL letter prefix — so the upper-right first molar is UR6. FDI uses a leading digit for the quadrant (1–4 for permanent teeth), giving a two-digit number, so the same tooth is 16 ("one-six"). FDI is easier to type and unambiguous; Palmer is more visual at the chairside.

How do you read tooth numbers?

Identify the quadrant first, then the tooth position. In FDI, read the two digits separately: in "36", the 3 means lower-left quadrant and the 6 means first molar, so it is the lower-left first molar. In Palmer, the prefix (e.g. LL) gives the quadrant and the digit gives the position, so LL6 is the same tooth. In Universal, the single number 1–32 maps to a fixed position — for example 3 is the upper-right first molar. Use the conversion table above, or the Tooth Notation converter, to move between systems.

Why are there three different dental notation systems?

They developed in different places for different reasons. Palmer (originally the Zsigmondy–Palmer system) became established in the UK and parts of the Commonwealth; FDI was adopted as the international ISO standard because two digits are unambiguous and translate cleanly into software and research; and the Universal system became the convention in the USA. Knowing all three lets you read records, referrals and literature from anywhere.