Palmer vs FDI Notation: Which Should Your Dental Practice Use?

Palmer vs FDI notation comes down to how a tooth is named. Palmer splits the mouth into four quadrants and numbers each tooth 1 to 8 from the midline, so the upper right first molar is UR6. FDI uses two digits, one for the quadrant and one for the tooth, so the same molar is 16. Both describe the same teeth. Palmer is familiar to most UK clinicians, while FDI is the international standard.

Most UK dental teams use both, often without thinking about it. A dentist dictates "upper right six". A referral letter says "UR6". A guideline or a radiograph report says "16". That works until a new associate, a locum or a referral partner reads one as the other. This guide explains both systems, gives a conversion list, and sets out how to keep notation consistent across your records and your software.

What is Palmer notation?

Palmer notation, sometimes called the Zsigmondy-Palmer or grid system, divides the mouth into four quadrants from the patient's point of view: upper right, upper left, lower left and lower right. Within each quadrant the teeth are numbered from the midline backwards:

• Permanent teeth: 1 to 8. The central incisor is 1, the canine is 3, the first molar is 6 and the wisdom tooth is 8.
• Deciduous (baby) teeth: letters A to E. The central incisor is A and the second molar is E.

On paper, the quadrant is shown by a right-angle bracket drawn around the number, like one arm of a cross. In typed notes and letters, most teams write the quadrant as letters instead: UR6, UL3, LL7, LR1. For a baby tooth, it becomes URE or LLD.

The strength of Palmer is speed. "Upper right six" is how many UK clinicians say it chairside, so the chart matches the spoken word. Its weakness is that the bracket symbols are hard to type and easy to misread in email or software that cannot draw them.

What is FDI notation?

FDI notation, also called the two-digit system, was developed by the FDI World Dental Federation. It is published as the international standard ISO 3950, Dentistry: designation system for teeth and areas of the oral cavity.

Every tooth gets two digits. The first digit is the quadrant. The second is the tooth, counted from the midline:

• Permanent quadrants: 1 upper right, 2 upper left, 3 lower left, 4 lower right.
• Deciduous quadrants: 5 upper right, 6 upper left, 7 lower left, 8 lower right.
• Tooth numbers: 1 to 8 for permanent teeth and 1 to 5 for deciduous teeth.

So the upper right permanent first molar is 16, the lower left permanent canine is 33, and the upper right deciduous second molar is 55. You read each code digit by digit: 16 is "one six", not "sixteen".

FDI is easy to type, sort and search, which is why computers and international bodies prefer it. UK guidance uses it too. The British Society of Periodontology's BPE guidelines define the six sextants in FDI numbers, such as upper right 17 to 14.

Palmer vs FDI: the key differences

• Quadrant shown by: Palmer uses a bracket or the letters UR, UL, LL, LR. FDI uses the first digit, 1 to 4 for adult teeth and 5 to 8 for baby teeth.
• Baby teeth: Palmer uses letters A to E. FDI keeps numbers and changes the quadrant digit.
• Typing: Palmer brackets are hard to type, so typed Palmer uses letters. FDI is plain digits.
• Where it is used: Palmer is widely used in UK practice and speech. FDI is the international and ISO standard.
• Risk of confusion: a lone "6" in Palmer means nothing without its quadrant. In FDI, "16" could be misread as a count if the context is unclear.

Palmer to FDI conversion list

For permanent teeth, the tooth number is the same in both systems. Only the way the quadrant is written changes:

• Upper right: UR1 to UR8 = 11 to 18
• Upper left: UL1 to UL8 = 21 to 28
• Lower left: LL1 to LL8 = 31 to 38
• Lower right: LR1 to LR8 = 41 to 48

For deciduous teeth, the Palmer letter becomes a number from 1 to 5, and the quadrant moves to 5 to 8:

• Upper right: URA to URE = 51 to 55
• Upper left: ULA to ULE = 61 to 65
• Lower left: LLA to LLE = 71 to 75
• Lower right: LRA to LRE = 81 to 85

That gives 32 permanent and 20 deciduous teeth, 52 in all. A few worked examples: UR6 is 16, LL8 is 38, ULC is 63 and LRE is 85.

What about the Universal system?

You will also meet the Universal Numbering System, used mainly in the United States. It numbers permanent teeth 1 to 32 around the mouth, starting at the upper right third molar, and uses letters A to T for baby teeth. In that system the upper right first molar is 3. It rarely appears in UK records, but it turns up in US software, textbooks and some imported templates. If a note says "tooth 3", check which system the author meant.

Which notation should a UK practice use?

There is no rule that forces one system on a UK practice. What matters is that everyone can read the record without guessing. A sensible policy looks like this:

1. Pick a house style for written records. Many UK practices use Palmer in the letter form (UR6) for notes and letters, because it matches how clinicians speak.
2. Never write a bare number. "6 needs a crown" is ambiguous. Always include the quadrant.
3. Match the reader in referrals. If a hospital or specialist uses FDI, write "UR6 (16)" so nobody has to convert.
4. Teach new starters both. Associates trained overseas often think in FDI. Nurses may have learned Palmer. A one-page conversion sheet at each chair saves mistakes.
5. Let the software do the converting. A digital chart should store each tooth once and show it in whichever notation the reader prefers.

Clear notation is part of good record keeping. The General Dental Council expects records to be "clear, legible, accurate" and "readily understood by others". Our guide to dental record keeping guidelines covers the rest.

Notation in dental charting software

Good charting software removes the argument. It stores every tooth under one code and lets each person choose how to see it. When you compare systems, check that:

• The chart can show Palmer or FDI, with deciduous teeth lettered properly in Palmer.
• Each clinician can choose their own view without changing it for everyone else.
• Surface names follow the tooth, so a front tooth shows labial rather than buccal.
• Mixed dentition can be shown, for children losing baby teeth.

DentiPoint's dental charting software works this way. The chart holds all 52 teeth under their FDI code and can show them in FDI or Palmer, with baby teeth lettered A to E. The practice sets a default notation and a default view of permanent, mixed or deciduous teeth, and each user can switch to the notation they read fastest without changing it for anyone else. Surface labels change with the tooth: buccal reads labial on a front tooth, lingual reads palatal on the upper arch, and occlusal reads incisal on incisors and canines. The chart sits on the patient record, next to clinical notes and recalls.

Frequently asked questions

What is the difference between Palmer and FDI notation?

Palmer shows the quadrant with a bracket or letters and numbers each tooth 1 to 8, using letters A to E for baby teeth. FDI uses two digits, a quadrant from 1 to 8 and a tooth number. UR6 in Palmer is 16 in FDI.

Which dental notation is used in the UK?

Both. Palmer is widely used in UK practice and in how clinicians speak. FDI is the international ISO standard and is used in many guidelines, such as the BSP's BPE sextants.

How do you convert Palmer to FDI?

For permanent teeth, keep the tooth number and replace the quadrant: UR is 1, UL is 2, LL is 3 and LR is 4. For baby teeth, use quadrants 5 to 8 and turn the letter A to E into 1 to 5.

How are baby teeth written in FDI notation?

With quadrants 5 to 8 and tooth numbers 1 to 5. The upper right deciduous second molar is 55, and the lower left deciduous canine is 73.

Is FDI the same as ISO 3950?

Yes. The FDI two-digit system is published as the international standard ISO 3950.

Palmer and FDI will both be around for years. The practical fix is a clear house style and software that shows each person the notation they read best. To see a chart that switches between the two, get started with DentiPoint or look at the full features list.