Dental Anatomy Question And Answers

Dental Anatomy

Write briefly about different tooth numbering systems.
(or)
FDI system of dental nomenclature.

Answer:

It is necessary to substitute the lengthy names of the individual teeth with some symbol.

• Thus, various numbering teeth by some symbol were introduced to designate individual teeth by a number or alphabetical letter.

1. Zsigmondy/palmer system:

1. It was introduced by Adolph Zsigmondy of Vienna in 1861 for permanent dentition and modified for primary dentition in 1874.

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For permanent dentition:

• As per this system, the oral cavity is divided into four quadrants and each permanent tooth has a specific number.
• Numbering progresses posteriorly from the midline.
• The central incisor was designated as 1 ending up with 8 for the third molar.

\(\begin{array}{l|l}
87654321 & 12345678 \\
\hline 87654321 & 12345678
\end{array}\)

For primary dentition:

• The deciduous central incisors are designated A & progress posteriorly up to the 2nd deciduous molar alphabetically designated E.

\(\begin{array}{l|l}
\text { EDCBA } & \text { ABCDE } \\
\hline \text { EDCBA } & \text { ABCDE }
\end{array}\)

2. Universal system:

For permanent dentition:

• In this system, the numbering starts from the right maxillary 3rd molar designated 1 to 16 designated to the left maxillary 3rd molar.
• Then beginning with the mandibular left 3rd molar, the teeth are numbered 17 to 32.

\(\begin{array}{l|l}
12345678 & 910111213141516 \\
\hline 3231302928272625 & 2423222120191817
\end{array}\)

For primary dentition:

• Alphabets are used starting from A-J for maxillary left 2nd molar.
• Then beginning with the mandibular left 2nd molar, the teeth are named K to T.

\(\begin{array}{l|l}
\text { ABCED } & \text { FGH I J } \\
\hline \text { TSRQP } & \text { ONMLK }
\end{array}\)

3. FDI numbering system:

• It is a two-digit system proposed by the federation dentaire international (FDI)

For permanent dentition:

• The first digit indicates the quadrant and is numbered from 1 to 4.
• The second digit indicates the tooth number starting from the central incisor as 1 to the 3rd molar as 8.

Thus,

For primary dentition:

\(\begin{array}{l|l}
1817161514131211 & 2122232425262728 \\
\hline 4847464544434241 & 3132333435363738
\end{array}\)

• The first digit indicating quadrant is numbered from 5 to 8.
• The second digit is numbered from 1 to 5 from the central incisor to 2nd molar

\(\begin{array}{l|l}
5554535251 & 6162636465 \\
\hline 8584838281 & 7172737475
\end{array}\)