denture·id
Glossary

Tooth surfaces and numbering

The letters and numbers used to say exactly where on which tooth a condition or restoration is.

Each tooth has five surfaces. Mesial (M) faces the midline and distal (D) faces away from it. The outer surface is buccal (B) on back teeth and facial or labial (F) on front teeth. The inner surface is lingual (L). The biting surface is occlusal (O) on back teeth and incisal (I) on front teeth. A filling charted “MOD” covers the mesial, occlusal and distal surfaces.

In the United States teeth are numbered with the Universal system: permanent teeth 1 to 32, starting at the upper right third molar and ending at the lower right third molar; primary teeth are lettered A to T. Most other countries use the two-digit FDI system.

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