Overview
This lecture explains the composition of adult dentition and details two tooth numbering systems: the Universal and International systems.
Adult Dentition Structure
- The adult dentition consists of 32 permanent teeth.
- Teeth are divided into four quadrants: upper right, upper left, lower left, and lower right.
- Each quadrant contains 8 teeth, arranged from mesial (midline) to distal.
- The order of teeth: central incisor, lateral incisor, canine, first premolar, second premolar, first molar, second molar, third molar.
Universal Tooth Numbering System
- The Universal system numbers teeth sequentially from 1 to 32.
- Counting starts at the patient's upper right third molar (#1) to upper left third molar (#16).
- Numbers continue from lower left third molar (#17) to lower right third molar (#32).
- Example: The upper left canine is tooth number 11.
International Tooth Numbering System
- The International system uses two digits for each tooth.
- The first digit indicates the quadrant: upper right (1), upper left (2), lower left (3), lower right (4).
- The second digit indicates the tooth's position within the quadrant, starting from the midline (central incisor as 1, third molar as 8).
- Example: Upper left canine is designated as 2-3 (second quadrant, third tooth from midline).
Key Terms & Definitions
- Quadrant — One of the four sections of the mouth; contains 8 teeth each.
- Mesial — Direction toward the midline of the dental arch.
- Distal — Direction away from the midline of the dental arch.
- Universal Numbering System — Tooth numbering system from 1 to 32, starting upper right to lower right.
- International Numbering System — Two-digit tooth identification: quadrant number and tooth position.
- Central Incisor — Tooth closest to the midline.
- Canine — Third tooth from the midline in each quadrant.
Action Items / Next Steps
- Review diagrams of permanent dentition with both numbering systems.
- Practice identifying and numbering teeth using both the Universal and International systems.