LAop: Classification systems of impacted teeth

Principles of management of impacted teeth
Chapter 9, Contemporary Oral and Maxillofacial Surgery, James R. Hupp

- Primary factor determining difficulty of removal is accessibility
- Majority of classification systems are based on radiograph analysis
-  3 main classification systems; used in conjunction to determine difficulty of an extraction

1. Angulation

• Angulation of long axis of impacted 8 wrt long axis of adjacent 7
• Easiest to most difficult to remove:
  Mesioangular (43%), Horizontal (3%), Vertical (38%), Distoangular (6%)
• Another angulation: Buccal, lingual, palatal, transverse (absolutely horizontal position in bl direction)

2. Relationship to anterior border of ramus (Pell and Gregory; Classes 1/2/3; easiest to hardest)

• Based on amount of impacted tooth that is covered with bone of mandibular ramus
• Analyse carefully the relationship between tooth and anterior part of ramus
• Class I: Mesiodistal diameter of crown is completely anterior to anterior border of ramus
• Class II: Approximately one-half of crown is covered by ramus
• Class III: Crown is located entirely within ramus

3. Relationship to occlusal plane (Pell and Gregory; Classes A/B/C)

• Based on depth of impacted tooth compared with height of adjacent second molar
• Degree of difficulty is measured by thickness of overlying bone
• Class A: Occlusal surface of impacted tooth is level or nearly level with (o) of 7
• Class B: Occlusal surface of impacted tooth between (o) plane and cervical line of 7
• Class C: Occlusal surface of impacted tooth is below cervical line of 7