Position of the mandibular third molar Risk degree of presumptive intervention (score)
Conventional (0) Simple (1) Moderate (2) Complicated (3)
Mesiodistal position in relation to the second molar - M and the mandibular ramus - R
Relation to the second molar - M Crown directed at or above the equator of the second molar Crown directed below the equator to the coronal third of the second molar root Crown/roots directed to the middle third of the second molar root Crown/roots directed to the apical third of the second molar root
Relation to the mandibular ramus - R Sufficient space in the dental arch Partially impacted in the ramus Completely impacted in the ramus Completely impacted in the ramus in distoangular or horizontal position
Apicocoronal position in relation to the alveolar crest - A and the mandibular canal - C (IAN injury risk)
Relation to the adjacent alveolar crest (from the uppermost point of the tooth) - A Tooth is completely erupted Partially impacted, but widest part of the crown (equator) is above the bone Partially impacted, but widest part of the crown (equator) is below the bone Completely encased in the bone
Relation to the mandibular canal (from the lowermost point of the tooth) - C ≥ 3 mm to the mandibular canal Contacting or penetrating the mandibular canal, wall of the mandibular canal may be identified Contacting or penetrating the mandibular canal, wall of the mandibular canal is unidentified Roots surrounding the mandibular canal
Buccolingual position in relation to mandibular lingual and buccal walls - B (LN injury risk)
Relation to mandibular lingual and buccal walls - B Closer to buccal wall In the middle between lingual and buccal walls Closer to lingual wall Closer to lingual wall, when the tooth is partially impacted or completely encased in the bone (A2 or A3)
Spatial position - S
Spatial position - S Vertical (90°) Mesioangular ≤ 60° Distoangular ≥ 120° Horizontal (0°) or inverted (270°)

IAN = inferior alveolar nerve; LN = lingual nerve.