According to Pederson difficulty index, what is the difficulty level of an impacted tooth
which is lying horizontally, at Level III and position C?
Pederson difficulty index based on Pell and Gregory classification:
(A) Spatial relationship:
Mesioangular = 1
Horizontal = 2
Vertical = 3
Distoangular = 4
(B) Depth:
Position A (highest portion of crown of 8 is above occlusal line of 2nd molar) =1
Position B (higher portion of crown of 8 is above CEJ of 2nd molar) = 2
Position C (highest portion of crown of 8 is below CEJ of 2nd molar) = 3
(C) Relation with ascending ramus:
Level 1 (mesiodistal width between 7 and ascending ramus is sufficient to accommodate mesiodistal width of 8) = 1
Level 2 (space slightly short to accomodate the entire mesiodistal width of 8) = 2
Level 3 (space very less to accomodate the entire mesiodistal width of 8 – tooth almost within ascending ramus ) = 3
Difficulty score = A+B+C
Score 3-4 = minimum difficulty
Score 5-7 = moderate difficulty
Score 8-10 = very difficult.
Other difficulty indices are: WHARFE Score, Parant and Modified Parant scale and using WAR lines.
Minimum difficulty
Moderate difficulty
Very difficult
Not impacted