Reliability of Pederson Scale in Surgical Extraction of Impacted Lower Third Molars: Proposal of New Scale

Table 1

Spatial relationship (position of the molar).

Mesioangular	1
Horizontal/transverse	2
Vertical	3
Distoangular	4
Depth
Level A: high occlusal level	1
Level B: medium occlusal level	2
Level C: deep occlusal level	3
Ramus relationship/space available
Class 1: sufficient space	1
Class 2: reduced space	2
Class 3: no space	3
Difficulty index
Very difficult	7–10
Moderately difficult	5–7
Slightly difficult	3-4