Table 4 Number and percentage of the common canal system types in mandibular third molars.
Group | No. of Roots | Type I | Type II | Type III | Type IV | Type V | Type VI | Type VII | Type VII | Additional types | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2-1 | 1-2-1 | 2-2 | 1-2 | 2-1-2 | 1-2-1-2 | 3-3 | 1-3-1 | 3-1 | 3-2 | 3-4 | 2-3 | 4-1 | 4-2 | 4-3 | 4-4 | ||
Three separate roots | ||||||||||||||||||
M root | 18 | 13 72.22% | 1 5.55% | – | 1 5.55% | 3 16.66% | – | – | – | – | – | – | – | – | – | – | – | – |
D root | 18 | 16 88.88% | – | – | – | 2 11.11% | – | – | – | – | – | – | – | – | – | – | – | – |
L root | 18 | 18 100% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Three roots: | ||||||||||||||||||
M&DL fused 83.33% | 18 | – | – | – | 15 5.55% | 1 5.55% | – | – | 1 5.55% | – | – | – | – | 1 5.55% | – | – | – | – |
D root | 18 | 16 88.88% | 1 5.55% | – | 1 5.55% | – | – | – | – | – | – | – | – | – | – | – | – | – |
Three roots: D fused | ||||||||||||||||||
D&DL fused | 2 | – | – | – | 1 50% | 1 50% | – | – | – | – | – | – | – | – | – | – | – | – |
M | 2 | 1 50% | 1 50% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Three roots all fused | 9 | – | – | – | – | – | – | – | 4 44.44% | – | – | 1 11.11% | 4 44.44% | – | – | – | – | – |
Two roots: separate | ||||||||||||||||||
M | 510 | 140 27.45% | 97 19.01% | 15 2.94% | 235 46.08 | 15 2.94% | 15 0.78% | 4 0.78% | 4 0.78% | – | – | – | – | – | – | – | – | – |
D | 510 | 455 89.21% | 4 0.78% | 6 1.17% | 42 8.23% | 3 0.58% | – | – | – | – | – | – | – | – | – | – | – | – |
Two roots: fused | 63 | – | 8 12.69% | – | 30 47.62% | 1 1.58% | – | – | 4 6.35% | – | 6 9.52% | 5 7.93% | 1 1.58% | 4 6.35% | 1 1.58% | 1 1.58% | – | 3 4.76% |
