Table 3 Number and percentage of the common canal system types in maxillary third molars.
Group | No. of roots | Type I | Type II | Type III | Type IV | Type V | Type VI | Type VII | Type VIII | 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 | 1-3 | 2-3 | 4-1 | 4-2 | 4-3 | 4-4 | 4-5 | ||
Three separate roots: | ||||||||||||||||||||
 MB root | 243 | 153 62.96 | 16 6.58% | 9 3.7% | 29 11.93% | 23 9.46% | 7 2.88% | 5 2.05% | 1 0.41% | – | – | – | – | – | – | – | – | – | – | – |
 DB root | 243 | 243 100% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
 P root | 243 | 242 99.59% | – | 1 0.41 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Three roots: B fused | ||||||||||||||||||||
 MB & DB fused | 23 | – | 6 26.08% | – | 12 52.17% | 1 4.35% | – | – | 2 8.69% | – | – | – | – | – | 2 8.69% | – | – | – | – | – |
 P | 23 | 23 100% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
Three roots | ||||||||||||||||||||
 MB & P fused | 23 | – | – | – | 13 56.52% | – | 2 8.69% | – | 3 13.04% | – | – | 1 4.35% | 2 8.69% | – | 2 8.69% | – | – | – | – | – |
 DB | 23 | 23 100% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
 Three roots all fused | 125 | – | – | – | – | – | – | – | 80 64.0% | – | 15 12.0% | 12 9.6% | 10 8.0% | – | 3 2.4% | – | – | 1 0.8% | 4 3.2% | – |
Two roots: separate | ||||||||||||||||||||
 Buccal | 27 77.77% | 21 7.4% | 2 14.8% | – | – | 4 | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
 Palatal | 27 | 27 100% | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – |
 Two roots: fused | 31 | – | 1 3.2% | – | 23 74.19% | – | 2 6.45% | – | – | – | – | 2 6.45% | – | – | 2 6.45% | – | – | 1 3.22% | – | – |
