JOVD 2001: Morphologic Features of the Root Canal System of the Mx PM4 and the Mn M1 in Dogs

Question 1

Authors?

Answer 1

S. Hernandez

V. Negro

Question 2

Aim and metho of study?

Answer 2

• To describe morphologic features of the root canal system of the Mx PM4 and MnM1 in dogs
• Prospective study on 72 MxPM4 and 59 MnM1 teeth extracted from euthanized dogs; dye with ink; decalcified for transparency and examined under stereoscopic binocular 20X

Question 3

What are Non apical ramifications (NAR)?

Answer 3

NAR: canal ramification that communicate with PDL but not through apical delta

• Collateral canals: course parallel to main canal and reach apex independently; not reported in vet. med.
• Lateral canals: exit main canal in the coronal 2/3 of root
• Secondary canals: exit main canal in the apical 1/3 of root
• Accessory canals: branch from secondary canals (only 1.5% in carnassial teeth of dogs)

Question 4

What are the % of NAR in MxPM4 and MnM1 in dogs?

Answer 4

• 46% of all roots (more in PM4 than in M1; diam. 0.05 - 1 mm)
  
  • 68% of MxPM4 have 1 or > NAR
    
    • 98% secondary canal; 2% lateral canal
    • Distal root: distal = mesial aspect
    • Mesiobuccal and palatal roots: distal > mesial
  • 20% of MnM1 have 1 or > NAR
    
    • 83% secondary canals; 17% lateral canals
    • Distal root: mesial
    • Mesial root: distal
  • So, more in MxPM4 than in MnM1; distal root of MxPM4 more NAR

Question 5

What is the lenght of the apical delta in MxPM4, MnM1?

Answer 5

• 1-3 mm (98% of PM4; 81% of M1)
  N.B.: since may be > 3mm in M1, should consider when Sx RCT
• 12 -18 % of the root length

Question 6

Were lateral canals present in the cervical 1/3 of the root or at fircuation?

Answer 6

No!

Question 7

Why is it important that the apical 1/3 of the root canal be well obturated in endo tx?

Answer 7

• Need to obliterate the opening of NAR and apical delta; NAR in dogs carnassial teeth are mostly secondary canals, so exit in the apical 1/3 of root canal and apical delta is 3 mm