Hunt for elusive canals

1. THE HUNT FOR ELUSIVE CANALS

2. ANALYSIS OF CAUSE OF FAILURE UNDER
MICROSCOPE DURING PERI-RADICULAR
MICROSURGERY
Leakage 30 %
Overfilling 3 %
Missed canal 19.7 %
Iatrogenic 2.8 %
Underfilling 14 %
Apical Calculus 1.8 %
Anatomical Complexity 8.7 %
80% Failures are asymptomatic
Minju Song et al, JOE Nov 2011

3. COMPLEX ROOT CANAL ANATOMY
Complexity is rule here in endodontia

4. COMMON MISSED CANALS
• MB2 – Upper first molar
• Middle mesial of lower molar
• Second distal canal in lower
molar
• Second canal in lower anterior
• Bifid canal in lower premolar

5. SECRET OF FINDING EXTRA CANALS
• Proper RCO
• Knowledge of root canal anatomy
Finding Extra canal is not big job, it is smart job
- Dr. John West

6. FIRST AND MOST IMPORTANT RULE
• Never touch floor of chamber with bur
• Never search canal with bur
• Always suspect extra canal

7. CHECK ANGULATED X RAY
10 -15 % horizontal
angulation

8. LOCATE LEVEL OF CEJ
Law of Centrality

9. GAUGING DEPTH OF ACCESS
Average 7 mm

10. Check Width and height
of pulp chamber

11. • TR 19 for bigger RCO
• TR 25 for smaller RCO

12. Safe end bur

13. EXAMINATION AND PALPATION OUTER
ANATOMY OF TOOTH
Law of centrality

14. EXAMINATION AND PALPATION OUTER
ANATOMY OF TOOTH
Law of concentricity

15. RCO – IMPORTANT FACTOR
(1) Permit the removal of all the chamber contents
Remove overhang over pulp horns
Which allow removal of
pulp tissue, calcification
and old filling material

16. REQUIREMENTS OF RCO
(2) Permit complete, direct vision of the floor of the pulp chamber
and canal openings
Dentinal Map
All the canal orifices are located
at the end of grooves of map

17. REQUIREMENTS OF RCO
(2) Permit complete, direct vision of the floor of the pulp chamber
and canal openings

18. REQUIREMENTS OF RCO
(3) Make entry of instruments easy into the root canal
Convex floor - Funnel shape
The walls prepared by the endodontist
and the floor created by Nature will
Guide the instrument toward the apex.

19. REQUIREMENTS OF RCO
(4) Straight line access (must for rotary)

20. REQUIREMENTS OF RCO
(4) Straight line access (must for rotary)

21. BEFORE HUNTING ELUSIVE CANAL
• Remove loose restorations and caries
• Irrigate with sod. Hypochlorite and dry
• Check dentinal map
• Locate orifices of main canals

22. LAW OF COLOR CHANGE
Pulpal (floor) dentin is usually
dark in color than axial(wall)
dentin. And canals are
invariably located at the
junction of these two.

23. METHODS OF LOCATION
• Walking the map
• Use of dyes
• Champange bottle test
• Looking for bleeding spot
• Transillumination
• Magnification

24. WALK THE MAP
Walking the map with the
explorer with straight tip over
the floor of the chamber and
remove any calcification or
debris if any present and feel
for any sinking which may be
either canal orifice or isthmus.
Endodontic Explorer - functions as
an extension of dentist’s fingers

25. USE OF DYES
1% Methylene Blue or
Ophthalmic dye.
dye can be applied or rubbed with applicator tip
and then washed after sometime. Spot may
indicate presence of canal where dye may have
penetrated deeper.

26. CHAMPANGE BOTTLE TEST
This test is done with either warm
hypochlorite or concentrated hypochlorite.
Fill the chamber with Hypochlorite and wait
for 30 seconds, as the pulpal tissue gets
precipitated a stream of bubbles appear
which indicates canal orifice and then
check it with the instrument.

27. BLEEDING SPOT
In vital case after exploration and
cleaning of main canals look for
bleeding spot in the floor which
invariably indicates canal orifice
which then may be explored with
the file or may be further explored
with ultrasonics
In non vital case it can be opaque
spot or in retreatment case it may
be dark brownish spot which may
be further explored.

28. TRANSILLUMINATION
Usually done with light
cure light – canals
would appear as dark
spots and isthmus
would be transparent

29. MAGNIFICATION
Loupes 2-4%
Microscope
4-24 %
Intraoral camera

30. ALSO GIVE IMPORTANCE TO
Good Quality Mirror
Chair light strength
Chair position
Patient position
Operator position
Isolation
Jaw stability (use prop)

31. LOCATING MB2 CANAL – 80-90 % UPPER 6
30-40 % UPPER 7
MB1
MB2
Palatal
DB
Follow the dentinal map
The MB2 canal is
palatal and often mesial
(under the marginal
ridge) to a line drawn
between the MB1 and
palatal canal

32. Start X #2
If MB2 is under the
mesial marginal ridge,
remove the mesial
dentin shelf which
represents the roof of
the pulp chamber
overlying the MB2
orifice with ultrasonic
tip

33. Start X #2

34. Enter the MB2 canal
from a flat pulpal floor
angling a precurved file
from the distal toward
the mesial.

35. LOCATING MB3 CANAL
May be found if distance
between MB & MB 2 is more

36. LOCATING MIDDLE MESIAL CANAL ~30% LOWER6
Located in the
mandibular molars
usually first molar
between two
regular mesial
canals.
Apically it tends to
merge with
mesiobuccal canal

37. LOCATING SECOND DISTAL CANAL IN LOWER
MOLAR
Principle of symmetry
Low of symmetry

38. SECOND CANAL IN LOWER ANTERIOR ~ 40%
(Law of Concentricity)
Outer examination
At level of CEJ, tooth
bulges in lingual side
suggests pulp chamber
also bulge in that direction.
Suspect two canal or
ribbon shape.

39. Proper RCO is only
answer
Labial canal is
located below the
incisal edge and
lingual canal is
below the bulge of
cingulum

40. BIFID CANAL IN LOWER PREMOLAR ~ 25%
Disappearing canals
Precurved file

41. C – SHAPE CANAL IN LOWER 7 ~ 2%

42. SOME CASES LIKE TO SHARE
WITH YOU

43. MB2
Missed MB2

44. MB3

45. MIDDLE MESIAL

46. SECOND CANAL IN DISTAL ROOT – LOWER 6

47. THREE CANAL IN DISTAL ROOT – LOWER 6

49. C- SHAPE CANAL IN LOWER 7

50. SECOND CANAL IN LOWER FIRST PREMOLAR

51. FACIAL CANAL IN UPPER CENTRAL INCISOR
Pre op

52. TWO CANAL IN LOWER SECOND PREMOLAR

53. Reasons why we don’t find
extra canal regularly
Lack of Clinical skill
Knowledge
Experience
Importance
Desire
Time

54. Eye will recognize what
his(dentist’s) brain
knows, and he will see
what he wants to see,
but he will not see what
he does not know.

55. Hunting elusive canals
will become easier, with
experience.
But it never becomes
EASY.
Good luck and good
hunting! ......