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3. 1. Introduction
2. Glossary of terms for contemporary molar endodontic access
3. A new model for endodontic access
5. Banking/soffit(360)(steppedaccess)
6. Ninja preparation
7. Conclusion
8. References

4. Sr . no. Learning objective Domain Level Criteria
1 Introduction Cognitive Must know All
2 Glossary of terms for contemporary molar
endodontic access
Cognitive Must know All
3 A new model for endodontic access Cognitive Must know All
4 Redesigned access Cognitive Must know All
5 Banking/soffit(360)(steppedaccess) Cognitive Must know All
6 Ninja preparation Cognitive Must know All
Specific learning objectives

5. The operator needs
The restoration needs
The tooth needs

7. Minimal Invasive
Endondontics

8. The world congress of MID defines minimally invasive
dentistry as those techniques, which respect health,
function and esthetics of oral tissue by preventing disease
from occurring, or intercepting its progress with minimal
tissue loss (Nový and Fuller 2008)

9. The endodontic-endorestorative-prosthodontic (EERP) continuum

10. Three-dimensional ferrule (3DF)
Pericervical dentin (PCD)

11. Banked tooth structure
The inverse funnel

12. Blind tunneling
Blind funneling

13. Banking/ Soffit (360)(Stepped access)
Preparation
• A contracted endodontic cavity preserves a
portion of the roof around the entire coronal
aspect of the pulp chamber. This dentin is
known as dentin roof strut or soffit.

14. Traditional parallel-sided access (left), compared with the Cala Lilly enamel preparation (right). (Left)
Unfavorable C factor and poor enamel rod engagement are typically present when removing old amalgam or
composite restorations or with traditional endodontic access of 90to the occlusal table. (Right) The enamel is cut
back at 45with the Cala Lilly shape. This modified preparation will now allow engagement of nearly the entire
occlusal surface.

16. Only moisture loss of 9% after root treatment.
The predominant reason that endodontically treated teeth are more
prone to fracture relates more than any other attribute to the
structural loss of those root treated teeth requiring restoration.
Helfer A R, Melnick S, Schilder H. Determination of the moisture content
of vital and pulp less teeth. Oral Surg Oral Med Oral Pathol 1972; 34:
661–670

17. • When endodontically treated teeth fail under function, that outcome is
determined primarily by 2 aetiologies. Those causes stated most simply
are:
1) the degree of stress experienced by the tooth under load
2) the inherent biomechanical properties of the remaining structure
responsible for resisting fracture.

19. A) The deroofing problem. The likely bur used by the referring general dentist is
a 56 carbide; one of the most popular burs in dentistry,6 it is possibly the most iatrogenic
instrument in modern medicine. Red arrow delineates the typical gouging. (B) Postoperative
view provided by the endodontist. Blue arrow indicates the grossly excessive dentin removal
of pericervical dentin (PCD). This serious gouging is typical of round bur access. Yellow
arrow indicates the large canal flaring with unacceptable dentin removal (blind funneling).
(C) Green circle highlights worsening lesion on mesial root ends.

20. A NEW MODEL FOR ENDODONTIC ACCESS
• Directed dentin and enamel conservation is the best and only
proven method to buttress the endodontically treated molar.
• No man-made material or technique can compensate for tooth
structure lost in key areas of the PCD.
• The primary purpose of the redesigned access is to avoid the
fracturing potential of the endodontically treated molar

21. Conservative and crafted
preparations
Sofitt
3D
Ferrule
Peri
cervical
dentin
Improved structural integrity

22. It has historically been described as axial wall
dentin covered by the axial wall of the crown (or
bridge abutment restoration).
The research varies on the actual minimal
vertical amount required, but the range of
absolute minimums is from 1.5 to 2.5 mm

23. Net taper
thickness
Vertical
component

24. • The absolute minimum thickness is 1 mm; however, 2
mm is obviously a safer number. Girth becomes more
important closer to the finish lines of the preparation.
• The thickness of the remaining dentin (the wall thickness)
between the external surface of the tooth at the finish line
and the endodontic access is more important apically.
• Axially deep finish lines on root structure can be
extremely damaging to 3DF.

25. 3 mm ferrule needed
4 mm ferrule needed
Deep chamfer marginal
zones common with
today’s porcelain crowns
Needed how much
ferrule???

27. Defined as the dentin near the alveolar crest.
• Critical zone roughly 4 mm coronal to the crestal bone -4 mm apical to
crestal bone. crucial -transferring load from the occlusal table to the root,
• PCD is irreplaceable.
No man-made material or technique can compensate for tooth structure lost
in key areas of the PCD.
Clark D, Khademi J. Modern molar endodontic access and directed dentin conservation.
Dent Clin North Am 2010

29. Why are Gates Glidden (GG) burs so
problematic?
• Since the introduction of rotary files, GG burs have been used more
aggressively and with more reliance on larger sizes (4, 5 and 6) to reduce
binding and fracture of rotary files.
• Gates burs have always been considered safe because they do not end cut
and are self-centering.
• There is a significant problem here, which is cervical self centering. Because
the shank of the GG is so thin, it is difficult to steer the GG away from high-
risk anatomy.
• As the GG straightens the coronal or high curve, it can shortcut across a
fluting or furcation and weaken or even create strip perforations.
• Dr Clark has abandoned, and Dr Khademi has severely curtailed, the use of
GG burs in their respective practices.

32. Why are round burs so
destructive?

33. Why is complete deroofing so dangerous?
• attempts at removing the soffit that are far more damaging to
the surrounding PCD.
• The primary reason to maintain the soffit is to avoid the
collateral damage that usually occurs, namely the gouging of
the lateral walls.
• This 360 soffit or roof-wall interface can also be compared
with the metal ring that stabilizes a wooden barrel.
Complete deroofing

34. • The new vision-based mental model is Look, Groom, and Follow.
• The new instruments are all round-ended tapers
• The rounded ends are to increase the radii of the gouges and nicks that can
act as stress concentration points.
• The flat sides help create smoother, flatter walls and minimize the gouges
and dings that inevitably occur even with the most careful technique
• Small, cone-shaped, low-speed bur (such as the EG2 [SS White ])

38. Banking/Soffit (360)(Stepped access)
Small border amount of the chamber roof near the
point where it curves 90° and becomes the wall
LEFT BEHIND
Tiny “lip” or “cornice” 0.5 mm- 3.0 mm
(strength
continuous
and
ring of
anatomy).
Dentin (BRAZING
EFFECT).
The 360 degree soffit or roof-wall interface provides a brazing effect

40. Dotted line shows the typical cut made to remove the entire
pulp horn.
Area between the lines should be maintained and is referred to
as the soffit

42. Robust coronal dentin -maintained good distance away
from the tooth’s centroid,(cervical) - tooth is stiffened,
resists bending, and should resist fracturing.
Clark D, Khademi J, Herbranson E. Fracture resistant
endodontic and restorative preparations. Dent Today 2013.

48. Blue arrows indicate gouges. Red arrows indicate perforations.

49. Blue arrows indicate gouges. Red arrows indicate perforations.

52. Ninja preparation

68. • Helfer A R, Melnick S, Schilder H. Determination of the moisture content of
vital and pulp less teeth. Oral Surg Oral Med Oral Pathol 1972; 34: 661–670
• Sedgley C M, Messer H H. Are endodontically treated teeth more brittle? J
Endod 1992; 18: 332–335.
• Krasner P, Rankow HJ. Anatomy of the pulp chamber floor;
JOE 2004,30:5
• Reeh E S, Messer H H, Douglas W H. Reduction in tooth stiffness as a
result of endodontic and restorative procedures. J Endod 1989; 15: 512–516.

69. • Yi-Tai Jou et al Endodontic Working Width: current concepts and
techniques
• Minimally invasive endodontics: challenging prevailing paradigms
A. H. Gluskin, C. I. Peters and O. A. Peters
• Pathways of pulp 10th ed. stephen cohen