Endodontic Instrumentation

1
Endodontic Instrumentation
2
Instrumentation Curved Canals are the Problem
3
Curves Rigid Instruments Transportation
4
Traditional Tapered Instrument
0.02 mm increase in diameter per 1 mm in length
5
What Taper is Correct?

• Is an 0.02 taper correct?
• Is a larger taper correct? .04, .06, .08, etc.
• How do we match the taper to the anatomy of the
  canal to avoid over or underpreparation?
• Have additional tapers solved our endo problems?

6
Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• Much emphasis has been focused on the preparation
  of a root canal taper, but this is only of
  significance for certain obturation techniques.

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
7
Reasons Given for Flaring

• Esthetically pleasing x-rays
• Better access to apical part of canal
• Better irrigation apically
• Necessary for warm vertical obturation to work
• Larger flare gives better results

8
Disadvantages of Taper

• Rapid increase in rigidity
• Increased removal of dentin coronally
• Difficult to get around curves
• Increased transportation at curve and apically
• Poor tactile feedback -- where is it binding?
• Increased bending fatigue and greater chance of
  fracture

9
Should both of these teeth be prepared to the
same size? same taper?
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Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• Root canal instruments are a lot like most other
  things in life
• One size does not fit all

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
11

Summary
Success Does Not Depend on Canal Shape Success
Does Depend on Canal Cleanliness
12

• I
• Always keep in mind that
• X-rays dont always tell the truth!

If the case looks bad it is If the case looks
good it may or may not be
13
Straight canal? Apical preparation size? Correct
taper?
LS Size 55
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Straight canal?
ISO Size 55
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2 Straight Canals?
No!
Clinical
Proximal
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Looks Okay?
17
Instruments Transported Completely Out of Canals
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Evaluation by Cross Section is More Reliable Try
it Yourself
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Take the Mystery Out of Working Length

• Dont always believe radiographs
• Use an apex locator whenever possible
• Understand apical anatomy

20
Cohen Burns, Pathways to the Pulp, 7th Edition,
Page 282
Ideal Working Length
Apical Foramen
Apical Constriction
The distance from foramen to constriction is
usually 0.5 - 1.0 mm
Apex
When the locator needle indicates Apex the file
is between the apical constriction and the foramen
21
Short, Long or Just Right?
22
Long by 2mm!

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Apical Anatomy
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Foramen at Apex 26 Foramen not at Apex 74
Dont be misled by ambiguous terminology
Constriction average ISO size 30 Foramen
average ISO size 60 Apex not the same as foramen
.7 mm
Kuttler, JADA 1955
25
Cohen Burns, Pathways to the Pulp, 7th Edition,
Page 282
Diameter
C
Foramen
Apex
If the average constriction C is .30 mm, then
what is the canal size Diameter? Note that F
is larger than C.
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Suggested Maxillary Apical Preparation (ISO) Sizes
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Suggested Mandibular Apical Preparation (ISO)
Sizes
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Ideal Working Length ??
D
D-C Junction
D-C Junction
Pulp
C
D
PDL
C
Body Defenses
Apical Foramen Human (x 25)
Immune System
29
Foramina rarely at apex
Gutierrez and Aguayo, OS OM OP, June 1995
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In Endodontics, Canal Diameter is the
Forgotten Dimension

• Dr. Carl Hawrish

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• Canals are Three Dimensional!
• Canal Length and Diameter are Important.
  Instrumenting to the Perfect Length is not Enough

Why is diameter the forgotten dimension?
What does research say about canal diameter?
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The hardest thing to explain is the glaringly
evident which everybody had decided not to see
Ayn Rand - Author
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Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• The most important part of the preparation is the
  very apical part of the root canal. This has
  often been forgotten in the new practices of
  crown down techniques.

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
34
After Second RC Treatment 4 year failure!
Why?
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Canal Diameter is Critical
Underprepared And Transported
Gutta Percha
Necrotic Tissue
1 mm From Apex
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Failing Endodontics with Gutta Percha
Root Canal Therapy Looks Good? Length OK Shape
OK Why did it fail?
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Mesial root - 1 mm from apex
necrotic tissue and debris
M - 1 mm Barry
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Mesial root - 2 mm from Apex
We must use nickel-titanium to instrument to
larger apical sizes Martin Trope, AAE 1999
M - 2 mm Barry
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Distal Root - Foramen
Poor Obturation
Apex Hi Power Barry
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Distal Root - 1 mm from Apex
Canal not instrumented to the correct diameter
Necrotic Tissue
D- 1 mm Barry
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Distal Root - 3 mm from Apex
Necrotic Tissue and Debris
D - 3 mm Barry
42
So, why did it fail?
Poor Instrumentation
Back to Basics
Good Obturation Requires a Clean Canal
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Instruments Shape Irrigants CleanFact or Myth?
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Canal Debridement Effectiveness of Sodium
Hypochlorite and Calcium Hydroxide as
MedicamentsYang, Rivera, Walton Baumgardner
J Endodon, October 1996
45
Results No significant differences between
NaOCl and unmedicated groups in either the 1 day
or 7 day time intervals. This was true in both
the main canal and inaccessible areas at the
apical, middle and coronal levels.
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Conclusions

• NaOCl was ineffective because of
• Limited surface contact
• Limited volume
• Limited exchange of solution

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Key PointsPerception versus Science

• NaOCl became effective only when canals were
  prepared to larger apical sizes.
• Even still, NaOCl cannot predictably disinfect
  canals. Bacteria in the tissue / debris are
  sheltered from the disinfecting action of NaOCl.
• Shuping et al. J Endodon December 2000

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Lateral Canal
Even after 30 minutes in main canal, NaOCl
was not effective
Main Canal
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Endodontic Success Rate

• 6 year study - Toronto University
• 120 teeth
• 92 success rate -- teeth without lesions
• 74 success rate teeth with lesions

This provides more evidence that infected canals
must be cleaned well for treatment to be
successful. In vital cases the pulp can help and
this is why even poor endo may be a long- term
success. E. S. Senia, DDS
Journal of Endodontics, Dec. 2003
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Key Points Perception versus Science

• Treatment
• Good Endo, Good Restoration
• Poor Endo, Good Restoration
• Good Endo, Poor Restoration
• Poor Endo, Poor Restoration

• Probability of Success
• 91
• 69
• 44
• 18

Ray Trope. Int Endod J 1995
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Proper Preparation of the Apical Third
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Dr. Stephen Cohen

• 1. Gotta get rid of the debris
• 2. NaOCl best irrigant but
• Gotta get rid of the debris
• 3. NaOCl doesnt work by itself over time
• Gotta get rid of the debris
• 4. One visit better if
• You get rid of the debris
• 5. Gotta seal it or it will
• Leak into the debris

Lecture - Endodontics Extraordinaire, 5-16-03
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Successful Instrumentation
Instrument to the Correct Length AND Instrument
to the Correct Diameter
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How to Determine Correct Diameter?

• Use a non-tapered instrument and
• use a technique that can predictably determine
  when the canals are clean

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Problem with Tapered Files File cuts in two
places On the inner side at the curve On the
outer side at the apex
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LightSpeed
Noncutting shaft
No taper
Perfect design for gauging the canals diameter
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Apical Gauging LightSpeed binds only at the tip
(blade)
14 mm
16 mm
18 mm
WL
20 mm
cementum
dentin
binds
canal
LS 27.5
LS 30
LS 32.5
LS 25
FLSB
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Apical Gauging LightSpeed binds only at the tip
(blade)
14 mm
16 mm
This process is called Apical Gauging and it is
done by hand. Apical Gauging only picks up the
SMALLEST diameter, your STARTING point. Dont be
misled by those who say apical gauging is your
ENDING point for instrumentation.
18 mm
WL
20 mm
cementum
dentin
binds
canal
LS 27.5
LS 30
LS 32.5
LS 25
FLSB
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How is the Correct Diameter Determined? (Let
LightSpeed Tell You)
14 mm
16 mm
18 mm
20 mm
WL
cementum
dentin
MAR Master Apical Rotary
Pecks 12
Pecks 8
Pecks 10
Pecks 5
LS 37.5
LS 40
LS 32.5
LS 35
FLSB
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Master Apical Rotary (MAR)

• The largest LightSpeed size used to working
  length.
• An instrument size large enough to clean the
  apical third of the canal.

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The MAR is
The first LightSpeed instrument that requires 12
or more pecks to reach the working length, 12
pecks rule
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Canal Area Cleaned and Enlargement Objective
Canal (oval)
Apical Cross-Section of Root
.50 mm
50 instrument
25 instrument
Size 50 is the minimum instrument size required
to touch (cut) all canal walls. The area of a 50
is 4 times larger than 25. For best results,
the instrument must be large enough to remove
dentin from all canal walls.
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Oval Canal
Necrotic Debris
Before
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Round Canal
Clean and Ready for Obturation
After
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Tan Messer, Journal of Endodontics, September
2002
LightSpeed vs. Hand Files
The Quality of Apical Canal Preparations Using
Hand and Rotary Instruments with Specific
Criteria for Enlargement Based on Initial Apical
File Size
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Tan Messer, Journal of Endodontics, September
2002
Summary Results

• LightSpeed allowed greater apical enlargement
  with significantly cleaner canals, less apical
  transportation and better canal shapes than both
  hand instrumentation groups.
• Greater apical enlargement using LS rotary
  instruments is beneficial as an attempt to
  further debride the apical third region.

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LightSpeed Significantly Better
Tan Messer, Journal of Endodontics, September
2002
68
LightSpeed Best Results
Tan Messer, Journal of Endodontics, September
2002
69
Uninstrumented Cross-Section
Apical
J Endodon 1995
70
Instrumented Cross-Section
LS 45
Ni-Ti K-file 45
Apical
J Endodon 1995
71
Single Visit Endodontics
72
Perception versus ScienceMartin Trope, Univ. of
North Carolina AAE Lecture, Atlanta 1999

• Is Single Visit Endodontics Supported by Science?

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Economic Motivation for Single Visit Endodontics
Three Visits Molar ( 3 hrs.) Revenue
700 Less Materials 125 Overhead 750 Net
Loss (175) Loss Per Hr. (58)
One Visit Molar ( 1 hr.) Revenue
700 Less Materials 75 Overhead 250 Net
Profit 375 Profit Per Hr. 375
Two Visits Molar (2 hrs.) Revenue
700 Less Materials 100 Overhead 500 Net
Profit 100 Profit Per Hr. 50
74
Exceptions to Single Visit Endodontics

• Cellulitis
• Acute apical abscess requiring incision and
  drainage
• Periradicular periodontitis with severe pain to
  touch
• A weeping canal that cannot be dried
• Difficult cases that extend beyond appointment
  time and patients tolerance

75
Key Points Perception versus Science

• Is the removal of most bacteria before obturation
  critical to achieving endodontic success?
• YES! Success averages 94 with a negative culture
  and less than 70 with a positive culture.
• Sjogren et al. Int Endod J 1997

76
Key Points Perception versus Science

• The suggestion that NiTi rotary instrumentation
  is faster and produces less procedural errors has
  popularized its use. Such features are important
  IF the practitioner is able to safely instrument
  to LARGER file sizes, thereby further reducing
  intracanal bacteria.
• Dalton et al. J Endodon November
  1998

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Key Points Perception versus Science

• Inadequate apical preparations with hand or
  tapered nickel-titanium rotary instruments
  require at least two appointments. One for
  instrumentation and another for obturation.
  Calcium hydroxide should be used between
  appointments to reduce the bacterial count.
• Shuping et al. J Endodon, December 2000

78

• Canals instrumented to larger apical sizes
  allowed for more irrigant to be placed closer to
  the apex.
• LightSpeed scored the best in removing debris and
  smear layer because of better irrigation.

O.A. Peters and F. Barbakow, Journal of
Endodontics, January 2000
79
Cleaner canalsMore effective irrigation Easier
obturationJustifies Single Visit TX
Advantages of Preparing to Larger Sizes - Apically
80
(1) Shuping, et al. Journal of Endodontics, Dec
2000(2) Card, et al. Journal of Endodontics,
Nov 2002
Increased Apical Enlargement Studies
(2)
(2)
60
(1)
46
36 46
81
Single Visit Endodontics

• With many teeth this regimen (larger instrument
  sizes) may substitute for treatment by a
  two-stage procedure utilizing a intracanal
  dressing.

Card, et al. Journal of Endodontics, Nov 2002
82

• Thorough cleaning of the canal is the essence of
  single visit endodontic success

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Tips to Avoid Instrument Separation
84
Causes of Instrument Failure

• Heavy handedness
• Working dry or semi-dry
• Unforgiving (poor) access preparation
• Failure to recognize acute curve
• Bad Technique
• Using handpiece incorrectly (speed and feed)
• Overusing instruments

85
Recommended Irrigation Procedure

• Irrigate with NaOCL after every 3 LightSpeed
  sizes until solution is clear, suction, then
  flood canal and chamber with EDTA (liquid form is
  best)
• More frequent irrigation is
  optional

86
Tips to Avoid Instrument Separation

• Dont overuse instruments

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LightSpeed Usage Recommendation
Average cases Sizes below ISO 50 use up to 8
teeth Sizes 50 and above use up to 16 teeth
Severe curves Use LightSpeed by hand using
watch winding motion Use instruments
once, then discard
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LightSpeed Instrument Organizer
track usage
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Tips to Avoid Instrument Separation
Use the correct handpiece (at the proper
settings)
90
Set Proper RPM (2000 max)
Set Proper Direction (forward)
Cordless Convenience
Simple to Use and Maintain
91
EndoMate Wizard Cordless Handpieces
Contra Angle Speed Ranges 11 2,000 10,000
rpm 41 500 2,500 rpm 161 125 -
625 rpm
92
Both Models Speed Range 125-10,000 Replaceable
Batteries
EndoMate Torque Controlled Auto Reverse
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Tips to Avoid Instrument Separation

• Dont overuse instruments
• Use the correct handpiece
• Follow the instructions!

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Technique Guides
95
Always Use a Very Light Apical Touch and Pecking
Motion!
Review Periodically Using LS Size 20
96
Why Use the Correct Pecking Technique?NiTi
instruments (any brand) can break in less than
1/6 of a second if locked in the canal without
controlling the torque
97
Cyclic Fatigue Testing of Nickel-Titanium
Endodontic InstrumentsPruett J., Clement D.,
Carnes D. J Endodon, February 1997
98
Short Radius Curve
Long Radius Curve
Degree of curvature is the same but the degree of
difficulty is NOT.
99
Nickel-Titanium / Cyclic Fatigue

• The larger the instrument the fewer the cycles to
  fracture (favors LightSpeed design)
• A long radius curve is safer than a short radius
  curve
• In a short radius curve separation occurred very
  quickly

100
Severe Curves
First, instrument coronal to severe curve using
normal LightSpeed technique Then, instrument
apical to severe curve with LightSpeed
(in hand) using a watch-winding motion
101
Severe Curves LightSpeed Hand Instrumentation
using Watch-Winding Technique

• Start with a new set of instruments
• Watch-winding (rather than full rotation) greatly
  reduces metal fatigue
• Takes a little longer but is safer

102
The LightSpeed Advantage

• Exceptional Flexibility
• Virtually Eliminates Ledges and Zips
• Addresses Canal Diameter
• Accurate Tactile Feedback

103
The LightSpeed Advantage

• Customized Shaping Dictated by Canal Anatomy
• Simple Technique
• Minimum Stress on Root
• Similar Technique in All Cases
• Cost Effective

104
Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• There is a strong emphasis on reducing the number
  of instruments the more popular instruments are
  in sets of 4 or 5. These techniques, however, do
  not produce a clean apical preparation in a
  diseased tooth.

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
105
Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• Of all available instruments, there is only one
  brand (LightSpeed) that allows for proper rotary
  preparation of the apical area of the root canal.

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
106
Preparation with LightSpeed Examination of
2085 Root Canal TreatmentsT. Rieger, ESE
Meeting, October 2001Results

• 96 success rate
• 4.3 minutes average preparation time per canal
• Instrument separation occurred in 29 cases,
  authors concluded instrument mismanagement
  (overuse) as primary cause
• Instrument separation reduced by 33 when
  instrument usage tracked properly

107
Clinical Cases
Feller Hermsen Klein Stewart Wildey
Clinical Video
108
Hybrid TechniqueUsing LightSpeed
109
Combines Desirable Features of Different Systems
A Hybrid Technique

• Uses tapered instruments for coronal
• and mid-root preparation
• Uses LightSpeed instruments for
• apical preparation

110

Hybrid Technique
Recommended only for those who have already
successfully mastered the art of tapered rotary
preparation
111
NEW EndoMate Wizard Cordless Handpieces
Easily switch from low speed (tapered) to higher
speed (LS)
112
EndoMate Wizard Cordless Handpieces
Contra Angle Speed Ranges 11 2,000 10,000
rpm 41 500 2,500 rpm 161 125 -
625 rpm
113

Why use LightSpeed for the Apical Preparation?
114
Key PointsThe Wonderful World of Rotary Root
Canal Preparation

• The most important part of the preparation is the
  very apical part of the root canal. This has
  often been forgotten.

L. Spangberg DDS, PhD, Editor Oral Surgery, Oral
Medicine, Oral Pathology, Nov. 2001
115
Animation of Hybrid Technique
116

Summary
Success Does Not Depend on Canal Shape Success
Does Depend on Canal Cleanliness
117

To Obturation