Endodontics:

Procedures That Finally Make Sense

Consequences of the present way endodontics is being taught

Rotating NiTi: continuous and interrupted

1. Increased chance of instrument separation

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.

Aggravated by the narrow mesio-distal dimensions of the canal and the greater taper of the rotating

NiTi instruments

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.3. Requires crown-down preparations and straight

line access.

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.3. Requires crown-down preparations and straight

line access.4. Both procedures remove excess tooth structure

in the mesio-distal plane.

The role of mechanical instrumentation in the cleaning or root canals. Zvi Metzger, Michael Solomonov, Anda Kfir. Endodontic Topics 2013;29:87-109.

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.3. Requires crown-down preparations and straight line

access.4. Both procedures remove excess tooth structure in

the mesio-distal plane.5. Not effective in cleansing in the bucco-lingual

plane.

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.3. Requires crown-down preparations and straight

line access.4. Both procedures remove excess tooth structure in

the mesio-distal plane.5. Not effective in cleansing in the bucco-lingual

plane.6. Produces dentinal micro-cracks.

1. Increased chance of instrument separation2. Increased degree of torsional stress to the

instruments and the tooth.3. Requires crown-down preparations and straight

line access.4. Both remove excess tooth structure in the mesio-

distal plane.5. Not effective in cleansing in the bucco-lingual

plane.6. Produces dentinal micro-cracks.7. With a non cutting tip and flutes that drive the

instrument apically, increased amounts of debris are driven apically.

The same rotating fluted design that draws the instrument beyond the apex will also drive the debris

in front of the tip beyond the confines of the root.

8. Reduces resistance to vertical fractures.

When tooth structure is excessively removed in the mesio-distal plane in teeth where the pulp is very

thin in that plane, the roots become weaker.

8. Reduces resistance to vertical fractures.9. Gives the canal a shape that increases the masticatory stresses.

Again, a result of excessive removal of tooth structure in the thinner mesio-distal plane.

8. Reduces resistance to vertical fractures.9. Gives the canal a shape that increases the masticatory stresses.10. Only for single usage.

8. Reduces resistance to vertical fractures.9. Gives the canal a shape that increases the masticatory stresses.10. Only for single usage.11. Very expensive.

8. Reduces resistance to vertical fractures.9. Gives the canal a shape that increases the masticatory stresses.10. Only for single usage.11. Very expensive.12. Increases procedural stress.

When the dentist must be constantly conscious of the impact of the procedures on the integrity of the instrument rather than the integrity of the

root, it underlines the fact that he/she is using a poorly conceived product.

8. Reduces resistance to vertical fractures.9. Gives the canal a shape that increases the masticatory stresses.10. Only for single usage.11. Very expensive.12. Increases procedural stress.13. Still dependent upon the K-file for the glide path.

K-files are used manually for the creation of the glide path producing hand fatigue and tend to

impact debris apically in curved canals resulting in loss of length before rotary NiTi is employed.

And that brings us to a far safer, more efficient, less expensive approach to endodontic instrumentation

that virtually eliminates hand fatigue and separation while preserving far more tooth

structure.

Now let us consider 30º reciprocation of modified reamers oscillating at 3000-4000 cycles per

minute.

1. Use of modified reamers rather than K-files that encounter less resistance making the shaping procedure faster.

K-File

Relieved Reamer

Relieved Vertically Fluted Instrument

K-File

We use these instruments rather than k-files.

Comparing relieved vertically fluted instruments to k-files we observe the following:

1. Fewer flutes on the 16 mm of working length of a relieved vertically fluted instrument than on a k-file approximately 16 flutes versus 30.

Consequences of fewer flutes:

1. There is less engagement along length.

2. Relieved vertically fluted instruments are more flexible than files because they are less work hardened and thinner in cross section.

3. The flutes are more vertically oriented. K-File

Relieved Vertically Fluted Instrument

Relieved Vertically Fluted Instrument

K- File

Consequences of less engagement:1. Less resistance along the shank as we negotiate apically.

Consequences of greater flexibility:1. Able to negotiate curved canals with less chance of distortion.

Consequences of more vertically orientedflutes:1. Able to cut dentin along canal length when the motion of the instrument is either horizontal rotation or reciprocation.

Taken together, the consequences of greater flexibility, lessengagement and more efficient cutting along length produce a superior tactile perception along length and at the tip of the instrument.

The consequences of superior tactile perception:1. Allows the safe incorporation of a cutting tip.

The consequences of a cutting tip:2. The ability to pierce pulpal tissue rather than impact it apically.

2. The ability to distinguish between a tight canal and hitting a wall when used in a watchwinding motion or a reciprocating handpiece.

The incorporation of the reciprocatinghandpiece allows a 30º arc of motionoscillating at 3000-4000 cpm.

A 30º arc of motion represents 1/12 of a circle or 5 minutes on the face of aclock.

The motion is so limited it virtually eliminates the 2 major factors that cause rotary NiTi files to break and unwind,namely, torsional stress and cyclic fatigue.

1. Use of modified reamers rather than K-files that encounter less resistance making the shaping procedure faster.2. No hand fatigue after the initial instrument goes to the apex.

1. Use of modified reamers rather than K-files that encounter less resistance making the shaping procedure faster.2. No hand fatigue after the initial instrument goes to the apex.3. Virtually no chance of instrument separation during the full shaping of the canal.

A 30º arc of motion virtually eliminates torsional stress and cyclic fatigue in turn eliminating

instrument separation and dentinal micro-cracks.

1. Use of reamers rather than K-files that encounter less resistance making the shaping procedure faster.2. No hand fatigue after the initial instrument goes to the apex.3. Virtually no chance of instrument separation during the full shaping of the canal.4. Far less tooth structure sacrificed in the mesio -distal plane.

Rarely, if ever, do we exceed an 04 taper, thus preserving dentin in the mesio-distal plane while removing more tissue in the bucco-lingual plane.

Nor is straight-line access necessary.

1. Use of reamers rather than K-files that encounter less resistance making the shaping procedure faster.2. No hand fatigue after the initial instrument goes to the apex.3. Virtually no chance of instrument separation during the full shaping of the canal.4. Far less tooth structure sacrificed in the mesio -distal plane.5. Greater debris removal in the bucco-lingual plane.

1. Use of reamers rather than K-files that encounter less resistance making the shaping procedure faster.2. No hand fatigue after the initial instrument goes to the apex.3. Virtually no chance of instrument separation during the full shaping of the canal.4. Far less tooth structure sacrificed in the mesio -distal plane.5. Greater debris removal in the bucco-lingual plane.6. No dentinal micro-cracks.

7. Less reduction in resistance to vertical fracture.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.10. Relatively inexpensive.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.10. Relatively inexpensive.11. Far less procedural stress.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.10. Relatively inexpensive.11. Far less procedural stress.12. Faithfully follows the glidepath created by the most flexible 02 tapered stainless steel reamers.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.10. Relatively inexpensive.11. Far less procedural stress.12. Faithfully follows the glidepath created by the most flexible 02 tapered stainless steel reamers.13. Pushes far less debris over the apex because of a cutting tip and not being drawn into the depths of the canal.

7. Less reduction in resistance to vertical fracture.8. Lesser tapered preparations making the tooth more resistant to masticatory forces.9. Used multiple times.10. Relatively inexpensive.11. Far less procedural stress.12. Faithfully follows the glidepath created by the most flexible 02 tapered stainless steel reamers.13. Pushes far less debris over the apex because of a cutting tip and not being drawn into the depths of the canal.14. Superior measurement control.

Simple predictable sequencing

(includes both the glide path and full canal shaping as part of the system)

30/04

30/02

You have been presented with a detailed rationale for modified reamers over K-files, 30º reciprocation

oscillating at 3000-4000 cycles per minute rather than continuous or interrupted rotations and the

predominant use of stainless steel 02 tapered instruments rather than greater tapered NiTi that will

increase the quantity and quality of the remaining dentin while increasing the speed and safety of your

procedures.

The relieved reamers combined with the 30º reciprocating handpiece are commercially known as

the SafeSider Instruments and oscillate in the handpiece called the Endo-Express.

For further information on learning these techniques call the offices of Dr. Barry Musikant.

The office number is 212-582-8161 and the address is 119 West 57th Street NYC, NY.

Our E-mail address is mdkdendo@aol.com

For those interested in reviewing supporting research it is available on request.