Easy Root Canal Preparation -
Applying Dr. James Roane's 'Balance Force Technique' with Rotary Files
It has been said that Dr. James Roane's "Balance Force Technique" is the most widely taught hand filing technique in the world. Others have said, "The 'Balance Force Technique' cuts the most dentin with the most control."
Preparing the root canal with hand files has been around for over a hundred years. Rotary instrumentation with the use of tapered files has been in use since before the turn of the century. Each of these methods have advantages and disadvantages.
Hand filing's disadvantage of apical transportation and ledging around curvatures is a problem. Engine-driven rotary instrumentation's disadvantage of sudden file separation when the file is over stressed in narrow and curved canals is a problem.
If we combine the good from each method, it is likely we could reduce the problems of each individual method. The following technique of root canal preparation has proven to reduce many problems of each of these systems to give the clinician another approach to safe tapered preparation.
Review of Dr. James Roane's Balance Force Technique
The following are highlights from the Dr. Roane's original 'Balance Force Technique' article. (Journal of Endodontics, vol.11, No 5, May 1985)
Best file design? Triangular cross section
- Provides cutting edges with identical rake angles.
- Cuts dentin in both directions - bidirectional (clockwise or counter-clockwise)
- Triangular cross section files have greater flexibility than square cross section files.
Technique - Simple File movement -
'Balance Force Technique' canal preparation can be generated simply by rotating the file to produce canal enlargement and should be refined to placement, cutting, and removal.
- Placement is accomplished using clockwise rotation.
- Cutting is accomplished using counterclockwise rotation with inward pressure adjusted to match the files strength, i.e. very light for small instruments and heavy for very large instruments.
- Cleaning or debris removal is accomplished using one or two non cutting rotations, no pressure clockwise rotations and remove file.
Explanation of this technique:
To understand this concept, one has to analyze file design and its result of variations of motion.
- The cutting edges of the rotary tapered files incline down the shaft at approximately 20 degrees from vertical axis and the flutes spiral clockwise. The result is simply that when rotated clockwise the file moves into the canal. When file is turned counter-clockwise rotation the file moves out of the canal.
- Clockwise rotation embeds the cutting edges into dentin. The resultant forces move the file into the canal when the torque is applied clockwise and as the file moves inwardly its helical taper forces the cutting blades deeper into the canal walls.
- Inward movement is a result of clockwise file rotation while outward movement is a result of counter-clockwise file rotation.
- The operator can sense the torque needed for the file to engage the dentin.
- When the file is rotated counter-clockwise and the operator exerts inward pressure the cutting of dentin happens when the applied inward pressure exceeds the shear strength of the engaged dentin and a cut results. This relationship finitely adjusts applied force against the engaged dentin and gives the operator complete control over each cutting action.
- Tactile sensitivity with the use of this system, allows the operator to recognize the accomplishment of cutting dentin when a slight 'bump' is felt or a pop is heard.
- Continuing counter-clockwise rotation enlarges the canal to the files cutting diameter as each blade will maintain its beginning position and enlarge the canal's diameter.
Summary of Technique
- Placement or engagement of the file in the canal with clockwise rotation.
- Cutting dentin with counterclockwise rotation and inward pressure is adjusted to match the files's strength.
- Cleaning or debris removal with clockwise rotation to pick up dentinal debris then withdrawal the file and clean flutes.
Dr. Roane's original study used standard .02 tapered files and has been taught though out the world and proven successful.
I believe its time to apply this ingenious concept to NiTi tapered rotary files.
Most rotary files come with "latch-type" attachment design for motor handpiece usage. "Latch-type" design is a terrible hand grip for the dentist. To give the doctor control of rotary files a new 'Rotary File Hand Grip' was developed.
Designed and patented by Dr. Steven S. Larsen and a team of endodontists and engineers, RoTAC, a slip-on Rotary File Hand Grip was the result.
View this video to see how the RoTAC rotary file grip controls the rotary file when it's used with Dr. Roane's 'Balane Force Technique'.
Uncomplicate root canal preparation.
RoTAC rotary file grips create excellent canal preparations and reduces the problems of standard hand filing and also reduces the problems of engine-driven motor instrumentation. Doctor controlled simple hand filing movement of the 'Balance Force Concept' can be applied to rotary tapered files for easy and safe canal preparation.
Evaulation reports of this new Balance Force Technique by general dentists and specialist is better than expected and dental students doing endodontics for the first time are creating great shapes with less complications.