Sealing Cap - Continued..
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Source: "Roots" From: B. Harvey Wiener, DDS Sent: Sunday, April 22, 2001 3:44 AM nice case Mark. You are doing just fine with your bending, but if you want a file bender. I believe you can find them in Analytic 's catalog. Harv B.Harvey Wiener, DDS, MScD, FRCD(C)
From: Mark Dreyer Sent: Sunday, April 22, 2001 3:58 AM Once I negotiate through to the "terminus" I don't let go. I continue to use as many as 100, 1.0mm or so vertical strokes following
From: Richard Schwartz Sent: Saturday, April 21, 2001 9:08 PM Gary, I wouldn't expect a rotary file to go around a sharp curve like the one you show. However, they follow most curves nicely. In most teeth I just don't think there is a problem taking the small sizes to the RT. It is like everything we do, nothing works all the time. Rick
From: Kachman Sent: Sunday, April 22, 2001 3:52 AM Rick...could you please describe how you curve your NiTi instruments... are you annealing them somehow?
From: Richard Schwartz Sent: Sunday, April 22, 2001 4:32 AM Phil, I don't have one of the Analytic instruments. I just do it with my fingers. Try it and you will see how easy it is. No annealing necessary. Rick
> Analytic has a nice instrument called the Endo-bender. > The Endo-bender is a great little device. Bill Watson DDS, MS, FAAOMP, MBA
Gary, I was of the opinion that by using the safe ended rotary files, I was pretty safe in avoiding a lateral or apical perforation. Not so? Mark Dreyer, DMD, PA 3503 13th Street St. Cloud, Fl. 34769
From: Richard Schwartz Sent: Saturday, April 21, 2001 8:45 PM Mark, I have done what Gary suggests with extracted teeth with curved roots, and I suggest you do the same. You will be surprised at how nicely the small files follow the curves. They are quite flexible and have a knack for following the right path. In addition, If you extend them past the apex a few mm, look at how nice and round the hole is at the end of the root. Little or no transportation. This is possible because the instruments are so flexible. Because they are so thin and flexible, you can't apply very much pressure. But they have a certain "feel" when they enter into a new segement of the canal or when they slip past a ledge. I always try to establish patency with small hand files, but if I can't, I try with the small rotaries. I haven't used the small Quantec files, but I would expect them to behave the same as the Profiles or any of the other choices, as long as they have a non-cutting tip. Also, because they are so flexible, almost flimsy, I think it would be very hard to cause a perforation. If you try it with extracted teeth, take some photos and post them. Show the root ends with the a file sticking out, to see if they followed the curves, and show the apical foramen, to see if it is transported. You are a good, impartial evaluator. Rick
From: Garry Nervo Sent: Monday, April 23, 2001 3:30 AM Dear Rick, I like to use end cutting instruments as the tip acts as a pilot guidind the end blades ( Quantec ) around the curves. A sensitive darting action is necessary.- Garry jnervo
To Gary Nervo, Hi Garry. Don't you run the risk of transporting the apical canal if you use rotaries with cutting tips when there is difficulty getting to the WL? Thompson, Dummer et al, kind of showed that, I believe, in plastic blocks (which are not the real deal). But, non-cutting tipped files, especially with rounded transition angles, may have a better chance of finding their way, without doing the nasty (transportation). I have found with hand files, the Flex-R files, that you can go around severe apical curves using the balanced force method, and get to your desired level. The file will come out distorted, but it will show you the "path of insertion" very nicely. Then you may be able to use rotaries. Just my humble opinion. Fred
From: Garry Nervo Sent: Monday, April 23, 2001 8:47 AM Dear Fred, your comments are valid. The transition angles are brutal. I have watched, many times, under a microscope, a number 15 tip .02 taper instrument transport the terminal part of the canal on a plastic analogue. Despite NiTi having a fifth the "will" of SS a continually running instrument will transport the canal whilst the transition angle is within the (plastic) root. This is why I made reference to a darting action, where presumably the point, pilot tip, prejudices the instrument to follow the , however fine, natural canal. The technique is a little more demanding that for "blunt tipped instruments". If you happen to pop through the quick darting action coupled with the radial lands makes the instruments safe concerning the fear of apical foramen transportation. The blunt tip instruments will not transport, nor will they penetrate if the blunt dome tip is bigger that the canal. If the tip goes to a, dare I say, spike the very tip tapers down to very small. If you view the tip as an equilateral triangular cross section the base is 15/100ths of a mm ( shoulder to shouler for a size 15 instrument ) , half way up the triangle the width of the base narrows to about 7.5/100ths of a mm, and then down to 6 and then 4 and then 3, etc etc. Do you have a size three patency file in your kit?? The use of blunt tipped instruments with very fine canals is different from the technique with cutting tips. I fear (suspect) that many of the researchers have poor technique when it comes to using and evaluating sharp vs blunt, or even warm gp vs lateral condensation. Don't you think that some one like Yosi would be a better critic of a "new" apex locator, having used them all for years, than some neophyte trying to punch out a research project? My generalization, by the way, is in no way to be presumed to refer to Thomson, Dummer et al or anyone in any particular state of the union etc etc etc. I agree with you that NiTi instruments are not good indicators of canal curvature as they "spring straight" once they are withdrawn from the canals. As shocking as it might sound I am not too particularly interested in which way the canal goes because the instrument, prejudiced by the "smart tip" has no choice about where it goes....it just follows the canal. - Garry j Nervo
From: Dr. John McSpadden Sent: Monday, April 23, 2001 8:28 PM Gary Nervo, as I would have suspected as a Ferrari owner, 'must' not always drive below 70 mph. How else to get proficient at 120 mph? His approach is one that can have exceptional and consistent results even when compared with the most judicious use of 6 & 8 hand files for apical preparation----But requires experience. Three factors work in Gary's favor: (1) you cannot transport unless you were first in the correct position. As long as the tip remains engaged 360 degrees no transportation can occur. (2) A cutting tip requires as little as 15% of the torque to rotate as a non- cutting tip.[ rotating at 350 rpms, inserting at 1mm/sec. 12mm into a .20 diameter plastic canal the Profile 25/04 required 317 gm/cm, the Quantec 25/04 non cutting LX required 271 gm/cm, and the Quantec cutting tip SC required 41 gm/cm. Smaller diameter smaller tapers should exhibit a greater difference.]. The increased efficiency enables progress with fewer strokes. (3) Repetitive strokes more likely result in greater cutting on one side of the canal. The trick is knowing when to get out. With increased efficiency that 'feel' as per Nervo can be developed. As with a ski jump, a propensity for slow can have dramatic results. John
From: Fred Barnett Sent: Tuesday, April 24, 2001 7:27 AM >(1) you cannot transport unless you were first in the correct position. As long as the tip remains engaged >360 degrees no transportation can occur. I have seen in plastic blocks that transportation is possible with hand files when rotating in a clock-wise manner. Especially with files that have sharp transitional angles. I would imagine that rotary files without proper tip geometry may cause the same effect. When looking at the Flex-R file and Pow_R file, this transportation was extremely rare. I believe that it is the modified tip geometry that minimizes transportation. Is this correct?? >2) A cutting tip requires as little as 15% of the torque to rotate ...... I have not used the Quantec SC files....can you elaborate on their use, sequence, etc.?? >(3) Repetitive strokes more likely result in greater cutting on one side of the canal. >The trick is knowing when to get out. Can you elaborate on this?
From: Dr. John McSpadden Sent: Tuesday, April 24, 2001 11:26 PM Fred, Perhaps the best way to think about tip action is to think in terms of non cutting (dull, burnishing, inefficient) and cutting (sharp, efficient). Most tip geometries are somewhere in between, for instance A. 75% burnishing and 25% cutting or B. 75%cutting and 25% burnishing. B will require a fraction of the time or number of rotations or pressure as A in order to obtain the same degree of enlargement. If you use B like A you get more than you bargined for (transportation). Both will seek the pathway of least resistance when engaged and will best follow the original axis of the canal when engaged. If the tip is loose the tendency for the file to straighten will cause increased force on one side of the canal and result in greater cutting on that side. Because of the taper of the file each time you disengage the file tip (repetitive strokes) it has an opportunity to cut on one side of the canal and transport. If the tip is mostly burnishing, little transportation occurs On the other hand if the file tip is cutting efficiently there is little reson to disengage it, but if you do, transportation also occurs efficiently. A cutting tip is most of most value when the canal is smaller than the tip requiring less torque therefore less tendency for breakage than non cutting. If the canal is larger than the tip non cutting is certainly more beneficial resulting in less transportation than the cutting tip. The technique for each is very different, flexibility, time and pressure being the most important factors. John.
John, Your explanation is excellent. However, the connection between my brain and my hands sometimes takes a detour. Am I correct that when using the cutting-tipped rotaries, a pecking motion may cause transportation? For a "routine" mesial root of a mandibular molar, for example, can you describe your technic and armamentarium? I have never used the cutting-tipped Quantec files, and would greatly appreciate your valuable input. - Fred
From: "Garry Nervo" Sent: Thursday, April 26, 2001 9:15 AM Dear Fred, I may have missed John's (further) reply but here is my 2cents worth. Don't give up on the questions because I believe you will definitely benefit from this path of exploration. The tip of whatever instrument we use acts as a pilot into the pulp space. Once the tip is larger than the canal it will either stop or cut its way free, depending on what force is applied to it and whether the tip has the ability to cut. In a hypothetical straight canal certain instrument tip types allow the instrument to proceed at a particular rate for a given force. John gave you the numbers. When the extremely fine tip of a Quantec SC, finer than any traditional patency file, is lead into and engages the canal, the tip, leading blades , shouler and blades follow, enlarging the canal and allowing further penetration. The engaged tip prejudices the progress of the instrument into the canal. Yes, tips, cutting or otherwise allow transportation if the tip and its associated "dangerous" shoulder are allowed to become free ( and rattle unprejudiced ) in the root canal. By using a continuous darting action you will continually reintroduce the rotating instrument's tip into the canal. I have watched John McSpadden on a few occasions do what appeared to be brutal things to plastic blocks, with no deviation of teh instrument from the glide patth of the curved canal. The key to non deviation or non transportation is keep the cutting tip engaged. Get in and get out. If you have a desire to recapitulate, use a hand operated patency file ( redundant, other than for irrigant introduction ). Slow recapitulation like movements with a rotation NiTi instrument willl transport. I do not believe the cutting tip causes transportation. The shoulder ( not much less aggressive on LX instruments ) on cutting and non cutting tips will deviate the preparation, not the correctly engaged tip.
From: Jerry Avillion Sent: Wednesday, April 25, 2001 1:26 AM I have, and they ledge like crazy on fine curved canals. Course, don't forget as endodontists we tend to see more difficult cases than John does. There are many good systems/techniques that work well on endodonTIC cases that don't work very well on endodonTIST cases. Jerry Avillion Fort Smith, Ark. MCV '84, MCV Endo '86
From: "Mark Dreyer, DMD, PA" Sent: Tuesday, April 24, 2001 8:01 PM Try Anteos-C 0.06 SS stiff file with watch winding action, if it does not go through then nothing will. If it seems to go through then it is as Gary wrote - a deviation Who sells these files? - Mark Dreyer, DMD, PA
From: Bill Watson Sent: Monday, April 23, 2001 6:41 PM I'm not a big believer in using these rotary files as suggested at the apical 2mm when a hand file will not go to patency. I agree. I believe that one of the MUSTS of consistently performing high quality canal shape and minimizing iatrogenic canal damage using rotary files is to have an unobstructed smooth path to the desired length of instrumentation using hand files. That's not necessarily to say that I have that path established prior to rotary file use but I do suggest stopping short of the obstruction so as not to ledge or compact debris in the potentially small path to patency. Contrary to popular belief, rotary files have the capability of compacting debris in small canals. In summary, it is a sound principle to state and follow that hand files should provide the smooth unobstructed glide path to the desired length prior to rotary instrumentation. Bill Watson DDS, MS, FAAOMP, MBA Practice Limited to Endodontics Clinical Assistant Professor U of Missouri-Kansas City College of Dentistry 215 South Hillside Wichita, KS 67211 USA 316-681-1099
From: Garry Nervo Sent: Tuesday, April 24, 2001 3:34 AM Dear Bill, I have a clinical impresson ( No science ) that cutting end Quantecs cut through the fibrous pulp tissue rather than pushing and compacting it ahead. No other method that I am aware of cuts and evacuates the debris at the tip - Garry J Nervo
Bill Watson DDS, MS, FAAOMP, MBA replies... That may be true. I don't use the SC Quantec series. Before (many years ago) I knew they had safe-cutting and non-cutting I had been using non-cutting but unawares ordered safe-cutting. After perforating two cases (ML roots of max molars) I called to find out what was going on. It was then that I learned the difference. I know John McSpadden's explanation of the VERY significantly reduced forces on files with the safe-cutting tips. I don't remember the last time I separated a file with a non-cutting tip. I know I have sacrificed efficiency for safety but this works well for me.
From: John J. Stropko, D.D.S. Sent: Saturday, April 21, 2001 8:37 PM John, I have found that these SOB roots need as much "straight-line" access as you can reasonably get. The canal will generally exit the pulpal floor at about a 20-30 degree angle to the lingual. Then about midroot it will take as much as a 45 degree turn to the buccal! Visualizing this DL canal like that has enabled me to successfully instrument the canal since. BTW, I strip-perfed the first two I did before I figured it out....guess I'm a slow learner. Hope this helps. Just another one of your secret fans. Had to do a surgery on one of these last August! Dr Olover Pontius, from Germany, was my assistant and even with his expert help, it was a bugger....but healed well! John Stropko
Fred and Jerry, On the key board as well as in the canal I'm limited to hunt and peck. I've never posted before but for your sake, Jerry, I'll get Jane to shooe the crows off the wire and give it a shot. In answer to your question, Fred, my rotary technique is verry simple. Start with any file and at the first hint of a change of pressure required to make any additional progress into the canal GET OUT. Change to any other taper or diameter and repeat. The best indication for me for dealing with the insidious nature of curvatures is changes in pressure. I try to plan my sequence in order not to engage more than 3mm of any file surface to any significant degree before changing instruments (usually less than 3 sec.). I peck .5-1 mm at a time. If I had my drathers, I would use crown to a curvature and the use step back for the remainder of the canal. I don't know how to label the images but in 15, extracted tooth, 3D inspection gives some hint of curvature and hint of the caution that needs to be exercised. With no pre-op apparent curvature, image 14 actually having slightly over 3mm of curvature, 3 seconds is the very limit of rotation. Image 16 illustrates the value of the use of an endoscope to discover apical bifurcations. In short apical curvatures such as these I might set the file by hand first then insert it in the hand piece for rotation, one second in this case( the only way I know to attempt 360 degree enlargement). Image 21and 22, probably the results of Tennesse inbreeding, maybe Arkansas, best illustrate exceptions to most of the rules we hear discussed, but we can get more into that at the summit. John
From: Kenneth S. Serota Sent: Thursday, April 26, 2001 4:15 PM The idea of a series of technique articles has been addressed in the past. Here is the first one - no mention of Quantec, ProTaper whatever; a generic epistle on the most effective way to treat a root canal system. Yosi et al; from this magnificent keystones of the endodontic literature are positioned in the arch that is the portal to the gateway to the pantheon of knowledge. Build from it and on it. Someone cross post this to icanaden, it is informatin that should be read by anyone practising dentistry.
John, Your explanation is excellent. However, the connection between my brain and my hands sometimes takes a detour. Am I correct that when using the cutting-tipped rotaries, a pecking motion may cause transportation? For a "routine" mesial root of a mandibular molar, for example, can you describe your technic and armamentarium? I have never used the cutting-tipped Quantec files, and would greatly appreciate your valuable input. Fred
From: Dr. John McSpaddrn Sent: Tuesday, April 24, 2001 1:57 PM Fred, Perhaps the best way to think about tip action is to think in terms of non cutting (dull, burnishing, inefficient) and cutting (sharp, efficient). Most tip geometries are somewhere in between, for instance A. 75% burnishing and 25% cutting or B. 75%cutting and 25% burnishing. B will require a fraction of the time or number of rotations or pressure as A in order to obtain the same degree of enlargement. If you use B like A you get more than you bargined for (transportation). Both will seek the pathway of least resistance when engaged and will best follow the original axis of the canal when engaged. If the tip is loose the tendency for the file to straighten will cause increased force on one side of the canal and result in greater cutting on that side. Because of the taper of the file each time you disengage the file tip (repetitive strokes) it has an opportunity to cut on one side of the canal and transport. If the tip is mostly burnishing, little transportation occurs On the other hand if the file tip is cutting efficiently there is little reson to disengage it, but if you do, transportation also occurs efficiently. A cutting tip is most of most value when the canal is smaller than the tip requiring less torque therefore less tendency for breakage than non cutting. If the canal is larger than the tip non cutting is certainly more beneficial resulting in less transportation than the cutting tip. The technique for each is very different, flexibility, time and pressure being the most important factors. John.
Fred Barnett wrote: Garry Nervo & John McSpadden: Three factors work in Gary's favor: (1) you cannot transport unless you were first in the correct position. As long as the tip remains engaged 360 degrees no transportation can occur.I have seen in plastic blocks that transportation is possible with hand files when rotating in a clock-wise manner. Especially with files that have sharp transitional angles. I would imagine that rotary files without proper tip geometry may cause the same effect. When looking at the Flex-R file and Pow_R file, this transportation was extremely rare. I believe that it is the modified tip geometry that minimizes transportation. Is this correct?? (2) A cutting tip requires as little as 15% of the torque to rotate as a non- cutting tip.[ rotating at 350 rpms, inserting at 1mm/sec. 12mm into a .20 diameter plastic canal the Profile 25/04 required 317 gm/cm, the Quantec 25/04 non cutting LX required 271 gm/cm, and the Quantec cutting tip SC required 41 gm/cm. Smaller diameter smaller tapers should exhibit a greater difference.]. The increased efficiency enables progress with fewer strokes.I have not used the Quantec SC files....can you elaborate on their use, sequence, etc.?? (3) Repetitive strokes more likely result in greater cutting on one side of the canal. The trick is knowing when to get out.Can you elaborate on this?
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Photos courtesy of Fred Barnett - www.rxroots.com |
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Jerry Avillion wrote: I have, and they ledge like crazy on fine curved canals. Course, don't forget as endodontists we tend to see more difficult cases than John does. There are many good systems/techniques that work well on endodonTIC cases that don't work very well on endodonTIST cases. - Jerry Avillion .....I have never used the cutting-tipped Quantec files, and would greatly appreciate your valuable input. - Fred..... Fred, I think you might be better served by directing your questions to Jerry. John
From: Fred Barnett Sent: Wednesday, April 25, 2001 4:13 PM Whoa....wait a second. I have a problem with Jerry's comment . Most of the cases that I have seen posted are NOT exceptionally difficult, where only Endodontists would be capable of treating them. Maybe I am misunderstanding something, but there are few of us that have the depth of understanding that John McSpadden has when it comes to these issues. And I have learned a great deal from him for the past two decades. If I misunderstood this entire matter, that please forgive me for being stupid. Respectfully, Fred Barnett
From: Jerry Avillion Sent: Wednesday, April 25, 2001 8:23 PM Ok, I apologize because I must have missed the cases John posted. Jerry Avillion
Jerry Avillion wrote: Thanks. Were all these cases done with the end cutting quantecs and the microseal obturation? Are you using the quantecs as patency files or are you using hand files? Jerry Avillion
From: Dr. John McSpadden Sent: Thursday, April 26, 2001 9:36 PM I only use end cutting in canals the diameter of which is smaller than the file, or in first passes. For instance, if I have enlarged with a 25/02T the 03T and larger tapered 25s would be non cutting. Non cutting, for my way of thinking, should be used any time the tip is smaller than the canal. All the canals were done with rotary only, a personal preference, and sealed with a version of microseal. Although I am a firm believer in patency I don't use patency files. I use square tapered NiTi blank files ultrasonically to ascertain patency. Please don't think I necessarily advocate these techniques; as I stated, these are my personal preferences. Good to talk with you. John
From: Fred Barnett Sent: Friday, April 27, 2001 7:12 AM John, How do you get the 25/.02T to the WL? Do you crown-down first with rotaries, hand files, gates, or just peck away? I ask, because you stated (I think) that you prefer not to have more than 3-4mm of file engaged in the canal. What is your first rotary that you take into a curved molar canal? You see why we need your input so badly. Fred
From: Dr. John McSpadden Sent: Friday, April 27, 2001 8:36 AM Fred, I attempt to go crown down, progressing with pecks as far apical with each file until any detectable increased pressure (you have to apply a specific pressure for each file in order to advance 1mm, that pressure should never be exceeded) necessary for advancement indicates I either have engaged too much of the file or I have encountered a curvature. Changing to a file that has little engagement and still requiring increased pressure indicates a curvature. Once a curvature is encountered I switch to step back usually beginning with a 15/02. My personal favorite file to start a canal enlargement is a 25/06. Subtle changes in sizes such as 25/06 to 25/05 to 25/04 provide me with less information in questions of the anatomy as do greater changes such as 25/06 to 20/02 to 25/04.because less of the instrument becomes engaged and a better feel I have. I know at first this sounds confusing but I believe once you can conceptualize what is happening then you can determine limitations and cookbook procedures become less meaningful---the thrust of my presentation but I appreciate your interest and feel to ask questions. John
From: Jerry Avillion Sent: Thursday, April 26, 2001 11:55 PM If the canal is curved and the file is straight and wants to stay straight, why wont the file cut into the side of the canal creating a ledge as opposed to following the canal around the curve? When I used the cutting end quantecs, I had fits with ledging. (I was probably using them incorrectly). Also, at Kit Weather's and Bill Watson's root camp, they didnt recommend the SC tips (but I can't remember the exact reason), maybe Bill can comment. Jerry Avillion
From: Dr. John McSpadden Sent: Friday, April 27, 2001 7:35 AM End cutting as per your concern certainly will ledge---If given the opportunity. The only difference compared with most files is it does it quicker. If any file tip can enlarge a canal it also has the ability to ledge. I think of it as a per unit time approach. If one tip is twice as sharp, you have half as long to hang around, however, you have somewhere around one half the torque which might cause failure and as an added benefit virtually no debris pushed in advance of the tip. Some practice is necessary but a 'feel' is easily developed to determine the comfort level for each case. As I stated before changes in pressure is my best indicator. For me a pressure transducer on the handpiece would be a greater benefit than torque. John
From: Garry Nervo Sent: Friday, April 27, 2001 2:25 PM Dear Jerry, The tip guides the instrument around the curve. The leading point. If you continue to move ( advance ) the only way is along the canal and around the curve ( if there is one ). If you are a little sluggish or stop concentrating on "darting" the canal the aggresive shoulder bring about a deviation and ultimately if it isn't recognized, a ledge. I have a good visual joke to tell you in Toronto which highlights the issue very well. John has made reference to combining crown down with a modified dstep back approach. There is no one way to skin a cat. Different instruments achieve different effects in diferent canals, the crown down approach frees up the tip of finer instruments to subsequently "dart " the apical part of the root canal. Once the glide path is established you can revert to the crown down approach using descending tapers. Practise with some plastic blocks watching the tips of the instruments under the microscope, as you vary the apically directed force you will notice ( in the curved situation ) how the tips blindly follow the canals, if the right amount of force is kept up. How do you get to Carnegie Hall? Practise, Practise. Isn't that what we do all the time. Garry J Nervo
