Patency filesFrom: "I. Blake McKinley, Jr." To: "ROOTS"
Fred replies: {allows for puffs} The puffs occur when there is a discrepency between the diameter of the cone and the diameter of the foramen. Isn't there always a discrepancy?; the foramen is a size #20, but you instrument to a size #30, let's say 0.25mm coronal to foramen so that you actually instrument the canal in that area. Or are you saying that the tip of your cone should be exactly the same size as your foramen? {The capture zone will becomes critically important and will then prevent an overfill, yes?} If the foramen is a size #10, will you use a size #10 gp cone to obturate? Fred
Fred, I am sure that there is always a discrepancy between the portal of exit and the cone tip diameter. The greater the discrepency the greater the spillage of sealer and the larger the puff. I know that when I extrude a lot of sealer, I know I missed in my accuracy somewhere along the way. My point is that the puff is not the goal, rather the goal is to have as precise of a fitting cone as is possible. I don't believe that opening the canal to a size 30 .25 mm coronal to the foramen is going to result in a significant extrusion of sealer. Typically, the cone will be fit to the point we cleaned and shaped and then cut back 0.5mm because we know that the cone will distort into that .5 mm space. One of Dr Schilder's principles of cleaning and shaping was to keep the foramen as small as practical (not as small as possible). Typically this would mean that the foramen would be between a size 20 and 25. Fred asks Does this mean you use a size #20 or 25 as patency files? However, understanding the variability of foramen sizes, the bore of the foramen should be discovered and sized individually versus manufacturing it to a preconceived size. This minimized trauma to the PA tissues and concequently, respects the apical region. Also, it seems that in order to predictable obturate the apical 5-7 mm the foramen can not be less than a 20. Look at some extracted teeth and guage the foramina, I bet you would be hard pressed to find many with a foramen less than a size 20. Since the shaping occurs smoothly from the foramen and is based on the bore of the foramen, I would say that you are correct that the capture zone has always been of critical importance. Blake.
From: PBery To: ROOTS Sent: Friday, September 07, 2001 7:51 AM Subject: [roots] Re: Patency Files Hi Blake: Your nice post has made me wonder...I would think the opposite of what you said happens: The greater the discrepancy between capt. zone and gp, the LESS sealer spillage and the smaller the puff. A very accurate fit, would of necessity "push" the sealer away and out of the apex, lat canals, whatever. If you do not have a good fit of your gp, then I would expect to see minimal or no sealer extrusion due to pooling and/or lack of hydraulics, unless there is some type of apical opening perf. that would allow the sealer to exit no matter what technique you use. What do you think? Regards -Paul Bery Paul, I agree. Less discrepancy may allow sealer to flow coronally, perhaps - Fred Bill Watson replies I have anecdotally found: 1-if sealer is preapplied in the canal with a paper point and a well-fitting cone is used there is spillage. 2-if the cone is buttered and a well-fitting cone is used there is spillage. 3-if the sealer is preapplied and/or the cone buttered and a less well-fitting cone is used there is still spillage. Hydraulics come much more into play early in cases 1 & 2, i.e., cone insertion. Hydraulics come into play later in case 3, i.e. on the down pack the pooled apical sealer is expessed apically. bill [what do you think]
Blake, How close to the actual WL does the tip of the SystemB or heat transfer instrument need to be to predictably "distort" the gp in the capture zone (apical 1mm)? If there is no distortion, than is it truly the so-called 3-D obturation technic? Buchanan says (I think) to go to within 4-6mm from the apex (foramen). Does gp distort at its tip 6mm from where heat is applied? If not, are we not doing a glorified single cone technic in the apical 1/3 of the canal? I ask because maybe 6mm is too far to be from the WL during the downpack(and because I truly don't know the answer)? Respectfully, Fred Fred: I agree with you. 6 mm. seems quite far. On occasion, obviously due to poor fit or poor choice of plugger, I have dislodged the gp point after using the system B, and have observed nary a deformation of that #$@%%^ gp point, and it upsets me. Now I make an effort to go to 3 to 4 mm. and I think it does make a difference. Next time it happens, I'll post a pic. Regards - Paul Bery
From: Senor To: ROOTS Sent: Friday, September 07, 2001 5:30 AM Subject: [roots] Re: Patency Files GREAT QUESTION!!!!!! i would like to know the answer too........
Fred, The heat tip needs to be within 5-7mm of the working length to allow the pluggers to predictably distort this segment of GP. Since GP is an insulator it is slow to take on heat and slow to give it off. Dr. Goodman demonstrated that heat travels 3-4 mm ahead of the heat tip and that the heat builds in cycles. Consequently, as the GP is warmed and then compacted with each cycle of the downpack, the GP is retaining more heat (not getting hotter necessarily) as one advances apically. Consequently, the apical segment of GP has benefitted from the previous warming cycles. Another BU guy (Dr Jim Stephens) showed in his thesis that one does not need the heat carrier extremely hot. In fact, clinically he uses his touch n heat at a setting of about 3-4 and simply warms the GP a bit longer. If done properly, the GP is distorted apically, if not then it is a glorified single cone technique. Consequently, it is important that the deepest plugger you fit, fits about 5 mm from the working length. I hope this answers your question. There is more to your question than this simple answer will address. I would recommend reading Dr. Goodman's articles. Beware, it is dry. Respectfully, Blake
From: Dr. Kenneth S. Serota To: ROOTS Sent: Wednesday, September 05, 2001 6:55 PM Subject: [roots] Patency Forget the obvious for a moment re; patency as to the removal of the inoculum continuum. I'm not the literature wiz kid, but in order to effectively do vertical condensation or System S, A, X, B or whatever, there has to be hydrostatics and hydraulics factored into the rheology that occurs with sealer and gutta percha. Pulpal pressure is measured, I assume that you can measure tissue fluid pressure in the periapex. Shirley this has to factor into the obturation equation in some manner.- Kendo
From: Paul To: "ROOTS"
Fred, as long as I wonīt have the chance to meet "Paul" personally side by side to you, I have to believe that he is your dark side "alter ego" and that Dr. Fred Jekyll and Mr. Paul Hide is one and the same person ;-) Regards - Hans
Fred replies... Where were you for the past 9 months when I was arguing these points for vital cases!! I also have come to learn that patency files don't mean jamming files through the foramen with reckless abandon (for most people). If patency files (to the foramen) allows for the prevention of many complications (apical blockage, transportation, apical stripping, apical perfs, not removing bacteria and necrotic tissue in the apical 1-3mm) than one must weigh the difference between doing it judiciously or not. {Hank is a total barbarian, if I'm not mistaken}. Dentin chips looked great in experiments in vital, unexposed teeth Scandinavian research has shown this as well. Holland et al (I believe) showed very poor results in necrotic/infected teeth. Once again, bacteria seem to make the difference...according to all biologic studies, IMHO. What is worse, whitelineophilia or whitelineophobia? ;-) Fred well said Fred -Garry J Nervo
Beware of A Radicidentis. - Uzi
Paul, I wonder then why, if cleaning and shaping to patency on vital cases results in greater failure rates, the vital cases I treat are not failing on recall exams for up to 5 years? Clinically, how in the world do you determine that the apical 1-2 mm of the pulpal stump is normal tissue? Could this be a situation where the research does not support clinical reality? Respectfully, Blake McKinley, Jr., DDS
Paul Bery replies Hello again Blake: Yes, several papers have shown great success with vital tissue left at the apex. Why not do it more often? I would think predictability. Who knows; if you only did vital cases with apparently nondegenerating dental pulps, you might get nice success, but how in heavens do you know where those two mm. are, and furthermore how clean and sterile they remain after your instrumentation. I do however think that that is an explanation on why those canals filled2,3,4,5 mm. short of the apex seem to work well. Also, several studies have shown that the presence of sterile dentin chips packed against the apex promote fuller histological healing (cementum barrier) than not having them. Holland and others did study that quite a bit. I am sorry I do not have the references at hand (I am at home now), but if curious, check out a simple, no big deal article I wrote in the JOE in 1984 (april, maybe?) on this. Many references (available at the time) are there. The paper is your basic dumb leakage paper where I wanted to see if purposelly packing dentin chips at the apex would or could create an impervious barrier, and that might be one of the reasons why these teeth filled short where succesful nonetheless. Well, wouldn't you know. dentin chips leak like sponges! They stop nuthin'. Thus, I feel that the favorable response obtained by that technique is due to pure biology in which the dentin chip pack acts as a "decompression chamber" (Huggins and Urist. Bone.), where mesenchymal cells and hystiocytes dedifferentiate and redifferentiate, given the proper environment, into osteoblasts and/or cementoblasts (that's my theory based on their findings and studies in connective tissue in rats, on what happens in these condition in the root canal). Furthermore, as Fred mentioned, infected dentin chips will not only NOT work, but perpetuate apical microabscesses. But in the end, it seems that fully instrumenting a canal is as of yet, the way to go in terms of predictability. Regards - Paul Bery
From: "Uziel Blumenkranz"
From: Yosef Nahmias To: ROOTS Sent: Thursday, September 06, 2001 12:16 PM Subject: [roots] Re: Patency Files As far as I know, GP requires to be heated only to about 42 to 43 C to become soft and compactable! This graph shows how the GPs temperature is elevated when heat is applied with a heat carrier ( Schilder's Technique!), I do not remember who did this study (Ben will know, is a BU study!). So, theoretically, if you apply heat to the GP and you are within 5 mm from its most apical portion, you will deform it enough to be able to compact it ! I bet Gary has lots of pics that can show this! Regards - Yosi
| Graph courtesy: Yosi |
Paul Bery replies Yes, Yosef, agreed. But that study was done with "waves" of condensation in which alternating hot and cold instruments where used. I don't know if that happens in the single wave (system B) of condensation, at least in the manner buchannan describes it. If you bring the gp to 42, 43 (or even higher) C's, you can bet that that temperature does not exist 6 mm. farther (maybe 2 or 3mm only). So I have never thought that those results compare to the newer techniques (not saying they are better or worse, just not equivalent). That is also why your yth or whatever it is called today makes more sense to me (and I have been doing for 4-5-years since we spoke about it) because it allows the heat to travel "slower" but disseminate better and remain longer. What do you say Guebotes? Fred replies Paul, Words of wisdom. Who knows if the SystemB replicates the Schilder method with regard to all those hydaulics or hydrostatics or whatever you guys say goes on at the apical 1/3. Maybe the YTHT is the REAL way to go. Or perhaps only the original Schilder method will provide the plasticity you desire. I will never forget Donald Yu saying.."the SystemB is the fake orgasm of warm vertical condensation". By the way...does the fake orgasm have no puff? Respectfully, Fred
Yosi: I think it was Goodman Aldrich and Schilder, 5 papers on properties of guttapercha, Triple Oral 197? Uzi
From: Dr. John McSpadden To: ROOTS Sent: Friday, September 07, 2001 4:09 AM Subject: [roots] Re: Patency Files More is required than only heat application. GP is a very poor conductor of heat and conduction is a poor method of coveying heat. Hold a GP cone and light a match to it. You will notice little if any difference. There are ways to utilize convection for the transfer of heat and lower fusing cones are available to facilitate adaptation (condensation and compaction are misleading terms). Multiple insertions with heat can cause some convection and result in a more distant plasticity. Many times, however, adding heat to the coronal portion only reduces the resistance in that area so the apical portion can be more effectively pushed to place (much like crown down preparation).
slow heating would seem more important like heating up modeling compound........if you put it in a direct flame only the outside will burn........but in a hot water bath it all becomes nice and pliable........ so should i go to a hot water bath with the gutta percha before obturation as a better method of heat alteration of gp.......????? - craig From: "Dr. John McSpadden"
Von: Sirendo@aol.com An: ROOTS Gesendet: Donnerstag, 6. September 2001 20:02 Betreff: [roots] Re: Patency Files Blake, How close to the actual WL does the tip of the SystemB or heat transfer instrument need to be to predictably "distort" the gp in the capture zone (apical 1mm)? If there is no distortion, than is it truly the so-called 3-D obturation technic? (HWH): Fred, 2-3 mm max. with System B 5 mm max. with Touch and Heat Buchanan says 5 - 7 mm (January 99) Hans
Fred replies Hans, Do you mean that with the SystemB you need to be no further away from the gp tip than 3mm to plasticize it?
Comments by Hans (HWH): Fred, may be Iīve been wrong, but I thought, you asked, how near I have to go to the tip of the GP cone in the canal with my System B tip to plasticize even the most apical part of the GP. That would be 2-3 mm max. with System B (i remember a study about that (JOE last 2 - 3 years ????) but Cliff Ruddle also mentioned those 3 mm (Feb 2001) 5 mm max. with Touch and Heat (also Cliff R.) Buchanan says 5 - 7 mm (January 99), which works not in my hands (at least in plastic blocks) So if your System B tip couldnt get less than 3 mm to the working length, maybe youīll have indeed a (great looking) single cone obturation at the apex. Couldnīt happen with System S, thanks John S., please catch some snakes for me, Iīm hungry.- Hans |
Yosi, It was Alvin Goodman (BU73) who wrote the three part OOO article on the thermo-mechanical properties of gutta percha. -Blake
From: benschein@prodigy.net To: ROOTS Sent: Friday, September 07, 2001 1:40 AM Subject: [roots] Re: Patency Files These are the references Blake mentioned. Al Goodman was my classmate (71-73) he teamed up with the boss, and a material science engineer (Aldrich W) from MIT. REFERENCE 1 OF 5) 81222163 Goodman A Schilder H Aldrich W The thermomechanical properties of gutta-percha. Part IV. A thermal profile of the warm gutta-percha packing procedure. In: Oral Surg Oral Med Oral Pathol (1981 May) 51(5):544-51 A thermal profile of the warm gutta-percha technique was produced by the thermocouple instrumentation of natural teeth and the subsequent monitoring of intraradicular temperature changes during the packing procedure. Although variations in thermal patterns resulted from individual differences in timing and instrumentation, certain clinically accepted patterns of activity produced consistent, representative temperature ranges to which the gutta-percha in the body of the canal was 80 degrees C., while the over-all peak temperature recorded in the apical region was 45 degrees C. Thermal penetration of the gutta-percha was expectedly limited, with significant thermal effects rarely exhibited more than 4 to 6 mm. into the material.
| Ben,...So, if you are more than 4-6mm from the tip with your heat source, does this mean that the apical gp will NOT plasticize and thus not deform into the 3D of the apex? Please explain this in English as it relates to what we do. Thanks, Fred |
Tim McManus wrote: Yosi, I will forward a case I completed today, one of my first ones employing Protapers exclusively, as soon as I have time to scan them.
From: "Dr. Kenneth S. Serota"
| Xrays courtesy Dr. Kenneth S. Serota |
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From: "Seņor"
From: "Julian Webber"
From:
Paul replies: I think you're looking in the wrong direction. After you've cleaned, disinfected and shaped the canal, you should use some sort of blocking agent as an interface between the root canal filling material and sealer and the periapical tissues. That way, there will be less inflammation. If you need an apical patency in order to use a vertical condensation technique, change your technique. It really depends on what your goal is: a good looking root canal filling or histologic healing. I know it's heresy in 2001, but I think the worship of three dimensional filling is a bunch of bull. I believe Marty Trope has postulated that the gutta percha we use is merely a vehicle for carrying the sealer to the walls of the canal. I think he's right. Lateral condensation, even though I personally don't use it often, is a great technique and with great instrumentation, works as well as any other filling technique. I've never seen any good study that shows that vertical condensation is superior to any other technique. I grant that it often looks better on the x-ray but that's about its only advantage. I could just as easily argue that this technique causes more failure because of excessive tooth structure removal. Shields up! ! - Paul
Bill Watson writes... There are so many points you have made to discuss but I will focus on only this one. > > Lateral condensation.........works as well as any other filling > technique. I've never seen any good study that shows that vertical > condensation is superior to any other technique. > It is true that there are no studies to support that one technique is better than another. I was taught and used lateral condensation for the first 10 years of my practice and then switched to warm vertical. When I used lateral condensation it was an infrequent event to notice an obturated lateral canal. Since my 'conversion' `2 years ago obturating lateral canals is a frequent occurrence. And then you may argue [Paul]: But there are no studies that show a higher incidence of obturated lateral canals or that they have only sealer in them. And then I would argue [Bill]: Is one of the objectives of excellent endodontics to obturate as much of the canal system as possible? Given the chooice, is it better to have canal space obturated with nothing or sealer? Paul: Yes, one of the objectives is to obturate as much of the canal space as possible if it is only with sealer, but there are no studies to show.......... and then at this point I would cease dialogue. bill (wishing I was Socrates) Bill: Please refer to the latest International Endodontic Journal. look for the results when comnparing lateral and warm vertical technique. Not on the statistics but on the quality. - Uzi Uzi, I'm not trying to take sides here. Just want to point out, unquestionably quality is better based on the standards they used in that study. The big question is, does it make a difference in long term success?? That can not be proven with todays literature. Joey D, We are doing some more experiments today for the telesurgery to Venezuela!
Fred: Histologic healing...ouch!! Remember Brynolf's study on cadavers: Complete histologic healing occurred in only 7% of the root filled teeth, and a tendency toward complete healing in anther 20% or so. The problem with her study of 119 endodontically treated teeth is that the endo procedures were not standardized with regard to technic, irrigants, medicaments, etc. It was quite interesting when she compared the xray findings with histology. For me, getting a puff is not the goal of my treatment. Doing a "complete" job a debridement and disinfection (cleaning & shaping for the biologically compromised) , filling the canal system with a biocompatible material, and having a proper coronal restoration placed is the recipe for success...histologic, radiographic and clinical. Paul, what method of obturation do you use as you mentioned that you rarely use lateral condensation? Fred
From: "Joseph Dovgan"
i don't seem to get a lot of lateral canals anymore since i changed to lateral condensation........for a while i used thermafil and i saw lateral canals all the time........is this a reason to believe that lateral condensation is inferior or am i just not a good lateral condenser?????/ and i have asked Fred this question but i would like to know what you think.........how do you feel about chemical alteration of gp in the use of lateral condensation.......i currently use eucalyptol and i like it........other than the shrinkage factors Fred has told me about what are your feelings........craig
I like to thank all for the response to my request!!! GRACIAS! -Yosi
