CE-stress-free endo 4/16/08 3:06 PM Page 58 continuing education Stress-free Endodontics by Dr. Barry Musikant Private Practice New York, NY Dentaltown is pleased to offer you continuing Educational objectives Upon completion of this course, participants should be able to achieve the following: education. You can read the following CE • Learn how to gain quick and simple endodontic access to root canals, includ- ing the MB2. article in the magazine and go online to • Learn alternatives to hand instrumentation and rotary nickel titanium. • Discover engine-driven reciprocation. www.dentaltown.com to take the post-test • Learn obturation techniques that enable you to fill canals laterally as well as and claim your CE credits, free-of-charge, apically, often without the need for lateral or vertical condensation. • Perform superior, single visit endodontics. or you can mail in your post-test for a nominal fee. See instructions on page 66. Most of us have a perception that the endodontic universe is divided into two worlds: traditional and engine-driven NiTi (rotary NiTi). Traditional endodontics uses stainless steel k-files to create a glide path and shape the root canal procedure whereas, engine-driven NiTi uses rotary NiTi shaping. Engine-driven NiTi has not completely escaped the shortcomings involved with traditional instrumentation, because k-files are still required to create a glide path, even when using rotary NiTi files for the shaping process. However, the use of the NiTi tools has enhanced effi- ciency and efficacy of the shaping procedure with increased flexibility, less hand fatigue and more accurate shaping. Approved PACE Program Provider FAGD/MAGD Credit Dentaltown.com, Inc. is an AGD Approval does not imply acceptance PACE Recognized Provider. by a state or provincial board of This course offers two AGD PACE dentistry or AGD endorsement. 12/01/04 to 12/01/08 Continuing Education Credits AGD PACE Approval Number: 304396 free-of-charge. continued on page 60 58 May 2008 ■ dentaltown.com CE-stress-free endo 4/16/08 3:06 PM Page 60 continuing education continued from page 58 Traditional endodontics has a well deserved reputation for being frustratingly ineffective. There are seven negative consequences of using traditional endodontics for shaping: overfills, squiggly fills, hand fatigue, distorted canals, fractured roots, puffs of cement in vital cases and blocked canals using files. There are two counterproductive legacies of endodontic education; they are the use of files rather than reamers and instilling fears of using Peeso reamers. These ideas made using traditional procedures more susceptible to hand fatigue and sub- sequently increased distortion. The use of standard reamers will provide more effi- ciency through less resistance by having fewer flutes. This will equate to less points “There are two counter- of contact which will result in less resistance. In fact, there are about 30 flutes on productive legacies of the shank of a file while there are 16 on the shank of a reamer. With about twice as many flutes, on a file, the flutes will be about twice as horizontally oriented as endodontic education; compared to those on a reamer. Once it was clearly established that a k-reamer is superior to a k-file, we wanted they are the use of files to find an instrument that was superior to a k-reamer. We realized that part of the rather than reamers superiority lay in the fact that it engaged the walls of a canal less than a k-file. By placing a flat along the length of the canal, the contact points are reduced from 64 and instilling fears of to 48. This will reduce the engagement along the canal while enhancing flexibility due to a thinner cross-section. The incorporation of a flat created two columns of using Peeso reamers. chisels that cut, one in the clockwise direction and the other in the counterclockwise These ideas made direction. This flat, in turn, enables our reamer to be used with a reciprocating hand- piece with no more than a 30 degree arc of motion in either direction at approxi- using traditional proce- mately 6,000 cycles per minute, creating highly efficient shaping with little resistance and no distortion. The above features of a flat sided (relieved) reamer allow dures more susceptible you to now have instrumentation that incurs less torsional stress than traditional k- to hand fatigue and files or k-reamers, has more durability than NiTi, is still more efficient than a rotary NiTi system – which is more susceptible to breakage, and is less costly. subsequently increased Interestingly, an article written more than 15 years ago by Dr. Anthony Martin, distortion. The use of an Australian dentist, concluded that the use of reamers used limited to a recipro- cating handpiece was the best way possible to negotiate through calcified canals. standard reamers will We believe that relieved reamers and a reciprocating handpiece are an improvement over an ordinary reamer, so Dr. Martin was most definitely on the right track. provide more efficiency NiTi and stainless steel reamers have their pros and cons. NiTi files or reamers through less resistance are more flexible and less likely to cause distortion in traditional circumstances; for example a NiTi instrument used in a rotary system vs. a traditional stainless steel by having fewer flutes.” k-reamer or k-file. However, due to its shape memory NiTi begins to become more vulnerable to causing outer canal wall distortion when the curve of the canal and taper of the instrument increases. Stainless steel has less flexibility and would cause even more distortion if used in a rotary system similar to the one used in NiTi. However, when pre-bent, guided manually to the initial point of the curvature and reattached to the reciprocating handpiece, distortion is far less likely to occur. Most importantly, the potential for separation does not exist when using these reamers in the reciprocating handpiece, which encourages the dentist to shape the canals to larger diameters allowing greater clearance of debris as well as improved irrigation. A relieved reamer provides the capability for a dentist to deduce information about the apical anatomy that they might encounter. The resistance of a non- relieved reamer with no flat side will remain constant even when the canal diame- ter varies throughout the apical path. The resistance and speed will stay the same. Additionally, it will not be able to detect the degree of roundness (fully round vs. an elliptical shape). When working with the elliptically shaped canal, the relieved continued on page 62 60 May 2008 ■ dentaltown.com CE-stress-free endo 4/16/08 3:06 PM Page 62 continuing education continued from page 60 reamers used in the SafeSider system will go from more resistance to less resistance as it is rotated manually. This happens as the flat of the instrument starts to line up with the long diameter of the elliptically shaped canal and back to more resistance as the flat starts to line up with the short diameter. This easily perceived change in resistance tells the dentist that he should open the canal wider apically to better cleanse the wider extensions that are most usually in the bucco-lingual plane. The remainder of this article will discuss the system from end to end, from the start of accessing the canal with initial negotiation through the pulp chamber, to negotiating the canal to obturation. Just about all the components, with the excep- tion of the NiTi reamers, can be used either manually or with a reciprocating hand- piece. Most of the instruments are relieved k-reamers given the name SafeSiders. There are also other relieved NiTi instruments all used in the reciprocating hand- piece – the 30/.04, 25/.06 and 25/.08 which is rarely used and if used no closer then 2mm. We insist that the NiTis only be used in the reciprocating hand-piece because the short envelope of motion that the reciprocating hand-piece generates makes for far safer shaping than if used manually where even a small amount of excessive torque can lead to separation. The only instruments that are not relieved are the 08 and 10, which, if a flat were incorporated, would make these already thin instruments too weak. The flat has its advantages; less resistant as the instruments get to the apex (allowing for faster instrumentation to the apex), the debris is pushed aside rather than clogging up the flutes, thinner cross section that makes instruments more flexible, more flexibility which allows the instruments to negoti- ate curved canals more easily and the need for less hand pressure which gives the dentist superior tactile perception. The reciprocating handpiece limits the arc of motion to 30 degrees, a small enough envelope of motion to virtually eliminate torsion stress and cyclic fatigue that can plague rotary NiTi. Even when a sharp curve calls for pre-bending and manual insertion of any of the stainless steel flat-sided instruments, the canal will be shaped without distortion to a size significantly wider than can be achieved dis- tortion free with rotary NiTi. The handpiece is connected to a source of power. An e-attachment is required. The connection can be made to an airline using a 4-hole air-driven motor or an electric attachment that all dentists who presently use rotary NiTi already have. The reciprocating handpiece is best used at about 6,000 cycles/ minute with a firm pecking motion. If used slower, the instrument becomes less efficient and the tactile perception decreases. The instruments are typically used in the following sequence: • Use a high-speed surgical length No. 4 round bur with a 7mm stop to make the proper depth cut in looking for the pulp chamber which is necessary before looking for the canals.