issn 2193-4673 • Vol. 17 • Issue 3/2021 roots international magazine of endodontics 3/21 feature Elements of dental instrument design case report Root canal therapy in a maxillary first molar with a highly curved mesiobuccal root opinion The impacts of the pandemic on dental practice

editorial | Magda Wojtkiewicz Managing Editor The importance of human connection The COVID-19 pandemic has changed life as we know it. Repeated lockdowns and restrictions have affected millions of people worldwide. The impact is huge, and we might not realise it yet completely. The pandemic situa- tion is still very uncertain and differs from region to region and country to country. Not everyone practises preven- tive measures such as mask wearing, maintaining a so- cial distance and washing hands frequently, but people are more willingly using digital technology for communi- cation. People who previously did not rely on the latest technology now have adopted novel digital methods to stay in touch with their friends, family or co-workers. Also many people are still working from home, and those who used to travel a lot are now travelling less or not at all. In medicine, we have observed the advancement of tele- health, which might soon become widespread for many specialties. Medical practitioners and patients who have used technology that allows them to conduct and re- ceive medical care remotely have found that it can work well for certain appointments, like cardiology check-ups and therapy for a mental health condition. It might not be an ideal solution for dentistry; however, certain help and information can be offered to the patient at a dis- tance, and many dental professionals have started offer- ing such remote dental consultations. Of course, there are problems for which patients need to see a doctor in person, but the pandemic introduced a new urgency to what had been a gradual transition to remote patient visits. The pandemic has affected private lives, businesses and movements. While everyone’s situation is different and some people have experienced enormous difficulties, many have found that it has been possible to deal with the crisis or even discovered new business opportuni- ties. During the pandemic, people have learned to take care of themselves in many new ways, as they have had to adapt to new work or school schedules, change their fitness routine and reduce social contact. Many have started looking for new stress management strategies, focusing more on health and well-being. One thing is common to continents and countries: many of us have realised how much we need other peo- ple, whether family, community or business colleagues. Human connection is invaluable, and even the most advanced technology cannot replace it. Magda Wojtkiewicz Managing Editor roots 3 2021 03

ROOT CANAL SHAPING MicroMega One RECI NEW Single file in reciprocating motion ´ Cutting efficiency ´ Safety ´ Flexibility ´ Minimally invasive TEST IT! Exploring opposite directions micromega.coltene.com/one-reci 1 2 6 0 . 5 6 7 6 0 0

feature | inside of a canal or inside of a cavity preparation.”2 My ex- perience has been that I can seldom intellectualise, during early stages of an invention, what the final product will look like and exactly how it will behave. Stated another way, I can only get half way there before a prototype must be fabricated and put into action to know any more about it. I have had 22 US and foreign patents granted and usually have several in process, and I can say without embarrass- ment that very few of my ideas ended up the way I thought of them working upon conception. 2 Successful innovation requires careful deconstruction of the failures of every round of prototyping, redesigning the next round to answer the identified problem(s) and fabricat- ing another prototype—rinse and repeat until it works the way you hoped. The design process for Kerr Endodontics’ Traverse rotary negotiation files required 23 prototype iterations before the instruments worked to my specifica- tions (Fig. 1). Once in a great while, the challenge is to accurately de- construct an unexpected success. This is undoubtedly a quality problem, but these can be as mystifying as the unexpected failures. It took me two and a half years of using a System B Heat Source (Kerr Endodontics) with the continuous wave of obturation technique before I under- stood how a method that took 2.5 seconds to perform could be superior to warm gutta-percha techniques taking 10–15 minutes to complete. Weirdly, the continuous wave electric heat pluggers I designed worked the first time they were used. More typically, GT Files took several years of trials to get right. Understanding the market In the same article, Fischer encourages potential inventors to study and realise what the dental market really is going to be like for the proposed product. He cautions that “early inventors can start doing multiplication, without ever sub- tracting or dividing. We’re usually multiplying, and we’re mul- tiplying how many units we feel are going to be bought by how many dentists who are going to use them. How many times a day can be multiplied by how many patients in a year. We can come up with tens of millions of dollars of projected successes. ... If we’re not careful, the numbers become so tantalising in our brains that it’s difficult for us to accept a small start that may be required first. It’s that human nature thing that can run away with us if we’re not careful.” Perhaps most important is that the tool solves a genuine problem that dentists currently encounter and that the ben- efit of the solution (the new tool) is greater than its cost. Taking it a step further, Drucker, in his book Innovation and Entrepreneurship, states that to be successful any new product, tool or technique must deliver a 10× advan- tage to make it worthwhile for new users to go through the expense and difficulty of changing their current mode Fig. 2: TrueTooth and TrueJaw 3D-printed procedural training replicas created by my company, DELabs. of work.3 The best tool on earth will not sell if it costs too much to buy and requires too much effort for too long for neophyte users to achieve competence. Finally, inventors must understand that both markets and technology are dynamic realities, a factor that must be se- riously considered. The right innovation developed before its time is not going to happen until its time arrives. Bill Gross, a serial entrepreneur from the age of 12, explains in his TED Talk, “The single biggest reason why start-ups succeed”, that timing trumps all other variables.4 My experience indi- cates that he is dead on in his assessment. Inventors must ask themselves whether the market is ready for their idea and whether all the technologies necessary for the suc- cess of their product already exist. Sometimes a great idea needs to be put on the back shelf until the timing is right. For example, when I met Chuck Hull, the inventor of stereo- lithography (3D printing), I asked him whether we could use 3D printing to print an actual-scale tooth replica from re- constructed CT scans. He replied that it was possible, but that it would be 20 years or so before costs would go down and the resolution of 3D printing would be small enough. 3 Fig. 3: Endo-Bender plier. Note the smooth ergonomic contours where the clinician’s thumb and palm connect with it and the end view showing the con- cave upper clamp jaw and the convex lower bending anvil jaw that together can immediately emboss a smooth curve on to the very last fl utes of a ne- gotiating fi le to enable it to bypass coronal or apical impediments. The lower jaw graduates from a 0.5 mm bending radius to fully fl at for straightening previously bent instruments or pluggers. roots 3 2021 07

feature | licensee of my GT System patent, Dr Ben Johnson’s pri- vately owned Tulsa Dental Products, rapidly finished devel- opment of my GT Hand File just in time for it to be swept up into the rotary revolution, and GT Rotary Files became Tulsa Dental’s flagship product for the following five years and still sell remarkably well. In this case, hedging my bet made the difference between success and failure, and since then I have had most of my licensing successes in tool design with privately owned companies. The problem with this strategy is that the ma- jority of those small, nimble companies that develop suc- cessful new products are bought by larger corporations, and then you have to work with them. The reason corporations buy smaller companies is be- cause of the much greater leeway these privately held companies have to spend development money and wait several years before seeing the return on their investment. The strength of corporations is their ability to wring every last penny of market value from existing intellectual prop- erty, but eventually they often suck more of the previously created intellectual property equity out of their acquisition than they create, and a long slow downward trend is seen unless further acquisitions can be put in place to obfus- cate this reality. The greatest entrepreneurial successes in endodontics— Tulsa Dental and EdgeEndo, for example—were only achieved because the endodontist inventors, Dr Johnson and Dr Charles Goodis, respectively, did it themselves by starting companies. Sonendo, a start-up out of a medical technology incubator with no previous dental experience, developed a multi-sonic root canal cleaning technology, building a company around it and in the process chang- ing the specialty of endodontics. Starting your own com- pany has the highest potential reward; however, it also has the highest risk profile—typical of most scalable revenue streams.6 Do not call my baby ugly: Some fi nal pieces of advice Be really fickle about whatever material, tool or technique you are currently using. I love tools for the power they provide to accomplish previously unattainable missions, like continuous wave electric heat pluggers reducing the time to three-dimensionally fill root canals from minutes to sec- onds. However, the day I find a better, faster or simpler way to fill root canals, continuous wave pluggers will be dead to me. Ideally, you obsolete your own inventions before somebody else does. Listen to everybody’s opinion, but make up your own mind in the final assessment. Most users have ideas about how existing products could be incrementally improved, but they lack the vision to ask for an entirely new product 6 Fig. 6: The Legacy Collection double-ended mirror with 16 and 20 mm Zirc Crystal HD mirror heads. These mirrors refl ect at least 30% more light and are more scratch-resistant than traditional rhodium-plated mirror surfaces. The 16 mm mirror size is great for views into mandibular molar access cavi- ties when sitting in the 12 o’clock position. category—nobody ever asked Apple for an iPod, iPhone, iPad or iWatch. You cannot get to the finish line without per- sistence, but persistence by itself will never get you there either. Those who persist, but can pivot on a dime when faced with new data will get there first. With that said, there is nothing like the thrill of successfully seeing an invention through all the impediments that stand in its way. Never forget that, with the right lever and fulcrum, you can move the world. Editorial note: A list of references is available from the publisher. This article was first published in the US edition of roots— the international magazine of endodontics, vol. 9, issue 1/2019. about Dr L. Stephen Buchanan, DDS, has lectured and taught hands-on endodontic continuing education courses for 30 years, both in his DELabs Academy in Santa Barbara in California in the US, as well as in dental schools and meetings around the world. He currently serves as an assistant clinical professor at the Herman Ostrow School of Dentistry of the University of Southern California and University of California, Los Angeles School of Dentistry, both in the US. Dr Buchanan is nationally and internationally known as an expert in the research and development of new technology, instruments and techniques in endodontics, designing many of these products, including 3D-printed teeth and jaw replicas TrueTooth and TrueJaw and the Legacy Collection dental instruments and procedural sets, for his company DELabs. He is the owner of more than 22 US and international patents, and his tools are used by endodontic specialists and general dentists worldwide. Dr Buchanan also maintains a private practice limited to micro-endodontics and implant surgery in Santa Barbara and is a diplomate of the American Board of Endodontics and a fellow of the International College of Dentists and American College of Dentists. roots 3 2021 09

technique | 1 2a 2b Fig. 1: Mandibular molar canal system. (Image: © Dr Holm Reuver) Figs. 2a & b: Maxillary molar. Diagnostic radiograph (a). Post-operative radiograph (b). (Images: © Dr Holm Reuver) apex.8 The bacteria are able to penetrate deep into the dentinal tubules up to 300 μm.9 The key to success: Access cavity Enterococcus faecalis has even been detected up to 500 μm away from the main canal.10 The problem with the elimination of bacteria from the root canal system is not the bacteria floating in planktonic form,11 that is, in the tissue fluid, but the bacteria organised within the biofilm. This is a conglomerate of different bac- terial species that are organised within an exopoly- saccharide matrix that adheres strongly to the canal walls and to the dentinal tubules.12 The exopolysac- charide matrix is produced by the bacteria organised in the biofilm itself. The bacteria are also networked.13 In all advanced stages of periapical periodontitis, an intra-canal infection caused by biofilm can be assumed.14 The greatest possible elimination of infected tissue, bacteria and, above all, biofilm is the factor that de- cides whether endodontic therapy is successful or not.15 Therefore, the application of a modern mechani- cal treatment concept, the adequate use of disinfecting solutions and the activation of the latter are of utmost importance (Figs. 2a & b). Complex root canal systems Generally, every root canal system has its own com- plexity. The best approach in order to avoid mistakes is to judge every root canal system as difficult. In par- ticular, the most challenging problems in the mechan- ical preparation of a root canal system are obliterated root canals, narrow root canals and severely curved root canals. Improper access will hinder a direct view of the pulp chamber floor and the detection of root canal orifices, as well as prevent the straight-line introduction of in- struments into the root canal system and controlled preparation and obturation. One can assume that the quality of the access cavity is pivotal for the treatment outcome in endodontics.16, 17 Recently, the right size of the access cavity has been a matter of debate. The traditional endodontic access cavity approach em- phasises the importance of convenience of form and the execution of extension for prevention.18 The con- servative endodontic access cavity approach stresses the preservation of sound tooth structure.19 The ultra- “...elimination of infected tissue, bacteria and, above all, biofilm is the factor that decides whether endodontic therapy is successful or not.” conservative approach of creating only small holes over each orifice is known as ninja access.20 Ultra- conservative access cavities have to be carried out using the dental microscope and CBCT and are technically very challenging. roots 3 2021 11

technique | 6 7 Fig. 6: Clipping area for apex locator. Fig. 7: U-Files with adapter. as medication and obturation materials. Ideally, the canal entrances form the cornerstones of the always slightly conical access cavity. Exploring the root canal orifices can occasionally be very challenging. One very useful tool is the Endo Holder and micro-files (MANI; Fig. 5). The holder is ergonomically designed and can be con- nected to different tips. These tips are hand files of differ- ent sizes and designs. For instance, you can use an ISO size 15 K-type micro-file with different angulations of the tip. The different tips can easily be changed by screwing them in or out using a screw thread. The great advan- tage of this design is the better view on to the tip of the instrument. That is very important to control whether the tip slightly enters into a root canal orifice. When using a classic hand instrument, the operator’s fingers constrict the operator’s field of vision. Another very helpful feature of the Endo Holder is the possibility of connecting it to an apex locator (Fig. 6), allowing working length deter- mination to be carried out with much more visual control compared with hand instruments. For the minimally invasive fine preparation of the access cavity, ultrasonic tips are an indispensable aid. These tips, which operate in a frequency range of 27–33 kHz, are operated by special generators based on piezoelec- tric ultrasound. Differently shaped tips with different sur- face coatings can be used to design the access cavity. What all instruments have in common is their minimally invasive removal of tooth structure. Diamond-coated tips in different designs can be used for removal of dentine. U-Files (MANI) are stainless-steel K-type files which can be connected to a piezoelectric ultrasonic device via an adapter (Fig. 7). They are available in ISO sizes 10–50 and can easily be adapted to every anatomical situation. They can be used for different purposes, such as acti- vation of disinfecting solution (passive ultrasonic irriga- tion), minimally invasive preparation of small isthmuses, removal of gutta-percha by plasticising it and removal of fractured instruments. The work is carried out dry to gain better visualisation. The power setting used is very low. This has the advan- tage of being able to control the removal of hard tooth substance at any time. In addition, preparation using ultrasound often enables the finding of previously uni- dentified canal systems by pressing dentine chips into the canal entrances. Once the canal entrances have been found, a coronal conical expansion takes place, which is also referred to as pre-flaring. This can be done with special NiTi instruments, for example with specifically designed NiTi access files or Gates-Glidden drills. If the canal entrances are very narrow, the initial pre-flaring should be carried out using small hand files together with the Endo Holder and later using larger tapered hand or rotary files. The slightly tapered canal entrance enables interference-free access to the root canals for all instruments to be used subsequently. From a bacte- riological point of view, good pre-flaring in the sense of the crown-down technique leads to a large reduction in bacteria in the coronal part. 8a 8b Figs. 8a & b: Pulp canal obliteration before (a) and after (b) gaining access with ultrasonic U-Files. roots 3 2021 13

technique | 13 14 Fig. 13: Same tip size but a different taper and flexibility. D = diameter. Fig. 14: JIZAI files. canals, the initial widening should be carried out using hand files. One advantage is that the risk of instrument fractures is lower in stainless-steel hand files then in small NiTi files.32 Secondly, the tactile feeling is much more direct to the fingers compared with rotary instruments. Historically, stainless-steel K-type files or reamers were used for the task of negotiating these sorts of root ca- nals. The ISO 3630 specification defines the design of endodontic hand files. One of the requirements is a con- stant taper of the working part from 0.02 mm. The length of the working part is 16 mm. Looking more closely at an ISO size 8 hand instrument, one can easily assume that the diameter of the tip is 0.08 mm (ISO size 8). In the mid- dle of the working part, 8.00 mm above, the diameter has already increased to 0.24 mm (ISO size 24) and at the end of the working part to 0.40 mm (ISO size 40). These con- siderations lead to the implication that even small hand files are too large in diameter in their middle and coronal parts to negotiate small canal systems. Often, the friction in the middle or coronal part is the reason why the file cannot be negotiated further apically. A further disadvantage of traditional hand files is their design. For instance, stainless-steel K-type files have a rectangular diameter and cutting edges all the way from the tip to the end of the working part. Therefore, the cut- ting edges can have friction all over the entire root canal, especially in narrow parts with deposition of secondary dentine. Thanks to its unique design features, the D Finder file (MANI) can be a helpful tool in these cases. First of all, the file has a D-like cross section. This cross section is the reason for the very good centring ability of the D Finder in the root canal system. The second unique feature is the working part (Figs. 10a & b). There are only some sharp cutting edges and very smooth surface areas in between. The diameter, together with the smooth sur- faces along the working part, results in the file gliding through the root canal and by passed any obstacles. Compared with traditional root canal instruments, the D Finder features increased stiffness or, technically speaking, a superior buckling resistance.33 That is the reason why slightly more downward force in the direc- tion of the tip can be generated. Ideally, the file is used in a balanced force technique. Thanks to its design, it nor- mally glides through the root canal. In case of too much friction, the canal space can be widened with the sharp cutting edges. D Finders are available in ISO sizes 8, 10 and 12 and in 21 and 25 mm lengths. Whenever pos- sible, one should choose a 21 mm D Finder, as it has better buckling resistance. “Perforations, incorrect alignment and excessive removal of sound tooth structure are some of the complications which frequently occur.” So much for equipment, now for technique. If you cannot advance with the smallest file (e.g. ISO size 8 D Finder) in a small root canal, do not try to push or force the file down. That is the road to failure! Instead, measure the length which the file can penetrate. As mentioned before, files seldom bind at the tip but very often in the middle or coronal section. Now change to the next larger file, for example an ISO size 10 or 12 D Finder, and prepare the canal to the provisional working length. Remember to irrigate copiously in between the files. Once you have reached the provisional working length and have irrigated copiously, change back to your smallest file (e.g. ISO size 8 D Finder) and try to advance further into the canal. In most cases, it is possible to penetrate deeper into the root canal. You can repeat this procedure roots 3 2021 15

technique | exhibits superior flexibility and superior safety compared with all competitors in the market. The idea behind de- veloping the JIZAI file was to make endodontics easier, more predictable and safer for every dentist around the world. The treatment manual is very easy to understand, and the files can be used for very easy to very compli- cated canal systems. The JIZAI file features some unique design elements. Together with a newly developed heat treatment pro- cedure, the result is outstanding handling. Looking at the file, one can immediately see its outstanding design (Fig. 14). Besides sharp cutting edges, it has very smooth surface areas formerly called radial lands. These bearing surfaces are one of the reasons for the excellent centring ability of the file inside the root canal and minimise the so-called screwing-in effect. The sharp cutting edges with varying angles are designed for an efficient cutting ability without being aggressive. The tip is a non-cutting tip (Fig. 15). The cross section is off-centred and rectan- gular with a rounded downside (Fig. 16). Therefore, the root canal wall is shaped only at the contact points of the cutting edges. Minimising the contact surface with the root canal dentine prevents taper lock and screw-in ef- fects in the root canal. This reduces the torsional stress,48 makes it easier to follow the complex root canal and facilitates root canal shaping.49 The unique heat treatment procedure delivers unmatched flexibility (Fig. 17). In addition to that, controlled memory makes the file bendable. Flexibility is directly associated with safety. Cyclic fatigue comparison to all competitors available showed more than 2.5-fold better values then the nearest competitor. Besides safety, another very important aspect is cen- tring ability, that is, how well a file preserves the origi- nal canal curvature. A recently published study showed that JIZAI files preserved original canal curvature signifi- cantly better than all other files and that the preparation time was significantly faster than the other file systems tested.50 All of these features are very important and demonstrate how reliable the JIZAI file is. For the practitioner, the most important points are user friendliness and simplicity. Using the JIZAI file system, the dentist will be enabled to cover nearly every canal anatomy, from very narrow and severely curved (Figs. 18a & b) to even very wide canal systems. The idea is to provide the practitioner with a very simple manual and a set of no more than three different files to cover nearly all treatment challenges. Conclusion The treatment of complex root canal systems is always challenging for every dentist. Respecting the microbial 18a 18b Figs. 18a & b: Retreatment with JIZAI files. Final preparation 24/.04 JIZAI file (a) and 35/.04 JIZAI file (b). principles of endodontics is one key to success. Despite some controversies about the right size of the access cavity, preparing straight-line access to the root canal system is another key factor. The use of a dental dam and ultrasonics facilitates the treatment procedures of every dentist. Especially in complex anatomies, the use of newly developed file systems manufactured from sophisticated heat-treated NiTi alloys which are very safe and user-friendly are other key points for success. But remember, training, patience and fun in performing endodontics can be very helpful as well! Editorial note: A list of references is available from the publisher. about Dr Ralf Schlichting is a specialist in endodontics, having completed the postgraduate programme in endodontics and dental traumatology of the Deutsche Gesellschaft für Endodontologie und zahnärztliche Traumatologie (German society for endodontics and dental traumatology). He is a member of the American Association of Endodontists and a certified member of the European Society of Endodontology. Dr Schlichting runs a private practice limited to endodontics. He is a long-time board member of the DGET and lectures worldwide. Dr Schlichting is the author of numerous peer-reviewed articles and has collaborated in several studies concerning activation and irrigation. He is involved in the development of endodontic instruments. contact Dr Ralf Schlichting Nibelungenplatz 1/2 94032 Passau Germany roots 3 2021 17

Despite the unclear initial situation, we wanted to perform safe and reliable preparation for our patient. This required an endodontic motor which minimises file stress and op- timally manages the applied torque forces by correcting the torque. The digital co-pilot was to react to obstacles in the root canal in good time and confirm that a file change at this point would definitely be advisable. Full preparation was performed with a sequence of flexible nickel–titanium files. Different file systems can be selected in the Jeni control program via the touch screen (Fig. 3). Pres- ently, the HyFlex CM, HyFlex EDM, MicroMega One Curve and MicroMega 2Shape (all COLTENE) are already pre-installed in the software. In addition, the so-called Doctor’s Choice program allows saving of individual sequences with up to eight files. When selecting the programmed sequences, the clinician can employ the fully automatic Jeni mode, in which rotational movements are fine-tuned and an acoustic signal gives a warning when resistance in the root canal becomes too great, thus making a file change advisable. After placement of a dental dam, the appropriate access cavity was prepared with an orifice opener. In addition to the composite in the canal entrance, the extreme curvature of the root canals in the apical third presented a challenge. It was all the more pleasing to observe how easily the file movement was adapted to the changing pressure exerted on the instrument. Light pressure is applied steadily from coronal to apical. This relentless pushing forwards with the contra-angle handpiece takes some getting used to at first, but makes treatment extremely efficient. Small dabbing movements after tactile feedback are no longer necessary; instead, the motor automatically adjusts the rotary movement of the file in the root canal. A 10/.05 HyFlex EDM file was followed by the next size, a 20/.05 file. The majority of the work in the mesial and distal root canals was then performed with the universal 25/~ HyFlex EDM OneFile (Fig. 4). Preparation was completed with the fol- lowing sequence: a 40/.05 file, a 50/.03 file and in the distal root canals additionally a 60/.02 file for delicate shaping. Api- cally, the last millimetres were prepared with a particularly fine- sized 20/0.05 instrument. An update function via microSD card is already planned for the endodontic motor so that alternative configuration options will certainly be possible in the future. Rinsing, please! the naturally shaped and cleanly prepared root canal profile despite the strong curvature (Fig. 5). Satisfied with the pres- ervation of his tooth, the patient could finally be discharged from our practice. Conclusion 4 5 Fig. 4: One File EDM. (Image: © COLTENE) Fig. 5: Post-op radiograph. Extremely curved root canal profiles make an- atomically natural preparation just as difficult as a restricted field of vision does when preparing the access cavity. Digital endodontic assistance systems navigate the clini- cian step by step through the mechanical and chemical preparation by adapting the variable file movements ac- cording to the situation. With the support of the navigator, the endodontic expert thus works with consistent pres- sure from coronal to apical, which makes treatment con- siderably more efficient and less prone to error—provided that, the same as a motorist, you generally take congestion messages and interval recommendations seriously. about Dr Thomas Rieger completed his dental degree at the University of Munich in Germany in 1992. Thereafter, he was an assistant dentist in private practice and then a research assistant at the University of Zurich in Switzerland. He has been in private practice in Memmingen in Germany since 1996. In 2009, Dr Rieger founded TEC2, which provides specialist endodontic training, in collaboration with the University of Pennsylvania in the US and is managing director and curriculum organiser. He has a long history of involvement in national and international training and teaching. He is author of the book Kiss, Arbeitsbuch der Endodontie and co-author of the book Endodontie Einfach Erfolgreich, a case history study of endodontically treated teeth. He is a certifi ed member of the German Association of Dental Implantology and German Board of Oral Implantology. Chemical preparation followed the classic rinsing protocol of sodium hypochlorite, EDTA and chlorhexidine, in each case at the appropriate interval. What was convenient this time, however, was that the endodontic motor recom- mends changing files with an acoustic signal and thus quite literally knows when rinsing is to be performed. Finally, the prepared and cleaned root canal was obturated with the gutta-percha-based bioactive filling material GuttaFlow bioseal (COLTENE). The final radiograph clearly showed contact Dr Thomas Rieger Zangmeisterstraße 24 87700 Memmingen Germany info@rieger-remensberger.de www.tec2-endo.de roots 3 2021 19

case report | 1 2 Fig. 1: Initial radiograph. Fig. 2: Irrigation with EDDY FLEX.CANNULA. dental microscope (ZEISS). The cleaned access cavity was refined with EndoExplorer 1–3 instruments (Komet). A total of three canal entrances could be detected and enlarged. with 5% NaOCl using the EDDY FLEX.CANNULA (Fig.2) (VDW), and the patency of the canal was checked with a pre-curved hand file. In the next step, initial scouting of the coronal root ca- nal sections was performed with C-PILOT hand files (VDW) in ISO sizes 08 and 10. In particular, the mesio- buccal canal was checked with pre-curved hand files to determine whether the curvature at the transition from the coronal to the middle root canal third could be managed. Because this was possible, this canal was enlarged and prepared up to the middle third with an R-PILOT instrument (VDW). The root canal was irrigated Using a second VDW.CONNECT Drive endodontic motor (VDW) and a R25 RECIPROC blue file (VDW), the canal was prepared in steps, alternating with the R-PILOT file initially to the apical third. Using the Root ZX mini apex locator (Morita) and a C-PILOT file ISO size 10, patency was confirmed and the working length determined. The apical canal third up to the working length was then mechanically prepared with R-PILOT and 20/.05 and 25/.04 VDW.ROTATE (Fig. 3) instruments (VDW). 3 4 Fig. 3: Size 20/.05 VDW.ROTATE. Fig. 4: R25 RECIPROC blue. roots 3 2021 21

case report | 7 8 Fig. 7: Canals prepared for root canal filling. Fig. 8: Final radiographic image. of the canal no longer being accessible to prepar- ation, and the bacterial microflora that is potentially present can lead to endodontic failures. When at- tempting to forcefully overcome ledges, blockages due to compaction of debris or, in the worst case, canal perforation may occur. Curved canals cause problems also for instruments because they always result in increased stress on the instrument, promot- ing fracture. “Root canal therapy of teeth with highly curved root canals is frequently associated with difficulties for the dentist.” As always in difficult treatment situations, proceeding in a slow and controlled manner is the key to success. Pre-curved (steel) hand files for initially opening and scouting of short canal sections and small, highly flex- ible NiTi instruments applied with absolutely no pres- sure help to avoid fundamental preparation errors. As a user of VDW instruments, switching between pre- curved C-PILOT, R-PILOT, R25 RECIPROC blue and flexible VDW.ROTATE instruments with a taper of .04 has proved successful for our office in difficult canals. The next larger instrument is used somewhat shorter than the previous. The canal is thus enlarged from the coronal to the apical third in small sections. After the larger instrument, a smaller one can then penetrate more deeply into the canal. To prevent step formation, pressure on the instruments must be avoided as much as possible. Mechanised instruments should always be kept moving. Constantly checking patency with a small steel file and frequent (sonically activated) irrigation can prevent blockage of the canal with debris. To ensure that irrigation solutions can also reach deep canal sec- tions, thin, flexible irrigation cannulas are useful. In my opinion, flexible plastic cannulas such as the EDDY FLEX.CANNULA are highly suitable. The sonic (or ultra- sonic) tips to activate the irrigation solutions should also be highly flexible. Conclusion It is critical for the success of endodontic treatments that the entire root canal system is chemically and me- chanically prepared as thoroughly as possible. Curved root canals are often a barrier to achieving this goal. Whether we were able to achieve this in the present case will be seen at the follow-up examinations. about Dr Jens Emmelmann completed his dental degree at Heidelberg University in Germany and the Medical University of Graz in Austria. He completed the postgraduate programme in endodontics and dental traumatology of the Deutsche Gesellschaft für Endodontologie und zahnärztliche Traumatologie (German society for endodontics and dental traumatology) to become a certified member of the society. Dr Emmelmann runs a dental practice specialising in endodontics and traumatology in Lieboch in Austria. roots 3 2021 23

case report | 1e 1g 1f 1h therapy or retreatment.2–4 Over the years, endodontic equipment, instruments and materials have been im- proved and better techniques have been developed. These developments have allowed greater understand- ing of the apical anatomy and increased the success rate of endodontic surgery, and consequently, it has become a more effective treatment.2, 3, 5 EMS requires a targeted osteotomy and root end resec- tion based upon anatomical landmarks and preopera- tive radiographs or CBCT measurements, and it com- bines the use of magnification and illumination provided by dental microscopes with the proper use of micro- instruments.1, 3, 5 This allows a more precise and predict- able approach with easier identification of root apices, smaller osteotomies and shallower resection angles that allow the maintenance of cortical bone and preserva- tion of root length and dental structures.3, 5 In addition, the use of dental microscopes allows the identification of anatomical details such as isthmuses, microfractures, lateral canals and fins of the resected root before root end preparation and filling. The advances in EMS along with modern diagnostic techniques, such as CBCT, used in diagnosis, pretreat- ment planning and post-treatment or follow-up evalua- tion contributed to higher success rates (85.0–96.8%) compared with more traditional approaches.3, 5 Some of the prognostic factors that may influence EMS outcomes include tooth position, lesion type, root end preparation, filling material and coronal restoration.6–8 Diffi- cult accessibility, thick buccal bone and anatomical obsta- cles (mental foramen, inferior alveolar nerve and maxillary sinus) have been related to poorer outcomes.2 The extent of periapical bone destruction and osteotomy may also contribute to postoperative complications, such as pain and swelling. When the buccal bone plate is still intact, the extent of osteotomy tends to be increased, because it is difficult to find the exact location of the root apex.2, 3, 5 1i 1j 1k roots 3 2021 25

case report | 2a 2b 2c Figs. 2a–m: Pre-op radiograph (a) and pre-op CBCT scan of tooth #15, sagital (b) and axial views (c). STL file obtained from the intra-oral scan (d). Planned template for guided endodontic microsurgery of tooth #15 (e). Printed template for guided endodontic microsurgery of tooth #15 (f). Full-thickness mucoperiosteal flap reflected (g). The template was adjusted and the limits of the cortical window were marked in the bone (h). Separated instrument out of the root near the apical area of tooth #15 (i). Removed separated instrument (j). Post-op radiograph after apicectomy, retro-preparation and retro-filling with TotalFill BC RRM Fast Set Putty (k). Sutured flap (l). Two years follow-up radiograph (m). An intra-oral scan (TRIOS) of the maxilla, and the re- sulting STL file (Fig. 2d) was combined with the DICOM files of the CBCT scan to plan a surgical guide using the Zirkonzahn.Implant-Planner software (Zirkonzahn) modified with Meshmixer (Autodesk). A template that marked the limits of a cortical window to accu- rately reach the apical area was designed and printed (Figs. 2e & f). ultra sonic tips (ACTEON) and sealed with TotalFill BC RRM Fast Set Putty (FKG) (Fig. 2k). The flap was sutured using 5/0 prolene suture material (Fig. 2l). The sutures were removed 72 hours postoperatively. After two years the patient came to our office for a follow-up radio- graph, the tooth was asymptomatic and in function (Fig. 2m). Discussion Under local anaesthesia, a full-thickness mucoperios- teal flap was reflected, providing visualisation of the buc- cal bone (Fig. 2g), and the printed template was used to mark the cortical window (Fig. 2h), which was cut with a Piezotome CUBE LED handpiece, and the separated instrument was exposed (Fig. 2i) and removed (Fig. 2j). After apicectomy, retro-preparation was done using The use of 3D-printing technology in the field of end- odontics has been described for surgical guides, guided endodontic access, autogenous transplantation, edu- cational models and clinical simulation and has become a valid treatment option in dentistry.1, 9 Even though the literature is still limited to case reports and preclinical studies, guided surgery seems to be a more accurate 2d roots 3 2021 27

case report | 2j 2k 2l 2m difficult cases, as it enables the acquisition of predictable results without the need for advanced surgical skills.9, 14 about However, this technique requires technical expertise involving a substantial learning curve for the preoper- ative preparation.1, 11 The precision of the printed ob- ject depends not only on the 3D printer but also on the CBCT and intra-oral scan images and the capacities of the designer and CAD software.1 Minimal accuracy errors can occur during the image acquisition, process- ing and manufacturing stages.19 It is necessary to prop- erly select cases for use of this technique and to design the template with care, as the presence of metallic res- torations, for example, may provoke scattering in CBCT images and consequently inaccurate superimposition with scanned models.2 In addition, guided microsurgery is preoperatively time-consuming, but it is expected that the time will be reduced once the digital workflow is established.12 The acquisition of the equipment and software for merging files and designing and 3D-printing surgical guides is also necessary,1, 11 leading to higher costs associated with this technique when compared with the traditional approach.11, 18, 19 The preservation of the cortical bone and dental structures may be considered an advantage of this technique and could justify additional planning time and cost.3 Conclusion Results suggest that guided endodontic surgery may be a promising approach, as the surgical procedure is simplified and the treatment efficiency seems to be improved. It helps to minimise the extent of osteotomy and facilitates the location of root apices in cases with intact buccal bone plate and near anatomical struc- tures. It also allows easier and rapid location of the root apex with minimal damage to soft and hard tis- sue and reduced iatrogenic injury. Nevertheless, further research and testing must be performed to validate this clinical approach. Dr Hugo Sousa Dias graduated with a DDS from University Fernando Pessoa in Oporto in Portugal and completed the postgraduate programme in endodontics at the University of Lisbon in Portugal. Besides running a practice limited to endodontics in Oporto, he is director of the master in endodontics clinical residency programme at Foramen Dental Education in Oporto. Dr Dias is the founder of the Portuguese Group for Endodontic Study (study club) and a member of the European Society of Endodontology and the Sociedade Portuguesa de Endodontologia (Portuguese endodontic society). He has given more than 20 lectures around the world and is co-author of a chapter in the book The Root Canal Anatomy in Permanent Dentition (Springer, 2018). Prof. Paula Andrea Villa Machado graduated in endodontics from CES University in Medellin in Colombia. She is co-founder of the graduate endodontic programme at Universidad de Antioquia in Medellin, where she is professor of endodontics. She is a past president of the Asociación Colombiana de Endodoncia (Colombian association of endodontics). She runs a private practice specialised in endodontics and endodontic microsurgery in Medellin. She can be contacted at paula.villa@udea.edu.co or paulavillam@gmail.com. Dr Felipe Restrepo is an associate professor at Universidad de Antioquia in Medellin, where he lectures postgraduate students in endodontics and is director of the dental emergencies diploma. Dr Restrepo has authored scientific articles in peer-reviewed journals. He can be contacted at felipe.restrepo@udea.edu.co. roots 3 2021 29

on the buccal aspect, followed by a perpendicular re- lieving incision in the distal region of tooth #24. The triangular flap was raised, and the lesion was located. The lesion was removed with curettes, and the root apex was sectioned using an ultrasonic tip (Bladesonic, Helse Ultrasonic). The root end treatment was also performed using an ultrasonic tip (E1, Helse Ultrasonic) with a depth equal to the active part of the tip. After the root end treatment, a sufficient amount of Bio-C Sealer was inserted into the cavity in order to completely fill the cavity preparation. This was achieved with a pre- viously curved irrigation needle following the angles of the ultrasonic tip (Fig. 2). With the cavity filled with this more flowable root canal sealer, a denser cement plug of Bio-C Repair was accommodated, using a surgical plugger (Fig. 3). After the complete filling of the cavity was observed, the material excess was removed by rinsing with saline solution (Fig. 4). After the clot formation, inter- rupted sutures were placed. The patient was medicated with antibiotics and anti- inflammatories for five days, and chlorhexidine mouth- washes were also recommended. The sutures were re- moved after ten days, and the radiographic follow-up was performed after 30 and 90 days (Figs. 5 & 6). Discussion Non-surgical endodontic therapy has a high success rate owing to the great advances that have occurred in all treatment steps, as well as the new materials, tech- niques and equipment available. Even so, there are still unsuccessful cases for which reintervention procedures are required.2 The first choice for unsuccessful cases is non-surgical retreatment, but there are situations in which we cannot rule out the use of surgery to comple- ment the initial treatment and/or retreatment. In this case report, we observed fast healing of the peri- apical lesion resulting from its surgical elimination as- sociated with a material that has osteogenic potential (i.e. a bioceramic-based sealer).3 However, future pe- riodic follow-ups will still be performed for long-term confirmation of the surgical success. As for the physicochemical characteristics of bioceramic- based materials, we can expect excellent properties, since they are derived from MTA, which has been exten- sively researched, and its effectiveness has been proved for cases like the one presented.4, 5 The ease of use of these cements should be emphasised. Ready-to-use materials facilitate and speed up care, reducing chair time and thereby noticeably improving service. Another advantage of ready-to-use materials is the elimination of operator error regarding such matters 4 5 6 Fig. 4: Periapical radiograph during the root end surgery, verifying the complete root end filling. Figs. 5 & 6: Periapical radiographic follow-up after 30 and 90 days, showing fast resolution of the periapical lesion and bone repair. as powder–liquid ratios, mixing time and material prepa- ration, also eliminating the possibility of incorrect use of the material. Conclusion The results of the clinical case described show that bioceramics promote excellent results and a fast healing process and offer easy handling. It was concluded that, if the results are maintained in the long term, these sealers may be the first choice for such clinical procedures. We were unable to evaluate any postoperative pain produced by these materials, because we routinely pre- scribe medications for pain control, and this obviously masks the materials’ effect in this regard. Editorial note: A list of references is available from the publisher. This article was first published in the US issue 1/20 of roots—the international magazine of endodontics. about Dr Renato Interliche, DDS, MSc, is a specialist in endodontics and in private dental practice in Ribeirão Claro in Brazil. Dr Douglas Giordani Negreiros Cortez, DDS, MSc, PhD, is a specialist in endodontics and implantology and is in private dental practice in Rolândia in Brazil. Dr Clauber Romagnoli, DDS, MSc, is a specialist in endodontics and implantology and is in private practice in Londrina in Brazil. roots 3 2021 31

clinical report | 4 5 2 3 Fig. 2: Six-month follow-up radiograph showing a thick dentinal bridge under the pulp capping. Fig. 3: Three-year follow-up radiograph showing the well-adapted restoration. Fig. 4: Video of a vital pulp therapy procedure (https://youtu.be/bfBksF35IjY). Fig. 5: Video of clinical techniques for the application of calcium silicate-based endodontic sealers (https://youtu.be/h3p1mZlNUzM). if the clinician wishes to avoid pulpectomy, vital pulp therapy might be a good choice, especially in young permanent teeth.8 Current bioceramics, mainly in putty consistency, are used for these purposes, owing to their ability to bond with dentine through the formation of a hydroxyapatite layer on the surface and their capacity to stimulate cell recruit- ment and differentiation at the level of the pulp exposure.9 Additionally, when compared with MTA, they show similar antibacterial properties against the main cariogenic bac- teria, Streptococcus mutans and lactobacilli.10 They also show good biocompatibility and can induce the formation of reparative dentinal bridges. Case 1 During an urgent appointment, a 35-year-old male patient reported sharp and short-lasting pain in tooth #15 in re- sponse to cold stimuli. The established diagnosis was reversible pulpitis and normal periapical tissue. During the removal of the old amalgam restoration, pulp exposure of approximately 3 mm in diameter was created at the level of the buccal pulp horn (Fig. 1a–g). As there was no profuse bleeding and the pulp diagnosis was reversible pulpitis, it was decided to proceed with a direct pulp capping procedure. 6a 6b 6c 6d Figs. 6a–d: Root canal therapy performed through a conservative access cavity in a tooth #37 with severe curvatures at the mesial root. The root canal obturation was performed by the hydraulic compaction technique. roots 3 2021 33

clinical report | 10 11a 11b 11c Fig. 10: Video of sonically activated placement of a calcium silicate-based endodontic sealer (https://youtu.be/CmXNk2uh6Mw). Figs. 11a–c: Radiographic sequence of the treatment performed in tooth #11. Initial radiograph. The root resorption and lateral radiolucent area were evident (a). Master cone fitting at the level of the complete working length (b). Completed root canal therapy (c). the respective teeth (Figs. 6a–7b). Both were approached minimally invasively, starting from the endodontic access cavity preparation and finishing with the post-endodontic core build-up. One of the most challenging situations when working through conservative openings is the root canal obtura- tion step. The lack of straight line access, compromised visibility and a reduced opening to properly clean the 12a 12b 12c Fig. 12: Radiographic sequence of the treatment performed in tooth #11. Initial radiograph. The root resorption and lateral radiolucent area were evident (a). Completed root canal therapy (b). Three-year follow-up radiograph showing complete healing of the lateral radicular radiolucent area and the correct sealing of the resorption (c). roots 3 2021 35

clinical report | 18a 18b 18c 19 Figs. 18a–c: Post-op suturing sequence. Immediate post-op suturing (a). Five-day follow-up clinical image, just before the suture removal (b). Clinical image immediately post-suture removal, showing good healing of the area (c). Fig. 19: Four-month follow-up radiograph showing the process of healing in both treated areas, the periapical surgery of tooth #11 and bone grafting at the extraction site of tooth #21. tooth #11 (Fig. 13). The established diagnosis for tooth #21 was previously treated and acute periapical abscess; cemental tears at mesial and distal root surfaces were de- tected, as well as a root fracture. The established diagno- sis for tooth #11 was previously treated and symptomatic periapical periodontitis. Tooth #21 was extracted, and a bone grafting material (DM Bone, Meta Biomed) was placed in the area to prepare the site for receiving an implant in the future (Fig. 14). Four weeks after the extraction, periapical surgery was performed on tooth #11, and the minimum amount of root was resected in order to avoid compromising the crown–root ratio. The retrocavity was prepared using ultrasonic tips (Fig. 15), and CeraPutty was used to retro-obturate the root (Figs. 16 & 17). The sutures were removed five days after surgery (Figs. 18a–c). The four-month follow-up radiograph showed the process of healing in both treated areas (Fig. 19). Conclusion Nowadays in the field of endodontics, it is important to have a sealer material that fulfils almost all of the ideal prop- erties described by Grossman, that is supported by evi- dence-based literature20 and that is easy to manipulate by practitioners who give pre-eminence to saving the natural dentition. Saving the natural teeth has great human and professional value, especially in the era of dental implants, where misdiagnosis might prematurely condemn the pa- tient to losing the natural dentition. During the daily jour- ney of endodontists, giving the best of themselves to pre- serving the natural dental organs, calcium silicate-based endodontic materials are an excellent ally because of their capacity to promote both healing and tissue mineralisa- tion, their excellent biocompatibility, their remarkable seal- ing properties, their hydrophilicity and their comfortable handling, among other properties. Access to good materials and equipment, combined with the skills of experienced dental practitioners, is essential to ensure successful results during the journey of saving natural teeth. Editorial note: A list of references is available from the publisher. contact Dr Jenner Argueta earned his degree in dentistry and master’s degree in endodontics from the Universidad de San Carlos de Guatemala, where he achieved multiple awards as an outstanding student. He is a certifi ed researcher at the Guatemalan national council for science and technology and teaches endodontics at the Universidad Mariano Gálvez de Guatemala. Dr Argueta also runs a clinical practice focused on micro-endodontics and micro-restorative dentistry. He was president of the Academia de Endodoncia de Guatemala (endodontic academy of Guatemala) from 2016 to 2020 and is the Guatemalan representative for the Latin American Endodontic Association. Dr Argueta can be contacted at jennerargueta@gmail.com. Dr Benjamín Rodríguez earned his degree in dentistry from the Universidad Francisco Marroquín in Guatemala and his MSc in endodontics from the Universidad de San Carlos de Guatemala. In 2019, after six years of clinical practice limited to endodontics, he earned a postgraduate degree in oral and maxillofacial radiology from the Universitat Internacional de Cataluña in Barcelona in Spain. roots 3 2021 37

conditions and socioeconomic background—to predict tooth loss in adults and to compare the performances of the different tools. To develop the screening tools, the research team used data from nearly 12,000 adults from the National Health and Nutrition Examination Survey. Socioeconomic characteristics decisive Comparing the performances of the different algorithms, the researchers found that those models which incor- porated socioeconomic characteristics, such as race and education, were better at predicting tooth loss than those models relying on traditional dental clinical indi- cators alone. “Our analysis showed that while all machine-learning models can be useful predictors of risk, those that in- corporate socioeconomic variables can be especially powerful screening tools to identify those at heightened risk for tooth loss,” said lead author Dr Hawazin Elani, assistant professor of oral health policy and epidemiology at HSDM, in a university press release. predicting tooth loss as assessing their clinical dental status,” she added. In addition to the socioeconomic background of patients, the research team also determined preexisting medical conditions as predictors of tooth loss. “We found that medical conditions—such as arthritis, diabetes, high cholesterol, hypertension and cardiovascular diseases— are among the predictors of tooth loss. Clinicians could use this information to screen patients at high risk for tooth loss and coordinate their referral and dental care,” they stated. Developed tool may be used by different health care providers The screening tool was designed to be applied world- wide and in a variety of health care settings, even by nondental professionals, as it assesses the risk for tooth loss without the need for a dental examination. However, any patient deemed at high risk for losing a tooth would still have to undergo an actual examination. “This work highlights the importance of social determi- nants of health. Knowing the patient’s education level, employment status, and income is just as relevant for The study, titled “Predictors of tooth loss: A machine learning approach”, was published online on 18 June 2021, in PLOS ONE. news | AD REGISTER FOR FREE DT Study Club – e-learning platform Dentistry's largest online education community webinars / live operations / online CE events / CE credits www.dtstudyclub.com @DTStudyClub Tribune Group is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry.This continuing education activity has been planned and implemented in accordance with the standards of the ADA Continuing Education Recognition Program (ADA CERP) through joint efforts between Tribune Group and Dental Tribune Int. GmbH.

news | papers were experimental in nature and not all were peer-reviewed, owing to the abundance of scientific research that is currently being conducted and the urgency of publishing it. The SDCEP review found that air cleaners were not recommended to reduce the risk of SARS-CoV-2 transmission, owing to a lack of “higher certainty evidence” on their efficacy as a mitigating tool. One of the studies that the SDCEP review analysed had been published by UK researchers in November 2020 under the title “A clinical study measuring dental aero- sols with and without a high-volume extraction device” in the British Dental Journal. The researchers measured and compared particle count during AGPs that were conducted with and without the use of high-volume extraction. They wrote: “Without the use of an external high- volume extraction device during aerosol generating pro- cedures, there is a significant increase of PM2.5- and PM10-sized particle count from the use of micromotor high-speed, air turbine high-speed, slow-speed and ultrasonic handpieces.” Extra-oral scavenging found to reduce particle count The SDCEP review also cited a study, titled “Fallow time determination in dentistry using aerosol measurement”, by researchers from the UK which was published on the preprint server medRxiV in January. The study examined the calculation of fallow time after AGPs in care facilities that were mechanically ventilated and non-mechanically ventilated, and whether extra-oral scavenging (EOS) could reduce aerosol production and fallow time. They found that AGPs carried out in mechanically ventilated treat- ment rooms produced a low particle count, which returned to baseline within a period of 10 minutes after AGPs. EOS was found to have a greater effect in non-mechanically ventilated environments, and to reduce the spike in particle counts in mechanically ventilated rooms. The authors wrote: “AGPs should not be carried out in surgeries where ventilation is not possible. Mechanical ventilation for AGPs should be gold standard; where not available or practical then the use of natural ventilation with EOS helps reduce FT.” particle count, which was further reduced through the use of an EOS device. “The additional use of an EOS device should be care- fully considered when performing treatments, such as high-speed tooth preparation, that generate particularly small particles when more people are present and all other protective options have been exhausted,” the authors wrote. The study, titled “The efficacy of an extraoral scaveng- ing device on reducing aerosol particles ≤ 5 µm during dental aerosol-generating procedures: An exploratory pilot study in a university setting”, was published in BDJ Open in May 2021. High-volume aspiration found to be viable mitigation strategy A study by researchers in Leeds in the UK aimed to evaluate risk mitigation strategies during AGPs by mea- suring viral air concentrations during crown prepara- tion and root canal access procedures. The procedures were carried out using an air turbine or high-speed contra-angle handpiece (HSCAH) with the mitigation strategies rubber dam or high-speed aspiration or with no mitigation strategy. The researchers wrote: “Compared to an air turbine, the HSCAH reduced settled bioaerosols by 99.72%, 100.00%, and 100.00% for no mitigation, aspiration, and rubber dam, respectively. Bacteriophage concen- trations in the air were reduced by 99.98%, 100.00%, and 100.00% with the same mitigations. Use of the HSCAH with high-volume aspiration resulted in no detectable bacteriophage, both on non-splatter set- tle plates and in air samples taken 6 to 10 minutes post-procedure.” The researchers concluded that the use of HSCAH together with high-volume aspiration or a rubber dam meant that a prolonged fallow period could be avoided. “Equipping our dental surgeries with these tools will be crucial to protecting the health, safety, and future of dental teams and services,” they wrote. The study, titled “Dental mitigation strategies to reduce aerosolization of SARS-CoV-2”, was published in the Journal of Dental Research in August. In May, researchers in Germany studied small particle concentration caused by AGPs during dental student training under high-flow suction both with and without the use of a mobile EOS device. Lower particle count was detected after high-speed tooth preparation when an EOS device was used. The researchers found that high-flow suction was effective in reducing the small The results of a number of studies suggest that air purifiers do help to reduce the risk of SARS-CoV-2 transmission in dental settings; however, as the SDCEP review found, the subject requires further study, meaning that owner-dentists may have to personally appraise the literature before a general consensus can be reached. roots 3 2021 41

surance; others choose to spend their reduced budgets on family necessities. It is important to identify these patients, educate them on the long-term economic and health ben- efits of preventive care, be empathetic, triage treatment needs and offer financial arrangements, when appropriate, so that they can continue with their oral care. Elevated communication Patient engagement can go a long way. As practices are experiencing challenges navigating the pandemic proto- cols and restrictions, it has become clear that patient com- munication is more important than ever, both prior to and between maintenance visits. It adds value to the patient experience and strengthens patients’ relationship with the dental care team. Many patients are still avoiding regular dental visits owing to COVID-19 concerns. It is critical to educate these patients about the consequences of neglecting oral care, explaining the importance of maintenance visits and how these visits allow early detection of dental or periodontal disease. Whether it is by e-mail, text message or phone call, inform- ing patients about the safety measures put in place, as- suring them that it is safe to visit the dentist and facilitating their navigation through pandemic protocols will encour- age them to attend their appointments. Patient outreach before visits can be the first step in the patient communication journey, and continuing that con- nection between visits reinforces patients’ trust in a way that goes beyond their time in the chair. This is an import- ant contributor to the success and survival of the dental practice. Extending appointments can help reduce team stress while allowing for increased time for patient educa- tion and, most importantly, an opportunity to address fears and answer questions. Presenting the science and emphasising home care Oral self-care has never been more important. All patients, regardless of their unique needs, look to us as dental pro- fessionals to guide them in achieving their oral fitness goals, be it primary prevention or reversing the effects of periodontal disease. One way we can help our patients is by offering them clear, easy and effective solutions, which includes placing evidence- based tools at their fingertips. For example, we know that electric tooth-brushes with sonic and oscillating–rotating technologies are significantly more efficient in reversing gin- givitis and removing plaque5 than are manual toothbrushes.6 Stannous fluoride (vs sodium fluoride) dentifrices, such as Crest Gum toothpastes, are additional examples of oral care aids with a well-established effectiveness profile in biofilm management and improvement of gingivitis.7, 8 Es- pecially now, with the post-pandemic reduction in ultra- sonic procedures, patients can be reminded that the tooth- paste they use matters when it comes to achieving opti- mum oral health. This is particularly true in endodontically treated cases, especially if the treatment is followed by prostheses or subgingival direct restorations. There are also programmes that offer affordable and sci- ence-backed solutions designed for oral self-care at home, reminding us that helping patients become healthy starts in our clinics, but continues at home. Online communica- tion tools are available to help improve our reach, consid- ering that most Canadian patients are between the ages of 25 and 59 and that over half of all patients prefer digital communication to phone calls.9 Helping patients feel their best Patients are always keen to improve their appearance to enhance their mental well-being, but we can only start talking about aesthetics when we are out of the woods with proper oral fitness. The pandemic has triggered an increased awareness of and interest in home self-care, and the upward trend of demand for effective, easy-to-use, versatile solutions is here to stay. Patients rely on us to educate them about the best products available to maintain their oral health and physical well-being. Editorial note: A list of references is available from the publisher. This article originally appeared in Oral Health Magazine (May 2021), and an edited version is provided here with permission from Newcom Media. contact Dr Gary Glassman is the author of numerous publications and lectures globally on endodontics and is on the staff at the University of Toronto’s Faculty of Dentistry in Canada in the graduate department of endodontics. As adjunct professor of dentistry and director of endodontic programming from 2010 to 2017, Dr Glassman helped develop the dental school curriculum for the oral health science programme for the University of Technology in Kingston in Jamaica. He is faculty chair for DC Institute and chief dental offi cer for dentalcorp in Canada, as well as endodontic editor of the Oral Health Magazine and Inside Dentistry. Dr Glassman is a fellow of the Royal College of Dentists of Canada and the American College of Dentists. His personal website is www.drgaryglassman.com, and his offi ce website is www.rootcanals.ca. He can be reached at gary@rootcanals.ca. roots 3 2021 43

practice management | Slow down everyone—dentistry does not need to be done at speed Part 3: “Slow Dentistry has resonated around the world and is growing exponentially” An interview with Dr Miguel Stanley, an ambassador for and the co-founder of Slow Dentistry By Iveta Ramonaite, Dental Tribune International Since 2010, Slow Dentistry has been encouraging dental professionals to manage their time at the clinic better and to practise ethical and quality care. Now, more than a decade later, the movement has achieved substantial growth and continues to gain strength de- spite the recent challenges of the COVID-19 pandemic. In this interview with Dental Tribune International, Dr Miguel Stanley, an ambassador for and the co- founder of Slow Dentistry, talks about some of the movement’s proudest achievements so far and about Slow Dentistry’s vision for the future. An increasing number of dental professionals are joining and advocating for the Slow Dentistry move- ment. What do you consider to be some of your proudest achievements so far? Just the fact that so many great dentists, hygienists and other dental professionals around the world have joined the Slow Dentistry global network, helping us spread the message of ethically driven treatment plan- ning and patient preparation, is a great achievement in itself. Slow Dentistry makes so much sense to peo- ple once they learn more about it. It is very straightfor- ward and requires no investment, no advanced tech- nology and no special training—just a desire to do the right thing for your team and your patients. That is why Slow Dentistry has resonated around the world and is growing exponentially day after day, and I’m very im- pressed with the fact that this growth is mostly organic and not driven by excessive marketing but rather by dentists’ motivation to separate themselves from those clinicians who are focused mostly on volume and profit over quality care. Another major achievement that happened in the last year thanks to the tireless efforts of our president, Nina Blaettler, was the transformation of Slow Dentistry from a limited liability company to a Swiss non-profit foun- dation. The foundation is called the FED, which stands for Foundation for Excellence in Dentistry, and this now Dr Miguel Stanley has been an ardent supporter of Slow Dentistry for over a decade now and is optimistic about its future. (All images: © Slow Dentistry) means that every single dental professional who signs up to our global network is actually contributing to a cause and not to a private company. Swiss non-profit foundations are highly regulated and their constant monitoring is required to ensure that the funds are used for the greater good. The entire objec- tive of the Slow Dentistry global network is to disrupt what we believe is a bad trend in dentistry, one where clinics are created solely for generating profit. There are so many loving and caring dental professionals around the world who needed a way to differentiate themselves from profit-seeking clinicians. Our network is expand- ing, and we’ve received numerous contributions from existing and new members, as well as donations from companies within the dental universe. We are gaining greater means to invest in educating the general pub- lic, helping them understand that they have basic rights when visiting a dentist. roots 3 2021 45

practice management | We are also working closely with companies and helping their marketing departments understand the value of do- nating to our global network, since by supporting us they are indirectly promoting ethical dentistry, which I truly be- lieve should the core value of every company. We want to support companies by supporting quality dentistry. You simply can’t practise quality dentistry in a rush. Everybody wins by practising Slow Dentistry. We’re also going to be coming out with some new badges that can be acquired by dental professionals who are al- ready members of the Slow Dentistry global network. These include the digital dentistry badge, the small busi- ness owner badge and the educator badge. Staying true to our message, these new areas will help identify prac- titioners who go the extra mile and make the extra invest- ments both in money and in time to better serve their pa- tients and their communities. For example, a dentist who uses surgical guides to place dental implants spends a lot of time planning the treatment and coordinating and designing cases just so that patients can have a more accurate and precise intervention, and that might actually end up requir- ing less chair time. These guys deserve recognition. This is almost counter-intuitive if you think about it. Slow Dentistry doesn’t mean more time in the chair or work- ing slowly; Slow Dentistry is about time invested to deliver quality care. So we believe that dentists who use digital technologies to mitigate failure and improve workflows deserve to be rewarded or at least recognised for the time spent investing, training and preparing these workflows to better treat their patients. The small business owner badge will identify clinicians who fulfil the following criteria: they only work in one clinic, own more than 50% of that clinic and are the clinical director of the practice. Why is this important? When you have all of your eggs in one basket, you tend to protect the basket a lot more. Through discussions with colleagues around the globe, we have found anecdotal evidence that, when these factors are in play, there is a lot more heart in the game and people care a lot more. Obviously, this doesn’t make you a better dentist, and there is nothing wrong with having many clinics, but some- times patients might want a dentist who is simply a dentist and not also a businessman, and they need a way to distinguish. Have you noticed any post-pandemic trends in den- tistry related to the movement? One thing we have noticed is that some copycat organisa- tions and academies are trying to imitate what we are doing, but are seeking to profit financially from this. We would hope that people understand that, as a non-profit foundation, the objective of our movement is not to make personal profit, as all of our team members are volunteers and so are our hon- orary global ambassadors around the globe. We don’t sell weekend courses, no one is trying to gain personally from this and we are focused on getting our message to as many people in the world as possible, in as many languages as possible. Everyone in our network is inclusive and positive and wants the best for dentistry and for patients. I think that millennial dentists have a different mindset in terms of their relationship with their patients and a work–life balance. I think that mental health has become a big issue, and there are a lot of great dentists that are publicly talking about this im- portant topic. Two of our global ambassadors, Drs Kyle Stanley and Simon Chard, use their platforms to promote mental health in dentistry. At the end of the day, there is a common thread to all of these discussions, and that is to do the right thing. Allowing younger dentists more time to get things right is im- perative in moving forward. Big-chain dental clinics or dental service organisations need to make sure that their younger dentists have all the time they need to work stress-free and to get things right the first time around. If we don’t facilitate this, we will soon be seeing a mental health pandemic in our profession, not to mention poor-quality dentistry. The truth is that the Slow Dentistry global network should not be necessary. Every dentist around the world should be practising it, but they’re not, and that is why it’s important that people understand our core values. We are not selling anything, no courses are needed to understand it and no- body is profiting from anything here; it’s truly a humanitar- ian effort on a global scale, and we are all in this together. What is next for Slow Dentistry, and what is the ulti- mate goal? One of the major decisions from Nina this year was that we would move slowly into the future. We don’t want to deviate from our core values and mission. We would like to grow our network to be in every single country around the world, supporting those dentists with marketing at a grass-roots level, ensuring that populations around the world understand that they have the right to a disinfected treatment room, a signed, valid consent form, pain-free dental treatment and a dental dam for all of their root ca- nal therapy and most of their restorative work. If we get this message across, we will have already made a deep impact. We are going to stay very true to our mission. Practising Slow Dentistry involves using the appropriate tools and developing the right mindset.

interview | flected in my collection. I have a lot of work that talks about the legacy of slavery and the movement of peo- ple, not just from Africa to the New World, but also later migrations of people from the Caribbean to England, the US and Canada. Stories that reflect these movements of people have been an important aspect of my collection. How did you start collecting art? In the early 2000s, I had just opened my dental office, and I was literally wedging artists into the mainstream by showing their work in a very intimate and personal space in my loft. It was around this time that Thelma Golden, a friend of mine and the director of the Studio Museum in Harlem, said to me: “Hey, you are doing these an- nual exhibitions in your home and bringing all of these international artists to Canada.” She asked: “Why don’t you start telling your own stories—instead of bringing the global local, why don’t you take the local and make it global?” This was something that I think I had been wait- ing to hear because I had been collecting Black Cana- dian artists, and this was an opportunity to start showing those artists and their work. At the same time, I started retaining one or two art works from every show that we did, as a kind of personal project. It was a very organic process, and I slowly became a collector. And this was happening while you practiced den- tistry? It was happening in the background, all the while. The collection was growing in terms of its prominence in my life, and it began taking up more hours in each week. It has been a process lasting more than 25 years. At the same time, though, my main job has been working as a dentist. Your dental practice is well-known in Toronto. Could you tell us about it? I started the practice in 1992 after graduating in 1987. During the first five years after graduation, I worked as an associate in a dental office where it wasn’t so much about the patients—it was more about the procedures; and so I learned how to do everything very efficiently, but I also learned what I did not want to do at my own practice, which was to rush through everything and be burned out at the end of the day. Instead, at my clinic, the idea from the start was to treat people, not do pro- cedures, and to utilise music and art almost as therapy in the office. Could you tell us more about the musical element? We were one of the first practices in Ontario that wasn’t playing elevator music in the background. We played music that would make me happy as the dentist—the kind of music that I would want to hear if I went to a den- tal office—and this was unusual in downtown Toronto at that time. I would play 1970s dub reggae music or, Jamel Shabazz, Untitled (Four Boys in Red, Posing), c. 1980–89. (Image: © Jamel Shabazz 2021) “For me, it is about showing the joy and the beauty of ordinary life.” depending on who was sitting in the chair, it might have been alternative rock or something from a jazz artist like John Coltrane or Miles Davis. So, it became this very eclectic kind of environment, and I think that the pa- tients also quickly learned to appreciate the art works on display. To this day, there is still a lot of anticipation when they come in, because I change the art in the waiting room and in the operatories regularly. Patients get to see an aspect of the dentist that they appreciate, and they get to see some of the art, which has evolved as my taste has broadened. roots 3 2021 49

interview | How has your immediate local community informed your work in dentistry and the arts? A very big part of my collector’s mind is focused on the local. And the whole thing actually started when I was in dental school. There were local artists and art shows that were affiliated with the two downtown Toronto art schools at the time. I was friendly with art students, and I even did some foundation classes—often running from dental school to make it to a six o’clock drawing class— because I loved art so much. I became intimately in- volved with the local arts community from the very start, and it was not such a stretch for those artists to end up coming to my dental clinic. But I would say that the influence has also been a spiritual one, because I feel very connected to the local community in a lot of ways—not just through the arts. I feel like my mission has been to take the var- ious stories around me, and to distil them and bring them together through the collection. In this way, the collection has been a vehicle, and it has enabled me to reflect my environment and my background. It has been a journey of my fascination with art outside of my world, and then my recognition that we have our own stories to tell right here in Canada and, locally, in Toronto. Could you tell us about one of your recent acquisi- tions and how it fits into the collection? Last year, I bought a new work from Sandra Brewster. Sandra was born in Canada to immigrant parents from the Caribbean, like myself; and so, the family has a similarly interesting and complicated history. I really see eye to eye with an artist like her, and when I look at the work, I find it echoes my own family history. I bought a beautiful work of hers about a decade ago, but her practice has really crystallised in the past five years. In her Blur series, her subjects are kind of caught in motion, but she uses a process to create the blur without having the subjects move. This very unique way of depicting a subject really appeals to me, and the movement that is inherent in the work echoes the movement of the subjects themselves in terms of their history and the movements and migrations of people and also in terms of their being seen within society. Many aspects of that work resonate with me and reflect where I am as a collector, and my own place in Canadian society. Art holds a mirror up to society. What would you say that your collection says about us and the times in which we are living? That is a challenging question. My collection has always been about the notion of uplift. The forthcoming book about the collection is going to be called As We Rise. My late father always said that we must “lift as we rise”— if you are doing well, you pull the other people up along Sandra Brewster, Blur 14 (2), 2016/17. (Image: © Sandra Brewster 2021) with you. As an assemblage of images of Black sub- jects, my collection has never been about works con- cerning oppression or poverty, or anything else that I think is negative in the depiction of Black communities. For me, it is about showing the joy and the beauty of ordinary life. Of course, there are moments when you just have to make a statement. For example, another recent acqui- sition is a work by a local artist named Jalani Morgan. It is a photograph taken at the first meeting of Black Lives Matter Toronto, which was a new chapter that “The choice has always been clear: the patients must come fi rst.” came together quite spontaneously a few years ago in response to the police killing of Eric Garner. There has, of course, been a whole new reckoning in the last year as a result of the murder of George Floyd, and now, Morgan’s image has a new resonance in that people are having important conversations and thinking more roots 3 2021 51

is coming to PRAGUE 26–29 May 2022 Prague, Czech Republic www.ROOTS-SUMMIT.com Tribune Group GmbH is an ADA CERP Recognized Provider. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry. Tribune Group GmbH designates this activity for 18.5 continuing education credits. This continuing education activity has been planned and implemented in accordance with the standards of the ADA Continuing Education Recognition Program (ADA CERP) through joint efforts between Tribune Group GmbH and Dental Tribune International GmbH.

manufacturer news | High-speed cordless endodontic motor FKG Dentaire expands its endodontic motor range with the new Rooter X3000 FKG Dentaire presents the Rooter X3000, redefining endodontic standards. This novel cordless endodontic motor combines technology, functionality and adaptability in a 20 cm unit. It stands out for the fastest speed on the market (3,000 rpm), ten programmable memories and preset programs for different types of FKG files. Its ergonomic design, light weight and 360° rotatable extra-slim contra-angle head ensure perfect handling and visibility. Every new FKG product responds to the most exacting needs of endodontists with leading-edge technology and uncompromising quality. The Rooter X3000 advances endodontics with a new cord- less, brushless endodontic motor with integrated apex locator. Adaptability as technical keyword Benchmark speed coupled with guaranteed stability and preci- sion are only the tip of the iceberg of Rooter X3000’s features. Adaptability reflects its core, starting with the four FKG presets: XP-endo Treatment, XP-endo Retreatment, RACE EVO and R-Motion. This saves time for endodontists, who can rely on the manufac- turer’s predefined recommendations for each file type. The end- odontic motor also provides ten user-programmable memories for all modes (EAL, CW, CCW, REC or ATR), more than 60 speeds and—of course—a high-precision built-in apex locator and a range of automatic apical functions. Agility as practical credo As with any device, practice validates innovation. With its ergo- nomic handpiece weighing only 157 g, perfect balance and fully rotatable ultra-slim contra-angle head, the Rooter X3000 en- sures a comfortable grip, agile handling and excellent visibility of the operating field. FKG has designed and developed all details to provide maximum freedom of use to the practitioner, opti- mising both speed and efficiency. Features include complete adaptability of the device and its display for both left- and right-handed users, a broad range of user-controlled settings, extensive file brand compatibility, wireless charging stand, and volume control. www.fkg.ch Editorial note: Rooter, XP-endo, RACE EVO and R-Motion are registered trademarks of FKG company. roots 3 2021 55

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