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Dental Tribune Middle East & Africa Edition | 2/2018 mCME ◊Page 12 Fig. 4: Root canal treatment of tooth #15 with four canals, diagnosed with irreversible pulpitis and acute apical periodontitis. The tooth was restored with a crown immedi- ately after finalizing the root canal treatment. Case courtesy of Dr Reza Hamid. extraction vary but in many cases teeth are either fractured or non-re- storable for other reasons.20,21 In consequence, a smaller coronal dimension of rotaries is consid- ered while maintaining apical sizes to support antimicrobial efficacy. There currently is no direct clini- cal evidence to support this strat- egy but it is clear that root fractures pose problems in the long-term outcomes of our patients. Another recent development is the emer- gence of certain specialized rotaries, such as dedicated orifice shapers and so-called glide path files. The orifice shapers have larger tapers, such as .08, which means that they are not flexible and can overprepare at the canal orifice level. Glide path files, for example PathFiles® and ProGlider® (Dentsply Sirona), are delicate instru- ments and may fracture when used incorrectly. It is recommended to use a small K-file (size #10) before any rotary instrumentation and to use a delicate touch. Clinical results While results from in vitro studies on rotary systems are abundant, clinical studies on these instruments are sparse. Comparing NiTi and stain- less steel K-files, Pettiette et al.7 found less canal transportation and fewer gross preparation errors such as strip perforations. Subsequently, using radiographic evaluation of the same patient group, they demonstrated better healing in the NiTi group.22 An earlier outcome study with three rotary preparation paradigms did not show any difference between the three systems with an overall favorable outcome rate of about 87 percent.23 The most consistent clinical results are obtained when the manufactur- er’s directions are followed. While these vary by instrument, a set of common rules applies to root ca- nal preparation. Root canal systems are best prepared in the following sequence: • Analysis of the specific anatomy of the case. • Canal scouting. • Coronal modifications. • Negotiation to patency. • Determination of working length. • Glide path preparation. • Root canal shaping to desired size. • Gauging the foramen, apical ad- justment. Obturation of the endodontic space A well-shaped and cleaned canal sys- tem should create the conditions for intact periapical tissues. On the other hand, this root canal system is inac- cessible to the body’s immune sys- Fig. 3: Root canal treatment of tooth #19 with four canals diagnosed with irreversible pulpitis and acute apical periodontitis. A second canal in the distal root of a mandibular molar is not infrequent. Note multiple apical foramina in both the mesial and the distal apices. Prior to temporization, the orifices were protected with a barrier of lightcuring glass ionomer. Case courtesy of Dr Paymon Bahrami. ever, such lubricants have not been shown to be beneficial and actually did increase torque for radial-landed ProFile® instruments.17 Therefore, it is recommended to flood the canal system with sodium hypochlorite (NaOCl) during the use of rotaries. The best way to do this is to create an access cavity that can act as a reser- voir (Fig. 3). There are several concerns about reusing NiTi instruments. The effec- tiveness of disinfection procedures is not clear. It has been shown that protein particles cannot completely be removed from machined nickel- titanium surfaces.18 Moreover, it is clear that with additional usage, the chance for instrument fracture in- creases. Current recommendations advise that clinicians are judicious when reusing rotary instruments as there is no conclusive evidence of disease transmission occurring. Recently, the term minimally inva- sive endodontics has been used to describe smaller-than-usual apical sizes and, perhaps more important- ly, an understanding that the long- term success of root canal-treated teeth will improve by retaining as much dentin structure as feasible.3 The thought process for this was the finding that most root-canal treated teeth survive 10 years and longer.19 In studies, the reasons cited for the mCME SELF INSTRUCTION PROGRAM CAPPmea together with Dental Tribune provides the opportunity with its mCME - Self Instruction Program a quick and simple way to meet your continuing education needs. mCME offers you the flexibility to work at your own pace through the material from any location at any time. The content is international, drawn from the upper echelon of dental medicine, but also presents a regional outlook in terms of perspective and subject matter. Membership Yearly membership subscription for mCME: 1,100 AED One Time article newspaper subscription: 250 AED per issue. After the payment, you will receive your membership number and allowing you to start the program. 13 tem and therefore it cannot combat coronal leakage. Accordingly, best practices dictate that root canals should be filled as completely as pos- sible to prevent ingress of nutrients or oral microorganism. None of the established techniques for root canal filling provides a definitive coronal, lateral and apical seal.24 Basic strategies in root canal obtura- tion Ideally, root canal fillings should seal all foramina leading to the peri- odontium, be without voids, adapt to the instrumented canal walls and end at working length. There are various acceptable materials and techniques to obturate root canal systems, including: • Sealer (cement/paste/resin) only. • Sealer and a single cone of a stiff or flexible core material. • Sealer coating combined with cold compaction of core materials. • Sealer coating combined with warm compaction of core materials. • Sealer coating combined with carri- er-based core materials. Several of these techniques have shown comparable success rates re- garding apical bone fill or healing of periradicular lesions, so a clinician may choose from a variety of tech- niques and approaches that works best for him or her. Existing research directs clinicians toward preparation and disinfection of the root canal as the single most important factor in the treatment of endodontic patho- sis, and no particular sealing tech- nique can claim superior healing success.25 Current developments in root canal obturation materials After the introduction of MTA (min- eral trioxide aggregate) as a mate- rial for perforation repair and api- cal surgery more than two decades ago, materials with similar bioactive properties now are available as root canal sealers. Bioceramic root canal cement (BC Sealer™, Brasseler) has clinically acceptable radiopacity and flow.26 Moreover, it is well-tolerated in cell culture experiments.27 How- ever, there is no clinical evidence that using this cement leads to better outcomes. In fact, most research has ÿPage 14 Completion of mCME • • • • • • • • mCME participants are required to read the continuing medical education (CME) articles published in each issue. 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