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ePaper created 2017-04-26, 11:33:32 | version 1.38.0
C.E. article_ instrumentation and obturation I canal systems are best prepared in the following sequence: •Analysisofthespecificanatomyofthecase. •Canalscouting. •Coronalmodifications. •Negotiationtopatency. •Determinationofworkinglength. •Glidepathpreparation. •Rootcanalshapingtodesiredsize. •Gaugingtheforamen,apicaladjustment. _Obturation of the endodontic space A well-shaped and cleaned canal system should create the conditions for intact periapical tissues. On the other hand, this root canal system is inaccessible to the body’s immune system and therefore it cannot combat coronal leakage. Accordingly, best practices dictate that root canals should be filled as completely as possible to prevent ingress of nutrients or oral mi- croorganism. None of the established techniques for root canal filling provides a definitive coronal, lateral and apical seal.24 _Basic strategies in root canal obturation Ideally, root canal fillings should seal all foramina leading to the periodontium, 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. •Sealerandasingleconeofastifforflexiblecore material. •Sealercoatingcombinedwithcoldcompaction of core materials. •Sealercoatingcombinedwithwarmcompac- tion of core materials. • Sealer coating combined with carrier-based core materials. Several of these techniques have shown com- parable success rates regarding apical bone fill or healing of periradicular lesions, so a clinician may choose from a variety of techniques and approaches that works best for him or her. Existing research directs clinicians toward preparation and disinfec- tion of the root canal as the single most important factor in the treatment of endodontic pathosis, and no particular sealing technique can claim superior healing success.25 _Current developments in root canal obturation materials After the introduction of MTA (mineral trioxide aggregate) as a material for perforation repair and Fig. 3 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 light- curing glass ionomer. Case courtesy of Dr. Paymon Bahrami. apical 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 radio- pacity and flow.26 Moreover, it is well-tolerated in cell culture experiments.27 However, there is no clinical evidence that using this cement leads to better out- comes. In fact, most research has indicated the type of cement used has comparatively little impact.28 In contemporary practice, heat generators are used to plasticize gutta-percha. Additionally, cord- less heating devices are available. Another recent addition is a carrier-based material, Guttacore® (Dentsply Sirona), which uses modified gutta-percha materials instead of plastic as its base. Early data indi- cate that obturation with this new material is similar to warm vertical compaction or lateral compaction.29 _Practical aspects of obturation The main steps in the sequence of root canal obturation are: •Choosingatechniqueandtimingtheobturation. •Selectingmastercones. •Canaldrying,sealerapplication. roots 1_ 2017 I 09