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I C.E. article_ microscopes Fig. 5a Fig. 5b Fig. 5c Fig. 5d and illumination.16,17 The effectiveness of vision en- hancement for the detection of second mesio-buccal canals (MB2) in maxillary molars was assessed both in vitro and in vivo. The detection rate of MB2 canals in vitro was shown to be 90 percent with the operat- ing microscope and 52 percent without aided vision. Gorduysus et al.18 demonstrated that the percentage of MB2 canal negotiation increased with the aid of higher magnification. Burley et al.19 described the successful identifica- tion of MB2s in 312 maxillary first and second molars in 57.4 percent of the cases when using the operating microscope, 55.3 percent with dental loupes and 18.2 percent with unaided vision. In first maxillary molars, the incidences of MB2 identification were 71.1 per- cent, 62.5 percent and 17.2 percent for the micro- scope, dental loupes and no magnification groups, respectively. Stropko20 treated a total 1,732 maxil- lary molars working at times with unaided vision and at times with a dental microscope. With more experience and a dental microscope, the incidence of locating MB2 canals increased from 73.2 percent to 93.0 percent in first molars and from 50.7 percent to 60.4 percent in second molars. Microscope use also increased the number of root ca- nal orifices located in mandibular mo- lars,21 and signifi- cantly increased the quality of access cavity preparation and the accuracy of canal identifica- tion when treat- Fig. 5a_Separated instrument in second mesio-buccal canal of left maxillary first molar (arrow). Situation after uncovering of fragment with ultrasonic tips and debris removal. Fig. 5b_Pre-operative radiograph. Fractured instrument in mesial root of lower left first molar. Patient was referred for fragment removal and continuation of treatment. Fig. 5c_Access to instrument fragment (arrows) in mesiobuccal canal using ultrasonic tips. Note loosely placed gutta-percha in mesiolingual canal to prevent any fragments or debris from accidentally blocking the canal. Fig. 5d_Radiograph verifying complete instrument removal. Temporary after first appointment. Canals are filled with non-radiopaque calcium hydroxide. Fig. 6_High- magnification inspection of resected root surface of left maxillary lateral incisor using a micro-mirror. Note leakage of previous root filling stained with methylene blue. Fig. 6 08 I roots 1_ 2018 ment was performed by dental students recently instructed in microscope use.22 _Nonsurgical treatment outcomes It was long uncertain if microscope usage re- sulted in improvements in nonsurgical treatment outcomes. Del Fabbro et al. conducted two Cochrane Reviews, in 200923 and 2015,24 to identify randomized controlled trials and quasi-randomized controlled trials comparing endodontic therapy performed with or without one or more magnification devices. Neither in 2009, nor in 2015, were the authors able to identify a single study reporting the outcome of either nonsurgical or surgical endodontic therapy matching the strict criteria put forward in their study. Hence, the authors concluded that it was unknown if and how any magnification device affected the treat- ment outcome, in particular, since a great number of factors besides the microscope can have a significant impact on the success of endodontic procedures. The authors suggested future long-term, well-designed randomized clinical trials. Recently, however, a study published by Monea et al.25 assessed the impact of the operating microscope on the outcome of nonsurgical treatments of a con- secutive series of 184 comparable teeth diagnosed with pulp necrosis and chronic apical periodontitis performed by postgraduate students. Success was defined as a decrease or disappearance of the ra- diolucency following the recommendations of the European Society of Endodontology. After follow-up periods of six months and 18 months, there were sig- nificant differences between microscope and control groups, with 94.8 percent versus 87.5 percent (healed and improved) at six months, and 95.9 percent and 91.9 percent at 18 months. At 18 months, 89 percent of cases available for follow-up in the microscope group were classified as completely healed. _Surgical treatment outcomes Another systematic review by del Fabbro et al.26 to investigate the use of magnification devices in endodontics identified three prospective clinical tri- als evaluating the outcomes of endodontic surgery. The authors were unable to identify significant dif- ferences in outcomes depending on treatment with loupes, microscope or an endoscope and suggested that different magnification devices could only minimally affect the outcome. In two meta-analyses, Setzer et al. described the differences in outcome of three techniques for endodontic surgery.27,28 Inves- tigated were clinical studies that applied traditional endodontic surgical techniques (TRS), including 12 studies with a total sample size of 925 teeth using no magnification, straight surgical handpieces and