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•  Clinicians should be aware of anatomical variations in cases with OFCD syndrome. •  Root canal treatment in such cases is challenging. •  In general, the majority of mandibular canines have one root and root canal, but 15% may have two canals, and a smaller number may have two distinct roots.

BackgroundSince the introduction of nickel–titanium (Ni–Ti) instruments to dentistry, a wide variety of Ni–Ti instruments have become commercially available. These Ni–Ti instruments are expensive, which limits their usage in developing countries and forces practitioners to use instruments repeatedly. Another problem is the possible prion cross-contamination associated with the multiple usage of endodontic instruments. In addition, the use of these instruments requires new skills and experience. In this article, the shaping capacities of two conventional rotary file systems, ProFile 25/0.06 and ProTaper F2, were reviewed and compared with the Reciproc single-file system.MethodsA total of 45 simulated canals with 40° curvature, in clear resin blocks, were prepared using conventional rotary systems consisting of ProFile orifice shaping (OS) #3 and final flaring #25/.06, Reciproc R25, and ProTaper shaping file SX and finishing file F2. Pre-and post-instrumentation images were analyzed at ten different levels, using AutoCAD 2007 software. The measurement positions were defined in 1-mm intervals: positions 0–3 established the apical part, positions 4–6 constituted the middle part, and positions 7–10 established the coronal part of the canal. The amount of removed resin, the transportation, instrumentation time, change in working length (WL), instrumentation fractures, and the presence of ledge were evaluated. Data were analyzed using ANOVA, Kruskal–Wallis and independent t-test (p < 0.001).ResultsProFile removed the least resin (p < 0.001) and caused less transportation than Reciproc and ProTaper, in total (p < 0.001). ProTaper caused more transportation ProFile and Reciproc in the apical part (p < 0.000). Reciproc caused more transportation than ProTaper and ProFile (p < 0.001), and the transportation tendency toward the inner aspect of the curvature in the middle part. Reciproc caused the less transportation than ProFile and ProTaper in the coronal part. The transportations tended to occur toward the outside of the curvature, except the middle part with Reciproc and at points 5 and 6 with ProTaper. There were no significant differences among the groups in terms of maintaining the original WL. Reciproc was significantly faster than the others group (p < 0.001). Only one instrument fracture (25/0.06 ProFile) was noted. All groups showed one ledge each.DiscussionThe results of the present study showed that both ProFile 25/06 and ProTaper F2, combined with a file used for coronal enlargement (OS3 and SX), have the potential to create satisfactory canal shape in the curved root canals. Further studies using real human teeth are needed to confirm our results.

Backround: frequent introduction of new dental instruments or devices into the market has been a concern for dentists worldwide, as the prices of such instruments are generally high, especially in developing countries. In addition, the use of these tools requires new skills and experience. For this reason, while innovations in dentistry are being pursued, it may be advantageous to update the dental instruments that we have been using for years. This study evaluated whether both ProFile and ProTaper files have the potential to reduce the number of files required for shaping curved root canals. Methods: A total of 45 simulated canals with 40o curvature in clear resin blocks were prepared with conventional rotary systems: ProFile orifice shaping (OS) #3 and final flaring #25/.06, Reciproc R25, and ProTaper shaping file SX and finishing file F2. Pre- and post-instrumentation views were analysed using digital images captured by a camera. Prepared inner and outer walls at 1–10 levels were measured using AutoCAD software. The time required for canal shaping and the frequency of broken instruments were recorded. Standardised pre- and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analysed using the one-way multivariate analysis of variance (ANOVA) and least significant difference test. The level of significance was set at 0.05. The transportation, instrumentation time, change of WL, and instrumentation fractures were evaluated. Data were analysed by ANOVA, Kruskal–Wallis and independent t-test (p<0.05). Results: Reciproc removed more mass in total and caused less transportation in the middle and coronal third (p<0.001). The transportations performed in the apical third were opposite to the curve. There was no significant difference among the groups in terms of maintaining the original WL. Reciproc was significantly faster (p<0.001). Only one instrument fracture (25/0.06 ProFile) was noted. All groups showed one ledge each. Discussion: According to this study, both ProFile and ProTaper files have the potential to reduce the number of files required for shaping curved root canals. However, Reciproc, which was produced using a single-file concept, was determined to be more advantageous in terms of time. This study suggests that the conventional rotary technique system might have comparable efficacy to the single-file system for root canal shaping.