Shaping ability of 2Shape and NeoNiTi rotary instruments in preparation of curved canals using micro-computed tomography

Background Various systems of nickel-titanium (NiTi) instrument have long been commercially available. However, the preparation of narrow and curved root canals has always been challenging. The purpose of this study was to compare the shaping ability of two NiTi systems (2Shape and NeoNiTi) in severely curved root canals with different morphological patterns using micro-computed tomography (Micro-CT). Methods A total of 22 human extracted permanent teeth of mandibular first molars, with the exact mesial angle of curvature of 25 and 35 degrees, according to Schneider’s technique, were distributed randomly into two groups (group I: 2Shape, group II: NeoNiTi) based on the rotary system used (n = 22). The groups were subdivided into two subgroups corresponding to the angle of canal curvature (25° and 35°) (n = 11). Canals were scanned using Micro-CT pre- and post-preparation to assess the volume of dentin removed; canal transportation; and canal centering ratio at 3, 6, and 9 mm from the apex. The Mann–Whitney U test was utilized to determine any significant differences between the two systems. The level of statistical significance was set at p < 0.05. Results There was no significant difference between the two groups in volume of dentin removed; canal transportation; and centering ability for 25° and 35° canal curvatures at 3, 6, and 9 mm from the apex (coronal, middle, and apical) thirds (p > 0.05). At the middle third, the NeoNiTi group demonstrated a statistically significant increase in volume of dentin removed for 35° canal curvatures compared to the 2Shape group. Conclusion Within the limitation of our in vitro study, 2Shape and NeoNiTi systems with severely curved canals were confirmed to be relatively safe in preparation and to respect original canal anatomy. Nevertheless, NeoNiTi instruments produced more centered preparation and minimal canal deviation compared to the 2Shape system.

A Successful Individual Endodontic Treatment of Severely Curved Root Canals in Mandibular Second Molars: A Case Report

Background and Overview The incidence rate of severely curved root canals in mandibular molars is low, and the root canal treatment of mandibular molars with this aberrant canal anatomy may be visibly and technically challenging. Case Description A 26-year-old Chinese female patient presented with intermittent and occlusal pain in the left mandibular second molar. The patient had undergone caries for filling restoration before endodontic consultation. With the aid of cone beam computed tomography (CBCT), a large periapical radiolucency was observed, and curved root canals in a mandibular second molar were confirmed, depicting a severe and curved distolingual root. Nonsurgical treatments, including novel individual preparation skills and techniques and the use of bioceramic materials as an apical barrier, were performed, and complete healing of the periapical lesion and a satisfactory effect were achieved. Conclusions and Practical implications A case of a severely curved root canal in a mandibular second molar was successfully treated and reported herein. The complex anatomy of the tooth and the postoperative effect were also evaluated via the three-dimensional (3D) reconstruction of CBCT images, which accurately identified the aberrant canal morphology. Furthermore, new devices and biomaterial applications combined with novel synthesis techniques can increase the success rate of intractable endodontic treatment.

What’s new for the clinician? - Excerpts from and summaries of recently published papers

Endodontic files are used to remove intracanal pulpal tissues, microbial biofilm, and toxic by-products and to develop a continuously tapering canal while maintaining the canal geometry that ultimately allows for the delivery of irrigating solutions and intracanal medicaments as well as the three-dimensional filling of the root canal system. Historically, stainless steel hand files have been used to perform canal shaping. However, these files are stiff and associated with increased operator fatigue, and when used in the preparation of curved root canals, the restoring forces of the files tend to return the file back to its original shape, resulting in canal transportation.

Comparative Evaluation of Extrusion of Apical Debris and Irrigant from Curved Root Canals Using Three Different Ni-Ti Instruments with Conventional Needle Irrigation Methods - An In Vitro Study

BACKGROUND Extrusion of debris, bacteria, and irrigant effect the inter-appointment flare ups and post-operative outcome of the endodontic treatment. So, it is necessary to make every effort to minimize such extrusion during cleaning and shaping of the canals. The present study was done to compare and evaluate debris and irrigant extrusion from curved root canals using different Ni-Ti systems. METHODS 30 mesial roots of mandibular molars were used in this study. Crown were decoronated, working length and initial apical diameter was established. 1.5 % agar gel model was used in this study. Samples were assigned randomly into 3 groups (n = 10 teeth per group). ProTaper Next, One Shape, FANTA AF BLUE F ONE files were used according to the manufacturer’s instructions for canal instrumentation. Apically extruded debris and irrigant was computed after the biomechanical preparation and their comparative analysis for each of the instruments and experimental models was performed. RESULTS Statistically significant difference was found between the three experimental groups. (P < .05). CONCLUSIONS All the instruments produced apically extruded debris and irrigant, but least was seen with FANTA AF BLUE F ONE and maximum with One Shape among the experimental groups. KEY WORDS Apical Debris, Irrigant, NiTi Files