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.

Comparison of the canal transportation of ProTaper GOLD, WaveOne GOLD, and TruNatomy in simulated double-curved canals

Background In root canal preparations, it is important to maintain the original canal shape. However, it is difficult to accomplish this, especially due to the complex canal anatomy. This study aimed to compare the shaping ability of the ProTaper GOLD, WaveOne GOLD, and newly developed TruNatomy in simulated S-shaped canals. Methods The root canals of 60 S-shaped resin blocks were dyed using ink and photographed. The blocks were then randomly divided into three groups: group ProTaper GOLD (n = 20), WaveOne GOLD (n = 20), and TruNatomy (n = 20). The simulated canals were instrumented according to the NiTi file system and photographed again after being dyed with red ink. The pre- and post-preparation images were superimposed, and the amount of resin removed from both the mesial and distal sides of the canal measured up to 9 mm from the apical terminus, with a 1 mm increment. The preparation time was also calculated. A paired t-test was used to determine the degree of deviation at different levels within the groups. To compare the degree of transportation at different levels between the groups, one-way ANOVA and Kruskal–Wallis tests were performed according to the normality. Results TruNatomy showed a significant deviation between the mesial and distal sides of the canal only in the coronal area at 6, 7, 8, and 9 mm levels of the canal (p < 0.05). When comparing the amount of transportation in the 3 groups at 9 different levels, TruNatomy showed significantly less canal transportation than the other groups at the 3-and 5-mm levels of the canal (p < 0.05), while ProTaper GOLD showed the largest amount of transportation in the apical curved area at the 2 and 3 mm levels (p < 0.05). TruNatomy removed less resin than other groups in all sections (p < 0.05), while ProTaper GOLD removed slightly more resin than WaveOne GOLD; however, there was no significant difference (p = 0.043). Shaping time was the least for TruNatomy, followed by the WaveOne GOLD and ProTaper GOLD (p < 0.05). Conclusions TruNatomy maintained the original apical canal curvature in S-shaped curved canals better than ProTaper GOLD and WaveOne GOLD.

Assessment of the shaping ability of three systems used in long oval canals

The aim of this study was to analyze volume variation, untouched walls, transportation, and centralization in long oval canals prepared with ProTaper Next (PTN), X File (XF) and X Gray (XG) by microcomputed tomography (micro-CT). Forty-five lower incisors were divided into three groups (PTN, XF and XG) with 15 specimens each, according to the micro-CT pre-instrumentation (PI) analysis. After the use of each instrument new exams were performed. Volume variation and untouched walls data were analyzed by two-way ANOVA, and for the first one, Tukey HSD or Games-Howell tests were applied in the sequence; data of transportation and centralization were compared by Kruskal-Wallis and Mann-Whitney test. The statistical significance was set at p < 0.05. Between thirds, higher wear values were found in the cervical (p <0.001). PI and the instrument X3 (30/.07) differed in all systems (p < 0.05). No significant difference concerning the percentage of untouched walls between the systems occurred (p = 0.836), while the degree of transportation and centralization was similar between then, with p values of 0.531 and 0.155, respectively. However, between thirds, significant difference was found (pc = 0.029), with the middle third presenting superior centralization than the apical (p = 0.010). In conclusion, PTN, XF and XG had similar results in the shaping ability, transportation, and centralization of long oval canals.

Comparison of Shaping Ability between Continuous Rotary and Manual Instrumentations in Pediatric Endodontics

Objective: The aim of this in vitro study was to evaluate the efficacy of rotary EndoArt Ni-Ti Gold Pedo Kit and K-files in shaping ability, canal transportation, centering ability and instrumentation time in primary molars. Methods: For the study total of 30 extracted primary molars root with minimum 7mm root length were selected. Shaping of root canals in primary molars were done using the two systems, and CBCT and specialized software were used for scanning and analysis of pre-operative and post-operative to evaluate the groups for their shaping properties, apical transportation and preparation time in primary root canals. Results: No differences were found in canal transportation measures and instrumentation time between the two groups (p>0.05). The EndoArt group removed more dentin compared to K-file in all sides of the root curvature. The statistical differences were significant for coronal and middle third of the root (p<0.05). Conclusions: Under the conditions of this study, rotary EndoArt Ni-Ti Gold Pedo Kit provided more conical canals than K-files in primary teeth.

Evaluation of the Shaping Ability of Three Thermally Treated Nickel–Titanium Endodontic Instruments on Standardized 3D-printed Dental Replicas Using Cone-Beam Computed Tomography

Background and Objectives: The aim of the present study is to compare the efficacy of three root canal preparation systems in the shaping of 3D-printed root canal replicas of single rooted teeth. Materials and Methods: Sixty 3D-printed root canal replicas were produced and divided into three groups, each consisting of twenty samples. Each group was shaped with a different instrument: Reciproc Blue R25/08 (VDW GmbH, Munich, Gemany), WaveOne Gold Primary 25/07 (Dentsply Sirona, Ballaigues, Switzerland), and ProTaper Gold F2 25/08 (Denstply Sirona). To ensure the reproducibility of pre- and post-operative CBCT images of the root canals, the endodontic printed replicas were placed in a mould of silicon impression material. A cone-beam computed tomography (CBCT) software was used to compare pre- and post-instrumentation images collected at three levels of the root canal length: 3, 6, and 9 mm from the apical foramen. The amount of transportation, centring ability, and curvature angle after shaping were evaluated for each system. The results were statistically analysed and compared using one-way analysis of variance (ANOVA). Results: Regarding the transportation of the root canal after shaping, significant differences between groups at 3 mm (p = 0.010721) and 6 mm (p = 0.000046) were recorded in the mesio-distal direction, while in the bucco-lingual significant differences were only observed at 6 mm (p = 0.000554). Reciproc Blue removed more dentin from the mesial and buccal wall of the root canal. When evaluating the centring ability of the three systems, significant differences were observed between the groups at the level of 9 mm (p = 0.037258) in the mesio-distal direction, and at the level of 6 mm (p = 0.038197) in the bucco-lingual direction. Significant differences of the canal curvature angle after shaping were also observed between groups (p = 0.000001). Reciproc Blue straightened the curvature the most, while ProTaper Gold the least. Conclusions: All systems produced minor root canal transportation. No instrument was able to achieve a perfect centring preparation of the root canal. All systems produced a small degree of root canal straightening.