Quantitative evaluation of the apically extruded debris from root canals prepared by single-file rotary and reciprocating file systems: An in vitro study.

Aim: The aim is to investigate and compare the amount of apically extruded debris after root canal preparation using single rotary and reciprocating file system. Materials and Methods: Forty single-rooted human mandibular premolars with straight canals were randomly assigned to four groups (n = 10). The root canals were instrumented according to the manufacturers' instructions using single-rotary file systems Hyflex EDM (HEDM), One Shape (OS) and single-reciprocating file systems Wave OneGold (WOG) and OneRECI (OR). The apically extruded debris was collected in preweighed glass vials using the Myers and Montgomery method. After drying, the mean weight of the extruded debris was assessed using a microbalance. Results and Conclusions: Multiple comparison between groups demonstrated that the mean weight of apically extruded debris in the HEDM group was significantly less compared to all other study groups, and the differences were statistically significant (P < 0.001). Under the condition of this study, all file systems caused apical debris extrusion. The mean apically extruded debris was significantly least in HEDM, followed by WOG, OneRECI and highest in the OS group.

Comparative evaluation of the remaining dentin volume following instrumentation with rotary, reciprocating, and hand files during root canal treatment in primary molars: An ex vivo study.

Background/purpose: The effectiveness of root canal treatments with different file systems in primary teeth is important in terms of clinical practice and the use of file systems that work with different principles in primary tooth pulpectomy is becoming widespread. The amount of remaining dentin in the coronal region of the root is important in terms of the prognosis of the tooth and the long-term success of the treatment in teeth that have undergone root canal treatment. The aim of this study was to evaluate the remaining dentin volume in the coronal part of the root after the use of rotary, reciprocating, and conventional hand files in primary tooth pulpectomy. Materials and methods: A total of 30 primary molars were divided into three groups. In each group, the preparations were made with three different file types: WaveOne Gold, which works with reciprocating motion; TruNatomy, which works with rotational motion; and conventional hand files. The three-dimensional images were evaluated for remaining dentin volume in the 2-mm coronal part of the root. Group means were compared using one-way analysis of variance, and post hoc analyses were performed with the Tukey test. Results: There was no statistically significant difference between the groups in terms of preoperative and postoperative dentin volume (P > 0.05). The mean difference after preparation was observed the most in the WaveOne Gold group and the least in the TruNatomy group. When the mean percentage differences were evaluated, it was observed that statistically significantly more dentin volume was preserved after the preparation with TruNatomy than with WaveOne Gold (P = 0.021). Conclusion: In primary tooth pulpectomy, file systems working with rotational motion can be preferred over file systems working with reciprocating motion in preserving the amount of dentin in the 2-mm coronal part of the root.

Time Required for Root Canal Retreatment Using Continuous Rotation, Reciprocation, and Optimum Torque Reverse Motions: An In-Vitro Study.

Objective This study aims to evaluate the time required for canal preparation using three different movement kinematics during retreatment: continuous rotational motion, reciprocating motion, and optimum torque reverse (OTR) motion. Materials and methods The sample comprised 45 single-canal mandibular first premolars. The crowns were sectioned to standardize the root length to 16 mm. The root canals were prepared using the AF Gold mechanical preparation system (25/06). The roots were obturated using the lateral condensation technique and kept at 100% humidity at 37°C for seven days. The sample was randomly divided based on the movement pattern used during retreatment into three groups (N = 15): group 1 is continuous rotational motion using the ProTaper Universal Retreatment system; group 2 is reciprocating motion using the WaveOne Gold system; and group 3 is OTR motion using the ProTaper Universal Retreatment system. The retreatment time was measured in seconds by summing two times: T1 (time to reach the apex) and T2 (time to achieve adequate cleaning). The data were statistically analyzed using a one-way ANOVA with a significance level of α = 0.05. Results The results showed that the time required for canal preparation during retreatment with WaveOne Gold files using reciprocating motion was significantly longer than the time needed with ProTaper Universal Retreatment files using continuous rotary motion or OTR motion (P < 0.05). Conclusions The use of OTR motion did not affect the canal preparation time when used with files designed for continuous rotary motion retreatment. The use of WaveOne Gold files for canal preparation during retreatment was associated with a longer working time than ProTaper Universal Retreatment files.

Unveiling the correlation between in vivo endodontic reciprocate instrumentation and crack formation.

INTRODUCTION: Dentinal microcracks have been supposedly associated with unrestorable vertical root fractures and consequently long-term treatment failure. This study aimed to investigate whether in vivo root canal instrumentation in mandibular incisors with vital pulps causes dentinal microcracks using two different irrigating solutions. METHODS: Five patients with four vital mandibular incisors indicated for extraction were included. In vivo root canal preparation was performed using Reciproc R40 (tip #40 and taper 0.06). From these, two teeth were randomly assigned for root canal instrumentation irrigated with 5.25 % sodium hypochlorite irrigation (n = 10) or 2 % chlorhexidine gel with saline solution irrigation (n = 10). In sequence, all teeth were carefully extracted, stored in saline solution until microtomography (µCT) scan. Images were reconstructed and assessed for the presence or absence of dentinal microcracks where microcracks originating from the root canal lumen would be considered. All reconstructed samples were analysed dynamically and rendered in videos through the entire extension of the teeth, evaluating the axial cuts considering each third separately from the apex to the enamel-dentinal junction. Teeth were analysed using the DataViewer software at 100 % magnification without filters by three examiners blinded to the condition allocation. RESULTS: No complete dentinal microcracks were observed after root canal instrumentation of mandibular incisors with vital pulps using Reciproc R40 regardless the irrigating solutions, 5.25 % sodium hypochlorite or 2 % chlorhexidine gel. CONCLUSIONS: In vivo root canal instrumentation of mandibular incisors with vital pulps and bone/periodontal insertion does not cause dentinal microcracks and the irrigating solutions tested did not influence this occurrence. Microcrack evaluation must be performed in vivo conditions of dental tissue moist and periodontal support to avoid dryness dentinal alterations after extraction provoking false positive results. CLINICAL RELEVANCE: Reciprocating instrumentation performed in vivo is safe and do not induce dentinal microcracks in mandibular incisors.

The Impact of Minimum Invasive Access Cavity Design on the Quality of Instrumentation of Root Canals of Maxillary Molars Using Cone-Beam Computed Tomography: An in Vitro Study.

Aim Minimally invasive dentistry has been facilitated by advances in instruments and restorative materials. This study aims to compare the change in the shaping ability of the RECIPROC blue rotary system in both traditional and conservative access cavities, using cone beam computed tomography (CBCT). Material and methods Sixty root canals of 20 artificial maxillary molars were assigned into two groups (n=30 root canals) according to the access cavity design used: Group I: traditional access cavity (TAC) and Group II: conservative access cavity (CAC). CBCT scans of samples were made before and after root canal preparation using the RECIPROC blue rotary system. The shaping parameters are evaluated in root canal transportation and the centering ability. Three CBCT sections per tooth were analyzed at 3, 6, and 9 mm from the apex to assess the canal transportation and centering ability at three levels, apical, middle, and coronal thirds. Data were analyzed using the GraphPad Prism (GraphPad Software, San Diego, CA). Results The results of this study showed a significant difference in transportation within the coronal and middle thirds. However, in apical thirds, there were no significant differences. Both groups observed a significant difference in the centering ability in the coronal third. Conclusion Within the limitations of this study, CAC can be recommended with caution as an alternative access to TAC.

Investigation of the effectiveness of prehospital amputation devices on cadavers.

Amputations take place in the operating rooms. At dangerous sites, circumstances may necessitate on-site amputation to save lives. Currently, there are no evidence-based guidelines for the execution of the amputation or the instruments to be chosen. Furthermore, there are no widely accepted criteria for the standardized characterization of amputation devices. The present study examined the effectiveness of commercially available cutting tools and instruments used by rescue services as possible on-site amputation tools. Five different tools (Holmatro type hydraulic cutter, with two cutting attachments, reciprocating saw, hacksaw, Gigli saw) were used to carry out amputations on designated locations on cadavers (brachial, antebrachial, femoral, and crural regions). During the experiment, the time required for amputation and the number of necessary cutting attempts to detach limbs were recorded. The proximal cut surfaces were analyzed with the help of post-amputation CT scan-based 3D models. An Amputation Index (AI) was determined for each device in each examined region based on the cut surface quality. An Amputation Score (AS) was calculated using the time required for cutting, the number of cutting attempts, and the AI. With the help of AS, the usability of the used devices was determined. According to our scoring system, the reciprocating saw proved the most effective tool. Based on our results, we recommend the consideration and further investigation of the reciprocating saw as a possible on-site amputation device, as well as the introduction of the Amputation Score as an objective and quantitative indicator in the future characterization of on-site amputation devices.

Feasibility of Laboratory Equipment-Based Simulation Methods to Assess the Impact of Vehicle Transportation on Product Quality of mAb Dosing Solutions.

Therapeutic monoclonal antibody (mAb) products for intravenous (IV) administration generally require aseptic compounding with a commercially available diluent. When the administration site is located away from the preparation site, the prepared dosing solution may need to be transported in a vehicle. The impact of vehicle transportation on the product quality of mAbs needs to be evaluated to define safe handling and transportation conditions for dosing solutions. The design and execution of actual vehicle transportation studies require considerable resources and time. In this study, we systematically developed three different laboratory equipment-based methods that simulate vehicle transportation stresses: orbital shaker (OS), reciprocating shaker (RS), and vibration test system (VTS)-based simulation methods. We assessed their feasibility by comparing the impact on product quality caused by each simulated method with that caused by actual vehicle transportation. Without residual polysorbate 80 (PS80) in the mAb dosing solution, transportation via a cargo van led to a considerable increase in the subvisible particle counts and did not meet the compendial specifications for the light obscuration method. However, the presence of as low as 0.0004%w/v (4 ppm) PS80 in the dosing solution stabilized the mAb against vehicle transportation stresses and met the compendial specifications. Vehicle transportation of an IV bag with headspace resulted in negligible micro air bubbles and foaming in both PS80-free and PS80-containing mAb dosing solutions. These phenomena were found to be comparable to the VTS-based simulated method. However, the OS- and RS-based simulated methods formed significantly more micro air bubbles and foaming in an IV bag with headspace than either actual vehicle transportation or the VTS-based simulated method. Despite the higher interfacial stress (micro air bubbles and foaming) in the dosing solution created by the OS- and RS-based simulated methods, 0.0004%w/v (4 ppm) PS80 in the dosing solution was found to be sufficient to stabilize the mAb. The study shows that under appropriate simulated conditions, the OS-, RS-, and VTS-based simulated methods can be used as practical and meaningful models to assess the impact and risk of vehicle transportation on the quality of mAb dosing solutions.

Optimal interval for delayed retrieval surgery with reciprocating morcellators after enucleation of giant prostatic hyperplasia in holmium laser enucleation of the prostate.

Objective: The aim of this research was to evaluate the efficiency of reciprocating morcellation for removing giant benign prostatic hyperplasia during holmium laser enucleation of the prostate, investigate whether performing morcellation as a two-stage procedure improves tissue retrieval efficiency, and seek to determine the optimal interval between the two surgeries. Methods: This study included nine cases of holmium laser enucleation of the prostate with an enucleated prostate weight exceeding 200 g, indicative of substantial prostate enlargement. Morcellation was performed on Day 0 (n=4), Day 4 (n=1), Day 6 (n=1), and Day 7 (n=3). The intervals were compared regarding the morcellation efficiency, beach ball presence, and pathology. Results: The mean estimated prostate volume was 383 (range 330-528) mL; the median enucleation weight was 252 (interquartile range [IQR] 222, 342) g; and the median enucleation time was 83 (IQR 62, 100) min. The mean morcellation efficiency was 1.44 (SD 0.55) g/min on Day 0 and 13.69 (SD 2.46) g/min on day 7. The morcellation efficiency was 4.15 g/min and 10.50 g/min on Day 4 and Day 6, respectively, with significantly higher in the two-stage group compared to one-stage group (11.0 g/min vs. 1.5 g/min; p=0.014). Efficiency was strongly correlated with intervals (p<0.001); the incidences of beach balls were 100% (4/4) and 60% (3/5) in the immediate and two-stage surgery groups, respectively. Conclusion: The efficiency of two-stage morcellation with reciprocating morcellators was highly related to the postoperative interval, with the maximum efficiency reached on Day 7.

SVT quest: The adventure diagnosing narrow QRS tachycardia.

In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled "SVT Quest" is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V-A-V or V-A-A-V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His-ventricular pathway-related tachycardia based on observations such as V-V-A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure!

A case of a permanent form of junctional reciprocating tachycardia with negative linking on atrial differential pacing.

This case of PJRT shows negative linking on ventriculoatrial intervals after atrial differential pacing. Interpreting the results of atrial differential pacing may be challenging in cases where the pacing site affects retrograde conduction or when retrograde conduction is unstable.

Economic analysis of reciprocating engine generating with bio-syngas at predicted maximum power condition.

In order to effectively utilize woody biomass, which has a low abundance density, it is necessary to develop a power generation system that can convert it with high efficiency even with a small capacity as less than 2 MW. For electricity generation, it is reasonable to use a small reciprocating engine. In the case of a naturally aspirated spark ignition reciprocating engine (SIRE), the amount of aspirated gas in one cycle is determined almost entirely by the displacement. The thermal efficiency of the SIRE generally increases with the power. Therefore, to improve the thermal efficiency, it is effective to make the low heating value (LHV) of the fuel higher to increase the power of the naturally aspirated SIRE. In this paper, three methods are used to increase the LHV of the bio-syngas: 1) reducing the nitrogen density of the bio-syngas (upgrade bio-syngas), 2) adding hydrogen to the bio-syngas, and 3) adding methane to the bio-syngas. Using these fuels, 1) the conditions for high power, and 2) the costs assumed for each condition, are evaluated through experiments and estimates. The results showed that the upgrade bio-syngas, obtained by gasification with oxygen-enriched air, had the highest power and the best cost-effectiveness.

Study on the Nodal Composite Bearing Performance of Nontruncated PHC Pipe Pile and Bearing Platform.

In this paper, low circumferential reciprocating load foot-scale tests were performed on two nontruncated PHC B 600 130 tubular piles with bearing nodes to characterize the damage process and morphology of the specimens and to investigate the load-carrying performance of the members. The test results reveal that under the action of tensile-bending-shear loading, the bearing concrete in the node area buckles and is damaged, the anchored reinforcement in the node area yields, the constraint is weakened, an articulation point is formed, and the node rotational capacity increases. When the embedment depth increases from 200 mm to 300 mm, the ultimate bearing capacities of the positive and negative nodes increase by 31.04% and 36.16%, respectively. A numerical simulation is used to verify the test results. Considering the four types of piles without truncated nodes, the numerical simulation is used to analyze the node-bearing capacity at different embedment depths. Finally, a preferred node type is proposed as follows: a terminal plate welded anchor bar and pipe pile core-filled longitudinal reinforcement anchored into the bearing node, with a preferred embedment depth of 250 mm.

Influence of the Brushing Motions on the Dynamic Cyclic Fatigue Resistance of the Reciproc Blue Instrument: In vitro Study.

INTRODUCTION: This study aimed to evaluate the dynamic cyclic fatigue resistance of Reciproc Blue files subjected to brushing motion. METHODS: Twenty Reciproc Blue files (R25, VDW, Munich, Germany) were employed for chemical-mechanical preparation in root canals of 3D printed replicas of mandibular molars. The instruments were divided into two groups (n = 10): Group brushing motion, instrumentation with brushing motions; Group without brushing motion , instrumentation without brushing motions. Subsequently, the same instruments underwent cyclic fatigue testing using artificial canals consisting of a stainless-steel plate and an apical segment with a 45° curvature. Data regarding the time to fracture, number of cycles to fracture, and length of the fractured fragment were collected and subjected to statistical analysis using the t-test or Mann-Whitney test, with a significance level of 5%. Additionally, the fractured fragments were examined under a scanning electron microscope. RESULTS: No statistical differences were observed between the groups in terms of time to fracture (P < .05), number of cycles to fracture (P < .05) and length of the fractured fragment (P < .05). CONCLUSION: The brushing motion did not affect the dynamic cyclic fatigue resistance of Reciproc Blue files.

Fifteen years of engine-driven nickel-titanium reciprocating instruments, what do we know so far? An umbrella review.

Numerous systematic reviews (SRs) have produced conflicting findings on engine-driven nickel-titanium reciprocating instruments (reciprocating instruments) since Yared's seminal study 15 years ago. This umbrella review analysed SRs examining the clinical and laboratory evidence regarding reciprocating instruments for root canal treatment. SRs that evaluated qualitatively and/or quantitatively the outcomes postoperative pain, oral health-related quality of life (OHRQoL), shaping ability, debris extrusion, microbial load, endotoxins reduction, cyclic fatigue, file fracture, dentinal cracks and root canal filling removal were included. The AMSTAR 2 tool was used to evaluate SRs quality, while the ROBIS tool to assess risk of bias (RoB). Forty SRs were included. The SRs revealed predominantly 'high' RoB and 'critically low' quality. Most focused on technical outcomes, exhibiting significant methodological and statistical heterogeneity. Findings suggest comparable efficacy between reciprocating and rotary instruments. However, due to the scarcity of high-quality evidence, future well-designed studies and reviews considering core outcome measures are needed.

Research on Lateral Resistance Performance of Prestressed Cross-Laminated Timber-Concrete Composite Structures under Reciprocating Loads.

Cross-Laminated Timber (CLT) and concrete composite structures represent an architectural system that integrates the strengths of both materials. In this innovative configuration, the CLT and concrete collaborate synergistically, harnessing their individual merits to achieve enhanced structural performance and functionality. Specifically, the CLT offers a lightweight design, superior bending resistance, and immense engineering plasticity, while concrete boasts exceptional compressive strength and durability. This study investigates the mechanical performance of CLT-concrete composite structures through quasi-static reciprocating loading tests in three full-scale CLT shear wall samples. Designed with varying initial prestressing forces and dimensions of the CLT panel, the prestressed CLT-concrete structures demonstrated a reduced dependence on the steel nodes, resulting in an increase in yield load, yield displacement, and maximum load-carrying capacity. Maximum capacity increased by 39.8% and 33.7% under initial prestressing forces of 23 kN and 46 kN on steel strands. Failure occurred due to localized compressive failure on prestressed steel strands and anchor plates. ABAQUS finite element analysis established three refined models, revealing that the increased initial prestressing force moderately enhanced stiffness but reduced ductility under similar cross-sectional dimensions. Furthermore, under consistent CLT material, dimensions, prestressing force, and loading conditions, prestressed CLT-concrete structures exhibited a higher maximum load-bearing capacity than prestressed CLT-steel composite structures. This study proposes structural design recommendations based on experimental and simulation results, incorporating specific assumptions.

Evaluation of mechanical properties of an original and a replica-like reciprocating instruments.

This study assessed the mechanical properties of the Only One File Blue and the Reciproc Blue instruments. A total of 80 new 25 mm reciprocating NiTi instruments (25/.08v) were evaluated for their mechanical performance (n = 40 per group). Cyclic fatigue resistance, torsional fatigue, flexural resistance and buckling resistance tests were conducted. Statistical analysis was employed with a significance level set at 5%. The results indicated no statistically significant differences in resistance to cyclic fatigue neither in the fragment length between the instruments (p > 0.05). However, the Reciproc Blue instrument exhibited greater torque to fracture and a larger rotation angle than the Only One File Blue instrument (p < 0.05). The Only One File Blue instrument demonstrated higher flexibility but lower resistance to buckling compared to the Reciproc Blue instrument (p < 0.05). In conclusion, the tested instruments exhibit differences in mechanical properties, with the Reciproc Blue instrument generally presenting greater advantages than the Only One File Blue.

Improving the Tribological Properties of WE43 and WE54 Magnesium Alloys by Deep Cryogenic Treatment with Precipitation Hardening in Linear Reciprocating Motion.

This paper presents the results of tribological tests on WE43 and WE54 magnesium alloys with rare earth metals performed in linear reciprocating motion for four different material couples (AISI 316-L steel, silicon nitride-Si3N4, WC tungsten carbide, and zirconium dioxide-ZrO2). Additionally, magnesium alloys were subjected to a complex heat treatment consisting of precipitation hardening combined with a deep cryogenic treatment. The study presents the effect of deep cryogenic treatment combined with precipitation hardening on the tribological properties of WE43 and WE54 alloys. Tribological tests revealed the most advantageous results for the magnesium alloy-AISI 316-L steel friction node. For both alloys tested after heat treatment, a nearly 2-fold reduction in specific wear rate has been achieved. Furthermore, microscopic examinations of the wear track areas and wear products were performed, and the wear mechanisms and types of wear products occurring in linear reciprocating friction were determined. Wear measurements were taken using the 3D profilometric method and compared with the results obtained from calculations performed in accordance with ASTM G133 and ASTM D7755, which were modified to improve the accuracy of the calculation results (the number of measured profiles was increased from four to eight). Appropriately selected calculation methods allow for obtaining reliable tribological test results and enabling the verification of both the most advantageous heat treatment variant and material couple, which results in an increase in the durability of the tested alloys.

An Experiment on the Dwell Time Effect of Rubber Seal O-Rings: Friction Force in Intermittent Reciprocating Motion.

The adhesive force between two contact surfaces often leads to an increase in the friction force of the rubber seal O-ring after a certain dwell time, forming dwell time effects and affecting the reliability of sealing. The dwell time effect may result in substantial instability with respect to the frictional behavior of rubber O-rings, which needs to be carefully taken into account in the design of rubber seals. Therefore, in this paper, the dwell time effect of the friction force was studied experimentally for intermittent reciprocating rubber seal O-rings coupled with stainless steel 316L and a sealing air medium. The friction force of three kinds of rubber materials, including fluorine rubber (FPM), silicone rubber (SI), and nitrile rubber (NBR), was measured under different dwell times, compression ratios, and seal pressure. The results showed that there was a rolling frictional force, and the second peak value of the frictional force caused by the O-ring's rolling under shear action and after the maximum static frictional force was observed at the starting stage of reciprocating motion. For FPM O-rings, the rolling friction force was much greater than the maximum static frictional force at about four times the value of the compression ratio at 9% and seal pressure at 0; moreover, the force was much greater at greater compression ratios. The dwell time effect was significant in the friction forces of rubber O-rings. The friction force increases with an increase in dwell time. The increase in maximum static friction force exceeded 50% after 5 dwell days. The increase in seal pressure led to the disappearance of the rolling friction feature and the rapid increase in friction during the starting stage. Under gas seal pressure conditions, the dwell time effect still led to a significant increase in friction force. The obtained results might provide guidance for the material selection of sealing designs.