Comparing the Technological and Intraoperative Performances of Da Vinci xi and DaVinci 5 Robotic Platforms in Patients Undergoing Robotic-Assisted Radical Prostatectomy.

INTRODUCTION: In the last two decades, several Da Vinci robotic platforms have been released in the market, revolutionizing the field of robotic-assisted surgery (1, 2).The system has seen numerous modifications, with several Da Vinci® robotic models being introduced, each featuring ongoing technological advancements in ergonomics,instrumentation,high-definition imaging, EndoWrist™ technology, and single-port surgery capabilities (3, 4).Building on this, the new generation Da Vinci 5 robot promises significant hardware and software improvements, with the potential for enhanced operative performance (2, 5). In this video, we will illustrate several technical advancements of the Da Vinci 5. MATERIAL AND METHODS: We performed a video compilation comparing the Da Vinci 5 and Da Vinci Xi during radical prostatectomy. The video will highlight the technical modifications of the new platform, showcasing the advancements and improvements in the Da Vinci 5 system. Additionally, this video will illustrate key aspects of the surgery, including anterior bladder neck access, lateral bladder dissection from the prostate, posterior prostate dissection and anastomosis. SURGICAL TECHNIQUE: We performed our RARP technique with our standard approach in all patients (6-8). With this new platform, we maintained our conventional technique without any modifications or adaptions from the trocar placement until anastomosis. The beginning of the case is performed as usual, we first identify the anterior bladder neck and then complete its dissection with Maryland and Scissors. Then, we proceed to the posterior bladder neck dissection, seminal vesicles control and nerve-sparing. In sequence, we control the prostate arterial pedicles with hem-o-lok clips and then we perform the apical dissection until dividing the urethra. Finally, we perform the hemostasis, posterior reconstruction (Rocco's technique) and anastomosis with barbed suture. RESULTS: The Da Vinci 5 features several key upgrades. The first part of our video described the console, patient cart, and energy tower modifications. The console has been ergonomically redesigned for a flat neck posture to decrease muscle fatigue, and the handgrip now includes a rubber surface for better grip (9). The patient cart, similar to the previous generation, has updated helm interfaces and integrated commands with the console and vision tower. In sequence, we described the instrument modifications and the step-by-step technique showing the DV5 and DV-Xi. Force feedback instruments provide three degrees of tactile feedback, enhancing tissue manipulation. A new security system ensures instruments can only be inserted when clear of tissues and obstructions, reducing the risk of errors. Another modification regards the ability to switch instruments and camera.

Sensing creatinine in urine via the iontronic response of enzymatic single solid-state nanochannels.

In this study, we investigate the integration of the enzyme creatinine deiminase into solid-state nanopore walls through electrostatic assembly for the development of creatinine sensors. In these asymmetric single nanochannels, ionic transport is determined by the surface charge inside the channel, resulting in diode-like behavior that rectifies ionic current. The efficiency of such rectification depends on the surface charge density. In the presence of creatinine, the enzymatic reaction generates ammonium, leading to an increase in local pH near the channel, which can be detected through changes in transmembrane ionic transport response. Changes in rectification efficiency can be well correlated with the analyte concentration, allowing for a detection limit of 5 nM creatinine. Furthermore, this solid-state nanopore-based device is capable of sensing in diluted urine samples, showing a good linear correlation between the response and the logarithm of the creatinine concentration over a wide range of concentrations (50 nM-100 µM). These results demonstrate the potential of systems based on the integration of enzymes that induce pH changes and solid-state nanopores for the development of biomarker sensors capable of operating in complex real samples.

Effectiveness of custom seating and mobility services for individuals with disabilities in Guatemala.

The purpose of this study was to evaluate the effectiveness of custom seating and mobility services provided via an international service learning (ISL) model on the occupational performance of individuals with disabilities in Guatemala. A one-group prospective pretest-posttest design was implemented using the standardized Wheelchair Outcome Measure (WhOM - Spanish) administered on the day of wheelchair fitting, and at 3- and 6-month intervals after receiving seating and mobility services. A two-tailed t-test demonstrated a statistically significant (p < 0.001) improvement in satisfaction for in-home and out-of-home occupations for all participants (n = 71) at 3-months with a huge effect size (d > 2) and this improvement was maintained at the 6-month interval. The results were consistent for various areas of occupational performance (e.g. activities of daily living). The provision of customized seating and mobility services by occupational therapists through an ISL model demonstrated effectiveness at improving satisfaction with occupational performance for individuals with disabilities in Guatemala. Cultural humility, customization of equipment based on personal and environmental factors, inclusion of education and training, and collaboration with in-country partners were identified as contributors to positive outcomes.

Custom seating and mobility services provided by licensed occupational therapists via an international service learning (ISL) model demonstrated a significant improvement on the occupational performance of individuals with disabilities in Guatemala.The customization of equipment based on environmental and personal factors and the provision of education and training were identified as contributors to positive outcomes.Rehabilitation services delivered using an ISL model should be developed and implemented with cultural humility in collaboration with in-country partners.

XP-Endo Finisher behaviour and irrigant temperature in intracanal environment: Clinical measurements.

AIM: To evaluate the behaviour of the XP-Endo Finisher and the variation in the intracanal temperature of the irrigant at rest and when activated over time. METHODOLOGY: Differential scanning calorimetry (DSC) determined the transformation temperatures of XP-Endo Finisher instruments. A digital thermocouple was used to measure the temperature of the irrigant inside the pulp chamber. Two measurements were performed for each tooth (n = 12): with the irrigant at rest and during XP-Endo agitation for 60 s to observe the temperature evolution. The data were statistically analysed using a t-test with a confidence level of 95%. RESULTS: DSC results suggested that the XP-Endo Finisher had a mixed R-phase and austenitic structure at room temperature. The temperature values at predetermined time points (0, 10, 40, 70, 120 and 240 s) were measured, and no statistical difference was observed between the values of the resting and activated solutions at any of the selected points (p > .05). For the protocol performed with the XP-Endo file, the mean irrigant temperature observed at instrument insertion inside the root canal was 28.65°C. After 60 s of agitation, the temperature was 34.02°C. The solution temperature stabilized inside the canal only after 211 s at 35.5°C. The mean maximum irrigation solution temperature recorded inside the canal was 35.5°C without agitation and after XP-endo agitation (p > .05). CONCLUSIONS: Although the XP-Endo Finisher system does not promote heating of the irrigation solution, file expansion responsible for improved instrument cleaning starts at a temperature below the expected value.

Attomolar sensitivity of a redox capacitive and DNA-receptive interface attained by quantum-rate signal amplification concept.

This study demonstrates the application of quantum capacitance (Cq) methods to develop highly sensitive genosensors. This is achieved by employing the quantum mechanical rate (ν∝e2/hCq) concept to enhance the signal response of a redox-active, DNA-receptive interface. In these DNA-receptive interfaces, electrons are transported through the redox-tagged component, enabling signal amplification by adding a redox probe to the sample containing the target DNA. This is effective provided the formal potential of the added redox probe aligns with the energy state E=e2/Cq of the redox-tagged interface. This signal amplification methodology allowed us to detect attomolar levels of DNA biomarkers for diagnosing head and neck squamous cell carcinomas, where amplification is advantageous due to the typically low concentrations of target DNA in biological samples. Designed redox-tagged and DNA-receptive interfaces exhibited a broad detection range, from 103 aM to 108 aM (without amplification) and 1 aM to 105 aM (with amplification), with limit-of-detections ranging from 1.5 fM (without amplification) to 2.2 aM (with amplification). This demonstrates the attomolar sensitivity of this quantum-mechanical signal amplification method for label-free and early clinical diagnosis of cancer, using a genomic receptive interface fabricated through well-established self-assembled monolayer approaches.

Experimental small fields output factors determination for an MR-linac according to the measuring position and orientation of the detector.

Purpose. To investigate the effect of the position and orientation of the detector and its influence on the determination of output factors (OF) for small fields for a linear accelerator (MR-linac) integrated with 1.5 T magnetic resonance following the TRS-483 formalism.Methods. OF were measured for small fields in the central axis following the recommendations of the manufacturer and at the dose maximum following the TRS-483 formalism. OF were determined using a microDiamond (MD), a Semiflex (SF) 31021 ionization chamber, Gafchromic EBT3 film and were calculated in Monaco treatment planning system (TPS). Additionally, the orientation response of SF was evaluated, placing it in parallel and perpendicular direction to the radiation beam. The values were compared taking film measurements as reference. The corrected factors,ΩQclinical,msrfclinical,msr, required the use of output correction factorkQclinical,msrfclinical,msrtaken from previous reports. Finally, there are proposed experimentalkQclinical,msrfclinical,msrfor SF and MD, following the measured values in this work.Results. In fields smaller than 4 cm, the positioning of the SF and MD in the central axis or at the point of dose maximum affects the reading significantly with differences of up to 6% and 4%, respectively. For the data calculated in the TPS, the maximum difference of the OF between MD and TPS for fields greater than 2 cm was 0.6% and below this field size the TPS underestimates the OF up to 10.6%. The orientation (parallel or perpendicular) of the SF regarding the radiation beam has a considerable impact on the OF for fields smaller than 3 cm, showing a variation up to 10% for the field of 0.5 cm.Conclusion. This study provides valuable information on the challenges and limitations of measuring output factors in small fields. The outcomes have important implications for the practice of radiosurgery, underscoring the need for accuracy in detector placement and orientation, as well as the importance of using more advanced technologies and more robust measurement methods.

A tension system for angular correction of bent intramedullary nails: in vitro analysis.

PURPOSE: Although several techniques have been described for bent intramedullary nail removal, there is no universally accepted strategy. We hypothesized that a device based on the action principle of a three-point bend fixture could facilitate extraction of bent intramedullary nails; this paper describes its design and experimental testing. METHODS: Five large synthetic left femurs and five steel intramedullary nails were used. The nails were bent in a manual hydraulic press and implanted into the model femurs, which had been previously sectioned as necessary. A device to correct the angular deformity imparted to the nails was designed, and a prototype fabricated from AISI 1045 steel. Specimens were secured in a vise and the device attached; manual tension was then applied to gradually correct the nail deformity. Plain radiographs were obtained, and the nails were removed. The model femurs and intramedullary nails were visually inspected for proper contact of the device tip, coronal and sagittal alignment, and points of failure. RESULTS: Before device application, the angles of the specimens averaged 40.2° (38.27°-41.32°) in the coronal plane and 7.22° (8.5°-10.2°) in the sagittal plane. After device application, these angles averaged 15.04° (2.5°-32.3°) and 4.16° (0°-9.8°), respectively. There were no implant fractures, but in two models, peri-implant fractures (one catastrophic) occurred close to the proximal and distal locking screws. CONCLUSION: The proposed device for bent intramedullary nail extraction was effective, but homogeneous behavior in terms of angle correction was not observed in the tested specimens. Further development is needed.

Development of a Multiple Temperature Sensors Device for the Characterization, Control and Monitoring of Microbiological Incubators.

An increasing number of projects require the precise knowledge and control of thermal conditions within the study system and their temporal evolution. This is particularly critical for equipment such as laboratory ovens and microbiological incubators, which are essential in various fields of chemistry and microbiology areas. These devices allow and facilitate the execution of experimental work in controlled environments, leading to reproducible experiments. This work presents a methodology for assembling and calibrating a highly accessible and low-cost data logger equipped with multiple temperature sensors. The final calibrated dispositive is straightforward to construct and allows the simultaneous and independent temperature measurement from multiple positions within the same system, which is then applied to the study, characterization, control, and monitoring of the internal thermal behavior of a laboratory oven dedicated to microbiological agents' cultivation. This approach ensures, through a robust methodology, a precise characterization by quantitative methods that allows objective decision making in the management and control of the temperature inside the system. Additionally, the device is suitable for extension and application in diverse research environments by modifying the sensor calibration to achieve a desired temperature range or number of measurement units, representing a potential work tool for laboratory systems.

Effects of a pre-enlargement on fracture incidence of reused reciprocating instruments: A clinical study.

This study assessed the impact of pre-enlarging the root canal using a size 25 K-file on the fracture incidence of three reciprocating instruments after multiple uses. After a glide path performed with a size 15 K-file, the instruments (Reciproc R25, Reciproc Blue R25, and WaveOne Gold Primary) were initially used in 936 root canals. Then, for the second and third uses (933 and 927, respectively), a pre-enlargement using a size 25 K-file at the working length was done. Periapical radiographs assessed fragment location and length, and chi-square tests compared observed and expected frequencies (α = 5%). The fracture incidence during reuse ranged from 0% to 0.64%. Reciproc did not fracture during reuse (P = 0.99), but experienced two fractures in the third use (P = 0.000). Reciproc Blue and WaveOne Gold each had one fracture during the second (P = 0.000) and third (P = 0.000) uses. Following a pre-enlargement using a size 25 K-file for the second and third uses in 1,860 canals, only 6 instruments fractured (0.32%), suggesting that this approach may prolong the lifespan of these instruments and serve as an alternative for their reuse with a reduced risk of fracture.

Development and validation of the thyroidectomy training box: cervical simulator for training endoscopic transoral thyroidectomy.

PURPOSE: To develop and validate a trans oral endoscopic thyroidectomy vestibular approach (TOETVA) simulator. METHODS: The first phase of the project consisted of designing and developing a transoral thyroid surgery simulator based on real surgeries. The product has the oral cavity for attaching the three trocars and the cervical part containing the thyroid and adjacent structures. In the second phase, the simulator was validated by specialists who performed an endoscopic thyroidectomy procedure. They all filled a questionnaire about the simulator and the simulation based on the Likert scale. RESULTS: The simulator consists of a console similar to a human bust and a high-resolution camera system connected to a 22-inch monitor. The simulator had excellent results in the visual evaluation (face validity), with 100% of responses between good and excellent for the following characteristics: synthetic structures, design, visibility of the surgery field, resistance, resilience, fulcrum effect, ergonomics, surgical material, and practicality. The last three were rated higher, with more votes for excellent. For content validity, the items that received the best ratings were, precisely, the steps relating to the surgical procedure: opening the intermuscular midline, isthmotomy, and thyroidectomy. CONCLUSIONS: The thyroidectomy training box showed great ability to simulate a TOETVA, with satisfactory evaluations concerning its visual and content validation.

Thermal Bed Design for Temperature-Controlled DNA Amplification Using Optoelectronic Sensors.

Loop-Mediated Isothermal Loop-Mediated Isothermal Amplification (LAMP) is a widely used technique for nucleic acid amplification due to its high specificity, sensitivity, and rapid results. Advances in microfluidic lab-on-chip (LOC) technology have enabled the integration of LAMP into miniaturized devices, known as µ-LAMP, which require precise thermal control for optimal DNA amplification. This paper introduces a novel thermal bed design using PCB copper traces and FR-4 dielectric materials, providing a reliable, modular, and repairable heating platform. The system achieves accurate and stable temperature control, which is critical for µ-LAMP applications, with temperature deviations within ±1.0 °C. The thermal bed's performance is validated through finite element method (FEM) simulations, showing uniform temperature distribution and a rapid thermal response of 2.5 s to reach the target temperature. These results highlight the system's potential for applications such as disease diagnostics, biological safety, and forensic analysis, where precision and reliability are paramount.

Effect of Battery Level During Successive Charging Cycles on the Performance of Certified and Low-cost Uncertified Light-curing Units Available on E-commerce.

OBJECTIVE: To evaluate the influence of battery level on power (mW), emission spectrum (mW/cm2/ nm), and light distribution on the active tip (mW/ cm2) of certified (FDA/ANVISA) and low-cost uncertified light-curing units (LCUs) purchased through e-commerce. METHODS: Seven LCUs, three certified: VALO Grand (Ultradent); Radii Xpert (SDI); and LED.B (Woodpecker); and four uncertified: 1 Sec; BS 300; LED curing light; and VAFU (VRN, AZDENT), were used. The LCUs were evaluated by calculating the power (mW) after each sequential five exposure cycles of 20 seconds and the emission spectrum (mW/cm2/nm) in the initial and final cycles, using an integrating sphere during three battery charging cycles. Beam profiling was used to check the light distribution on the LCU tip after every 50 exposure cycles until the battery fully discharged. Data were analyzed by linear regression between power and the number of exposure times (R2). RESULTS: The certified LCUs VALO Grand (R2=0.005), LED.B (R2=0.02), and Radii Xpert (R2=0.09) and the uncertified LCU VAFU (R2=0.002) had no significant power reduction during the three battery charging cycles. The uncertified LCUs BS 300 (R2=0.87), 1 Sec (R2=0.60), and LED curing light (R2=0.83) showed significant power reduction, decreasing the emission spectrum (mW/cm2/nm) at the end of the battery charging cycle. The light distribution on the active tip across the level battery was modified significantly with successive exposure times. CONCLUSIONS: The certified LCUs (VALO Grand, Radii Xpert, and LED.B) and uncertified LCU (VAFU), maintained power, emission spectrum, and light distributions during the tested battery life cycles. Low-cost certified LCU LED.B exhibited inhomogeneous light concentrated at the center of the tip. Low-cost uncertified LCUs-BS 300, 1 Sec, and LED curing light-had significant power reductions during the battery cycles and increased inhomogeneous light distribution along the successive exposure times.

Modular and Portable System Design for 3D Imaging of Breast Tumors Using Electrical Impedance Tomography.

This paper presents a prototype of a portable and modular electrical impedance tomography (EIT) system for breast tumor detection. The proposed system uses MATLAB to generate three-dimensional representations of breast tissue. The modular architecture of the system allows for flexible customization and scalability. It consists of several interconnected modules. Each module can be easily replaced or upgraded, facilitating system maintenance and future enhancements. Testing of the prototype has shown promising results in preliminary screening based on experimental studies. Agar models were used for the experimental stage of this project. The 3D representations provide clinicians with valuable information for accurate diagnosis and treatment planning. Further research and refinement of the system is warranted to validate its performance in future clinical trials.

Analysis of the positive expiratory pressure valves of coupled oronasal mask.

Positive expiratory pressure (PEP) is a technique used in respiratory physiotherapy to treat diseases related to the respiratory system through spontaneous breathing. This equipment consists of an oronasal mask coupled to a T connector with a unidirectional valve. Studies that evaluate whether the pressure level in the one-way valve corresponds to the actual pressure level provided are scarce in the scientific literature. In order to investigate the failures, bench tests were carried out on the spring-loaded valves, using a U-tube manometer. This pressure was exerted on the valve using a syringe that generated air flow inside the U-tube, allowing analysis numerical value of the measured pressure and the specified values of the valve, thus verifying the disparity of these measured values in relation to the PEP values operated by valves (0 to 20 cmH2O) from the three manufacturers under study. PEPs generated by spring-loaded valves from all three manufacturers were higher than pressures in the range of 2.5 to 20 cmH2O, with significant differences between manufacturers. This bench study showed inaccurate operation of all spring-loaded PEP valves of the three manufactures. The results obtained and the performance of the valves require a reevaluation of manufacturing procedures to preserve product quality and efficacy in clinical application.

Bioinspired cooperation in a heterogeneous robot swarm using ferrofluid artificial pheromones for uncontrolled environments.

This article presents a novel bioinspired technology for the cooperation and coordination of heterogeneous robot swarms in uncontrolled environments, utilizing an artificial pheromone composed of magnetized ferrofluids. Communication between different types of robots is achieved indirectly through stigmergy, where messages are inherently associated with specific locations. This approach is advantageous for swarm experimentation outside controlled laboratory spaces, where localization is typically managed through centralized camera systems (e.g. infrared, RGB). Applying pheromone principles has also proven beneficial for various swarm behaviors. We introduce a detection methodology for the artificial ferrofluid pheromone using low-cost magnetic sensors, along with signal processing and parameter characterization. Experiments involved a heterogeneous swarm consisting of two types of robots: one equipped with camera and image processing capabilities and the other with basic sensor technologies. Validation in multiple uncontrolled environments (with varying floor surfaces, wind, and light conditions) demonstrated successful cooperation among robots with differing technological complexities using the proposed technology.

Development and evaluation of low-cost flat plate photobioreactors for microalgae and cyanobacteria cultivation with biotechnological potential.

The high performance of biomass and metabolite biosynthesis by photosynthetic microorganisms is directly influenced by the cultivation system employed. Photobioreactors (PBRs) stand out as controlled and fundamental systems for increasing the production of biocompounds. However, the high costs associated with these systems hinder their viability. Thus, a more practical and economical approach is necessary. Accordingly, this study aimed to design and evaluate low-cost flat-panel photobioreactors on a laboratory scale for the cultivation of photosynthetic microorganisms, using economical materials and instruments. Additionally, internal optimization of the low-cost system was aimed to maximize growth and biomass production. The PBRs were designed and built with uniform dimensions, employing 4 mm translucent glass and agitation through compressors. The internally optimized system (PBR-OII) was equipped with perforated acrylic plates used as static mixers. To evaluate the performance of the low-cost PBR-OII, a comparison was made with the control photobioreactor (PBR-CI), of the same geometry but without internal optimization, using a culture of Synechocystis sp. CACIAM 05 culture. The results showed that the PBR-OII achieved maximum biomass yield and productivity of 6.82 mg/mL and 250 mg/L/day, respectively, values superior to the PBR-CI (1.87 mg/mL and 62 mg/L/day). Additionally, the chlorophyll concentration in the PBR-OII system was 28.89 ± 3.44 µg/mL, while in the control system, the maximum reached was 23.12 ± 1.85 µg/mL. Therefore, low-cost photobioreactors have demonstrated to be an essential tool for significantly increasing biomass production, supporting research, and reducing costs associated with the process, enabling their implementation on a laboratory scale.

Perception and satisfaction of blind individuals regarding an electronic cane prototype with a wearable haptic device.

PURPOSE: This study aimed to evaluate the perception and degree of satisfaction of blind individuals regarding an electronic cane prototype with a wearable haptic interface. METHODS: Two scenarios with different obstacles were created to conduct tests with the canes (the user's cane and the prototype one). The perception and satisfaction of participants regarding the electronic cane were assessed using a questionnaire, the number of collisions during the tests, and the time each individual took to complete the course in each scenario. RESULTS: Ten blind individuals who used the white cane participated in this study. Eight were males, and two were females. Their age ranged from 23 to 43 (average 32.3 ± 7.13 years and median 32 years). There was a tendency for fewer collisions with ground obstacles when the electronic cane was used than when the white cane was used. However, there was no statistically significant difference between the number of collisions and the course completion time in each scenario with either canes tested. CONCLUSION: Overall, the perception and satisfaction of individuals regarding the prototype used were positive.

Construction and enhancement of a prototype for a medical-hospital equipment for hypodermoclysis: a qualitative study.

OBJECTIVES: to construct a Subcutaneous Hydration Device semi-functional prototype and gather initial information to improve this prototype design and realize its acceptance potential. METHODS: a qualitative, descriptive and exploratory study, which used focus group, following the Technology Acceptance Model. The group was held at the Escola Superior de Enfermagem de Coimbra, Portugal, in December 2022, composed of nine participants from six different disciplinary areas, and followed thematic analysis. RESULTS: four topics emerged associated with the device components: elastomeric infusion pump; needle/access device; clamp; administration set. From these topics, topics were triggered that highlighted: characteristics about the target population; ease of use and accessories; patient comfort and safety; and device application context. FINAL CONSIDERATIONS: the Subcutaneous Hydration Device semi-functional prototype is viable and interesting for the clinic. The results support its improvement and direct future investments for experimental studies.

Cyclic fatigue resistance of two pediatric rotary files manufactured with different heat treatments: an in-vitro study.

Nickel-titanium (NiTi) instruments offer many advantages during endodontic instrumentation; however, the fracture risk within the canal remains a concern. Manufacturers continuously develop and introduce instruments to the market with supposedly enhanced cyclic fatigue resistance and increased flexibility, achieved through different proprietary manufacturing processes, the details of which have not been made public. In recent years, two rotary systems specially designed for deciduous teeth have been commercially available, but information about their performance is lacking. This investigation aimed to identify which manufacturing process provides better cyclic fatigue resistance: the AF-H Wire technology used in the AF baby rotary files (AF-f) or the CM-Wire technology used in the i3 Gold deciduous teeth rotary files (i3G-f). Forty rotary International Organization for Standardization (ISO) 25/04 files were tested in artificial canals with a standard geometry of 60° angle and 2.5 mm radius until fracture. The number of cycles to fracture was calculated, and the length of the fragments was measured. A scanning electron microscope (SEM) was used to examine the fracture surfaces and fragments. Energy dispersive spectroscopy (EDS) was used to determine the percentage weight of NiTi in each file. The statistical analysis (Mann-Whitney test) showed that the cyclic fatigue resistance of the AF-f was significantly higher (p < 0.0001) than that of the i3G-f. Additionally, there was a significant difference (p = 0.0419) in the length of the fractured fragments. All instruments showed one or more types of manufacturing defects and presented similar NiTi percentages by weight. The manufacturing process is critical to cyclic fatigue resistance, and there seems to be responsible for the difference in cyclic fatigue resistance between these similar instruments.