Instrument Size Research Articles

Evaluation of cyclic fatigue and bending test for different Nickle-Titanium files.

To compare cyclic fatigue resistance and bending for three different nickel-titanium (NiTi) rotary files. A sample of 90 NiTi instruments size (25.06) was divided into three groups with 30 files in each: Race Evo files (FKG Dentaire, Switzerland); Tia Tornado Blue files (TiaDent Inc., Texas- USA); One Curve files (Micro-Mega, France). Then each group was subdivided into two groups with 15 files in each; a bending test was performed for one group, and a dynamic cyclic fatigue test at body temperature was performed for the other group. Files fractured by cyclic fatigue were randomly picked from all tested groups for Scanning Electron Microscopy (SEM) (Jeol, Tokyo, Japan). In addition, the test included measuring the broken part of the files tested using (Electronic Micrometre Calliper with LCD Screen, Inch and Millimetre Conversion, Adoric- Taiwan). Data were statistically analyzed using a one-way ANOVA with Tukey-HSD post hoc test. It was found that maximum load [gf] was less (meaning more flexible) in the group of Tia Tornado Blue with a statistically significant difference in comparison with Race Evo and One Curve. The number of cycles to fracture (NCF) in the Race Evo group was significantly higher than the groups of One Curve and Tia Tornado Blue. Within the limitation of the study, it could be concluded that Race Evo files were more resistant to cyclic fatigue fracture and Tia Tornado Blue files were more flexible compared to the other tested files.

To flat or not to flat? Exploring the impact of flat-side design on rotary instruments using a comprehensive multimethod investigation.

To assess the influence of a flat-side design on the geometry, metallurgy, mechanical performance and shaping ability of a novel nickel-titanium rotary instrument. Sixty-five new 25-mm flat-side rotary instruments (size 25, taper 0.04) and their nonflat-side prototypes (n = 65) were assessed for major deformations and examined regarding macroscopic and microscopic design, determination of nickel and titanium elements ratio, measurement of phase transformation temperature and evaluation of mechanical performance parameters including time/cycles to fracture, maximum torque, angle of rotation, maximum bending and buckling strengths and cutting ability. Additionally, unprepared canal areas, volume of hard tissue debris and percentage reduction of dentine thickness were calculated for each tested instrument after preparing mesial canals of mandibular molars (n = 12), using micro-CT imaging. Statistical analyses were performed using the U-Mann-Whitney test and independent Student t-test (α = 5%). The number of spirals (n = 8) and blade direction (clockwise) were similar between both flat and nonflat instruments, whilst the helical angles were equivalent (⁓25°). Flat-instruments showed inconsistencies in the homogeneity of the gold colour on the flat-side surface, blade discontinuity, and incomplete and variable S-shaped cross-sections. The titanium-to-nickel ratios were equivalent, but significant differences in the R-phase finish and austenitic start phase transformation temperatures were observed between the flat and nonflat-side instruments. The flat-side instruments demonstrated superior cutting ability compared to the nonflat instruments, as well as, significantly lower values for time to fracture, rotation to fracture and maximum torque to fracture (p < .001). No statistical difference was observed between tested instruments regarding angle of rotation (p = .437), maximum bending (p = .152) and buckling load (p = .411). Preparation protocols using flat and nonflat instruments did not show any statistically significant differences (p > .05). All flat-side instruments exhibited deformation after shaping procedures. The flat-side instrument showcased enhanced cutting ability compared to its nonflat counterpart. However, it exhibited inferior performance in terms of time, rotation and maximum torque to fracture, along with distinct phase transformation temperatures. No differences were observed in the titanium-to-nickel ratios, angle of rotation, maximum bending, buckling load, preparation time, percentage of untouched canal walls, volume of hard tissue debris and percentage reduction of dentine thickness.

Phase transformation behavior and mechanical properties of HyFlex EDM nickel-titanium endodontic rotary instrument: Evaluation at body temperature

Background/purposeTemperature-dependent phase compositional changes influence the mechanical properties of heat-treated nickel-titanium (NiTi) rotary instruments. This study evaluated the phase composition, bending properties, and cyclic fatigue resistance of HyFlex EDM NiTi rotary instruments against differently heat-treated and non-heat-treated NiTi instruments at body temperature (BT). Materials and methodsHyFlex EDM OneFile (EDM) instruments, heat-treated HyFlex CM (CM) and Twisted File (TF) instruments, and non-heat-treated K3 instruments (size #25/.08) were subjected to differential scanning calorimetry, and the martensitic, R-phase, and reverse transformation starting and finishing temperatures were determined. A cantilever bending test and a cyclic fatigue test were conducted at BT (37 °C ± 1.0 °C), and the bending load and number of cycles to failure (NCF) were recorded. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney U tests (α = 0.05). ResultsTF and K3 had reverse transformation finishing temperatures lower than BT, while those for EDM and CM were higher than BT. The bending loads at a 0.5 mm deflection were in the order of EDM < TF < CM < K3 (P < 0.05), and those at a 2.0 mm deflection were EDM < CM and TF < K3 (P < 0.05). EDM had the highest NCF among the four instruments (P < 0.05). ConclusionThe EDM instrument had a reverse transformation finishing temperature higher than BT indicating its martensite/R-phase composition at BT. The EDM instrument had superior flexibility and greater resistance to cyclic fatigue than the CM, TF, and K3 instruments at BT.

The use of sodium hypochlorite mixed with etidronic acid during canal preparation increases debris extrusion.

The purpose of this study was to compare the impact of different irrigation protocols on debris extrusion. Single-rooted teeth were distributed into groups based on the irrigation protocols (n = 40): 2.5% NaOCl (biomechanical preparation: 20 mL and final irrigation: 5 mL); 2.5% NaOCl (biomechanical preparation: 20 mL) + 17% EDTA (final irrigation: 2 mL) + 2.5% NaOCl (final irrigation: 3 mL); and a mixture of 5% NaOCl +18% HEDP (biomechanical preparation: 20 mL and final irrigation: 5 mL). The canals were prepared using a reciprocating instrument size 40/0.06. For final irrigation, the groups were reassigned based on the agitation methods (n = 10): (a) no agitation; (b) ultrasonic; (c) sonic; and (d) continuous rotation. The control group (n = 10) received saline solution without agitation. The amount of debris extruded was measured by weight and analysed using One-way ANOVA (α < 0.05). The subgroups treated with NaOCl + HEDP mixture showed a significantly higher amount of extruded debris (p < 0.05), while there was no difference among agitation methods in all groups (p > 0.05).

Lunar ore geology and feasibility of ore mineral detection using a far-IR spectrometer

Lunar sulfides and oxides are a significant source of noble and base metals and will be vital for future human colonies’ self-sustainability. Sulfide detection (pyrite and troilite) applies to many technological fields and use cases, for example, as a raw material source (available in situ on the Lunar surface) for new solar panel production methods. Ilmenite is the primary iron and titanium ore on the Moon and can provide helium-3 for nuclear fusion and oxygen for rocket fuel. The most important ore minerals have prominent absorption peaks in a narrow far-infrared (FIR) wavelength range of 20–40 μm, much stronger than the spectral features of other common minerals, including significant silicates, sulfates, and carbonates. Our simulations based on the linear mixing of pyrite with the silicates mentioned above indicated that areas containing at least 10%–20% pyrite could be detected from the orbit in the FIR range. MIRORES, Multiplanetary far-IR ORE Spectrometer, proposed here, would operate with a resolution down to &amp;lt;5 m, enabling the detection of areas covered by 2–3 m2 of pyrite (or ilmenite) on a surface of ∼17 m2 from an altitude of 50 km, creating possibilities for detecting large and local smaller orebodies along with their stockworks. The use of the Cassegrain optical system achieves this capability. MIRORES will measure radiation in eight narrow bands (0.3 µm in width) that can include up to five bands centered on the ore mineral absorption bands, for example, 24.3, 24.9, 27.6, 34.2, and 38.8 µm for pyrite, marcasite, chalcopyrite, ilmenite, and troilite, respectively. The instrument size is 32 x 32 x 42 cm, and the mass is &amp;lt;10 kg, which fits the standard microsatellite requirements.

Clinical Study of Antimicrobial Efficacy of Laser Ablation Therapy with Indocyanine Green in Root Canal Treatment

IntroductionLaser ablation (LA) therapy is used as an adjunct to endodontic treatment to improve microbial reduction. However, studies evaluating the impact of LA with indocyanine green (ICG) are scarce. This study aimed to evaluate the antimicrobial efficacy of LA therapy with ICG in root canal treatment. MethodsSixty patients with periapical lesions in teeth with a single canal and absence of pain, edema, and previous treatment were selected. Patients were randomly allocated into 3 groups according to the apical sizes used (n = 20); 25/04, 30/04, and 35/04 were the final sizes used. In half the patients of each group, 2.5% sodium hypochlorite was used as an irrigating solution, and in the other half, saline solution was used. After instrumentation, all patients received LA therapy with ICG. Root canal sampling was performed before (S1) and after (S2) root canal instrumentation and immediately after LA therapy with ICG (S3). Colony-forming units were counted, and statistical tests were applied (P < .05). ResultsThere was a significant reduction in colony-forming units from S1 to S2 in all treatment protocols (P < .05); 2.5% sodium hypochlorite as an irrigating solution showed a greater microbial reduction compared with saline solution (P < .05). LA therapy with ICG further reduced the microbial counts significantly (S2 to S3 and S1 to S3) whether sodium hypochlorite or saline was used (P < .05). ConclusionsLA therapy with ICG significantly increased microbial reduction in root canals regardless of instrumentation sizes or the irrigation solution used.

Design of Angklung Music Scoring System Based on Remote Training

Angklung is a traditional musical instrument from West Java, Indonesia. To play a song using this instrument can only be played in groups. The size of the musical instrument is quite large and prone to damage if carried anywhere, making it challenging to practice except in schools or music clubs. Since the pandemic, it has become increasingly difficult for students to practice angklung due to the limitations of face-to-face learning. This study aims to make it easier for students to practice and play angklung. The system is based on online multiplayer games so that students can learn and play angklung with more fun, and players can play anywhere. Players can use the mobile version of the angklung application as a substitute for the angklung instrument. Players can perform a duet with other players in playing the same song. The results of the player's performance will be displayed as scores and stored in the database. Besides that, a real-time feedback function is always displayed for each note played. To distinguish individual players and/or notes, we use vibration sensor technology installed in each mobile application or signal processing, and the system will recognise them properly. We propose a Short-time Fourier Transform (STFT) algorithm as a scoring system and realtime-feedback performance. We use class diagrams to describe the whole application system and describe the functionality of the system in detail. We collect some research related to angklung and technology. Currently, there is a little study that could answer all the problems of learning and training angklung. The results of this study in the form of a system design are the initial research stage and are used for the following research phase. In conclusion, the design of this study can solve the existing problems so that the system will make it easier for students to practice and play angklung.

Chaos Bells: Instrument Size and Entangled Music Performance

ABSTRACT There is a current trend in the instrument design industry of scaling down physical dimensions, resulting in smaller and smaller ‘desktop’ instruments, but research conducted with large interfaces reveals the role of instrument size on music performance. Chaos Bells is a very large digital musical instrument designed with both artistic and analytical goals in mind: it is a probe into the effect of instrument size on performance, while also being a vehicle for the first author’s performance practice. Drawing on entanglement theories of HCI we supplement the findings of lab-based studies with Chaos Bells with new discoveries made by the first author when touring with Chaos Bells. This research elucidates the indirect influences of stakeholders on instrument design culture, and ways that taking a large instrument design approach can benefit designers of instruments of all sizes.

In vivo Study to Evaluate the Effect of Instrument Size on the Accuracy of Three Different Apex Locators when Various Irrigation Solutions are used in Vital and Non-Vital Teeth.

Root canal success requires working length (WL) optimization. The current study examined how different apex locators on vital and non-vital teeth responded to instrument size. Three hundred patients (180 men and 120 women) receiving root canal therapy at the department of Conservative Dentistry and Endodontics were evaluated. Therefore, we determined that 200 of the patients' teeth (100 vital and 100 non-vital teeth from the upper and lower jaws' first molars) qualified for inclusion in our study. The pulp chamber was accessed using a sterile round bur. The coronal region of the root canal was preflared with successive Gates Glidden drills (Mani Inc. Japan) and irrigated with any one of the solutions 3% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), or 17% ethylenediaminetetraacetic acid (EDTA) solution after checking canal patency with a size #10 K file, where (#-number). Later, the working length was established using Ingle's technique and a radiovisiograph (RVG) 0.5 mm short of the radiographic apex. Two endodontists approved this RVG. Overall, the #15 K file and apex locators did not differ from Ingle's method. While the #8 K file differs significantly from all apex locators, the #10 K file showed a significant difference with all apex locators except Root ZX with 2% CHX (P = 0.06). Irrigation didn't influence apex locators' accuracy. Even in the presence of irrigating solutions, electronic apex locator (EAL) can be utilized to calculate the working length with accuracy. The apex locators #15 k files, #10 k files, and #8 k files showed the most promising results.

Rapid and Portable Detection of Hg and Cd in Grain Samples Based on Novel Catalytic Pyrolysis Composite Trap Coupled with Miniature Atomic Absorption Spectrometry.

As toxic metals, Hg and Cd are a concern for food safety and human health; their rapid and portable analysis is still a challenge. A portable and rapid Hg-Cd analyzer constructed from a metal-ceramic heater (MCH)-based electrothermal vaporizer (ETV), an on-line catalytic pyrolysis furnace (CPF), a composite Pt/Ni trap, and a homemade miniature atomic absorption spectrometer (AAS) was proposed for grain analysis in this work. To enhance sensitivity, a new folded light path was designed for simultaneous Hg and Cd analysis using charge coupled device (CCD) in AAS. To eliminate the grain matrix interference, a catalytic pyrolysis furnace with aluminum oxide fillers was utilized to couple with a composite Pt/Ni trap. The method limits of detection (LODs) were 1.1 μg/kg and 0.3 μg/kg for Hg and Cd using a 20 mg grain sample, fulfilling the real sample analysis to monitor the grain contamination quickly; linearity R2 > 0.995 was reached only using standard solution calibration, indicating the sample was free of grain matrix interference. The favorable analytical accuracy and precision were validated by analyzing real and certified reference material (CRM) grains with recoveries of 97-103% and 96-111% for Hg and Cd, respectively. The total analysis time was less than 5 min without sample digestion or use of any chemicals, and the instrumental size and power consumption were <14 kg and 270 W, respectively. Compared with other rapid methods, this newly designed Hg-Cd analyzer is proven to be simple, portable, and robust and is, thus, suitable to quickly monitor Hg and Cd contamination in the field to protect grain and food safety.

Female Surgical Ergonomics in Otolaryngology: A Qualitative Study.

To explore the surgical ergonomic challenges experienced by women in otolaryngology, identify specific equipment that is ergonomically challenging, and assess the impact of suboptimal ergonomics on female otolaryngologists. We performed a qualitative study using an interpretive framework rooted in grounded theory. We performed semi-structured qualitative interviews of 14 female otolaryngologists from nine institutions at various stages in training and across subspecialties. Interviews were independently analyzed by thematic content analysis by two researchers and inter-rater reliability was assessed via Cohen's kappa. Differing opinions were reconciled via discussion. Participants noted difficulties with equipment including microscopes, chairs, step stools, and tables as well as difficulty using larger surgical instruments, preference for smaller instruments, frustration with lack of smaller instruments, and a desire for a larger spectrum of instrument sizes. Participants reported neck, hand, and back pain associated with operating. Participants suggested modifications to the operative environment, including a wider variety of instrument sizes, adjustable instruments, and more focus and attention on ergonomic issues and the range of surgeon physiques. Participants felt that optimizing their operating room set-up was an additional burden on them, and that lack of inclusive instrumentation affected their sense of belonging. Participants emphasized positive stories of mentorship and empowerment from peers and superiors of all genders. Female otolaryngologists face unique ergonomic challenges. As the otolaryngology workforce becomes increasingly diverse, it is important to address the needs of a diverse set of physiques to avoid inadvertently disadvantaging certain individuals. N/A Laryngoscope, 133:3034-3041, 2023.

Effect of instrument type and one-handed versus two-handed grips on force application during simulated instrument-assisted soft tissue mobilisation

ObjectiveThe purpose of this study was to examine whether the forces used by trained clinicians during a simulated instrument-assisted soft tissue mobilisation (IASTM) treatment varied across five different instruments during...

A High Kinetic Energy Ion Mobility Spectrometer for Operation at Higher Pressures of up to 60 mbar

High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) are usually operated at absolute pressures around 20 mbar in order to reach high reduced electric field strengths of up to 120 Td for influencing reaction kinetics in the reaction region. Such operating points significantly increase the linear range and limit chemical cross sensitivities. Furthermore, HiKE-IMS enables ionization of compounds normally not detectable in ambient pressure IMS, such as benzene, due to additional reaction pathways and fewer clustering reactions. However, operation at higher pressures promises increased sensitivity and smaller instrument size. In this work, we therefore study the theoretical requirements to prevent dielectric breakdown while maintaining high reduced electric field strengths at higher pressures. Furthermore, we experimentally investigate influences of the pressure, discharge currents and applied voltages on the corona ionization source. Based on these results, we present a HiKE-IMS that operates at a pressure of 60 mbar and reduced electric field strengths of up to 105 Td. The corona experiments show shark fin shaped curves for the total charge at the detector with a distinct optimum operating point in the glow discharge region at a corona discharge current of 5 μA. Here, the available charge is maximized while the generation of less-reactive ion species like NOx+ is minimized. With these settings, the reactant ion population, H3O+ and O2+, for ionizing and detecting nonpolar substances like n-hexane is still available even at 60 mbar, achieving a limit of detection of just 5 ppbV for n-hexane.

Effects of the airfoil probes on the aerodynamic performance of a transonic compressor cascade

The airfoil probe is typical instrumentation for measuring total pressure/temperature in the research fields of turbomachinery. Besides causing measurement error itself, it also generates extra flow loss inevitably and further affects the measuring accuracy. This paper utilizes the Reynolds-averaged Navier Stokes (RANS) and high-fidelity methods to understand the effects of airfoil probes on the aerodynamic performance of a compressor cascade. With the inclusion of airfoil probes, the load capacity and the shock waves decline, to some extent, mainly because of the streamwise vortex. The shedding vortex induced by the probes triggers an earlier and non-separated flow transition, which contributes to a suppression of the separation bubble on the suction surface and a reduction of the profile loss. However, through the quantitative traceability analysis of the flow loss, the extra loss is generated and redistributed to the overall flow field. The separated flow forms at the junction of the end wall, blade, and probe's pipes, due to the high adverse pressure gradient aggravated by shock waves. It is one of the reasons why the measuring accuracy of airfoil probes is quite sensitive to the Mach numbers. The Delayed-Detached Eddy Simulation (DDES) shows superiority in capturing small-scale coherent vortex structures. The shedding streamwise vortex generated by the probe's pipe is distinguished for the first time. Its transport progression to the wake region is revealed basically, which has been masked previously by the conventional RANS method. In addition, due to the supplement of the streamwise vortex generated by probes, the wake vortices maintain a higher shedding frequency. This work offers a glimpse of the complex fluid mechanisms in a transonic regime, which suggests carefully considering the size of instruments in the design and measurement process.

Development of the Miniature Robotic Electrodialysis (MR ED) System for Small‐Scale Desalting of Liquid Samples With Recovery of Organics

AbstractWhile liquid environments with high salt content are of broad interest to the Earth and Planetary Science communities, instruments face challenges in detecting organics in hypersaline samples due to the effects of salts. Therefore, technology to desalt samples before analysis by these instruments would be enabling for liquid sampling on missions to Mars or ocean worlds. Electrodialysis (ED) removes salt from aqueous solutions by applying an electric potential across a series of ion‐selective membranes, and is demonstrated to retain a significant percentage of dissolved organic molecules (DOM) in marine samples. However, current electrodialysis systems used for DOM recovery are too large for deployment on missions or for use in terrestrial fieldwork. Here, we present the design and evaluation of the Miniature Robotic Electrodialysis (MR ED) system, which is approximately 1/20th the size of heritage instruments and processes as little as 50 mL of sample at a time. We present tests of the instrument efficiency and DOM recovery using lab‐created solutions as well as natural samples taken from an estuary of the Skidaway River (Savannah, GA) (Verity, 2002) and from South Bay Saltworks (San Diego, CA) (Roseman &amp; Watry, 2008; Survey, 2011). Our results show that the MR ED system removed 97%–99% of the salts in most samples, with an average DOC recovery range from 53% to 77%, achieving similar capability to tabletop instruments. This work both demonstrates MR ED as a possible field instrument and increases the technology readiness level of miniaturized electrodialysis systems for future missions.

Calculation method based on a BGO+SiPM detector for ^13N gas coincidence detection efficiency

To reduce the lower detection limit of 13N gas, we design a γ-γ coincidence measuring instrument including two detectors, a sampling vessel, and a summation and coincidence circuit in this work. The detector uses a 13 cm × 5 cm oversized Bi4Ge3O12 (BGO) scintillator and 172 silicon photomultiplier (SiPM) tubes, which greatly reduce the instrument size while improving the coincidence detection efficiency. The 13N gas coincidence detection efficiency is improved by installing a multilayer metal absorber plate inside the cylindrical sampling vessel. Due to the short half-life of 13N gas, it cannot be stored for a long time; additionally, it is difficult to obtain. It is not possible to directly scale the coincidence detection efficiency of this instrument using a 13N gas source with known activity in engineering projects. Based on the spatial distribution of the relative efficiency of the sampling vessel and the absolute efficiency of the reference point, we use a combination of 22Na solid point source experiments and Monte Carlo simulations to calculate the coincidence detection efficiency of this instrument for 13N gas in this work; the coincidence detection efficiency is approximately 4%, which meets the engineering design requirements.

Excellent Correlation of the Patient-Reported Outcomes Measurement Information System Upper Extremity Score With Legacy Outcome Scores Preoperatively and at 1 Year After Arthroscopic Rotator Cuff Repair

To assess the preoperative and postoperative performance of the Patient-Reported Outcomes Measurement Information System Upper Extremity (PROMIS-UE, version 2.0) outcome score in comparison to the American Shoulder and Elbow Surgeons (ASES) and Western Ontario Rotator Cuff Index (WORC) instruments in patients undergoing rotator cuff repair. This prospective longitudinal study included 91 patients undergoing rotator cuff repair. Patients completed the PROMIS-UE, ASES, and WORC instruments preoperatively and postoperatively at 2 weeks, 6 weeks, 3 months, and 12 months. The Pearson correlation coefficient (r) between these tools was calculated at each time point. Correlations were graded as excellent (>0.7), excellent-good (0.61-0.7), good (0.4-0.6), or poor (<0.4). Responsiveness to change was assessed using the effect size and the standardized response mean. Floor and ceiling effects for each instrument were also assessed. The PROMIS-UE instrument showed good to excellent correlation with the legacy instruments at all time points. There were variations in the measured effect sizes of the various instruments, with the PROMIS-UE instrument showing responsiveness to change at 3 and 12 months but the ASES and WORC instruments showing responsiveness at 6 weeks, 3 months, and 12 months. Both PROMIS-UE and ASES scores displayed ceiling effects at 12 months. The PROMIS-UE instrument shows excellent correlation with the ASES instrument and a rotator cuff-specific outcome instrument-the WORC instrument-preoperatively and at 1 year after arthroscopic rotator cuff repair. Variations in the measured effect sizes at different postoperative time points and high ceiling effects of the PROMIS-UE instrument at the 1-year time point may limit its utility in the early postoperative phase and at long-term follow-up after rotator cuff repair. The performance of the PROMIS-UE outcome measure after arthroscopic rotator cuff repair was investigated.

Noncustodial parents, instrumental networks, and child support compliance

Research on child support compliance has focused on the characteristics of noncustodial parents (NCPs) that are associated with compliance, finding that compliance with child support orders is primarily related to the ability to pay support as demonstrated by earnings. Yet, there is evidence linking social support networks to both earnings and noncustodial parents' relationships with children. Using a social poverty framework, we show that relatively few NCPs are completely isolated: most have at least some people in their network who can loan money, provide a place to stay, or provide a ride. We explore whether the size of these instrumental support networks is positively linked to child support compliance both directly and indirectly through earnings. We find evidence of a direct association between instrumental support network size and child support compliance, but no evidence of an indirect association via increased earnings. These findings suggest the importance for researchers and child support practitioners to consider the contextual and relational factors of the social networks in which parents are embedded, and to more thoroughly examine the process by which support from one's network can lead to child support compliance.

Effects of Conservative Access and Apical Enlargement on Shaping and Dentin Preservation with Traditional and Modern Instruments: A Micro-computed Tomographic Study

IntroductionThis ex vivo study aimed to evaluate the shaping abilities and preservation of dentin with traditional and modern instruments after using sizes 25 and 40 in oval canals of mandibular incisors with conservative access. MethodThirty mandibular incisors with single straight oval canals were selected and assigned into 2 groups (n = 15) according to the instrument system used during preparation, Slim Shaper (SS) plus Apical Shaper (AS) and Protaper Gold (PG). The samples were subjected to micro-computed tomography before and after preparation with sizes 25 and 40. The shaping parameters evaluated included canal volume and surface area, amount of unprepared root canal walls, and reduction in pericervical dentin. ResultsCanal volume and surface area were significantly increased after enlargement with each instrument size (P < .01). The percentage of unprepared areas showed a significant intragroup decrease after using PG F2 and F4 or SS 3 and AS (P < .05). Intergroup comparison showed no significant differences. Pericervical dentin was reduced in all groups. The intragroup comparison only revealed a significant reduction (P < .01) between PG F2 and F4. In addition, a significant decrease in pericervical dentin (P < .05) was observed between PG F4 40/.06 and AS 40/.03. No significant differences were observed between PG F2 25/.08 and SS 3 25/.04. ConclusionIncreasing the instrumentation size from 25 to 40 significantly reduces the percentage of unprepared areas regardless of the system used. In addition, using a modern system with a regressive taper allows the maintenance of pericervical dentin without compromising shaping efficacy in the apical third of the mandibular incisors with oval canals and conservative access.

Color-scalable flow cytometry with Raman tags.

Flow cytometry is an indispensable tool in biology and medicine for counting and analyzing cells in large heterogeneous populations. It identifies multiple characteristics of every single cell, typically via fluorescent probes that specifically bind to target molecules on the cell surface or within the cell. However, flow cytometry has a critical limitation: the color barrier. The number of chemical traits that can be simultaneously resolved is typically limited to several due to the spectral overlap between fluorescence signals from different fluorescent probes. Here, we present color-scalable flow cytometry based on coherent Raman flow cytometry with Raman tags to break the color barrier. This is made possible by combining a broadband Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) flow cytometer, resonance-enhanced cyanine-based Raman tags, and Raman-active dots (Rdots). Specifically, we synthesized 20 cyanine-based Raman tags whose Raman spectra are linearly independent in the fingerprint region (400 to 1,600 cm-1). For highly sensitive detection, we produced Rdots composed of 12 different Raman tags in polymer nanoparticles whose detection limit was as low as 12nM for a short FT-CARS signal integration time of 420 µs. We performed multiplex flow cytometry of MCF-7 breast cancer cells stained by 12 different Rdots with a high classification accuracy of 98%. Moreover, we demonstrated a large-scale time-course analysis of endocytosis via the multiplex Raman flow cytometer. Our method can theoretically achieve flow cytometry of live cells with>140 colors based on a single excitation laser and a single detector without increasing instrument size, cost, or complexity.