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1.
Cureus ; 16(3): e56860, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38659556

RESUMO

Background and objective Resin-based restorative materials are the backbone of modern restorative dentistry. But in spite of being an excellent material, there are many shortcomings with direct resin restorative materials such as polymerization shrinkage and microleakage that complicate the rate of clinical success. Hence, the aim of the present study is to compare the microleakage caused by composite restorations using two different bevels, primary and zigzag bevels, while restoring fractured anterior teeth. Materials and methodology Thirty non-carious maxillary central incisors were split into two divisions wherein Group I received the primary bevel and Group II received the zigzag bevel. After receiving the bevel, the samples are restored with direct filling composite material (Neo Spectra ST, Dentsply Sirona, Charlotte, NC, USA). The restored samples underwent thermocycling (Holmarc, Kochi, India) and were assessed for microleakage under a stereomicroscope (Leica M205, Wetzlar, Germany). For the statistical analysis, IBM SPSS Statistics for Windows, V. 23.0 (IBM Corp., Armonk, NY) was used. Descriptive statistics were expressed in mean and standard deviation. Analytical statistics including the independent Student t-test was used to assess the difference derived from both groups at p<0.05. The normality of the data was assessed using the Shapiro-Wilk test. Results In the primary bevel, 53.3% of the samples showed first-degree microleakage, and 46.7% showed second-degree microleakage, respectively, and in samples restored using the zigzag bevel, 66.7% of the samples had no microleakage, and 33.3% of the samples had first-degree microleakage. The independent t-test revealed that the microleakage of the zigzag bevel showed a significant difference, being superior to the primary bevel at p<0.01. Conclusion Acknowledging the limitations of the study conducted, both bevel designs had a certain degree of microleakage when restored with composite material in anterior fractured teeth. However, the zigzag bevel produced significantly lesser microleakage as compared to the primary bevel restorations.

2.
Materials (Basel) ; 17(5)2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38473656

RESUMO

Loaded meshing transmission performance optimization has been an increasingly significant target for the design and manufacturing of aerospace spiral bevel gears with low noise and high strength. An innovative data-driven multi-objective optimization (MOO) method is proposed for the loaded meshing transmission performances of aerospace spiral bevel gears. Data-driven tooth surface modeling is first used to obtain a curvature analysis of loaded contact points. An innovative numerical loaded tooth contact analysis (NLTCA) is applied to develop the data-driven relationships of machine tool settings with respect to loaded meshing transmission performance evaluations. Moreover, the MOO function is solved by using an achievement function approach to accurate machine tool settings output, satisfying the prescribed requirements. Finally, numerical examples are given to verify the proposed methodology. The presented approach can serve as a powerful tool to optimize the loaded meshing transmission performances with higher computational accuracy and efficiency than the conventional methods.

3.
Trials ; 25(1): 138, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38388956

RESUMO

BACKGROUND: Cornea is the most important refractive media in the eye, and damage to the corneal endothelium is one of the most common causes of poor visual outcome following cataract surgery, particularly in those with predisposing factors. The role of phaco tip position during phacoemulsification on corneal endothelial damage is ambiguous, and there is no consensus regarding the most cornea-friendly phaco tip position (bevel-up or bevel-down). The objective of the trial is to compare the effect of phaco tip position (bevel-up vs. bevel-down) during phacoemulsification using direct chop technique on corneal endothelial cell count. METHODS AND DESIGN: TIPS is a randomised, multicentre, parallel-group, triple-masked (participant, outcome assessor, and statistician) trial with 1:1 allocation ratio. A total of 480 eligible participants, aged > 18 years with immature cataract, will be randomly allocated into bevel-up and bevel-down groups at two centres. Randomisation will be stratified according to the cataract grade. The primary outcome is postoperative endothelial cell count at 1 month. Secondary outcomes are central corneal thickness on postoperative days 1, 15, and 30 and difference in intraoperative complications. CONCLUSION: In this paper, we describe the detailed statistical analysis plan (SAP) for the TIPS trial, which was prepared prior to database lock. The SAP includes details of planned analyses and unpopulated tables, which will be reported in the publications. We plan to lock the database in July 2023 and publish the results later in the same year. SAP Version 0.1 (dated: 28 April 2023) Protocol version:2.0 TRIAL REGISTRATION: Clinical Trial Registry of India CTRI/2019/02/017464. Registered on 5 February 2019; https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=29764&EncHid=&userName=2019/02/017464.


Assuntos
Catarata , Facoemulsificação , Humanos , Facoemulsificação/efeitos adversos , Facoemulsificação/métodos , Acuidade Visual , Estudos Prospectivos , Contagem de Células , Córnea/cirurgia
4.
Clin Oral Investig ; 28(3): 170, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38396049

RESUMO

OBJECTIVES: This in vivo study aimed to assess the impact of needle bevel design on puncture pain, anesthetic success, and mechanical deformations in intraligamentary injection (ILA) cases, comparing a short triple facet cut (STF) to a triple lancet cut (TL) after single or repetitive use. MATERIALS AND METHODS: In a prospective single-blind trial, 200 ILA needles (STF, n = 100; TL, n = 100) were randomly assigned for dental procedures. Patients received ILA either with STF or TL needles, used once (group A; n = 50 each) or repeatedly (group B; n = 50). Puncture pain was assessed using a numerical rating scale (NRS). Anesthetic success was determined via cold spray (yes/no), and scanning electron microscopy (SEM) analyzed needle tip deformations. RESULTS: Puncture pain did not significantly differ between STF and TL, regardless of needle use or injection area. Success rates were comparable in single use (82% STF vs. 79% TL; p > 0.05). For repetitive use, STF exhibited a significantly higher success rate (80% vs. 69%; p = 0.012). Mechanical deformations were prevalent in 97.5% of needles, with TL showing greater deformations than STF after single and repeated uses. Barbs were more common in TL (90/100) than STF (84/100), with a higher relative risk for barbed-like deformation in TL (RR single use: 1.26; p < 0.001; multiple use: 7.87, p < 0.001). CONCLUSIONS: The short triple facet-designed bevel demonstrated significantly less mechanical deformation, suggesting potential advantages in maintaining needle lumen patency. CLINICAL RELEVANCE: The intraligamentary needle bevel design is linked to mechanical deformation and anesthetic success after repetitive use, but not to puncture pain.


Assuntos
Anestesia Dentária , Anestésicos , Humanos , Anestesia , Agulhas , Dor , Estudos Prospectivos , Método Simples-Cego
5.
Heliyon ; 10(3): e25002, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38322890

RESUMO

Percutaneous needle insertion is a minimally invasive surgery with broad medical application prospects, such as biopsy and brachytherapy. However, the currently adopted rigid needles have limitations, as they cannot bypass obstacles or correct puncture deviations and can only travel along a straight path. Bevel-tip flexible needles are increasingly being adopted to address these issues, owing to their needle body's ease of deformation and bending. Successful puncture of flexible needles relies on accurate models and path planning, ensuring the needle reaches the target while avoiding vital tissues. This review investigates puncture models and path-planning algorithms by reviewing recent literature, focusing on the path-planning part. According to the literature, puncture models can be divided into three types: mechanical, finite element method (FEM), and kinematic models, while path-planning algorithms are categorized and discussed following the division used for mobile robots, which differs from the conventional approach for flexible needles-an innovation in this review. This review systematically summarizes the following categories: graph theory search, sampling-based, intelligent search, local obstacle avoidance, and other algorithms, including their implementation, advantages, and disadvantages, to further explore the potential to overcome obstacles in path planning for minimally invasive puncture needles. Finally, this study proposes future development trends in path-planning algorithms, providing possible directions for subsequent research for bevel-tipped flexible needles. This research aims to provide a resource for researchers to quickly learn about common path-planning algorithms, their backgrounds, and puncture models.

6.
Cureus ; 15(10): e46770, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37954790

RESUMO

Inflammatory gingival enlargement, sometimes referred to as gingival hyperplasia or gingival hypertrophy, is an abnormal proliferation of gingival tissues caused by underlying inflammation. It might also be related to long-term periodontitis. Herein, we discuss the case of a young, otherwise healthy male patient wherein the anterior regions of both the upper and lower arches were affected by long-standing gingival growth. The overgrowth was removed, and an excellent aesthetic outcome was achieved, using a surgical procedure termed gingivectomy. After a 15-day follow-up period, the healing process was satisfactory and no negative effects were found.

7.
Materials (Basel) ; 16(11)2023 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-37297316

RESUMO

The tooth surface structure of spiral bevel gear is complex and requires high machining accuracy. In order to reduce the tooth form deformation of heat treatment, this paper proposes a reverse adjustment correction model of tooth cutting for heat treatment tooth form deformation of spiral bevel gear. Based on the Levenberg-Marquardat method, a stable and accurate numerical solution for the reverse adjustment amount of the cutting parameters is solved. Firstly, a mathematical model of the tooth surface of spiral bevel gears was established based on the cutting parameters. Secondly, the effect law of each cutting parameter on tooth form was studied by using the method of small variable perturbation. Finally, based on the tooth form error sensitivity coefficient matrix, a reverse adjustment correction model of tooth cutting is established to compensate the heat treatment tooth form deformation by reserving the tooth cutting allowance in the tooth cutting stage. The effectiveness of the reverse adjustment correction model of tooth cutting was verified through experiments on reverse adjustment of tooth cutting processing. The experimental results show that the accumulative tooth form error of the spiral bevel gear after heat treatment is 199.8 µm, which is reduced by 67.71%, and the maximum tooth form error is 8.7 µm, which is reduced by 74.75%, after reverse adjustment of cutting parameters. This research can provide technical support and a theoretical reference for heat treatment tooth form deformation control and high-precision tooth cutting processing of spiral bevel gears.

8.
Biomimetics (Basel) ; 8(2)2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-37092386

RESUMO

The purpose of the current study is to emphasize the characteristics and phenomena of leading-edge twisting in flapping wing vehicles. A fused deposition modeling (FDM) 3D printing method is applied to develop the flapping mechanisms with bevel gears to achieve the leading-edge twisting. Three flapping mechanisms were developed, including simple flapping only (type-A1: normal servo mechanism), flapping with continuous leading-edge twisting (type-B: servo-bevel gear mechanism), and flapping with restricted leading-edge twisting via mechanical stoppers (type-B1: servo-bevel gear mechanism with adjustable mechanical stoppers). Utilizing a low-speed wind tunnel, the aerodynamic performances of these mechanisms are examined by extracting their lift and net thrust forces. The wind tunnel testing data showed that the flapping with restricted leading-edge twisting via mechanical stoppers (type-B1) showed better performance than the simple flapping (type-A1) by 32.9%, and also better performance than the flapping with continuous leading-edge twisting (type-B) by 64%. Next, MATLAB software was used to create the 3D wing surfaces from the instantaneous stereophotography Kwon3D trajectories to fully sketch the leading-edge twisting features. The 2D airfoil cut sections at the mean aerodynamic chord at different stroke moments depict the instantaneous angles of attack to justify the aforementioned wind tunnel testing data and it was verified using a theoretical trajectory model. This comprehensive study using the 3D-printed mechanisms is well suited for the quantitative evaluation of the lift contribution from leading-edge twisting.

9.
Sensors (Basel) ; 23(5)2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36904858

RESUMO

Straight bevel gears are widely used in mining equipment, ships, heavy industrial equipment, and other fields due to their high capacity and robust transmission. Accurate measurements are essential in order to determine the quality of bevel gears. We propose a method for measuring the accuracy of the top surface profile of the straight bevel gear teeth based on binocular visual technology, computer graphics, error theory, and statistical calculations. In our method, multiple measurement circles are established at equal intervals from the small end of the top surface of the gear tooth to the large end, and the coordinates of the intersection points of these circles with the tooth top edge lines of the gear teeth are extracted. The coordinates of these intersections are fitted to the top surface of the tooth based on NURBS surface theory. The surface profile error between the fitted top surface of the tooth and the designed surface is measured and determined based on the product use requirements, and if this is less than a given threshold, the product is acceptable. With a module of 5 and an eight-level precision, such as the straight bevel gear, the minimum surface profile error measured was -0.0026 mm. These results demonstrate that our method can be used to measure surface profile errors in the straight bevel gears, which will broaden the field of in-depth measurements for the straight bevel gears.

10.
Respiration ; 102(5): 386-395, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36921594

RESUMO

BACKGROUND: Advancing the endotracheal tube (ETT) over a flexible bronchoscope (FB) during awake fiber-optic intubation (AFOI) is often impeded. Various maneuvers and tracheal tubes designed to overcome this obstruction may also be unsuccessful or costly. OBJECTIVE: The current study aimed to assess how the novel double configuration ETT affected AFOI success rates on the first attempt. METHODS: A randomized controlled experiment including 40 individuals receiving awake fiber-optic orotracheal intubation was performed in a 1:1 ratio with a single ETT railroaded with its bevel posteriorly (ST) or railroading with a double setup ETT (DT) over a flexible videoscope (FVS) for tracheal intubation. The number of intubation attempts, time spent intubating, and adverse events were examined and compared between the two groups. RESULTS: Twenty patients received a single ETT railroaded with the bevel posteriorly, and 20 patients received railroading with the double setup ETT during AFOI. Intubation on the first attempt was significantly greater in the DT group (90%) than in the ST group (35%). The intubation time was considerably shorter for the DT group (12.8 [7.8-16.9] s) when compared with the ST group (27.9 [16.3-91.0] s). Five patients were intubated by the alternative technique after failure to intubate for several attempts, and 3 cases were found to have a crease in the FVS after intubation in group ST. During topical anesthetic, three individuals in each group experienced transient oxygen desaturation. CONCLUSIONS: Our study discovered that the novel double setup tube could significantly improve the intubation success rate on the first attempt during AFOI for patients with challenging airway when a strategy based on a reduced gap between ETT and FB could not be applied.


Assuntos
Tecnologia de Fibra Óptica , Vigília , Humanos , Intubação Intratraqueal/efeitos adversos , Broncoscopia
11.
Materials (Basel) ; 16(4)2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36837186

RESUMO

Shrink fitting of forging mold (SFFM) is an effective method for improving mold strength, extending the mold's service life and reducing the manufacturing cost of forging mold. However, due to the asymmetric geometry and complex stress distribution, the precise design of SFFM for the precision forging of noncircular bevel gears is very difficult. In this paper, a new precise design method of SFFM for the precision forging of noncircular bevel gears is proposed, which mainly includes the following five parts. First, a new design method for the mold parting surface-the curved surface parting method-is proposed to design the forging mold of noncircular spur bevel gears. Then, new dimension design methods for the gear mold and shrink rings based on the uniform shrinkage force are proposed. Third, a new design method for the inhomogeneous interference value between shrink rings and the gear mold is developed to provide a precise, uniform shrinkage force. After that, a strength correction method for the shrink-fitted gear mold is proposed to ensure the gear mold and shrink rings have sufficient strength both in the assembly process of the shrink-fitted gear mold and precision in the forging process of noncircular spur bevel gears. Ultimately, finite element simulations and verification experiments are performed to verify the proposed precise design method of SFFM for the precision forging of noncircular bevel gears. The precise design method of SFFM proposed in this paper is not only applicable to the precise design of the high-strength gear mold for noncircular bevel gears, but can also provide a valid reference for the precise design of the high-strength mold for other complicated asymmetric parts.

12.
Int J Artif Organs ; 46(1): 40-51, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36397288

RESUMO

Needle insertion is executed in numerous medical and brachytherapy events. Exact needle insertion into inhomogeneous soft biological tissue is of useful importance due to its significance in clinical diagnosis (especially percutaneous) and treatments. The surgical needles used in such processes can deflect during the percutaneous process. Needle deflecting which affects needle - soft tissue interface and needle controllability have a crucial role in establishment precision. In this paper, we have analyzed a mechanics-based model both rotational and non-rotational needle insertion, and studied the deflection phenomenon in both insertion cases, we validated it with a real-time nonlinear Dassault Systèmes® ABAQUS simulation model. For definite contact force, the maximum the contact stiffness was, the minimum it inserted, the cohesive surface model was used to investigate the needle insertion analysis, where the fracture point was defined by a failure strain and with the help of the in, the fully failed components would be removed. Using living tissue comparable PVA gel materials, the needle insertion force model is developed from insertion experimentations with the help of two different processes (rotational and non-rotational needle insertion). In a rotational needle, deflection is less than in a non-rotational needle. The preliminary insertion was observed in the rotational needle at 1.261 mm (experiment), and 1.538 mm (simulation), and for non-rotational needle insertion, the initial insertion was noticed at 1.756 mm (experiment) and 1.982 mm (simulation). The main aim of this study is to navigate the surgical needle in an accurate way to reduce the erroneousness for a clinical diagnosis like anesthesia, brachytherapy, biopsy, and modern microsurgery operation.


Assuntos
Braquiterapia , Agulhas , Simulação por Computador , Fenômenos Mecânicos , Modelos Anatômicos
13.
Indian J Dent Res ; 34(3): 304-307, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38197352

RESUMO

Background: The endocrown is described as monobloc ceramic component. The pull-out bond strength acts as a real-life scenario of failure that occurs in endocrown. The different preparation designs have been included to assess the type of preparation that resists the least failure. Aim: To evaluate the effect of three different types of preparation designs on the pull-out bond strength (PBS) of computer-aided design/computer-aided manufacturing (CAD/CAM) monolithic endocrowns. Methods and Materials: Thirty extracted mandibular first molars were used for this study. Root canal treatment was done. Samples were divided into three groups of 10 samples each. Group A consists of traditional endocrown preparation with a butt joint preparation. The group B consists of a modified preparation with 50-60 degree inward slope. The group C consists of preparation with a 50-60 degree outward slope. Endocrowns were fabricated using CAD/CAM lithium disilicate glass-ceramics. The endocrowns were adhesively bonded to the respective preparations. Pull-out bond strength was calculated using the universal testing machine at a crosshead speed of 1 mm/min. Statistical Analysis: The results were statistically evaluated by one-way ANOVA and Tukey's post hoc analysis. Results: Group B had higher pull-out bond strength compared to the other two types of preparation designs and showed a statistically significant value with a mean significant difference at 0.05 level (P < 0.05). Conclusion: The 50-60 degree inward bevel in endocrown preparation increased the pull-out bond strength in lithium disilicate endocrowns.


Assuntos
Desenho Assistido por Computador , Dente Molar , Análise de Variância , Tratamento do Canal Radicular
14.
Materials (Basel) ; 15(22)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36431463

RESUMO

High temperature and strain will occur in the cutting area during dry milling of contour bevel gears, which causes plastic deformation of the workpiece, resulting in changes in the physical properties of the machined surface's metamorphic layer, reducing the quality of the workpiece's machined surface. Therefore, it is necessary to investigate the properties of the metamorphic layer and the work hardening behavior of the machined surfaces of contour bevel gears. The paper first establishes a single-tooth finite element simulation model for a contour bevel gear and extracts the temperature field, strain field and strain rate at different depths from the machined surface. Then, based on the simulation results, the experiment of milling contour bevel gears is carried out, the microscopic properties of the machined metamorphic layer are studied using XRD diffractometer and ultra-deep field microscopy, and the work hardening behavior of the machined metamorphic layer under different cutting parameters is studied. Finally, the influence of the cutting parameters on the thickness of the metamorphic layer of the machined surface is investigated by scanning electron microscopy. The research results can not only improve the surface quality and machinability of the workpiece, but are also significant for increasing the fatigue strength of the workpiece.

15.
J Vasc Access ; : 11297298221075169, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35773962

RESUMO

BACKGROUND: Peripheral intravenous catheter (PIVC) insertion often fails on the first attempt. Risk factors include small vein size and dehydration, causing vein deformation and displacement due to puncture resistance of the vessel. The authors developed a short, thin-tipped bevel needle and compared its puncture performance with needles of four available PIVCs using an ex vivo model. METHODS: The PIVC with the thin-tipped short bevel needle was compared to four available PIVCs using an ex vivo model which simulated the cephalic vein of the human forearm. The ex vivo model consisted of a porcine shoulder and porcine internal jugular vein, and was used for evaluation of the rate of vein deformation and vessel displacement during needle insertion. RESULTS: An ex vivo model was created with a vessel diameter of 2.7-3.7 mm and a depth of 2-5 mm. The thin-tipped short bevel PIVC needle was associated with a significantly lower compressive deformation rate and venous displacement compared to the needles of the other four PIVCs. CONCLUSION: The thin-tipped short bevel needle induced lower compressive deformation and displacement of the vein than the conventional needles. This needle has the potential to improve the first-attempt success rate of peripheral intravenous catheterization in patients with difficult venous access.

16.
J Clin Pediatr Dent ; 46(2): 119-124, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35533227

RESUMO

Few long-term reports exist concerning the treatment of idiopathic gingival fibromatosis, which is a rare autosomal dominant genetic disorder associated with non-inflammatory, benign, and chronic fibrous gingival proliferation and which causes serious esthetic problems. The aim of this study was to report a case of idiopathic gingival fibromatosis treated with a gingivectomy using an inverse bevel flap method and comprehensively followed up for 15 years. A female patient visited a pediatric dentist at 7 years of age; however, a gingivectomy was not performed until the age of 20 years because of an uncertain prognosis. Now, more than 15 years after the gingivectomy, there has been no significant recurrence and the disease is well managed. Treatment by gingivectomy with an inverse bevel flap approach may provide long-term prevention of recurrence of gingival fibromatosis into adulthood. The aim of this study was to obtain new findings on the pathogenesis and prognosis of this rare disease and to review the case reports previously published.


Assuntos
Fibromatose Gengival , Gengivectomia , Adulto , Criança , Odontólogos , Feminino , Fibromatose Gengival/genética , Fibromatose Gengival/cirurgia , Seguimentos , Gengiva , Gengivectomia/métodos , Humanos , Adulto Jovem
17.
Brain Circ ; 8(4): 215-218, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-37181844

RESUMO

Recent data suggested aspiration thrombectomy as the first-pass approach in endovascular treatment of acute stroke and is accepted as a safe and efficient alternative to stent-retriever thrombectomy. The efficiency of mechanical thrombectomy for complete removal of the clot is directly related to the catheter trackability, aspiration force, and inner diameter of the aspiration catheter. Zoom 71 Aspiration catheter (Imperative Care, Campbell, California, USA) is a novel aspiration catheter with a beveled tip aiming to increase the tip surface area, increased suction force, and advanced trackability. This case report describes the successful use of Zoom 71 aspiration catheter in a left middle cerebral artery M2 branch occlusion and highlights technical details including navigation without the support of a microcatheter microwire combination.

18.
J Mech Behav Biomed Mater ; 126: 105034, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34906863

RESUMO

INTRODUCTION: The aim of this in vitro study was to investigate the mechanical deformation rate of dental cannula tips after injection simulation in a new developed animal model. MATERIALS AND METHODS: A new mechanical device was designed to define forces (100 g for 60 s) to impact a pigs jaw bone with different cannulas (25-Gauge/27-Gauge) from dental local anaesthesia syringes. 8 different products (100 cannulas each) were evaluated. Cannula tips were examined for deformation under the digital microscope VHX-100 (500-fold magnification). RESULTS: 27G and 27G free flow showed a significantly lower likelihood of bending (OR 0.05; p = 0.0001). Comparing 27G cannulas of the same outer diameter but different inner diameter, large inner diameter produced a significantly higher deformation rate than those of cannulas with a standard inner diameter. 12-38% of the cannulas showed manufacturing defects and production-related deformation. CONCLUSIONS: Cannula deformation seems to depend on the inner diameter, bevel and cutting profile. Multiple use of the same cannula could result in more pronounced deformation, increasing the risk of complications during local anesthesia.


Assuntos
Anestesia Dentária , Anestesia Local , Animais , Desenho de Equipamento , Injeções , Agulhas , Suínos
19.
ISA Trans ; 128(Pt B): 646-663, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34953581

RESUMO

Low-risk transmission performance including elastic deformation, loaded contact pattern, load distribution and loaded transmission error is of paramount significance to the actual manufacturing for non-orthogonal aviation spiral bevel gears. The advanced digital twin technology is introduced into tooth flank grinding. A new digital twin modeling considering low-risk transmission performances is proposed. In the modeling, low-risk transmission performance driven simulation, sensitivity analysis and robust control are developed, respectively Firstly, data-driven tooth surface modeling is developed by simulating free-form tooth surface grinding including gear tilt method and pinion double helical method. With local geometric boundary setup meshing stiffness is determined by using local Rayleigh-Ritz solution. Then, to deal with the sensitivity of gear assembly, an improved tooth contact analysis (TCA) is developed. Moreover, numerical loaded tooth contact analysis (NLTCA) is performed to build a bridge between of low-risk performances and hypoid generator parameters. The low-risk transmission performance driven control model is established by using hypoid generator parameters modification. Finally, sensitivity analysis strategy-based robust control model is solved by using Levenberg-Marquardt method for accurate hypoid generator parameters having modification amount. The provided numerical instance can verify the proposed method.

20.
Small Methods ; 5(5): e2001264, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34928087

RESUMO

The bevel structure of organic multilayers produced by finely controlled Ar gas cluster ion beam sputtering preserves both the molecular distribution and chemical states. Nevertheless, there is still an important question of whether this method can be applicable to organic multilayer structures composed of complex or ambiguous interfaces used in real organic optoelectronic devices. Herein, various bevel structures are fabricated from different types of organic semiconductors using a solution-based deposition technique: complicatedly intermixed electron-donor and electron-acceptor bulk heterojunction structure, thin film structure with an internal donor-acceptor concentration gradient, and multi-layered structure with more than three layers. For these organic material combinations listed above, the bevel structure is fabricated with finely tuned Ar gas cluster ion beam sputtering. The location-dependent X-ray photoelectron spectroscopy (XPS) results obtained for each bevel structure exactly correspond to the XPS depth profiles. This result demonstrates that the bevel structure analysis is a powerful method to distinguish subtle differences in chemical component distributions and chemical states of organic semiconductors even with complex or ambiguous interfaces. Ultimately, due to its reliability as verified by this study, the proposed bevel structure analysis is expected to greatly expand other analytical techniques with a limited spatial or depth resolution.

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