Strain Induced by Bio-High-Performance Polymers and Cobalt-Chromium Digitally Constructed Telescopic Partial Dentures after 1 Year Simulation of Function

BACKGROUND: Numerous attempts were made to reduce the adverse effects of the distal extension removable partial dentures (RPDs) and enhance their prognosis. High-performance polymers (HPP) were utilized in the construction of RPDs to maintain the health of the supporting structures. AIM: Thus, this study was prompted to compare the strains induced by Bio HPP and Cobalt- Chromium (Co Cr) Computer Assisted Design and Computer Assisted Manufacturing telescopic RPDs after 1 year of function. MATERIALS AND METHODS: A maxillary Kennedy class I was used in this study. Twelve telescopic RPDs were fabricated from two different materials. In Group A, six telescopic RPDs were milled from Co-Cr and in Group B, six telescopic retained RPDs were milled from Bio-HPP. Each partial denture was seated on the cast and introduced into the chewing simulator. The strain values were recorded using four strain gauges connected to a four-channel strain indicator. Statistical analysis of the resultant data was done using one-way ANOVA, followed by Tukey’s HSD for comparison within the same group. Student t-test was used for comparison between the different groups. The significance level was set at p ≤ 0.05. RESULTS: During unilateral loading, the results showed higher strains in Group A at the abutments (473.33 μm/m ± 10.8, 193.39 μm/m ± 10.8) and at the distal aspect of the ridge (470.83 μm/m ± 13.93, 185 μm/m ± 20.83) than Group B. Independent t-test showed statistically significant difference between strains at the abutments of both groups (t = 70.4, p ≤ 0.0001), (t = 36.84, p ≤ 0.0001). Furthermore, there was a statistically significant difference between strains at the saddles of both groups (t = 51.62, p ≤ 0.0001), (t = 34.72, p ≤ 0.0001) respectively (DOF = 10). CONCLUSIONS: In telescopic RPDs, Co Cr induces higher strain values on the abutments and the distal aspect of the ridge than Bio-HPP during bilateral and unilateral loading. During unilateral loading, Bio-HPP telescopic RPDs direct high strain values on the distal aspect of the ridge of the loaded side. CLINICAL IMPLICATIONS: The materials that induce less stresses on the supporting structures of telescopic partial dentures on the long-term can be used to maintain the health of periodontally affected abutments.

Data-driven estimation of deterioration curves: a railway supporting structures case study

A significant portion of railway network income is spent on the maintenance and restoration of the railway infrastructure to ensure that the networks continue to provide the expected level of service. The execution of the interventions – that is, when and where to perform maintenance or restoration activities, depends on how the state of the infrastructure assets changes over time. Such information helps ensure that appropriate interventions are selected to reduce the deterioration speed and to maximise the effect of the expenditure on monitoring, maintenance, repair and renewal of the assets. Presently, there is an explosion of effort in the investigation and use of data-driven methods to estimate deterioration curves. However, real-world time history data normally includes measurement of errors and discrepancies that should not be neglected. These errors include missing information, discrepancies in input data and changes in the condition rating scheme. This paper provides solutions for addressing these issues using machine learning algorithms, estimates the deterioration curves for railway supporting structures using Markov models and discusses the results.

Overdentures the realms of overshadowness or obliviousness

The overdenture is a predictable and valuable option in the treatment of a patient with multiple missing teeth. It aids by preservation of alveolar bone, teeth and supporting structures, maintenance of proprioceptive response and neuromuscular co-ordination, and enhances the quality of a prosthesis by improving the stability, retention and patient acceptance. Often while fabricating an overdenture with retained attachments it becomes mandatory to cast the wax pattern and by no means can that be judged for parallelism with the abutments. A lucid method of obtaining parallelism has been described, adjunct with significant improvement of bite force has been portrayed.Careful case selection and abutment preparation as well as periodic recall is the key to a successful over denture rehabilitation. This case report also depicts the tooth supported overdenture as a viable option with the use of a customized parallelometer which has its ease of use and cost effectiveness for determining parallelism of abutments using a prefabricated ball attachment system and deciphers the increase in bite force in a dynamic manner.

Efficient Mounting of a Tank for the Transport of Flammable Liquids on a Freight Vehicle

The design and construction of tanks used for the carriage of dangerous liquid materials fall within strict standards (i.e., EN13094:2015, R111). According to these standards, their supporting structures (Ss), used for the mounting of the tank on the freight vehicle, need to be able to sustain the developed stresses. Optimizing the number of supporting structures can lead to more efficient tank designs that allow the tank to transport more liquid material and need less time to be manufactured. In the present paper, the effect of the reduction of the number of supporting structures in (a) the structural integrity of the tank construction, (b) its dynamic behavior and (c) the load-sharing of the tank to the axles of the freight vehicle is investigated using the finite element (FE) method. As a case study a box-shaped tank mounted on a four-axle freight vehicle with a technical permissible maximum laden mass of 35 tn, five Ss are used. Four FE models with a decreasing number of Ss were built in ANSYS® 2020R1 CAE Software and their structural integrity was investigated. For each design, a feasible design was developed and evaluated in terms of structural integrity, dynamic behavior and axle load distribution. The results of the FE analysis were reviewed in terms of maximum equivalent Von Mises stress and stress developed on the welding areas. Additionally, the axle-load sharing was qualitatively assessed for all feasible designs. The main outcome of this work is that, overall, the use of two Ss leads to a more efficient design in terms of the manufacturing and the mounting of the tank construction on the vehicle and on a more efficient freight vehicle. More specifically, the reduction of the number of Ss from five to two lead to reduction of the tank tare weight by 9.6% with lower eigenfrequencies.

Robotic Spatial Printing For Designers

<p>This research developed a fully-integrated robotic printing system, using new methods of additive manufacture (AM) that enables users to explore spatially printed structures with increased freedom of geometric complexity. Current AM technologies, such as Fusion Deposition Modelling (FDM), can rapidly translate design ideations into solid forms by precisely depositing consecutive layers of material in coordination with the movements of a robotic platform. Using this method, solid objects are digitally deconstructed into linear toolpaths and physically reconstituted with thermoplastic extrusion equipment; the toolpath becomes the form. Spatial printing, using methods such as those demonstrated in this research, offers a new way of building 3D forms. By harnessing the potential of FDM equipment and materials for generating self-supporting structures, the user can create complex free-standing structures unshackled from the layered constraints of typical additive manufacturing processes. Here, the user acts as an informed negotiator between digital form and physical manifestation where movement realises form. A complete spatial printing system was built that harnesses the complexity of robotic movements and responds to the needs of printing materials through a feedback loop that draws from the results of experimentation. Bespoke printing equipment and computational processes strive to improve the craft qualities and printability of input materials with a specific focus on compatibility with co-extrusion biopolymer filaments developed by Scion. This thesis illustrates the development of a versatile spatial printing system and subsequent investigations into the craft qualities and freedom of complexity that this system offers to designers and architects.</p>

Robotic Spatial Printing For Designers

<p>This research developed a fully-integrated robotic printing system, using new methods of additive manufacture (AM) that enables users to explore spatially printed structures with increased freedom of geometric complexity. Current AM technologies, such as Fusion Deposition Modelling (FDM), can rapidly translate design ideations into solid forms by precisely depositing consecutive layers of material in coordination with the movements of a robotic platform. Using this method, solid objects are digitally deconstructed into linear toolpaths and physically reconstituted with thermoplastic extrusion equipment; the toolpath becomes the form. Spatial printing, using methods such as those demonstrated in this research, offers a new way of building 3D forms. By harnessing the potential of FDM equipment and materials for generating self-supporting structures, the user can create complex free-standing structures unshackled from the layered constraints of typical additive manufacturing processes. Here, the user acts as an informed negotiator between digital form and physical manifestation where movement realises form. A complete spatial printing system was built that harnesses the complexity of robotic movements and responds to the needs of printing materials through a feedback loop that draws from the results of experimentation. Bespoke printing equipment and computational processes strive to improve the craft qualities and printability of input materials with a specific focus on compatibility with co-extrusion biopolymer filaments developed by Scion. This thesis illustrates the development of a versatile spatial printing system and subsequent investigations into the craft qualities and freedom of complexity that this system offers to designers and architects.</p>

A Legorization method based on 3D color printing trajectory

In this paper, a Legorization method which can reconstruct LEGO model with complex internal and external structures from 3D color printing trajectory is proposed. Different from voxelization methods, by combining advanced adaptive slicing algorithm with building “high-resolution” regions with thin plates, the reconstruction accuracy of initial LEGO units can be guaranteed. Furthermore, the tree structure is employed for automatically generating support structures which can be converted into LEGO support structures. By adopting split assembly appropriately and implementing combination of these parts accurately, the reducing supporting structures can be further simplified. In order to optimize the Legorization scheme, a machine learning method is used to guarantee the quality and efficiency of the reconstruction work. Complex LEGO models are provided to demonstrate the effectiveness of the proposed method.

A heart in a heart: a case report of spontaneous flail of bicuspid aortic valve

Background Aortic regurgitation is attributed to congenital and acquired abnormalities of the aortic valve or aortic valve supporting structures. The most common cause of aortic regurgitation is atherosclerotic degeneration of the valve, especially in the presence of a bicuspid aortic valve. Case summary A 25-year-old Persian man with no past medical history, developed dyspnea since 1 week before his first visit to the physician. He was an active person up to this time, and had no history of trauma or chest pain. Transthoracic echocardiography showed severe aortic regurgitation in the context of flail bicuspid aortic valve, with no evidence of endocarditis. Laboratory tests including blood cultures were negative for infection. The patient underwent aortic valve replacement and the diagnosis was confirmed at time of surgery. Conclusion This case represents noninfective and nontraumatic spontaneous flail of bicuspid aortic valve.

Determining the Influence of Casing Vibrational Behaviour On Rotordynamics

Casings of machinery and support structures have an influence on the rotordynamic behaviour which is commonly considered by simplified models (e.g. one degree of freedom models). These are in many cases insufficient. Hence, more accurate modelling approaches are required which can be used in the design process or the rotordynamic calculation to achieve a better representation of the overall vibrational behaviour. To study the effects of casing and supporting structures on rotordynamics, the casing modal parameters of an axial compressor are determined by an experimental modal analysis. In parallel, a numerical model is established. As experimental data are rarely found in the literature, this work focuses on the parameter identification of the casing structure. The results are subsequently incorporated into a model updating strategy, in order to tune and improve the numerical model. Experimental and numerical data are compared to assess the quality of the data and the results gained. The ultimate objective is a reduced order model, which can be integrated in existing rotordynamic tools via an interface while keeping the calculation time low.