scholarly journals A Computerized Simulation of the Occlusal Surface in Equine Cheek Teeth: A Simplified Model

2022 ◽  
Vol 8 ◽  
Author(s):  
Tomas Sterkenburgh ◽  
Ellen Schulz-Kornas ◽  
Michael Nowak ◽  
Carsten Staszyk

Equine mastication, as well as dental wear patterns, is highly important for the development of treatments in equine dentistry. During the last decades, the stress and strain distributions of equine teeth have been successfully simulated using finite element analysis. Yet, to date, there is no simulation available for dental tooth wear in equines. In this study, we developed a simplified two-dimensional computer simulation of dental wear. It provides a first tentative explanation for the development of the marked physiological inclination of the occlusal surface and for pathological conditions such as sharp enamel points in equine cheek teeth. The mechanical properties of the dental structures as well as the movement of the mandible during the equine chewing cycle were simulated according to previously published data. The simulation setup was optimized in preliminary test runs. Further simulations were conducted varying the lateral excursion of the mandible and the presence or absence of incisor contact during the chewing cycle. The results of simulations showed clear analogies to tooth wear patterns in living equids, including the formation of wear abnormalities. Our analysis indicates that small variations in the pattern of movement during the masticatory cycle, as well as incisor contacts, are leading to marked changes in the occlusal tooth wear patterns. This opens new research avenues to better understand the development of dental wear abnormalities in equines and might have serious implications on captive animal health, welfare, and longevity.

2008 ◽  
Vol 19 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Priscila de Oliveira Serrano ◽  
Fernanda Faot ◽  
Altair Antoninha Del Bel Cury ◽  
Renata Cunha Matheus Rodrigues Garcia

This study described changes in mandibular movements during pronunciation of /m/ and /s/ sounds in Portuguese, in patients presenting dental wear before and after appliance insertion and tooth reconstruction. Subjects were divided into a control group of dentate patients and an experimental group of patients with incisal tooth wear due to bruxism. A magnetic jaw tracking device measured the jaw opening, and translations to left and right sides of the mandible during pronunciation of phonemes. Evaluations were carried out 1 week and immediately before appliance insertion; 24 h, 7, 30 and 60 days after appliance insertion; and 1 week and 1 month after tooth reconstruction. Data were submitted to two-way ANOVA, Mann-Whitney and Friedman tests (p<0.05). Jaw opening was different (p<0.05) for both sounds in all periods. The anteroposterior amplitude for /s/ showed differences immediately before and 1 month after appliance insertion (p<0.05). Lateral amplitude for the right side showed differences between groups after appliance insertion for /s/, and 1 and 2 months after appliance insertion for the /m/ (p<0.05). Volunteers with anterior tooth wear had a wider opening movement, and the movements during speech of /m/ and /s/ sounds were not changed after appliance insertion and reconstruction of teeth.


Author(s):  
Peng Qi ◽  
Hongbin Liu ◽  
Lakmal Seneviratne ◽  
Kaspar Althoefer

Flexible robot arms have been developed for various medical and industrial applications because of their compliant structures enabling safe environmental interactions. This paper introduces a novel flexible robot arm comprising a number of elastically deformable planar spring elements arranged in series. The effects of flexure design variations on their layer compliance properties are investigated. Numerical studies of the different layer configurations are presented and finite Element Analysis (FEA) simulation is conducted. Based on the suspended platform’s motion of each planar spring, this paper then provides a new method for kinematic modeling of the proposed robot arm. The approach is based on the concept of simultaneous rotation and the use of Rodrigues’ rotation formula and is applicable to a wide class of continuum-style robot arms. At last, the flexible robot arms respectively integrated with two different types of compliance layers are prototyped. Preliminary test results are reported.


Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Jessica Diaz ◽  
Aspen T. Reese

AbstractBecause of its potential to modulate host health, the gut microbiome of captive animals has become an increasingly important area of research. In this paper, we review the current literature comparing the gut microbiomes of wild and captive animals, as well as experiments tracking the microbiome when animals are moved between wild and captive environments. As a whole, these studies report highly idiosyncratic results with significant differences in the effect of captivity on the gut microbiome between host species. While a few studies have analyzed the functional capacity of captive microbiomes, there has been little research directly addressing the health consequences of captive microbiomes. Therefore, the current body of literature cannot broadly answer what costs, if any, arise from having a captive microbiome in captivity. Addressing this outstanding question will be critical to determining whether it is worth pursuing microbial manipulations as a conservation tool. To stimulate the next wave of research which can tie the captive microbiome to functional and health impacts, we outline a wide range of tools that can be used to manipulate the microbiome in captivity and suggest a variety of methods for measuring the impact of such manipulation preceding therapeutic use. Altogether, we caution researchers against generalizing results between host species given the variability in gut community responses to captivity and highlight the need to understand what role the gut microbiome plays in captive animal health before putting microbiome manipulations broadly into practice.


2021 ◽  
Author(s):  
Sara B Mullaney ◽  
Heather Bayko ◽  
Gerald D Moore ◽  
Hannah E Funke ◽  
Matthew J Enroth ◽  
...  

ABSTRACT Introduction U.S. Army Veterinary Corps provides highly skilled and adaptive veterinary professionals to protect and improve the health of people and animals while enhancing readiness throughout the DOD. Army veterinarians must be trained and credentialed for critical tasks within the animal health and food protection missions across all components. The Veterinary Metrics Division in the U.S. Army Public Health Center’s Veterinary Services and Public Health Sanitation Directorate is responsible for tracking readiness metrics of Army veterinarians and maintains a robust online Readiness Metrics Platform. Readiness targets were developed based on trends in readiness platform data, input of senior veterinary subject matter experts, and feedback from the field. To date, no data have been published describing the cases presented to DOD-owned Veterinary Treatment Facilities (VTFs). Without capturing and codifying the types of cases that present to the VTF and comparing to cases typically encountered during deployments, it is difficult to determine whether the VTF serves as an adequate readiness platform. In this study, we compare a representative random sample of non-wellness VTF patient encounters in garrison to cases reported from two different combat zones to determine if the VTF is a suitable clinical readiness platform. Materials and Methods Multiple data sources, including pre-existing published data and new data extracted from multiple sources, were used. The Iraq 2009-2010 dataset includes data collected from a Medical Detachment, Veterinary Service Support (MDVSS) deployed to Iraq from January 5, 2009 through August 23, 2010. The Iraq 2003-2007 dataset originated from a retrospective cross-sectional survey that included database and medical record abstraction. The Afghanistan 2014-2015 dataset includes data collected from the MDVSS deployed to Afghanistan from June 2014 to March 2015. Working dog veterinary encounter data were manually extracted from monthly and daily clinical reports. Data for the Garrison 2016-2018 dataset were extracted from the Remote Online Veterinary Record. A random representative sample of government-owned animal (GOA) and privately owned animal (POA) encounters seen across all DOD-owned VTFs from June 2016 to May 2018 were selected. Results We found that animals present to the VTF for a wide variety of illnesses. Overall, the top 10 encounter categories (90.3%) align with 84.2%, 92.4%, and 85.9% of all the encounter types seen in the three combat zone datasets. Comparing these datasets identifies potential gaps in readiness training relying solely on the VTF, especially in the areas of traumatic and combat-related injuries. Conclusions Ultimately, the success of the DOD Veterinary Services Animal Health mission depends on both the competence and confidence of the individual Army veterinarian. As the MHS transitions and DOD Veterinary Services continues to transform emphasizing readiness through a public health and prevention-based Army medicine approach, Army veterinarians must strike a delicate balance to continue to provide comprehensive health care to GOAs and POAs in the VTFs. Leaders at all levels must recognize the roles VTFs play in overall public health readiness and disease prevention through the proper appropriation and allocation of resources while fostering the development, confidence, and competence of Army veterinarians training within these readiness platforms.


2021 ◽  
Vol 11 (2) ◽  
pp. 104-107
Author(s):  
Vladimir Tlustenko ◽  
Valentina Tlustenko ◽  
Sergey Komlev ◽  
Alexander Ivaschenko ◽  
Vladimir Koshelev

Examination along with implant treatment was carried out in 21 patients with severe tooth wear on the occlusal surface. This disorder features a variety of clinical symptoms including changes in the facial features and the lower jaw movement amplitude, disturbed canine and incisor guidance, supercontacts, asynchronous operation of the masticatory muscles, etc. We have proposed a treatment algorithm aimed at eliminating these issues. The temporary non-removable dentures allowed creating occlusal marks (Stage 1) followed with their transfer onto permanent orthopedic structure (Stage 2) using implants. The complexity of the approach to treating this disease, as well as the effectiveness of our method has been confirmed by clinical data and the outcomes obtained through an instrumental study involving electromyography and electronic axiography. The extra additional research methods employed, such as electromyography and electronic axiography, allowed to assess the activity of masticatory muscles and the lower jaw articulation, thus to ensure occlusal-articulation interaction when restoring the lower facial height.


2017 ◽  
Vol 2017 (1) ◽  
pp. 000635-000640
Author(s):  
Zhenzhen Shen ◽  
James Storey ◽  
Otto Fanini ◽  
Michael Osterman

Abstract Wire bonds are used to connect device terminals to package terminals or substrate terminal that forms circuits that are needed to create desired higher level functions. If a wire bond breaks or becomes detached during operation, the desired function will be lost. Depending on the design, a loss in function could be catastrophic. Aluminum, gold, and copper wires are used to create wire bonds in electronic products. These materials have been selected for their ability to be formed as fine wires and their ability to provide low electrical resistance. In many electronics packages, wire bonds are encapsulated in a polymer molding compound that is used to protect the electronic device. However, in some electronic devices such as hermetically sealed cavity packages, wire bonds may be free-standing. Under vibration loading, free-standing wire bonds may be subject to failure due to mechanical fatigue. In this work, an analytic model is presented for predicting natural frequency of a free-standing wire bond and for assessing a wire bond time to failure under a harmonic loading condition. The model for natural frequency is calibrated by finite element analysis and validated through experimental testing. The life prediction model, a test plan, and preliminary test results are presented.


2011 ◽  
Vol 26 (suppl 2) ◽  
pp. 79-83 ◽  
Author(s):  
Juliane Avansini Marsicano ◽  
Patrícia Garcia de Moura Grec ◽  
Lídia Barbieri Belarmino ◽  
Reginaldo Ceneviva ◽  
Sílvia Helena de Carvalho Sales Peres

PURPOSE: To evaluate oral changes, such as dental caries, periodontal disease, dental wear and salivary flow in bariatric patients. Fifty four obese patients who underwent bariatric surgery were studied before (n=54), up after 3 months (n=24) and 6 months (n=16). METHODS: Indices for evaluating oral conditions were: DMFT, CPI, DWI and salivary flow. OIDP questionnaire was used to assess the impact of oral health on quality of life. ANOVA and Spearman correlation were used (p<0.05). RESULTS: DMFT was 17.6±5.7, 18.4±4.1 and 18.3±5.5 (P>0.05), presence of periodontal pockets in 50%, 58% and 50% of patients (p>0.05), tooth wear in dentin present in 81.5%, 87.5% and 87.5% before, 3 and 6 months after surgical treatment respectively. There were differences between the three periods for prevalence and severity of dental wear (p = 0.012). Salivary flow was 0.8±0.5 ml/min before surgery, 0.9±0.5 ml/min for 3 months and 1.1±0.5m/min for 6 months (p>0.05). The impact of oral health on quality of life decreased with time after bariatric surgery (p= 0.029). CONCLUSION: The lifestyle changes after bariatric surgery and these changes may increase the severity of pre-existing dental problems. However, these alterations in oral health did not influence the quality of life.


Author(s):  
Bryce L. Fowler ◽  
Raymond K. Yee

Polymers constitute a large class of nearly incompressible solid materials (i.e., Poisson’s Ratio near 0.5). These materials are often used as passive vibration isolators. Accurately modeling vibration isolators made of nearly incompressible materials has been extremely difficult with standard finite element analysis. This paper provides an alternative to the specialized finite element formulations currently used to model incompressible materials. The finite volume methodology of computational fluid dynamics is employed in this paper to solve the Hooke’s Law equations in solid mechanics. Test cases have been performed to evaluate the performance of finite volume method applied to solid mechanics problems. The formulation has been coded in Matlab for practical use. Based on the preliminary test case results, the finite volume formulation compares favorably to finite element method.


Public Health ◽  
2008 ◽  
Vol 122 (9) ◽  
pp. 942-948 ◽  
Author(s):  
S.H. de Carvalho Sales-Peres ◽  
S. Goya ◽  
J.J. de Araújo ◽  
A. Sales-Peres ◽  
J.R.P. Lauris ◽  
...  
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