Diagnostic Accuracy of a Novel On-site Virtual Fractional Flow Reserve Parallel Computing System

Direct resin composite restoration of endodontically-treated permanent molars in adolescents: bite force and patient-specific finite element analysis

Abstract Objective To evaluate the influence of three levels of dental structure loss on stress distribution and bite load in root canal-treated young molar teeth that were filled with bulk-fill resin composite, using finite element analysis (FEA) to predict clinical failure. Methodology Three first mandibular molars with extensive caries lesions were selected in teenager patients. The habitual occlusion bite force was measured using gnathodynamometer before and after endodontic/restoration procedures. The recorded bite forces were used as input for patient-specific FEA models, generated from cone-beam computed tomographic (CT) scans of the teeth before and after treatment. Loads were simulated using the contact loading of the antagonist molars selected based on the CT scans and clinical evaluation. Pre and post treatment bite forces (N) in the 3 patients were 30.1/136.6, 34.3/133.4, and 47.9/124.1. Results Bite force increased 260% (from 36.7±11.6 to 131.9±17.8 N) after endodontic and direct restoration. Before endodontic intervention, the stress concentration was located in coronal tooth structure; after rehabilitation, the stresses were located in root dentin, regardless of the level of tooth structure loss. The bite force used on molar teeth after pulp removal during endodontic treatment resulted in high stress concentrations in weakened tooth areas and at the furcation. Conclusion Extensive caries negatively affected the bite force. After pulp removal and endodontic treatment, stress and strain concentrations were higher in the weakened dental structure. Root canal treatment associated with direct resin composite restorative procedure could restore the stress-strain conditions in permanent young molar teeth.

Toward a grey box approach for cardiovascular physiome

The physiomic approach is now widely used in the diagnosis of cardiovascular diseases. There are two possible methods for cardiovascular physiome: the traditional mathematical model and the machine learning (ML) algorithm. ML is used in almost every area of society for various tasks formerly performed by humans. Specifically, various ML techniques in cardiovascular medicine are being developed and improved at unprecedented speed. The benefits of using ML for various tasks is that the inner working mechanism of the system does not need to be known, which can prove convenient in situations where determining the inner workings of the system can be difficult. The computation speed is also often higher than that of the traditional mathematical models. The limitations with ML are that it inherently leads to an approximation, and special care must be taken in cases where a high accuracy is required. Traditional mathematical models are, however, constructed based on underlying laws either proven or assumed. The results from the mathematical models are accurate as long as the model is. Combining the advantages of both the mathematical models and ML would increase both the accuracy and efficiency of the simulation for many problems. In this review, examples of cardiovascular physiome where approaches of mathematical modeling and ML can be combined are introduced.

Use of 3d printing in preoperative planning and training for aortic endovascular repair and aortic valve disease

Abstract Introduction: Three-dimensional (3D) printing has become an affordable tool for assisting heart surgeons in the aorta endovascular field, both in surgical planning, education and training of residents and students. This technique permits the construction of physical prototypes from conventional medical images by converting the anatomical information into computer aided design (CAD) files. Objective: To present the 3D printing feature on developing prototypes leading to improved aortic endovascular surgical planning, as well as transcatheter aortic valve implantation, and mainly enabling training of the surgical procedure to be performed on patient's specific condition. Methods: Six 3D printed real scale prototypes were built representing different aortic diseases, taken from real patients, to simulate the correction of the disease with endoprosthesis deployment. Results: In the hybrid room, the 3D prototypes were examined under fluoroscopy, making it possible to obtain images that clearly delimited the walls of the aorta and its details. The endovascular simulation was then able to be performed, by correctly positioning the endoprosthesis, followed by its deployment. Conclusion: The 3D printing allowed the construction of aortic diseases realistic prototypes, offering a 3D view from the two-dimensional image of computed tomography (CT) angiography, allowing better surgical planning and surgeon training in the specific case beforehand.

Bayesian Network Model to Evaluate the Effectiveness of Continuous Positive Airway Pressure Treatment of Sleep Apnea / 대한의료정보학회지

OBJECTIVES: The association between obstructive sleep apnea (OSA) and mortality or serious cardiovascular events over a long period of time is not clearly understood. The aim of this observational study was to estimate the clinical effectiveness of continuous positive airway pressure (CPAP) treatment on an outcome variable combining mortality, acute myocardial infarction (AMI), and cerebrovascular insult (CVI) during a follow-up period of 15.5 years (186 ± 58 months). METHODS: The data set consisted of 978 patients with an apnea-hypopnea index (AHI) ≥5.0. One-third had used CPAP treatment. For the first time, a data-driven causal Bayesian network (DDBN) and a hypothesis-driven causal Bayesian network (HDBN) were used to investigate the effectiveness of CPAP. RESULTS: In the DDBN, coronary heart disease (CHD), congestive heart failure (CHF), and diuretic use were directly associated with the outcome variable. Sleep apnea parameters and CPAP treatment had no direct association with the outcome variable. In the HDBN, CPAP treatment showed an average improvement of 5.3 percentage points in the outcome. The greatest improvement was seen in patients aged ≤55 years. The effect of CPAP treatment was weaker in older patients (>55 years) and in patients with CHD. In CHF patients, CPAP treatment was associated with an increased risk of mortality, AMI, or CVI. CONCLUSIONS: The effectiveness of CPAP is modest in younger patients. Long-term effectiveness is limited in older patients and in patients with heart disease (CHD or CHF).

Simulating the behavior of patients who leave a public hospital emergency department without being seen by a physician: a cellular automaton and agent-based framework

The objective of this study was to develop an agent based modeling (ABM) framework to simulate the behavior of patients who leave a public hospital emergency department (ED) without being seen (LWBS). In doing so, the study complements computer modeling and cellular automata (CA) techniques to simulate the behavior of patients in an ED. After verifying and validating the model by comparing it with data from a real case study, the significance of four preventive policies including increasing number of triage nurses, fast-track treatment, increasing the waiting room capacity and reducing treatment time were investigated by utilizing ordinary least squares regression. After applying the preventing policies in ED, an average of 42.14% reduction in the number of patients who leave without being seen and 6.05% reduction in the average length of stay (LOS) of patients was reported. This study is the first to apply CA in an ED simulation. Comparing the average LOS before and after applying CA with actual times from emergency department information system showed an 11% improvement. The simulation results indicated that the most effective approach to reduce the rate of LWBS is applying fast-track treatment. The ABM approach represents a flexible tool that can be constructed to reflect any given environment. It is also a support system for decision-makers to assess the relative impact of control strategies.

Patient-specific instrumentation in total knee arthroplasty. Should we adopt it? / Instrumentação personalizada na artroplastia total do joelho. Devemos adotá-la?

ABSTRACT Total knee arthroplasty (TKA) is a surgical procedure of paramount relevance that restores a substantial degree of function in arthritic knees. Increased consideration has been given to the influence of limb alignment on longevity after TKA, as errors in component placement can be associated with inferior function and compromised long-term performance. Consequently, numerous studies comparing patient-specific instrumentation (PSI) to standard instruments (SI) have been published. Patient-specific approaches use preoperative imaging to create specific materials for each patient's anatomy and were designed to achieve a higher rate of success in TKA, causing the entire procedure to be more efficient and cost-effective. However, it is not clear to what degree these studies support the potential advantages of PSI. Thus, the present study aimed to review the current evidence comparing PSI to SI, concerning alignment, cost-effectiveness, and postoperative functional evaluation.

RESUMO A artroplastia total do joelho (ATJ) é um procedimento cirúrgico de fundamental relevância que restaura boa parte da função de joelhos artríticos. Maior atenção tem sido dada à influência do alinhamento do membro na longevidade após a ATJ, uma vez que erros no posicionamento dos componentes podem estar associados a uma menor função e comprometimento do desempenho em longo prazo. Consequentemente, vários estudos compararam a instrumentação personalizada para cada paciente (IPP) com a instrumentação padrão (IP). As abordagens personalizadas usam imagens pré-operatórias para criar materiais específicos para a anatomia de cada paciente e foram projetados para atingir uma maior taxa de sucesso na ATJ e tornar todo o processo mais eficiente e rentável. No entanto, não está claro até que ponto tais estudos respaldam as vantagens potenciais da IPP. Assim, o presente estudo teve como objetivo avaliar as evidências atuais e comparar IPP e IP com respeito ao alinhamento, à relação custo-benefício e à avaliação funcional pós-operatória.

Reliability of Bolton analysis evaluation in tridimensional virtual models

Objective: The present study aimed at evaluating the reliability of Bolton analysis in tridimensional virtual models, comparing it with the manual method carried out with dental casts.Methods:The present investigation was performed using 56 pairs of dental casts produced from the dental arches of patients in perfect conditions and randomly selected from Universidade Federal da Bahia, School of Dentistry, Orthodontics Postgraduate Program. Manual measurements were obtained with the aid of a digital Cen-Tech 4"(r) caliper (Harpor Freight Tools, Calabasas, CA, USA). Subsequently, samples were digitized on 3Shape(r)R-700T scanner (Copenhagen, Denmark) and digital measures were obtained by Ortho Analyzer software.Results:Data were subject to statistical analysis and results revealed that there were no statistically significant differences between measurements with p-values equal to p = 0.173 and p= 0.239 for total and anterior proportions, respectively.Conclusion:Based on these findings, it is possible to deduce that Bolton analysis performed on tridimensional virtual models is as reliable as measurements obtained from dental casts with satisfactory agreement.

Objetivo: o presente estudo teve como objetivo avaliar a confiabilidade da análise de Bolton em modelos virtuais tridimensionais, comparando-a com a realizada em modelos de gesso.Métodos:foram utilizados 56 pares de modelos de gesso das arcadas dentárias de pacientes oriundos do Curso de Especialização em Ortodontia da Faculdade de Odontologia da Universidade Federal da Bahia, escolhidos aleatoriamente e em perfeito estado. Medidas manuais foram obtidas utilizando-se o paquímetro digital Cen-Tech(r) 4" (Harpor Freight Tools, Calabasas, CA, EUA). Em seguida, os mesmos foram digitalizados pelo scanner R-700TM(3Shape(r), Copenhagen, Dinamarca) e, por meio do programa Ortho AnalyzerTM, da mesma marca, foram obtidas as medidas digitais.Resultados:os dados foram submetidos a testes estatísticos e os resultados demonstraram que não houve diferença estatisticamente significativa nos dois tipos de medições com valores de p = 0,173 e p = 0,239, respectivamente, para as proporções total e anterior.Conclusão:com base nesses achados, pode-se inferir que a análise de Bolton realizada em modelos virtuais tridimensionais é tão confiável quanto a obtida em modelos de gesso, apresentando uma concordância satisfatória.

Efectos de diferentes tipos de entrenamiento en el aprendizaje de una discriminación condicional / Effects of different types of training in learning a conditional discrimination / Efeitos de diferentes tipos de treinamento na aprendizagem de uma discriminação condicional

Se diseñó un experimento para analizar el papel funcional de la retroalimentación, las instrucciones y la observación de un modelo aprendiz empleando una tarea de igualación a la muestra de segundo orden. Treinta y nueve estudiantes se asignaron aleatoriamente a uno de los tres grupos experimentales que difirieron en el entrenamiento: exposición directa a la tarea, observación de un modelo aprendiz (confederado), o uso de instrucciones precisas sobre los criterios de igualación. A algunos participantes se les ofreció un incentivo económico por su participación. Se encontró que las instrucciones precisas promovieron un aprendizaje más acelerado en comparación con los otros tipos de entrenamiento. El empleo del incentivo económico tuvo un efecto diferencial según el tipo de entrenamiento; hizo que los participantes tuvieran un mejor desempeño en la condición de observación del modelo aprendiz, pero no influyó en los otros tipos de entrenamiento. Estos resultados sugieren que el incentivo puede operar como un factor motivacional o disposicional, dado que afecta la probabilidad del establecimiento del control abstracto del estímulo.

An experiment was designed to analyze the functional role of feedback, instructions and observation of a learning model using a second-order matching-to-sample task. Thirty nine students were randomly assigned to one of the three experimental groups which differed among them in the type of training used: direct exposure to the task, observation of a learning model (confederate) or use of precise instructions about the matching criteria. Some participants were offered an economic incentive for participation. It was found that precise instructions promoted a faster acquisition than the other types of training. The use of economic incentives had a differential effect depending on the type of training. It promoted a high performance on the modeling condition but it did not have any effect on the other two types of training. These results suggest that incentives can operate like a motivational or dispositional factor since they affect the establishment of abstract stimulus control.

Criou-se um experimento para analisar o papel funcional da retroalimentação, as instruções e a observação de um modelo aprendiz empregando uma tarefa de igualação à mostra de segunda ordem. Trinta e nove estudantes foram distribuídos aleatoriamente em três grupos experimentais que diferiram no treinamento: exposição direta à tarefa, observação de um modelo aprendiz (confederado), o uso de instruções exatas sobre os critérios de igualação. A alguns participantes foi oferecido um incentivo econômico pela sua participação. Encontrou-se que as instruções exatas promoveram uma aprendizagem mais acelerada em comparação com os outros tipos de treinamento. O emprego do incentivo econômico teve um efeito diferencial segundo o tipo de treinamento; fez com que os participantes tivessem um melhor desempenho na condição de observação do modelo aprendiz, mas não influiu nos outros tipos de treinamento. Estes resultados sugerem que o incentivo pode operar como um fator motivacional ou disposicional, dado que afeta a probabilidade do estabelecimento do controle abstrato do estímulo.