Polymeric Piezoelectric Sensors and Remote Communication for Detection of Bruxism

Active materials are capable of responding in a controlled way to different external physical or chemical stimulus by changing some of their properties. These materials can be used to design and develop sensors, actuators and multifunctional systems with a large number of applications for developing medical devices (for both surgery and implants). On the other hand, Bruxism is a health problem consisting on grinding or tightly clenching the upper and lower teeth, and both phenomena lead to wear of the teeth and produce a noise during the night that is sufficiently loud to disturb the sleep of anyone sharing the bedroom. The tension produced also causes problems in the muscles, tissues and other structures surrounding the jaw, ear pain, headaches, lesions to the teeth and disorders in the jaw joints. For an early, rapid, effective and economical diagnosis of bruxism, we propose the use of instrumented splints based on the use of active materials, in order to detect and record the intensity and duration of interdentally pressure episodes. This paper introduces the design, manufacture and testing of using instrumented splint for diagnosing bruxism. The contribution of this work basically focus on using piezoelectric polymeric sensors, taking advantage of their reduced thickness, and avoiding the alteration of the patient¿s bite. In addition, the system allows a quantitative assessment of intraoral pressure that consequently allows the diagnosis of bruxism behaviour at an early stage, aiming to perform corrective actions before irreversible dental wear appears. The first trials performed allowed to demonstrate the feasibility of the system, which also includes wireless communication capabilities for improving telemedicine tasks

Physical ageing of a PU based shape memory polymer: influence on their applicability to the development of medical devices.

The variation in the properties of polymeric materials through ageing has considerable implications, since it affects the performance of any associated devices. Specially in the case of implantable devices with shape memory, any change in the switching temperature can give rise to problems in the thermal activation of the geometrical changes necessary to treat certain pathologies.This paper presents a study about the physical ageing of a polyurethane based shape memory polymer, SMP, at different temperatures using differential scanning calorimetry, DSC, and microhardness, MH, tests. The benefits of the combinated application of both testing techniques is shown, since DSC tests give information on the evolution of the glass transition temperature and the MH tests provide details of changes regarding mechanical properties

Models for predicting friction coefficient and parameters with influence in elastohydrodynamic lubrication

This article shows different friction prediction models applicable to lubricants in point contacts under an elastohydrodynamic regime. The types of models used are two variations of the Newtonian theory, the Limiting Shear Stress model and the one based on Carreau's equation. The article sets out the theoretical calculation procedures and the ensuing equations for calculating the friction coefficient. The aims of the article are to study the effect of the parameters with influence on friction and to compare the model's results with those given by an experimental stage performed on a mini traction machine. This test system allows the measurement of friction coefficient in point contacts (ball–disc) under a wide range of variation of parameters such as temperature, slide-roll ratio, lubricant, material, load, or velocity

Cálculo de la resistencia a la fatiga superficial en superficies con lubricación elastohidrodinámica mediante el criterio de Dang Van

Los fenómenos de fatiga superficial en sus diferentes escalas (micropitting, pitting, spalling), aparecen en multitud de elementos mecánicos en contacto lubricado como pueden ser los engranajes o rodamientos o en elementos con contacto seco como son las ruedas de ferrocarril. Los defectos que aparecen en las superficies en contacto debidos a estos fenómenos empeoran las condiciones de funcionamiento, provocando vibraciones, desgaste prematuro y en los casos más extremos el fallo de la máquina. El procedimiento que se sugiere en este artículo se inicia con el cálculo de los parámetros que definen el contacto elastohidrodinámico y que tienen influencia en la resistencia a fatiga del contacto: espesor de película, distribución de presión y coeficiente de fricción. Una vez se tiene la presión y el coeficiente de fricción en la superficie de contacto, se procede al cálculo de las tensiones en el interior del material obteniendo la distribución de tensiones. Conocidas las tensiones en todo punto interior y el proceso de carga completo se aplica el criterio de fatiga de Dang Van y se verifica si existe, o no, probabilidad de fallo por fatiga. El criterio de Dang Van es aplicable para el cálculo de la vida a fatiga para un alto número de ciclos (donde el tiempo de propagación de grieta es despreciable frente al tiempo de iniciación) y se basa en la aproximación a la escala mesoscópica y la existencia de un plano crítico. Una vez descrita la teoría se propondrá una aplicación para el cálculo de tensiones en contactos puntuales y contactos lineales y el análisis de fatiga superficial en engranaje

The Evolution and Development of Mechanical Engineering through large cultural areas

Mechanical Engineering is probably the forerunner of many branches of Engineering and has persistently been their companion up to the present. For this reason, the History of Machines embraces a very broad period of the History of Mankind, and can be studied from many perspectives. This paper attempts to link progress in Mechanical Engineering to the great cultures that have arisen throughout the History of Mankind. This paper begins with the anonymous mechanical developments that appeared in Prehistory and opened up the way to the first civilisations, marked to a large extent, maybe, by Greco-Roman culture in Europe and by China in Asia. After them came the Islamic world, which, in the Middle Ages stimulated society to find new mechanical devices and set the foundations that would lead to the Renaissance. Outstanding in this period was the expansion of Italian, French and German creative and innovative thinking with its “Treatises on Machines”, which, for a short time, coincided with the advance of the Iberian Empire and the development of machinery for the New World. Finally, the Industrial Revolution became the climax of all previous developments and a period of rapid mechanical evolution began that was to be highly interesting from a historical and technological point of view. This was accompanied by a parallel interest in reflecting on and analysing machines, which has led to the appearance of countless “Treatises on Machines”

Instrumented splint for the diagnosis of bruxism

Bruxism is a health problem consisting in grinding or tightly clenching the upper and lower teeth. Both the grinding and sliding lead to wear of the teeth and produce a noise during the night that is sufficiently loud to disturb the sleep of anyone sharing the bedroom. The tension produced causes problems in the muscles, tissues and other structures surrounding the jaw, ear pain, headaches, lesions to the teeth and disorders in the jaw joints. For an early, rapid, effective and economical diagnosis of bruxism, we propose the use of instrumented splints to detect and record the intensity and duration of inter dental pressure episodes. This paper sets out the design, manufacture and testing of an instrumented splint for diagnosing the signs of bruxism. The system stands out for its use of piezoelectric polymeric sensors which, because of their reduced thickness, do not cause any alteration to the patient’s bite. It lets a quantitative assessment of intraoral pressure be made and bruxism behavior be diagnosed at an early stage, so as to being able to programme corrective actions before irreversible dental wear appears. The first “in vitro” simulations and “in vivo “trials performed served to demonstrate the feasibility of the system in accordance with the initial objectives

Novel system for bite-force sensing and monitoring based on magnetic eear field communication

Intraoral devices for bite-force sensing have several applications in odontology and maxillofacial surgery, as bite-force measurements provide additional information to help understand the characteristics of bruxism disorders and can also be of help for the evaluation of post-surgical evolution and for comparison of alternative treatments. A new system for measuring human bite forces is proposed in this work. This system has future applications for the monitoring of bruxism events and as a complement for its conventional diagnosis. Bruxism is a pathology consisting of grinding or tight clenching of the upper and lower teeth, which leads to several problems such as lesions to the teeth, headaches, orofacial pain and important disorders of the temporomandibular joint. The prototype uses a magnetic field communication scheme similar to low-frequency radio frequency identification (RFID) technology (NFC). The reader generates a low-frequency magnetic field that is used as the information carrier and powers the sensor. The system is notable because it uses an intra-mouth passive sensor and an external interrogator, which remotely records and processes information regarding a patient?s dental activity. This permits a quantitative assessment of bite-force, without requiring intra-mouth batteries, and can provide supplementary information to polysomnographic recordings, current most adequate early diagnostic method, so as to initiate corrective actions before irreversible dental wear appears. In addition to describing the system?s operational principles and the manufacture of personalized prototypes, this report will also demonstrate the feasibility of the system and results from the first in vitro and in vivo trials

Rapid prototyping for biomedical engineering: current capabilities and Challenges

A new set of manufacturing technologies has emerged in the past decades to address market requirements in a customized way and to provide support for research tasks that require prototypes. These new techniques and technologies are usually referred to as rapid prototyping and manufacturing technologies, and they allow prototypes to be produced in a wide range of materials with remarkable precision in a couple of hours. Although they have been rapidly incorporated into product development methodologies, they are still under development, and their applications in bioengineering are continuously evolving. Rapid prototyping and manufacturing technologies can be of assistance in every stage of the development process of novel biodevices, to address various problems that can arise in the devices' interactions with biological systems and the fact that the design decisions must be tested carefully. This review focuses on the main fields of application for rapid prototyping in biomedical engineering and health sciences, as well as on the most remarkable challenges and research trends

Soporte tridimensional para producción artificial de órganos y otras estructuras del organismo humano y método de obtención del mismo

Soporte tridimensional para producción artificial de órganos y otras estructuras del organismo humano y método de obtención del mismo. La invención se refiere a un método de obtención de un soporte tridimensional de apoyo a tareas de producción artificial de órganos y otras estructuras del organismo humano caracterizado por una geometría exterior, que se adapta a la forma de la estructura biológica original, rellena de un conjunto de semillas fractales sólidas que conforman una retícula tridimensional, que permite enfoques personalizados para adaptarse de forma óptima a las características propias del órgano o estructura del organismo objeto de producción artificial y que promociona el crecimiento de células vivas sobre el soporte tridimensional sintético obtenido.Peer reviewedUniversidad Politécnica de Madrid, Consejo Superior de Investigaciones Científicas (España)B2 Patente sin exámen previ