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This paper aims at encouraging the use of laser treatment as an environmentally friendly technique to improve the mechanical properties of metallic materials over conventional quenching and tempering techniques through the study of the tribological behavior of AISI 1538 MV steel subjected to surface laser quenching treatment. Sliding wear tests were carried out by the pin-on-disk method. In order to identify the wear mechanisms, the worn surfaces on the disks were evaluated by scanning electron microscopy and the wear scars on the ball were observed by optical microscopy. Results reveal that laser treatment reduces the average friction coefficient by 25% and the wear rate by 60% compared with those achieved by the conventional methods, while the depths of the wear track and hardness of the cross section and surface are maintained.

Tumors, trauma and infections are the main reasons for subjecting a patient to a bone reconstruction made with the use of bone grafts or prosthetic elements, using for example components such as osteosynthesis plates, meshes and screws for their stabilization.This study focuses on the photoelastic analysis of a customized prosthesis of the jaw for a patient diagnosed with osteonecrosis. A resin model was manufactured as follows: DICOM files were processed in ScanIP software to obtain an STL file that was used to generate an antagonist model of the healthy section of the jaw using CATIA software, then, models were printed in Acrylonitrile Butadiene Styrene (ABS). Following the resin casting technique, the printed model of the jaw was used to construct a resin model, which is tested to determine its mechanical behavior.After carrying out the photoelastic analysis, it was found that the assembly process generates stress concentration zones. Here, the stress reaches a maximum value after the application of a bite force of 130.9 N in the premolars. In this study near the premolars, 3 stress concentration zones were identified and overlap of stress fields is reveled.The results show the importance of planning in the design and assembly process to obtain the best results in the reconstruction, reducing in this way the risk of a surgical reoperation due to problems of rupture or loosening of the prosthesis.

Today, assisted design software offers more capacity and iterations, and its methodology optimally solves geometries with enough rigidity and weight, keeping their specific characteristics desirable for some design objectives, and thus achieving originality, affordable functionality and reproducibility through manufacturing systems such as three-dimensional manufacturing. For this reason, the present study uses a computerized generative design method to optimize the main components of a cranial distraction system aiming to perform a geometric optimization of the original components and preserving the actual mechanical performance in spite of reducing the weight of the distractor components. By the use of commercial software packages such as PTC Creo Parametric©, PTC Creo Simulate©, Frustum©, Autodesk fusion 360°©, and Solid edge©, several generative proposals were evaluated. These evaluations were performed under load and boundary in order to preserve the cranial distractor function and optimize the amount of material used by the additive manufacture technique.

This work proposes and demonstrates the application of Biomechanics to make printed designs in 3D systems, in order to improve customized prosthetic components. The study provides solutions that benefit patients with orthopedic area defects. In addition, the publication of this work will increase the scientific production and international recognition of the National Polytechnic Institute.

Equinovarus foot or known as clubfoot is a frequent musculoskeletal deformity occurring at birth. It comprises a misalignment of the foot and shortened tendons and produces pain and serious physical limitations. It occurs mainly in patients with cerebral palsy, duchenne muscular dystrophy, residual clubfoot deformity, and spina bifida. The initial gold standard treatment for an equinovarus foot is the structural correction with the use of ortheses aimed to allow the patient to walk and perform rehabilitation exercises. These ortheses come mainly in the form of boots molded with plaster of Paris or fiberglass bandages. Premanufactured ortheses are also available and yield great resistance and support to the foot; however, they can be very costly and out of reach for some population. Recently, our research center of investigation and biomechanics laboratory (CILAB), with the assistance of the Instituto Politecnico Nacional (IPN) started printing three-dimensional personalized ortheses for diverse musculoskeletal problems, including clubfoot patients aiming to lower the costs of treatment for our pediatric patients. Our preset study analyzed the resistance of two 3D printed ortheses: one for a normal subject and another for a clubfoot patient through optical interferometry and numerical analysis. Our purpose was to anticipate failure of our personalized designs, especially in cases, where the foot gait is abnormal such as in the case of clubfoot patients.

Scoliosis and lordosis are medical conditions, which present an atypical curvature of the spine. These deformations can be easily diagnosed, altogether with the degree of their severity through orthopedic measurement processes and clinical reviews. However, the preformed studies which classify the severity of these deformations are, in their majority, empirical and present great opportunity for improvement. Therefore, they are based on radiographies that offer a clear image of the spine, but present the problem of a constant patient’s exposition to ionizing radiation and as a consequence an increment of potential hazards for health. This also means, results are subject to the physician’s interpretation and expertise. The present work intends to describe and analyze the design and function of a mechanical system that is capable of significantly reducing the radiological exposure of patients with scoliosis and lordosis. The main goal of this device is to diagnose both deformations by obtaining the angles of curvature of the patient’s spine, using a method that does not depend entirely on human interpretation.

This work details the study of the effectiveness in the use of plates, as a treatment support during the fracture of a mandibular angle. It also analyzes the mechanical operation of the fissure repair plates on the jawbone using methods like finite element simulation and image correlation experimentation. With the purpose to evaluate the mechanical capacities of a new prototype plate compared to one of the commonly used namesakes, since the mechanical capacities of the new model are unknown.

Human bone tumors, severe trauma, and infection are the main causes of large bone defects. Currently, these defects are repaired using reconstruction plates that connect remaining bone, without any bone grafting. This study focuses on two aspects: the first, experimental testings using digital image correlation and secondly numerical testing studies in order to evaluate the influencing factors in the design of a custom prosthesis and maxillofacial applications. In this work, it is proposed to design and characterize a prototype mandibular prosthesis for hemimandibulectomy recovery class IVc to a patient with bone cancer. For the design and prototype, the physical and morphological characteristics of the patient as well as the strength properties of the used material are necessary. The mandibular prosthesis prototype design will be created based on the 3D reconstruction of the mandible of tomographic studies, which were obtained using the ScanIP software. Subsequently, the 3D models were exported to a CAD software in order to fix the necessary adaptations to the bone. The 3D models were printed in acrylonitrile butadiene styrene, and a digital image correlation was used in order to evaluate the residual stress and strain differences which can be observed in all the cases, also in the case of implants and the remaining healthy bone, caused by masticatory forces.

La importancia de las pruebas mecanicas en la investigacion de nuevos materiales capaces de ser utilizados como elementos de remplazo para la estructura maxilofacial son imprescindibles, y tienen el objetivo de garantizar su correcto funcionamiento estructural una vez implantados; es por ello por lo que el presente trabajo se enfoca en la obtencion de las propiedades mecanicas en flexion y compresion de un nuevo material compuesto a base de resina isoftalica, hueso, hidroxiapatita y acero inoxidable; informacion que es usada en un ensamble virtual y estatico, cuyos componentes son: la protesis de rama y condilo, la estructura osea mandibular restante y los elementos de sujecion (tornillos). En dicho ensamble se contemplan de manera independiente las propiedades mecanicas de los materiales de cada uno de los elementos que lo conforman, con la finalidad de obtener datos reales y relevantes de su comportamiento, y de esta forma determinar desde el punto de vista mecanico, si puede ser usado en la manufactura de protesis maxilofaciales.

In this work, the design and numerical evaluation of a personalized hip prosthesis for a 31-year-old male patient, who suffered of unilateral coxarthrosis, was performed. Based on the information obtained of the patient’s computerized axial tomography and the employment of specialized design platforms such as Solidworks®, a numerical analysis was performed for the prosthetic model in conjunction with the anthropometric data of the patient following the finite element mathematical method. Furthermore, the natural posture of the patient was taken into consideration every time the patient balanced the total weight on one leg. Furthermore, the structural mechanical evaluation of the prostheses was set under evaluation, considering the osseous integration of the femoral bone and the acetabulum before and after surgery.

Flexible flat foot in infants can cause pain and physical limitation. Surgical treatment is preferred when pain is severe. Evans enlargement of the lateral aspect of the calcaneus has good results but has complications due to the collapse of bone grafts. Tridimensional segmentation of anatomical areas allows to obtain stereolithographic models that can be numerically analyzed. A stereolithographic model of a healthy calcaneus was obtained from a CT and virtually sectioned to simulate Evans osteotomy. A wedge-shaped implant was made and implanted as described by Evans. Both models were analyzed with a finite element software, the calcaneus model comprised cortical and cancellous bone layers (E = 20 GPa and 457 MPa respectively) The wedge-shaped was assigned PMMA properties (E = 2.4GPa). Three phases of human gait were simulated and stress obtained. The highest von Mises stress occurred at the stance phase (18.25 MPa). None of the stress exceeded the yield stress for all materials in all phases. Reconstruction of anatomic models and implants using a stereolithographic technique allow to predict stress and failure. These models could also be printed 3D to elaborate novel implants.

In the present work, the creation of a tridimensional electronic prosthesis which intends to replace the left hand’s phalanges of a patient who suffered severe burns and needed to undergo a partial amputation surgery was performed. Parting of a CT tomography composed of 539 images, the contour delimitation, and separation of each phalanx was carried out through the usage of computerized platforms, such as 3D Slicer and Scan IP. Both software allow the user to analyze every single image in three different planes (axial, sagittal and coronal) and segment the areas of interest, in this case, the index, middle, ring and little fingers’ phalanges. Subsequently, with the support of the platform SolidWorks©, each phalanx was detailed for its connection and posterior 3D printing, implementing an electronic mechanism capable of reproducing flexion-extension movements. The computerized final model was also submitted to mechanical force tests and force simulations based on the analysis of finite elements to ascertain the selected material’s and model’s resistance.

The design and development of highly accurate prostheses for individual cases according to the patient’s condition is one of the current challenges in the fields of medicine and engineering. The use of tomographic archives uploaded to a specialized computer program for its rendering (creation of a 3-D model) allows specialists decide on the surgical approach to take, by creating a model which possesses precise dimensions, corresponding to the exact anatomy of the patient. The use of computational programs (CAD/CAM programs) not only allows the development of better designs, but also the evaluation of the proposed models through a force moment analysis in conjunction with the assignment of the endorsed materials for its posterior development by setting the prototypes to the Maximum Shear Stress principle and analyzing the results of its displacement’s and the Stress von Mises’ tests, specialists have the opportunity to know if the final design will be able to support the muscular tensions and occlusion forces caused by the elongation of the muscular fibers.

In the present work, the importance and consideration of the use of scaffold structures for biomaterials is highlighted in order to be applied in prosthetic cases where it is possible to consider a three dimensional porous structure, maintaining the mechanical properties that are necessary for the right functioning of the models under preoperative and postoperative loads. The requirements for biodegradable and bioactive properties of the models are indicated by surgical specialists, with the purpose of considering both the shape and type of the scaffold and its influence in the building of diverse mechanical supports. A specific maxillofacial application case of models, a mandibular implant, whose numerical-experimental properties and behaviors based on bone, polymers and metal alloy structures used in the manufacturing of models, were used to compare the variation of the scaffold structure types. Furthermore, models printed in 3D using an acrylonitrile butadiene styrene (ABS) polymer with different fiber orientations and type of scaffolds will be considered as an initial part of the case studies.

In this work, a temporomandibular joint prosthesis system is designed in order to be manufactured and implanted. A computer tomography study of a patient with bone cancer and temporomandibular ankylosis was used. The specific design also considered a local socket to replace the mandibular fossa. The manufacturing of the system used stainless steel (AISI-316L). Mechanical evaluation and numerical testing were done using ANSYS code and PTC CREO Parametric 3.0, while in the biomechanical reconstruction, SCAN IP software was used. The fixation of the prosthesis in the patient is an important requirement and the structural behavior is studied using the finite element method (FEM). In order to design and personalize the implants, quick prototyping printer systems (ABS and PLA) were used, while for the manufacturing process, stainless steel 316L was considered, in order to get low costs. As a result of this research, the chewing process of the patient will be performed.

Tomando como base las estadisticas de la Organizacion Mundial de la Salud (OMS), se estima que 82% de las amputaciones de miembro inferior estan relacionadas con enfermedades vasculares. Ademas, solo una de cada 10 personas que sufrio alguna amputacion logra rehabilitarse, y solo el 30% tiene un buen funcionamiento del miembro protesico. Una de las consecuencias del mal desempeno son, que las protesis no se ajustan completamente a la persona y no cumplen los requisitos ergonomicos. Ademas, no se adaptan a las necesidades fisicas. Ocasionando, que el ciclo de marcha con una protesis inadecuada sea doloroso y anormal.

"La tecnología es tan antigua como el hombre mismo. Así loshombres se convirtieron en tecnólogos cuando aprendie-ron a aprovechar los materiales y fenómenos naturales delmundo físico que los rodeaba [8]. La planificación y la reso-lución de problemas forman el núcleo de la tecnología. Lamecanización de procesos han maximizado la fuerza muscu-lar, las computadoras el poder mental, los sentidos del hom-bre se han maximizado por medio de los dispositivos demedición como los sensores y aparatos de medición. Estedesarrollo de sistemas de tecnología avanzada ha dado lu-gar al desarrollo de sistemas tan complejos como son losrobots, los cuales son máquinas que integran sistemas me-cánicos, eléctricos, electrónicos dotados de un sistemainformático para su control en tiempo real [9]. La robóticaindustrial trata fundamentalmente de dotar de flexibilidad alos procesos productivos incrementando al mismo tiempola productividad. Otro sector de importancia creciente enlas aplicaciones de la robótica son los robots de servicio,entre los cuales se incluyen los robots domésticos, de apo-yo a los discapacitados y asistentes en general."

In this work, the design and manufacture of a new jaw prosthesis for a young patient with articular Ankylosis is reported. The required models were obtained with a Computed Axial Tomography (CAT) in conjunction with computed aided design (CAD) and engineering codes. Several tomography slices were taken in digital format (DICOM). Each slice was processed with Scan IP, CATIA and Solidworks. The main objective of this study is to show the digital and a physical processing for manufacturing the desired model, taking into account the anthropometry of the young patient, who expects to receive this fixation as a maxillary implant. The STL and FEM model allowed creating biomechanical prototypes in order to adjust the disorders that this young patient has suffered by three incorrect medical procedures. It will allow manufacture the final mold by using of a quick prototyping printer system (dust). This prosthesis will be created as an only piece, and the main body will be created by a strong, low weight and polymeric material Poly(methyl methacrylate)—(PMMA), while a low friction metal will be considered for the condylar joint. The expectation for this final implant requires the approval of the Specialty Hospital “La Raza” (IMSS) in order to be installed on the patient. For this purpose, biomechanical engineering procedure and 3D manufacturing quick prototyping was used for the prototype. The clinical case discussed in this paper is related to a 17-year-old individual. He was treated in the area of maxillofacial and plastic surgery. The severity of the deformation was based on congenital disease. Calcium hydroxyapatite, Poly(methyl Methacrylate) polymers and stainless steel, which are highly biocompatible materials, were used for this purpose. It is very important to mention that this procedure avoided the employment of bone tissue taken from the ribs and cranial regions as in other research publications referred. As a result of this research, a unique 3D personalized jaw model could be presented in order to be fixed in the patient.

La finalidad de disenar una protesis, es obtener una replica similar al miembro faltante. Las protesis deben garantizar las necesidades del paciente como son; comodidad, funcionalidad y estetica. Ademas, debe de permitir al individuo realizar actividades comunes de la vida diaria con el menor gasto de energia posible. Con el fin de satisfacer las necesidades, los componentes deben de colocarse de forma precisa y comoda, tambien deben ser elegidos correctamente, montados y alineados para proporcionar un maximo restablecimiento de la funcion y desviacion minima de la marcha. Sin embargo, es importante mencionar, que en la practica protesica actual, la alineacion y ensamblaje final de la protesis se logra utilizando la habilidad y la experiencia del protesico y los comentarios del paciente. Derivado lo anterior, para optimizar el proceso de seleccion de los componentes, en este trabajo se utilizan las redes neuronales artificiales para encontrar los parametros y componentes adecuados en el ensamblaje de una protesis modular de miembro inferior en pacientes con amputacion transfemoral. El objetivo principal es que la protesis proporcione el mejor funcionamiento y que cumpla con los requisitos de demanda por el paciente. Asimismo, se espera que el resultado obtenido, sirva como apoyo a los medicos protesistas para la toma de decisiones de los componentes protesicos, disminuyendo asi, el tiempo de ensamblaje y manufactura.

RESUMEN: El presente trabajo se basa en el caso medico de un paciente de 19 anos de edad, con problemas serios en el maxilar entre los que resaltan: la ausencia de una seccion de hueso a causa de una deformidad de nacimiento (congenita), asimetria facial y problemas de articulacion, entre otros. A lo largo de su vida, el paciente ha sido intervenido quirurgicamente en por lo menos cuatro ocasiones, con el objetivo de solucionar los problemas previamente mencionados, y con ello devolverle la movilidad y funcionalidad a esta importante estructura osea, pero tales intentos fallaron, pues las protesis o implantes terminaban por romperse, esto debido a que no se conto con una correcta planeacion quirurgica sobre el uso adecuado de materiales, ensambles, geometrias e identificacion de zonas de falla potenciales. Con el proposito de tener un resultado positivo en la futura intervencion quirurgica, se hace una planeacion minuciosa de la misma, basada en herramientas computacionales de modelado tridimensional y estereolitografia, que se encausan en la reproduccion de un modelo tridimensional de resina fotoelastica para realizar un ensayo experimental, cuyo objetivo unicamente se enfoca en identificar las zonas de posible falla en la protesis cuando esta se encuentre instalada en el paciente, y usar esta informacion para reforzar el ensamble de ser necesario, ya que todas las protesis usadas en las intervenciones pasadas se fracturaron. Palabras clave: protesis, maxilar, estudio fotoelastico, estereolitografia, modelo tridimensional.

This work shows a methodology to successfully generate an anatomically appropriate mandibular prosthesis for two patients with different conditions affecting the bone: cancer and necrosis. A common technique for bio-modeling was used in both cases, which includes tomographic slices of 0.5 mm for each clinical case. As a result of the processing a stereolithographic model was performed using two different techniques, were the affected area was reconstructed. In the osteonecrosis case, with the use of auxiliary guide paths and drawings in the CATIA platform a 3D model was produced, achieving a partial replacement with lateral support; while in the cancer case a left lateral replacement with the ramus was produced by reconstructing surfaces and patterns of the required area in PowerShape® and Solidworks® platforms. The region to replace was defined by the surgical expertise of a maxillofacial physician. Both cases were printed in acrylonitrile butadiene styrene (ABS) polymer producing a three-dimensional model, which was adjusted by the maxillofacial surgeon and subsequently integrated into a compound that includes cyanoacrylate with low toxicity, calcium powder, hydroxyapatite and isophthalic resin as a fundamental basis. The models were analyzed numerically using the same conditions that will be applied mechanically and clinically in order to obtain preliminary information on stress concentration zones and material deformation.

In this work, the design and manufacture of a new assembled prosthesis for a jaw for a young Mexican patient with Temporo Mandibular Disorder (TMD) and articular ankilosys is reported. The required models were obtained with a computed axial tomography (CAT) in conjunction with computed aided design (CAD) and engineering codes. Several tomographic slices were taken digital format (DICOM). Each slice was processed with Scan IP, Unigraphics and Solidworks. The main objective of this study is to show the digital and a physical processing for manufacturing the desired model, taking into account the anthropometry of the young patient, who expects to receive this fixation as a maxillary implant. The parametric FEM model allows creating biomechanical testings in order to evaluate its mechanical response before the final manufacturing by using of a quick prototyping printer system (dust). This prosthesis will be created as an assembly, and the condylar joint will be created by a low friction metal. The expectation for this final implant requires the approval of the Hospital “La Raza” (IMSS) in order to be installed on the patient. For this purpose, a biomechanical engineering procedure and 3D manufacturing quick prototyping was used for the prototype. The clinical case discussed in this chapter is related to a 17 year-old individual. He was treated in the area of maxillofacial and plastic surgery. The severity of the deformation was based on congenital disease. Calcium hydroxyapatite, polymethylmethacrylate polymer and stainless steel, which are highly biocompatible materials, were used for this purpose. It is very important to mention that this procedure avoided the employment of bone tissue taken from the ribs and cranial regions as in other research publications referred. As a result of this research, an assembled 3D personalized jaw model could be presented in order to be fixed in the patient.