Precision and accuracy of pre-surgical planning of non-cemented total hip replacement with calibrated digital images and acetates.

BACKGROUND: When approaching a joint replacement procedure, pre-surgical planning is essential to predict an accurate estimation of implant size and position. There are currently two methods to achieve it, analog and digital. The present study aims to demonstrate how the hybrid technique is accurate and precise for pre-surgical planning in a non-cemented total hip replacement. METHODS: Concordance-type study is used against a gold standard, as well as inter- and intra-observer consistency evaluation of two orthopedic surgeons and two orthopedic surgery residents. Accuracy was calculated with the intra-class correlation coefficient (ICC). Afterwards, the same calculation was done considering a margin of error with one size more and one less. RESULTS: Thirty-eight patients were included in the study: 19 women and 19 men. Twenty-two prostheses (57.89%) were right-sided and 16 were left (42.11%). Twelve prostheses (31.57%) were Stryker and 26 Johnson & Johnson (68.43%). Acetabular cup correlation compared with the gold standard was moderate: ICC reported 0.45 (95% CI, 0.15-0.76). When adjusted by ± 1 size, ICC was 0.48 (95% CI, 0.18-0.79). On the other hand, results from the femoral stem reported ICC 0.85 (95% CI, 0.07-0.98). When adjusted by ± 1 size, ICC was 0.86 (95% CI, 0.06-0.99). CONCLUSIONS: Hybrid templating is a reliable substitute for analog or digital planning. It is quick, inexpensive, accurate, and better results are observed in the femoral component regardless the level of expertise of the evaluator. LEVEL OF EVIDENCE: Grade IV.

Use of cone beam computed tomography, a desktop 3D printer and freeware for manufacturing craniofacial bone prostheses: a pilot study / Utilización de la tomografía cone-beam para la confección de protesis óseas craniofaciales por impresora 3D de escritorio usando programas libres: un estudio piloto

The aim of this study was to reconstruct missing bone parts using cone beam computed tomography (CBCT), freeware and a desktop 3D printer. Materials and Methods: A human skull was used and osteotomies were performed in the frontal process of the zygomatic bone, zygomatic process of the temporal bone and part of the parietal bone. The 3D image was then obtained CBCT and the DICOM file was transformed into STL and exported using InVesalius software. Missing bone parts were modeled by overlapping with OrtogOnBlender software for later printing using a desktop 3D printer. Result: The obtained prostheses had very good adaptation to the missing bone parts. Conclusion: It is feasible to make bone prostheses by 3D printing using low-cost desktop printers, as well as the use of free open-source software programs through CBCT.

El objetivo de este estudio fue el de reconstruir partes óseas faltantes usando tomografía computarizada de haz cónico, programas de licencia libre e impresora 3D de escritorio. Materiales and Métodos:Se utilizó un cráneo humano y se le realizó osteotomías en la apófisis frontal del hueso cigomático, apófisis cigomática del temporal y parte del parietal. Seguidamente se obtuvo la imagen en 3D por medio de la tomografía cone-beam y se exportó el formato DICOM para STL usando el programa libre InVesalius. Se modelaron las partes óseas faltantes por superposición con el programa libre OrtogOnBlender para su posterior impresión utilizando una impresora 3D de escritorio. Resultados: Las prótesis obtenidas tuvieron muy buena adaptación en las partes óseas faltantes. Conclusión:Es factible confeccionar prótesis óseas por impresión 3D utilizando impresoras de escritorio de bajo costo, así como la utilización de programas libres de código abierto a través de la tomografía cone-beam.

A strategy for designing of customized electromechanical actuators of blood pumps.

Congestive heart failure is a pathology of global incidence that affects millions of people worldwide. When the heart weakens and fails to pump blood at physiological rates commensurate with the requirements of tissues, two main alternatives are cardiac transplant and ventricular assist devices (VADs). This article presents the design strategy for development of a customized VAD electromagnetic actuator. Electromagnetic actuator is a brushless direct current motor customized to drive the pump impeller by permanent magnets located in rotor-stator coupling. In this case, ceramic pivot bearings support the VAD impeller. Electronic circuitry controls rotation switching current in stator coils. The proposed methodology consisted of analytical numerical design, tridimensional computational modeling, numerical simulations using Maxwell software, actuator prototyping, and validation in the dynamometer. The axial flow actuator was chosen by its size and high power density compared to the radial flow type. First step consisted of estimating the required torque to drive the pump. Torque was estimated at 2100 rpm and mean current of 0.5 A. Numerical analysis using finite element method mapped vectors and fields to build stator coils and actuator assemblage. After tests in the dynamometer, experimental results were compared with numerical simulation and validated the proposed model. In conclusion, the proposed methodology for designing of VAD electromechanical actuator was considered satisfactory in terms of data consistency, feasibility, and reliability.

Design and Control of a New Biomimetic Transfemoral Knee Prosthesis Using an Echo-Control Scheme.

Passive knee prostheses require a significant amount of additional metabolic energy to carry out a gait cycle, therefore affecting the natural human walk performance. Current active knee prostheses are still limited because they do not reply with accuracy of the natural human knee movement, and the time response is relatively large. This paper presents the design and control of a new biomimetic-controlled transfemoral knee prosthesis based on a polycentric-type mechanism. The aim was to develop a knee prosthesis able to provide additional power and to mimic with accuracy of the natural human knee movement using a stable control strategy. The design of the knee mechanism was obtained from the body-guidance kinematics synthesis based on real human walking patterns obtained from computer vision and 3D reconstruction. A biomechanical evaluation of the synthesized prosthesis was then carried out. For the activation and control of the prosthesis, an echo-control strategy was proposed and developed. In this echo-control strategy, the sound side leg is sensed and synchronized with the activation of the knee prosthesis. An experimental prototype was built and evaluated in a test rig. The results revealed that the prosthetic knee is able to mimic the biomechanics of the human knee.

Diseño de exoesqueletos para miembro inferior / Exoskeleton design for lower limb

Introducción: La desarticulación de cadera es realizada por cirujanos para prevenir el crecimiento de enfermedades malignas en casos que no pueden ser tratados en forma conservadora. Existe la posibilidad que la desarticulación pueda ser causada por un accidente traumático que comprometa uno o los dos miembros inferiores. Objetivo: modificar el diseño de una prótesis para personas con problemas de tensión muscular, para cargas pesadas y movimientos repetitivos, para ser usada en personas con desarticulación unilateral o bilateral de cadera, partiendo de la patente de invención. Métodos: El diseño se realizó teniendo en cuenta desplazamiento similar al sistema locomotor humano, el confort, las posibles lesiones en las prominencias óseas, la repetitividad y el bajo costo. Para garantizar el menor impacto en la prominencia ósea disminuyendo el riesgo de ruptura o ulceras se usó un escáner 3D con sensores de presión para una correcta distribución de la presión sobre toda la prominencia de la cadera. Resultados: El sistema propuesto resultó en una alternativa para personas con limitaciones de movilidad en miembro inferior permitiendo un movimiento más natural y así mejorar la calidad de vida de este tipo de pacientes. La técnica permitió al usuario un alto nivel de independencia en situaciones de pérdida de los miembros inferiores. Conclusiones: El estudio se centró en la modificación de una prótesis para miembro inferior usado para personas con baja tonicidad muscular o actividades repetitivas a un sistema para personas con desarticulación bilateral de cadera o pérdida de un solo miembro inferior(AU)

Introduction: Hip disarticulation is performed by surgeons to prevent the growth of malignant diseases in cases that can not be treated conservatively. There is a possibility that the disarticulation may be caused by a traumatic accident involving one or both lower limbs. Objective: to modify the design of a prosthesis for people with muscular tension problems, for heavy loads and repetitive movements, to be used in people with unilateral or bilateral hip disarticulation, starting from the patent of invention. Methods: The design was made taking into account displacement similar to the human locomotor system, comfort, possible lesions in bony prominences, repetitiveness and low cost. To guarantee the least impact on the bone prominence, reducing the risk of rupture or ulcers, a 3D scanner with pressure sensors was used to correctly distribute the pressure over the whole hip prominence. Results: The proposed system resulted in an alternative for people with mobility limitations in the lower limb allowing a more natural movement and thus improving the quality of life of this type of patients. The technique allowed the user a high level of independence in situations of loss of the lower limbs. Conclusions: The study focused on the modification of a lower limb prosthesis used for people with low muscle tone or repetitive activities to a system for people with bilateral hip disarticulation or loss of a single lower limb(AU)

Experimental implantation of an arterial substitute made of silicone reinforced with polyester fabric in rabbits

OBJECTIVES: The aim of this study was to analyze silicone tubes with an internal diameter of 4 mm as a possible material for vascular prostheses. METHODS: Grafts were implanted into the infrarenal aortas of 33 rabbits. Fluoroscopic examinations were performed within 150 days after surgical implantation. Sample grafts were analyzed via electron microscopy to evaluate the eventual endothelialization of the prostheses. RESULTS: The patency rates of the prostheses were 87% (±6.7%) after 30 days, 73% (±9.3%) after 60 days and 48% (±12%) after 120 days. The material presented characteristics that support surgical implantation: good tolerance promoted by polyester tear reinforcement, ease of postoperative removal and a lack of pseudoaneurysms. However, intimal hyperplasia was a limiting factor for the patency rate. CONCLUSIONS: We concluded that polydimethylsiloxane has limited potential as an alternative material for small vascular prostheses.

Structural and mechanical characterization of custom design cranial implant created using additive manufacturing

Background: Reconstruction of customized cranial implants with a mesh structure using computer-assisted design and additive manufacturing improves the implant design, surgical planning, defect evaluation, implant-tissue interaction and surgeon's accuracy. The objective of this study is to design, develop and fabricate cranial implant with mechanical properties closer to that of bone and drastically decreases the implant failure and to improve the esthetic outcome in cranial surgery with precision fitting for a better quality of life. A customized cranial mesh implant is designed digitally, based on the Digital Imaging and Communication in Medicine files and fabricated using state of the Art-Electron Beam Melting an Additive Manufacturing technology. The EBM produced titanium implant was evaluated based on their mechanical strength and structural characterization. Results: The result shows, the produced mesh implants have a high permeability of bone ingrowth with its reduced weight and modulus of elasticity closer to that the natural bone thus reducing the stress shielding effect. Scanning electron microscope and micro-computed tomography (CT) scanning confirms, that the produced cranial implant has a highly regular pattern of the porous structure with interconnected channels without any internal defect and voids. Conclusions: The study reveals that the use of mesh implants in cranial reconstruction satisfies the need of lighter implants with an adequate mechanical strength, thus restoring better functionality and esthetic outcomes for the patients.

Combining Virtual Surgical Planning, Intraoperative Navigation, and 3-Dimensional Printing in Prosthetic-Based Bilateral Microtia Reconstruction.

Reconstructing auricular deformities for bilateral microtia is a demanding challenge especially after failed autologous reconstruction. This case report presents a novel application of virtual surgical planning, computer-assisted design, and intraoperative surgical navigation to preplan and execute placement of custom-tailored silicone auricular prostheses and titanium osseointegrated implants for a bone-anchored hearing aid system in a patient with Treacher Collins syndrome in whom autologous reconstruction had previously failed. Through a collaborative approach between the reconstructive surgeon and anaplastologist, the implementation of advanced digital technologies may offer a superior esthetic and functional outcome to patients with previously failed reconstruction.

Quantification and Analysis of Leaflet Flutter on Biological Prosthetic Cardiac Valves.

The use of porcine or bovine pericardium biological cardiac valves has as its main disadvantage a relatively short lifespan, with failures due to calcification and fatigue. Increasing these valves' durability constitutes a great challenge. An understudied phenomenon is the effect of flutter, an oscillation of the leaflets that can cause regurgitation and accelerate calcification and fatigue. As a starting point to study how to reduce or prevent these oscillations, a method was developed to quantify the flutter frequencies occurring at the point of the valve's full opening. On a test bench that simulates the heart flow, the cusp behaviors of eight biological valves were filmed with a high speed camera at 2000 frames per second at different flow rates and motion capture software obtained the frequencies and amplitudes of the vibrations of each leaflet. Oscillations in the range of 200 Hz with average amplitudes of 0.4 mm were found; larger nominal diameter valves obtained lower values, and bovine pericardial valves had superior performance compared to porcine valves. A dimensionless analysis was performed to find a relationship between the geometric and mechanical properties of the valves with the critical speed of the onset of fluttering. This relationship inspired a method to predict whether flutter will occur in the bioprosthesis. This method is a new tool for the consideration of maximizing the life of prosthetic valves.

Experimental implantation of an arterial substitute made of silicone reinforced with polyester fabric in rabbits.

OBJECTIVES: The aim of this study was to analyze silicone tubes with an internal diameter of 4 mm as a possible material for vascular prostheses. METHODS: Grafts were implanted into the infrarenal aortas of 33 rabbits. Fluoroscopic examinations were performed within 150 days after surgical implantation. Sample grafts were analyzed via electron microscopy to evaluate the eventual endothelialization of the prostheses. RESULTS: The patency rates of the prostheses were 87% (±6.7%) after 30 days, 73% (±9.3%) after 60 days and 48% (±12%) after 120 days. The material presented characteristics that support surgical implantation: good tolerance promoted by polyester tear reinforcement, ease of postoperative removal and a lack of pseudoaneurysms. However, intimal hyperplasia was a limiting factor for the patency rate. CONCLUSIONS: We concluded that polydimethylsiloxane has limited potential as an alternative material for small vascular prostheses.

Skull reconstruction after resection of bone tumors in a single surgical time by the association of the techniques of rapid prototyping and surgical navigation.

PURPOSE: Presentation of a new cranioplasty technique employing a combination of two technologies: rapid prototyping and surgical navigation. This technique allows the reconstruction of the skull cap after the resection of a bone tumor in a single surgical time. METHODS: The neurosurgeon plans the craniotomy previously on the EximiusMed software, compatible with the Eximius Surgical Navigator, both from the company Artis Tecnologia (Brazil). The navigator imports the planning and guides the surgeon during the craniotomy. The simulation of the bone fault allows the virtual reconstruction of the skull cap and the production of a personalized modelling mold using the Magics-Materialise (Belgium)-software. The mold and a replica of the bone fault are made by rapid prototyping by the company Artis Tecnologia (Brazil) and shipped under sterile conditions to the surgical center. The PMMA prosthesis is produced during the surgical act with the help of a hand press. RESULTS: The total time necessary for the planning and production of the modelling mold is four days. The precision of the mold is submillimetric and accurately reproduces the virtual reconstruction of the prosthesis. The production of the prosthesis during surgery takes until twenty minutes depending on the type of PMMA used. The modelling mold avoids contraction and dissipates the heat generated by the material's exothermic reaction in the polymerization phase. The craniectomy is performed with precision over the drawing made with the help of the Eximius Surgical Navigator, according to the planned measurements. The replica of the bone fault serves to evaluate the adaptation of the prosthesis as a support for the perforations and the placement of screws and fixation plates, as per the surgeon's discretion. CONCLUSIONS: This technique allows the adequate oncologic treatment associated with a satisfactory aesthetic result, with precision, in a single surgical time, reducing time and costs.

Prótese óculopalpebral com captação de movimento palpebral: proposta de dispositivo mecânico / Oculopalpebral prosthesis with eyelid motion capture: mechanical appliance proposition

Introdução: A reconstrução de grandes defeitos da face nem sempre é passível de correção cirúrgica, podendo ser restaurados com as próteses faciais. Apesar da prótese óculopalpebral apresentar uma aparência natural, ela é facilmente notada, pois não apresenta os movimentos palpebrais de abertura e fechamento sincronizadas com o olho contralateral, tornando assim a reconstrução protética um grande desafio. Objetivos: Planejar, desenhar, viabilizar e construir um protótipo com recurso mecânico/elétrico possibilitando sincronia dos movimentos palpebrais com o olho sadio para utilização em prótese óculopalpebral. Material e Métodos: Confecção de uma prótese óculopalpebral com um dispositivo de pálpebra móvel em silicone médico capaz de conectar-se a um sistema mecânico-elétrico responsável por realizar movimentos de abertura e fechamento da pálpebra móvel da prótese. Resultados e Discussão: Foi confeccionada uma prótese óculo-palpebral em resina acrílica termicamente ativada, criando-se um nicho para a acomodação de um sistema elétrico e possibilitar a livre movimentação de uma fina pálpebra em silicone interligada ao dispositivo tornando possível a conexão desse sistema com um sensor que capta o movimento palpebral de um olho saudável. Conclusão: No presente estudo um protótipo mecânico - elétrico foi planejado, desenhado e desenvolvido acoplado a uma prótese óculopalpebral estabelecendo e sincronizando seus movimentos palpebrais com o olho sadio.

Introduction: Surgical reconstruction of large facial defects may not be always possible. Extraoral maxillofacial prosthesis are a good restorative option. Even though when the oculopalpebral prosthesis presents a natural appearance, it can be easily noticed because its eyelids do not move. It is desirable for the eyelids to open and close synchronously with contralateral eye. Thus, prosthetic reconstruction of oculopalpebral region is a great challenge. Objectives: To plan, design, enable and build a oculopalpebral prosthesis prototype with mechanical and electric features allowing eyelid motion with synchronization with the sound eye. Material and method: Fabrication of an oculopalpebral prosthesis with a medical grade silicone movable eyelid which has the capability to connect itself to an mechanical-eletrical system responsible to make opening and closing movements on prosthesis movable eyelid. Results and discussion: An oculopalpebral prosthesis was made in thermoactivated acrylic resin. A gap was created to accomodate an electrical system and also allow free motion of a thin silicone eyelid attached to the dispositive. This system can be connected to a sensor which captured the eyelid motion of a sound eye. Conclusion: A mechanical-electrical prototype was planned, designed and developed attached to an oculopalpebral prosthesis stablishing and synchronizing its eyelid movements with the sound eye.

Three Dimensional Morphometry of Distal Femur to Design Knee Prosthesis for Indonesian Population / Morfometría Tridimensional del Fémur Distal para Diseñar Prótesis de Rodilla para la Población Indonesia

The objective of this study was to design custom-made prosthesis in a certain population, the morphometry needs to be measured. The results of this study were expected to provide basic data to design the ideal size of the total knee arthoplasty prosthesis for Indonesian population. This was an anthropometric study conducted on 100 healthy Indonesian population based on Computer Tomographic (CT) imaging on the distal femur resected surface. The parameters being used were Femoral Medio Lateral (fML) length, Femoral Antero Posterior (fAP) length, Femoral Medial Antero Posterior (fMAP) length, Femoral Lateral Antero Posterior (fLAP) length, and Femoral Aspect Ratio (FR). We found that the mean fAP and fML were 54.60±5.71 and 65.98±6.51, respectively. The morphometry of the distal femur were significantly different between male and female (male have larger build), however one of parameters showed different result: fLAP. This study showed that Indonesian people have smaller build compared with their Western counterpart. The proposed dimensions can be used as the basic data to design the ideal size of the custom-made knee arthoplasty prosthesis for Indonesian population.

El objetivo fue diseñar una prótesis a medida para una determinada población, por tanto la morfometría debía ser medida para proporcionar datos básicos para diseñar el tamaño ideal de una prótesis total para la artroplastia de rodilla en población de Indonesia. Se realizó un estudio antropométrico sobre 100 sujetos sanos indonesios, basados en tomografías computadorizadas (TC) de la superficie resecada del fémur distal. Los parámetros que se midieron fueron longitud femoral mediolateral (FML), longitud femoral anteroposterior (FAP), longitud femoral medial anteroposterior (FMAP), longitud femoral lateral anteroposterior (FLAP), y razón de aspecto femoral (FR). Las medias FAP y FML fueron 54,60±5,71 y 65,98±6,51, respectivamente. La morfometría del fémur distal fue significativamente diferente entre hombres y mujeres (mayor tamaño en hombres), sin embargo uno de los parámetros mostró resultados diferentes, la FLAP. Las personas indonesias son de menor tamaño en comparación con su contraparte occidental. Las dimensiones propuestas se pueden utilizar como los datos básicos para diseñar el tamaño ideal para una prótesis de rodilla a medida para la población de Indonesia.

Pulsatile stent graft: a new alternative in chronic ventricular assistance.

OBJECTIVE: Heart failure is currently one of the most common hospitalization causes. Several chronic circulatory assist devices have been tested and are highly complex. The objective is the description of a pulsatile endoprosthesis capable of applying a chronic pulse within the descending aorta, similar to that produced by intra-aortic balloon. METHODS: Pulsatile stents composed of nickel-titanium were built and positioned to engage latex tubes simulating the aorta. Different electric currents were applied to units connected in series in order to cause structure contraction and displacement of a liquid column. There were two sequence tests: first composed of two metallic cages and the second composed of five cages. At first sequence tests was applied a voltage of 16.3 volts and a current of 5 amperes. In the second, voltage of 15 volts and current of 07 amperes. RESULTS: In the first sequence was obtained the pulsatile effect of stent, with contraction of the tube and displacement of the water column sufficient to validate the pulsating effect of the endoprosthesis. The two structures ejected a volume of 2.6 ml per cycle, with a range of 29 mm in height of the column of water equivalent to 8% shrinkage during the pulse. In the second sequence, it reachead a variation of 7.4 mL per cycle. CONCLUSION: The results obtained confirm the stent pulsatile contractility activated by electrical current. The continuity of the study and material improvement are necessary to obtain more efficient model from the point of view of energy and pulse, to allow ejection volumes comparable with the intra-aortic balloons.

Stent aórtico pulsátil: uma nova alternativa na assistência ventricular crônica / Pulsatile stent graft: a new alternative in chronic ventricular assistance

OBJETIVO: A insuficiência cardíaca é uma das causas mais comuns de internação. Dispositivos para assistência circulatória crônica foram testados e, em sua maioria, são de alta complexidade. O objetivo deste estudo é a descrição de uma endoprótese contrátil com capacidade de pulsação crônica no interior da aorta descendente, de maneira semelhante à produzida pelo balão intra-aórtico. MÉTODOS: Endopróteses pulsáteis compostas de níquel-titânio foram posicionadas de forma a envolver tubos de látex, simulando a aorta. Diferentes correntes elétricas foram aplicadas a unidades ligadas em série, de modo a causar contração da estrutura e deslocamento de uma coluna líquida. Foram realizadas duas sequências de testes: a primeira com duas gaiolas metálicas e a segunda com cinco gaiolas. Na primeira sequência de testes, aplicou-se tensão de 16,3 volts e corrente de 5 amperes e, na segunda sequência, tensão de 15 volts e corrente de 7 amperes. RESULTADOS: Na primeira sequência de testes, obteve-se o efeito pulsátil dos 2 stents, havendo contração do tubo e deslocamento da coluna d'água suficientes para validar o efeito pulsátil da endoprótese. As duas estruturas ejetaram um volume de 2,6 mL por ciclo, com uma variação de 29 mm na altura da coluna de água, equivalente a 8% de contração durante a pulsação. Na segunda sequência, conseguiu-se uma variação de 7,4 mL por ciclo. CONCLUSÃO: Os resultados obtidos comprovam a contratilidade da endoprótese pulsátil ativada pela aplicação de corrente elétrica. Continuidade do estudo e aperfeiçoamento do material se fazem necessários para obtenção de modelo mais eficiente do ponto de vista energético e com maior pulsação, para permitir volumes de ejeção comparáveis aos de balões intra-aórticos.

OBJECTIVE: Heart failure is currently one of the most common hospitalization causes. Several chronic circulatory assist devices have been tested and are highly complex. The objective is the description of a pulsatile endoprosthesis capable of applying a chronic pulse within the descending aorta, similar to that produced by intra-aortic balloon. METHODS: Pulsatile stents composed of nickel-titanium were built and positioned to engage latex tubes simulating the aorta. Different electric currents were applied to units connected in series in order to cause structure contraction and displacement of a liquid column. There were two sequence tests: first composed of two metallic cages and the second composed of five cages. At first sequence tests was applied a voltage of 16.3 volts and a current of 5 amperes. In the second, voltage of 15 volts and current of 07 amperes. RESULTS: In the first sequence was obtained the pulsatile effect of stent, with contraction of the tube and displacement of the water column sufficient to validate the pulsating effect of the endoprosthesis. The two structures ejected a volume of 2.6 ml per cycle, with a range of 29 mm in height of the column of water equivalent to 8% shrinkage during the pulse. In the second sequence, it reachead a variation of 7.4 mL per cycle. CONCLUSION: The results obtained confirm the stent pulsatile contractility activated by electrical current. The continuity of the study and material improvement are necessary to obtain more efficient model from the point of view of energy and pulse, to allow ejection volumes comparable with the intra-aortic balloons.

Influence of artificial accelerated ageing on the colour stability of paints used for ocular prosthesis iris painting.

OBJECTIVES: To evaluate the colour stability of paints used for ocular prosthesis iris painting submitted for accelerated artificial ageing (AAA). MATERIALS AND METHODS: Forty specimens of acrylic resin for sclera (16 × 2 mm) were made and separated into eight groups (n = 10) according to the type of paint (gouache, GP; oil, OP; acrylic AP; and composite resin for characterisation, CR) and the colours used (blue/brown). After drying (72 h), a new layer of colourless acrylic resin was applied and the initial colour readout was performed (Spectrophotometer PCB 6807). New colour readouts were performed after AAA, and ΔE was calculated. RESULTS: Statistical analysis (two-way anova-Bonferroni, p < 0.05) demonstrated that the brown colour showed lower ΔE means in comparison with the blue colour, with statistically significant difference for AP only. Blue colour showed no statistically significant difference with regard to the type of paint used. Brown AP showed lower ΔE than the other groups, with significant difference for OP and GP. GP showed greater alteration in ΔE for the brown colour, being statistically similar only to OP. CONCLUSIONS: Only the AP group for brown pigment shows clinically acceptable values for colour stability after AAA.

Porque e como reproduzir a guia anterior em prótese sobre implantes em ambiente laboratorial: técnica da personalização da mesa incisal em ASA

A estética final de uma prótese cerâmica de arco total sobre implantes dentários sofre grande influência da guia de movimentação andibular anterior. A guia incisal define parâmetros estéticos importantes e está entre um dos difíceis passos a serem repassados pelos clínicos aos técnicos em prótese dentária. Uma prótese provisória (PP) bem executada e ajustada clinicamente pode ser uma excelente ferramenta para melhorar essa comunicação. O Articulador semi-ajustável (ASA) e o arco facial também auxiliam os profissionais envolvidos na execução de um trabalho de prótese dentária que respeite a estética e função dos pacientes com um mínimo de ajustes clínicos. As PPs sobre implantes podem ser adaptadas a modelos montados em ASA objetivando a personalização da mesa incisal com resinas auto polimerizáveis que resultem em mais informações do dentista ao laboratório para confecção da prótese final. O presente trabalho irá descrever e discutir, com o exemplo de um caso clínico, a técnica da personalização da mesa incisal

Nasalance and nasality at experimental velopharyngeal openings in palatal prosthesis: a case study

The use of prosthetic devices for correction of velopharyngeal insufficiency (VPI) is an alternative treatment for patients with conditions that preclude surgery and for those individuals with a hypofunctional velopharynx (HV) with a poor prognosis for the surgical repair of VPI. Understanding the role and measuring the outcome of prosthetic treatment of velopharyngeal dysfunction requires the use of tools that allow for documenting pre- and post-treatment outcomes. Experimental openings in speech bulbs have been used for simulating VPI in studies documenting changes in aerodynamic, acoustic and kinematics aspects of speech associated with the use of palatal prosthetic devices. The use of nasometry to document changes in speech associated with experimental openings in speech bulbs, however, has not been described in the literature. Objective: This single-subject study investigated nasalance and nasality at the presence of experimental openings drilled through the speech bulb of a patient with HV. Material and Methods: Nasometric recordings of the word "pato" were obtained under 4 velopharyngeal conditions: no-opening (control condition), no speech bulb, speech bulb with a 20 mm² opening, and speech bulb with 30 mm² opening. Five speech-language pathologists performed auditory-perceptual ratings while the subject read an oral passage under all conditions. Results: Kruskal-Wallis test showed significant difference among conditions (p=0.0002), with Scheffé post hoc test indicating difference from the no-opening condition. Conclusion: The changes in nasalance observed after drilling holes of known sizes in a speech bulb suggest that nasometry reflect changes in transfer of sound energy related to different sizes of velopharyngeal opening.

Diseño personalizado de una interfaz mioeléctrica para una prótesis de miembro superior / Custom design of a myoelectric interface for upper limb prostheses

Desde los años sesenta se utilizan las señales electromoigráficas (EMG) como señales de control para prótesis actuadas por servomotores, así como en la estimulación de músculos que sufren de parálisis o de atrofia parcial. Mediante el avance tecnológico se ha logrado mejorar el diseño, así como la fabricación de sistemas protésicos, que funcionan como extensiones de algún miembro del cuerpo humano, agregando además con los nuevos diseños, características básicas como: flexibilidad, estética morfológica, incremento de la relación resistencia/peso así como multifuncionalidad. Una prótesis mioeléctrica es una estructura desarrollada con el fin de reemplazar una parte o la totalidad de un miembro del cuerpo humano, lo mismo que suplir las funciones perdidas de este, sin dejar de lado la imagen corporal del paciente. Estas prótesis son accionadas por actuadores que se controlan a través de señales EMG, las cuales se obtiene mediante agujas intramusculares superficiales o por medio de electrodos colocados en el muñón del paciente. Este tipo de prótesis es cada vez más aceptado por personas con amputación de mano, ya que proporciona un mejor desempeño y permite el incremento de funcionalidad para el paciente que la utiliza, debido a que su control es más sencillo.

Since 60’s electromiographical signals (EMG’s) are used like a control signals for prostheses acted by servomotors, as well as stimulation of muscles that are affected due to partial or total paralysis. By means of technological advance, it has been possible to improve the design as well as the production of prosthetic systems that work as extensions of some member of human body, adding with the new designs also basic characteristics as: flexibility, aesthetic morphology, and superior strength/weight relationship, as well as multi-functionality. Mioelectric prosthesis is a structure developed with the purpose of replacing a part or the entirety member of human body, same as to replace the lost functions of this, without leaving aside patient's corporal image. These prostheses are acted by actuators that are controlled through EMG signals, which are obtained by means of intramuscular or superficial needles, or by means of electrodes placed in patient's stump. This class of prostheses is more and more accepted by people with hand amputation since it provides a better acting, that which allows a superior functionality for patient that uses it, because its control is simpler.