Thermal lensing approach based on parabolic approximation and Mach-Zehnder interferometer.

A thermal lensing approach based on parabolic approximation and Mach-Zehnder interferometer for measuring optical absorption and thermal diffusivity coefficients in pure solvents is described in this work. The approach combines the sensitivity of both thermal lensing methods and interferometry techniques. The photothermal effect is induced by a pump laser beam generating localized changes in the refractive index of the sample, which are observed as a shift in phase of the interference pattern. Each interference pattern is recorded by means of a digital camera and stored as digital images as a function of time. The images are then numerically processed to calculate the phase shifting map for a specific time. From each phase shifting map, the experimental phase difference as a function of time is calculated giving a phase-time transient, which is fitted to a mathematical model to estimate the optical absorption and thermal diffusivity of the sample. The experimental results show that the sensitivity is approximately λ/4800 for the minimum phase difference measured.

Design and Development of a MOEMS Accelerometer Using SOI Technology.

The micro-electromechanical system (MEMS) sensors are suitable devices for vibrational analysis in complex systems. The Fabry-Pérot interferometer (FPI) is used due to its high sensitivity and immunity to electromagnetic interference (EMI). Here, we present the design, fabrication, and characterization of a silicon-on-insulator (SOI) MEMS device, which is embedded in a metallic package and connected to an optical fiber. This integrated micro-opto-electro-mechanical system (MOEMS) sensor contains a mass structure and handle layers coupled with four designed springs built on the device layer. An optical reading system using an FPI is used for displacement interrogation with a demodulation technique implemented in LabVIEW®. The results indicate that our designed MOEMS sensor exhibits a main resonant frequency of 1274 Hz with damping ratio of 0.0173 under running conditions up to 7 g, in agreement with the analytical model. Our experimental findings show that our designed and fabricated MOEMS sensor has the potential for engineering application to monitor vibrations under high-electromagnetic environmental conditions.

Linear and areal surface roughness assessments for the study of tooth wear in human enamel.

OBJECTIVES: To test 8 models of linear surface roughness assessment in characterizing surface profile description and to correlate these models with equivalent areal parameters over sound human enamel in vitro. MATERIALS AND METHODS: Thirty enamel blocks were randomly selected. The roughness data (2D-Rp; Rv; Rz; Rc; Rt; Ra; Rq; Rsk; Rku/3D-Sp; Sv; Sz; Sa; Sq; Ssk; Sku) was obtained in duplicate in a non-contact 3D optical profilometer. The models were composed by 1 single vertical trace (model 1) until 8 traces (model 8 composed by three vertical traces, three horizontal traces, and two diagonal). RESULTS: The addition of linear sampling traces to the enamel blocks did not result in Rp, Rv, Rz, Rc, Rt, Ra, Rq, Rsk, and Rku value changes (low power-from 5 to 72%). Significant Spearman's correlation coefficients were obtained in most correlation analysis (Rp ↔ Sp; Rv ↔ Sv; Rz ↔ Sz; Ra ↔ Sa; Rq ↔ Sq; and Rku ↔ Sku). CONCLUSIONS: A single vertical trace in the middle of the sample was representative of the overall enamel surface roughness (Rp, Rv, Rz, Rc, Rt, Ra, Rq, Rsk, and Rku) models. The majority of the assessed models in the correlation evaluation presented significant and positive association. CLINICAL RELEVANCE: The findings highlight the applicable model for roughness analysis over human enamel recommended for research and in situ trials assessments.

Implementation of a Fuzzy Inference System to Enhance the Measurement Range of Multilayer Interferometric Sensors.

This work presents a novel methodology to implement a fuzzy inference system (FIS) to overcome the measurement ambiguity that is typically observed in interferometric sensors. This ambiguity occurs when the measurand is determined by tracing the wavelength position of a peak or dip of a spectral fringe. Consequently, the sensor measurement range is typically limited to the equivalent of 1 free spectral range (FSR). Here, it is demonstrated that by using the proposed methodology, the measurement range of this type of sensor can be widened several times by overcoming the ambiguity over some FSR periods. Furthermore, in order to support the viability of the methodology, it was applied to a couple of temperature interferometric sensors. Finally, experimental results demonstrated that it was possible to quintuple the measurement range of one of the tested sensors with a mean absolute error of MAE = 0.0045 °C, while for the second sensor, the measurement range was doubled with an MAE = 0.0073 °C.

Feasibility of Using Shear Wave Ultrasonic Probes as Pump-Wave Sources in Concrete Microcrack Detection and Monitoring by Nonlinear Ultrasonic Coda Wave Interferometry.

This paper represents a first attempt to study the feasibility of using shear wave (SW) ultrasonic probes as pump-wave sources in concrete microcrack detection and monitoring by Nonlinear Ultrasonic Coda Wave Interferometry (NCWI). The premise behind our study is that the nonlinear elastic hysteretic behavior at microcracks may depend on their orientation with respect to the stationary wave-field induced by the pump-wave source. In this context, the use of a SW probe as a pump-wave source may induce the nonlinear elastic behavior of microcracks oriented in directions not typically detected by a conventional longitudinal pump-wave source. To date, this premise is hard to address by current experimental and numerical methods, however, the feasibility of using SW probes as a pump-wave source can be experimentally tested. This idea is the main focus of the present work. Under laboratory conditions, we exploit the high sensitivity of the CWI technique to capture the transient weakening behaviour induced by the SW pump-wave source in concrete samples subjected to loading and unloading cycles. Our results show that after reaching a load level of 40% of the ultimate stress, the material weakening increases as a consequence of microcrack proliferation, which is consistent with previous studies. Despite the lack of exhaustive experimental studies, we believe that our work is the first step in the formulation of strategies that involve an appropriate selection and placement of pump-wave sources to improve the NCWI technique. These improvements may be relevant to convert the NCWI technique into a more suitable non-destructive testing technique for the inspection of microcracking evolution in concrete structures and the assessment of their structural integrity.

Ocular biometry in dense cataracts: Comparison of partial-coherence interferometry, swept-source optical coherence tomography and immersion ultrasound.

PURPOSE: To assess the axial length (AL) measurement failure rate using partial-coherence interferometry (PCI) and swept-source optical coherence tomography (SS-OCT) in dense cataracts. As a secondary outcome, the SS-OCT biometry was compared to immersion ultrasound. METHODS: This is a prospective cross-sectional and comparative study. Seventy eyes from 70 patients with dense cataracts were enrolled in this study. Dense cataract was defined according to the Lens Opacities Classification System III (LOCS III) scores equal to or more than NO4, NC4, C4, and P3. The failure rate of AL measurement was evaluated using PCI and SS-OCT. Anterior chamber depth (ACD), lens thickness (LT), and AL measurements obtained by SS-OCT were compared with IUS. RESULTS: AL measurement failure rate with PCI was 68.57% and 21.43% with SS-OCT (P = 0.007). AL measurement was achieved in 69.23% of NO4, 66.6% of P3, and 15.3% of mixed cataracts using PCI, while SS-OCT was achieved in 100% of NO4, NO5, P3, and P5 and 76.9% of mixed cataracts. Cortical cataracts alone did not influence AL measurement. Biometric data of ACD, LT, and AL were statistically different comparing US and SS-OCT with a good correlation of AL. CONCLUSION: SS-OCT significantly improves the rate of successful AL measurements when compared to PCI in dense cataracts. The LOCS III clinical cut-off for the use of SS-OCT ocular biometry may well be up to P4 and NO5.

Novel murine mAbs define specific and cross-reactive epitopes on the latex profilin panallergen Hev b 8.

The production of specific antibodies able to recognize allergens from different sources or block interactions between allergens and antibodies mediating allergic reactions is crucial for developing successful tools for diagnostics and therapeutics. Panallergens are highly conserved proteins present in widely different species, implicated in relevant cross-reactions. The panallergen latex profilin (Hev b 8) has been associated with the latex-food-pollen syndrome. We generated five monoclonal IgGs and one IgE from murine hybridomas against recombinant Hev b 8 and evaluated their interaction with this allergen using ELISA and biolayer interferometry (BLI). Affinity purified mAbs exhibited high binding affinities towards rHev b 8, with KD1 values ranging from 10-10 M to 10-11 M. Some of these antibodies also recognized the recombinant profilins from maize and tomato (Zea m 12 and Sola l 1), and the ash tree pollen (Fra e 2). Competition ELISA demonstrated that some mAb pairs could bind simultaneously to rHev b 8. Using BLI, we detected competitive, non-competitive, and partial-competition interactions between pairs of mAbs with rHev b 8, suggesting the existence of at least two non-overlapping epitopes on the surface of this allergen. Three-dimensional models of the Fv of 1B4 and 2D10 IgGs and docking simulations of these Fvs with rHev b 8 revealed these epitopes. Furthermore, these two mAbs inhibited the interaction of polyclonal IgE and IgG4 antibodies from profilin-allergic patients with rHev b 8, indicating that the mAbs and the antibodies present in sera from allergic patients bind to overlapping epitopes on the allergen. These mAbs can be useful tools for immune-localization studies, immunoassay development, or standardization of allergenic products.

Comparing the postoperative refractive predictability of Pentacam HR and IOLMaster 500 after a multifocal intraocular lens implantation / Comparação da previsibilidade refrativa pós-operatória do Pentacam HR e IOLMaster 500 após implante de lentes intraoculares multifocais

ABSTRACT Purpose: To compare the postoperative refractive predictability of IOLMaster 500 and Pentacam HR on the basis of keratometry and anterior chamber depth values in eyes with an indication for multifocal intraocular lens (IOL) implantation. Methods: This was a retrospective study conducted on 118 eyes treated with phacoemulsification and multifocal intraocular lens implantation. Only the eyes that achieved emmetropia in the dynamic refraction performed on postoperative day 30 were included. Haigis' formula was used in each case to calculate the intraocular lens power, and the intraocular lens with the target refraction closest to emmetropia was implanted. Four lens calculation scenarios were tested by combining keratometry and anterior chamber depth measurements obtained using the two devices. Results: IOLMaster 500 and Pentacam HR differed with regard to mean keratometry (D 0.07 ± 0.03 D; p=0.0065) and anterior chamber depth (D 0.08 ± 0.01 mm; p<0.001). In the analysis of covariance, the following differences were obtained using the Haigis' formula when confronted with the biometric values obtained by inserting keratometry and anterior chamber depth values, respectively: Penta/IOL x IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/Penta × IOL/Penta (0.13 ± 0.03; p<0.0001); Penta/IOL × IOL/IOL (0.11 ± 0.03; p=0.001); Penta/Penta × IOL/IOL (0.11 ± 0.03; p=0.002); IOL/IOL × IOL/Penta (0.02 ± 0.03; p=0.865); and Penta/IOL × Penta/Penta (0.002 ± 0.03; p=0.99). The difference was smaller when measuring the anterior chamber depth using the IOLMaster 500, regardless of which device was used to measure keratometry. Conclusions: Pentacam HR significantly differed from IOLMaster 500 when calculating keratometry. As regards the anterior chamber depth, the two devices were equally accurate.

RESUMO Objetivo: Comparar a previsibilidade refrativa pós-operatória do IOLMaster 500 e Pentacam HR com base nos valores de ceratometria e profundidade de câmara anterior nos olhos com indicação de implante de lentes intraoculares multifocais. Métodos: Estudo retrospectivo realizado em 118 olhos tratados com facoemulsificação e implante de lentes intraoculares multifocal. Apenas os olhos que atingiram a emetropia na refração dinâmica no 30º dia pós-operatório foram incluídos. A fórmula de Haigis foi usada em cada caso para calcular o poder das lentes intraoculares, e a lente intraocular com a refração alvo mais próxima da emetropia foi implantada. Cenários de cálculo de quatro lentes foram testados pela combinação de medidas de ceratometria e profundidade de câmara anterior obtidas usando os dois dispositivos. Resultados: IOLMaster 500 e Pentacam HR diferiram quanto à média de ceratometria (D 0,07 ± 0,03 D; p=0,0065) e profundidade de câmara anterior (D 0,08 ± 0,01 mm; p<0,001). Na análise da covariância, as seguintes diferenças foram obtidas usando a fórmula de Haigis quando confrontadas com os valores biométricos obtidos pela inserção dos valores de ceratometria e profundidade de câmara anterior, respectivamente: Penta/IOL x IOL/Penta (0,13 ± 0,03; p<0,0001); Penta/Penta x IOL/Penta (0,13 ± 0,03; p<0,0001); Penta/IOL x IOL/IOL (0,11 ± 0,03; p=0,001); Penta/Penta x IOL/IOL (0,11 ± 0,03; p=0,002); IOL/IOL x IOL/Penta (0,02 ± 0,03; p=0,865); Penta/IOL x Penta/Penta (0,002 ± 0,03; p=0,99). A diferença foi menor ao medir a profundidade da câmara anterior usando o IOLMaster 500, independentemente de qual dispositivo foi usado para medir a ceratometria. Conclusões: O Pentacam HR diferiu significativamente do IOLMaster 500 no cálculo de ceratometria. Quanto à profundidade da câmara anterior, os dois dispositivos foram igualmente precisos.

Low-Finesse Fabry-Pérot Interferometers Applied in the Study of the Relation between the Optical Path Difference and Poles Location.

Interferometry sensors are frequently analyzed by applying the Fourier transform because the transformation separates all frequency components of its signal, making its study on a complex plane feasible. In this work, we study the relation between the optical path difference (OPD) and poles location theoretically and experimentally, using the Laplace transform and a pole-zero map. Theory and experiments are in concordance. For our study, only the cosine function was considered, which is filtered from the interference pattern. In experimental work, two unperturbed low-finesse Fabry-Pérot interferometers were used. First, a Fabry-Pérot interferometer that has a cavity length of ~1.6 mm was used. Its optical path difference was 2.33 mm and the poles were localized at points ±i12. rad/nm. Secondly, a Fabry-Pérot interferometer with a cavity length of ~5.2 mm was used, and its optical path difference was 7.59 mm and the poles were localized at points ±i40.4 rad/nm. Experimental results confirmed the theoretical analysis. Our proposal finds practical application for interferometer analysis, signal processing of optical fiber sensors, communication system analysis, and multiplexing systems based on interferometers.

Evolución de la biometría de coherencia óptica y las nuevas plataformas / Evolution of optical coherence biometry and the new platforms

RESUMEN La interferometría de coherencia óptica es un procedimiento esencial para calcular la potencia óptica de la lente intraocular. La presente revisión describe la evolución de la biometría óptica por interferometría, las nuevas plataformas, las características técnicas, los parámetros de calibración, la interpretación de los resultados y las situaciones especiales con indicación de cirugía de catarata. Para efectuar el trabajo fueron consultadas las bases de datos de la plataforma Infomed, específicamente en la Biblioteca Virtual de Salud, PubMed, Cochrane Database-Wiley Online Library, LILACS y Scielo. El IOL Máster favorece la medición de los parámetros biométricos oculares, ya que realiza mediciones sólidas y repetibles que incluye fórmulas de cuarta generación para el cálculo de potencia de lentes intraoculares. Actualmente se dispone en el mercado de varias plataformas para la biometría ocular usando los métodos interferométricos de alta resolución que tienen el potencial de mejorar significativamente los resultados refractivos. Estos estudios son de alta predictibilidad, lo cual permite obtener una buena agudeza visual y evita la sorpresa refractiva((AU)

ABSTRACT Optical coherence interferometry is an essential procedure for calculating the optical power of the intraocular lens. The present review describes the evolution of optical biometry by interferometry, the new platforms, technical features, calibration parameters, interpretation of results, and special situations in which cataract surgery is indicated. Information was collected from the databases on the Infomed platform, specifically the Virtual Health Library, PubMed, Cochrane Database-Wiley Online Library, LILACS and Scielo. IOL Master facilitates the measurement of ocular biometric parameters, since it performs solid, repeatable measurements that include fourth-generation formulas for the calculation of intraocular lens power. Several ocular biometry platforms are currently available in the market which use high resolution interferometric methods with the potential to significantly improve refractive results. These studies are characterized by their high predictability, making it possible to obtain good visual acuity and avoid refractive surprise(AU)

Analytical modelling of a refractive index sensor based on an intrinsic micro Fabry-Perot interferometer.

In this work a refractive index sensor based on a combination of the non-dispersive sensing (NDS) and the Tunable Laser Spectroscopy (TLS) principles is presented. Here, in order to have one reference and one measurement channel a single-beam dual-path configuration is used for implementing the NDS principle. These channels are monitored with a couple of identical optical detectors which are correlated to calculate the overall sensor response, called here the depth of modulation. It is shown that this is useful to minimize drifting errors due to source power variations. Furthermore, a comprehensive analysis of a refractive index sensing setup, based on an intrinsic micro Fabry-Perot Interferometer (FPI) is described. Here, the changes over the FPI pattern as the exit refractive index is varied are analytically modelled by using the characteristic matrix method. Additionally, our simulated results are supported by experimental measurements which are also provided. Finally it is shown that by using this principle a simple refractive index sensor with a resolution in the order of 2.15 × 10(-4) RIU can be implemented by using a couple of standard and low cost photodetectors.

Measurements of anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter using two Scheimpflug imaging devices / Medida da profundidade da câmara anterior, distância branco a branco, ângulo da câmara anterior e diâmetro pupilar usando dois dispositivos de imagens de Scheimpflug

Purpose: To compare the ocular anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, as measured with two different Scheimpflug imaging devices. Methods: This transversal study included 80 right eyes from 80 subjects aged from 20 to 40 years. Their spherical equivalents ranged from -4.25 to +1.00 diopters (D). Each eye's anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, were measured for far vision using both the Galilei G4 (double Scheimpflug camera) and the Pentacam HR (single Scheimpflug camera) systems. Results: Mean anterior chamber depths were calculated as 3.12 ± 0.23 mm and 3.19 ± 0.24 mm when measured with the Galilei G4 and the Pentacam HR, respectively. The mean white-to-white distance measured was 11.84 ± 0.31 mm and 11.90 ± 0.43 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Mean pupil diameters were measured as 3.22 ± 0.58 mm and 3.22 ± 0.52 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Finally, the mean anterior chamber angle was 34.30 ± 2.86 degrees when it was measured with the Galilei G4, and 39.26 ± 2.85 degrees when measured with the Pentacam HR. A comparative analysis revealed that the Galilei G4 yielded a significantly lower (P<0.05) measurement for the anterior chamber depth, anterior chamber angle, and pupil diameter, than the Pentacam HR system. Comparable values (P>0.05) for both devices were obtained for the white-to-white distance measurements. Conclusion: The Galilei G4 and Pentacam HR Scheimpflug systems cannot be used interchangeably because they produce significant measurement differences. .

Objetivo: Avaliar a medida da profundidade da câmara anterior, distância branco a branco, ângulo da câmara anterior e diâmetro pupilar usando dois dispositivos de imagens de Scheimpflug diferentes. Métodos: Este estudo transversal incluiu 80 olhos direitos de 80 indivíduos com idades entre 20 e 40 anos. O equivalente esférico variou de -4,25 a +1,00 dioptrias (D). A profundidade da câmara anterior de cada olho, a distância branco a branco, o ângulo da câmara anterior e o diâmetro pupilar, foram medidos para visão de longe usando tanto o Galilei G4 (câmera de Scheimpflug dupla) e os sistemas Pentacam HR (câmera de Scheimpflug simples). Resultados: A profundidade média da câmara anterior foi 3,12 ± 0,23 mm e 3,19 ± 0,24 mm, usando o Galilei G4 e o Pentacam HR, respectivamente. A distância média da medida de branco a branco com o Galilei G4 foi 11,84 ± 0,31 mm e com o HR Pentacam foi 11,90 ± 0,43 mm. A média do diâmetro pupilar foi 3,22 ± 0,58 mm e 3,22 ± 0,52 mm, medidos com o Galilei G4 e o Pentacam HR, respectivamente. Finalmente, a média do ângulo da câmara anterior foi de 34,30 ± 2,86 graus quando foi medido com o G4 Galileu, e 39,26 ± 2,85 graus com o Pentacam HR. A comparação revelou que o dispositivo Galilei G4 mediu significativamente menor (P<0,05) profundidade da câmara anterior, ângulo da câmara anterior e diâmetro da pupila do que o sistema de Pentacam HR, enquanto valores comparáveis (P>0,05) entre os dois dispositivos Scheimpflug foram obtidos para as medidas da distância branco a branco. Conclusão: O Galileu G4 e o Pentacam HR não podem ser usados indiferentemente, devido ás diferenças entre os dois aparelhos terem sido significativas sob o ponto de vista clínico. .

The effect of essential oil of Syzygium cumini on the development of granulomatous inflammation in mice

The anti-inflammatory and apoptotic activity of the essential oil of Syzygium cumini (L.) Skeels, Myrtaceae, leaves was investigated in vivo. The anti-inflammatory action and chronic granulomatous inflammation in BALB/c mice, intravenously infected with Mycobacterium bovis, BCG, (Bacillo Calmet Guerim), was judged by measuring and classifying the granulomas formed in the hepatic parenchyma. The degree of apoptosis in the inflammatory cells was also measured. A reduction in the granulomatous area and a change in the pattern of the granulomas were found. Anti-mycobacterial activity of the essential oil against M. bovis was detected in vitro by an interferometric method in liquid culture medium. The chemical constituents of the essential oil were determined by GC/MS. Higher yields of the essential oil of S. cumini leaves were obtained by extraction in a Clevenger apparatus when the fresh leaves were previously frozen as a pre-processing step. The essential oil obtained from this plant demonstrated a statistically significant and dramatic effect in the chosen model system.

Comportamento mecânico de sistemas prótese/implante em região dos elementos finitos e interferometria holográfica / Mechanical behavior of prosthesis / implant systems in the anterior maxilla: analysis by finite element method and holographic interferometry

A proposta deste estudo foi analisar, por meio do método de elementos finitos (MEF), o comportamento mecânico das estruturas envolvidas em uma reabilitação implanto suportada de 4 elementos na região anterior de maxila, utilizando apenas 2 implantes, variando os posicionamentos dos implantes e o tipo de conexão protética (hexágono externo, hexágono interno e cone-Morse) e ainda validar metodologia de análise computacional por meio da interferometria holográfica, uma técnica experimental. Modelos tridimensionais baseados em um banco de tomografias computadorizadas foram criados para todas as situações estudadas (Implantes nos Incisivos Laterais - IL; Implantes nos Incisivos Centrais - IC e Implante no Incisivo Central e Incisivo Lateral - ILIC). Uma carga equivalente à 150N foi aplicada a 45° na região de cíngulo de cada elemento dentário. Para a validação da metodologia de elementos finitos por meio da interferometria holográfica, criou-se um modelo prototipado com as mesmas situações estudadas e comparou-se os deslocamentos direcionais resultantes da aplicação de 3 intensidades de força. Como resultado foi observado: o menor deslocamento da estrutura protética e maior deslocamento na estrutura óssea no grupo IC. No tecido ósseo, a tensão de von Misses localiza-se predominantemente na região cortical. O valor máximo de tensão de von Misses foi observado no implante vizinho ao cantilever no grupo ILIC. Na conexão cone Morse, o parafuso protético mostrou metade da tensão de von Misses em relação a conexão hexágono interno e hexágono externo. Comparando-se os deslocamentos direcionais nas duas metodologias, verificou-se que havia uma correlação positiva entre os resultados, porém os valores obtidos experimentalmente eram superiores aos do modelo computacional. Pode-se concluir...

The purpose of this study was to analyze, by finite element method (FEM), the mechanical behavior of structures involved in an implant supported rehabilitation of 4 elements in the anterior maxilla, using only 2 implants, varying the placements of the implants and prosthetic connection types (external hexagon, internal hexagon and Morse taper) Moreover to validate the methodology of MEF by holographic interferometry, an experimental technique. Three-dimensional models based on a database CT scans were created for all situations studied (Implants in Lateral Incisors - IL; Implants in Central Incisors IC and Implant in Central e Lateral Incisor - ILIC). An equivalent load of150N was applied at 45° in the cingulum of each tooth. To validate the finite element method by Holographic Interferometry, a prototyped model was created with the same situations studied and compared the directional displacements, resulting from the application of the 3 intensities of force. As results it was observed: the lowest prosthetic displacement structure and greater displacement in the bone structure in the IC group. In bone tissue, the von Mises stress is located predominantly in the cortical region. The maximum value of von Mises stress was observed in the implant neighboring to cantilever in the group ILIC. In Morse taper connection, the prosthetic screw showed half the von Misses stress in relation to internal and external hexagon connection. Comparing the directional displacement in both methodologies, an positive correlation between the results was found, although the experimentally values obtained were higher than those of the computational model. It can be concluded that the placement of implants and prosthetic connection type have influence in the intensity and distribution of stress/strain on the implant-supported rehabilitation of anterior...

Comportamento mecânico de sistemas prótese/implante em região anterior de maxila: análise pelo método dos elementos finitos e interferometria holográfica / Mechanical behavior of prosthesis/implant systems in the anterior maxilla: analysis by finite element method and holographic interferometry

A proposta deste estudo foi analisar, por meio do método de elementos finitos (MEF), o comportamento mecânico das estruturas envolvidas em uma reabilitação implanto suportada de 4 elementos na região anterior de maxila, utilizando apenas 2 implantes, variando os posicionamentos dos implantes e o tipo de conexão protética (hexágono externo, hexágono interno e cone-Morse) e ainda validar metodologia de análise computacional por meio da interferometria holográfica, uma técnica experimental. Modelos tridimensionais baseados em um banco de tomografias computadorizadas foram criados para todas as situações estudadas (Implantes nos Incisivos Laterais - IL; Implantes nos Incisivos Centrais - IC e Implante no Incisivo Central e Incisivo Lateral - ILIC). Uma carga equivalente à 150N foi aplicada a 45° na região de cíngulo de cada elemento dentário. Para a validação da metodologia de elementos finitos por meio da interferometria holográfica, criou-se um modelo prototipado com as mesmas situações estudadas e comparou-se os deslocamentos direcionais resultantes da aplicação de 3 intensidades de força. Como resultado foi observado: o menor deslocamento da estrutura protética e maior deslocamento na estrutura óssea no grupo IC. No tecido ósseo, a tensão de von Misses localiza-se predominantemente na região cortical. O valor máximo de tensão de von Misses foi observado no implante vizinho ao cantilever no grupo ILIC. Na conexão cone Morse, o parafuso protético mostrou metade da tensão de von Misses em relação a conexão hexágono interno e hexágono externo. Comparando-se os deslocamentos direcionais nas duas metodologias, verificou-se que havia uma correlação positiva entre os resultados, porém os valores obtidos experimentalmente eram superiores aos do modelo computacional. Pode-se concluir que o posicionamento dos implantes e o tipo de conexão protética em reabilitação anterior de maxila influenciam a distribuição e intensidade de tensão/deformação nas estruturas da prótese implanto-suportada e ainda que o MEF pode ser usado como uma eficiente técnica para a análise de tensão, deformação e deslocamento quando utilizada com modelos validados experimentalmente

The purpose of this study was to analyze, by finite element method (FEM), the mechanical behavior of structures involved in an implant supported rehabilitation of 4 elements in the anterior maxilla, using only 2 implants, varying the placements of the implants and prosthetic connection types (external hexagon, internal hexagon and Morse taper) Moreover to validate the methodology of MEF by holographic interferometry, an experimental technique. Three-dimensional models based on a database CT scans were created for all situations studied (Implants in Lateral Incisors - IL; Implants in Central Incisors IC and Implant in Central e Lateral Incisor - ILIC). An equivalent load of150N was applied at 45° in the cingulum of each tooth. To validate the finite element method by Holographic Interferometry, a prototyped model was created with the same situations studied and compared the directional displacements, resulting from the application of the 3 intensities of force. As results it was observed: the lowest prosthetic displacement structure and greater displacement in the bone structure in the IC group. In bone tissue, the von Mises stress is located predominantly in the cortical region. The maximum value of von Mises stress was observed in the implant neighboring to cantilever in the group ILIC. In Morse taper connection, the prosthetic screw showed half the von Misses stress in relation to internal and external hexagon connection. Comparing the directional displacement in both methodologies, an positive correlation between the results was found, although the experimentally values obtained were higher than those of the computational model. It can be concluded that the placement of implants and prosthetic connection type have influence in the intensity and distribution of stress/strain on the implant-supported rehabilitation of anterior maxilla and moreover the FEM can be used as an efficient technique for analysis of stress, strain and displacement when used with experimentally validated models

Comparación de los valores del espesor corneal central según los equipos Lenstar, Galilei y Pentacam / Comparative study of the central corneal thickness measurements taken by Lenstar, Gallilei and Pentacam equipment

Objetivo: Comparar valores del espesor corneal central obtenidos mediante la paquimetría con el sistema de interferometria de coherencia parcial (Lenstar) con los sistemas Scheimpflug (Pentacam; Oculus) y Galilei (Ziemer, Suiza). Métodos: Se realizó un estudio prospectivo, comparativo en 120 ojos de 60 pacientes. Para la comparación se tomaron varias mediciones recomendadas por los fabricantes para probar la eficacia del equipo con el nuevo biómetro Lenstar LS 900 (Haag Streit AG) y con los equipos Pentacam y Galilei. La comparación de los valores se realizó mediante el análisis de regresión lineal y correlación de Pearson. Resultados: El análisis reveló que existe una alta correspondencia en los valores del espesor corneal central entre Lenstar y los topógrafos Galilei y Pentacam. Conclusiones: Existe una alta correspondencia entre los valores del espesor corneal central obtenidos por los equipos Lenstar, Pentacam y Galilei. Por esto el equipo Lenstar es útil en la cirugía de catarata y la cirugía refractiva.

Objective: To compare the central corneal thickness measurements taken by pachimetry with the partial coherence interferometry, Lenstar and with Scheimpflug systems (Pentacam; Oculus) and Galilei (Ziemer, Switzerland). Methods: Comparative and prospective study of 120 eyes from 60 patients. Several recommended measurements were taken with the optical biometers LenstarLS 900 (Haag Streit AG) and with Pentacam y Galilei topographers. The results were evaluated using the linear regresión analysis and Pearson´s correlation. Results: There is high correlation among the central corneal thickness measurements taken by the Lenstar equipment and topographers Pentacam and Galilei. Conclusion: The new biometer LENSTAR provided results that correlated very well with those of the Pentacam and Galilei systems. The Lenstar is a precise device that will be helpful for any cataract or refractive surgery.

Interferometría en aplicaciones odonto-estéticas / Interferometry on odonto-esthetic applications

Introducción y Objetivo: La armonía facial es un elemento que juega un rol importante en la estética del rostro humano, contribuyendo casi en su totalidad al ajuste de las deformaciones producidas en el mismo, debido a la ausencia de una prótesis total o su errada colocación. El objetivo del presente estudio está enfocado a determinar y visualizar a través de imágenes y su respectivo levantamientotopográfico, las dimensiones verticales del rostro humano, con la finalidad de detectar de manera precisa las medidas necesarias, en cuanto a rehabilitación protésica se refiere. Materiales yMétodos: Tres casos clínicos: un caso edéntulo total antes y después de la rehabilitación protésica, al cual se le aplicó la técnica de proyección lineal y el cálculo de las dimensiones verticalesrespectivas, los otros dos casos uno se le aplicó la técnica de proyección lineal y el otro se le aplicó la técnica de patrones moiré, a todos se les realizó el levantamiento topográfico de la imagen en 3D. Resultados: La propuesta aplicada en seres humanos permite el cálculo de los parámetros quelogran armonía del perfil facial y el levantamiento de las imágenes en 3D basada en dos técnicasde interferometría: proyección lineal y patrones moiré. Conclusión: Ambas técnicas, ofrecen alodontólogo la visualización en 3D del rostro además, la técnica de proyección lineal permite la obtención de las medidas requeridas con mayor precisión y con técnicas no invasivas.

Introduction and Objective: Facial harmony is an element that plays an important role in the esthetics of the human face, contributing almost totally to the adjustment of deformations produced in it due to the absence of complete denture or its incorrect installment. The objective of this study isto determine and visualize through images and their topographical elevation, the vertical dimensionsof the human face with the objective of detecting in a precise manner the necessary measurements regarding prosthetic rehabilitation. Materials and Methods: The sample comprises three cases: a completely edentulous patient before and after prosthetic rehabilitation on whom the linear projection technique and the calculation of the respective vertical dimensions was applied; on the secondcase a technical linear projection was used and on the third one the moiré patterns technique wasapplied; all were performed with 3D image mapping. Results: The proposal applied to humans allows the calculation of parameters that achieve harmony of the facial profile and mapping of 3Dimages, based on two interferometry techniques: linear projection and Moiré patterns. Conclusion: Both techniques offer the dentist a 3D visualization of the face, and in addition the linear projection technique allows obtaining the required measurements with greater precision and with a noninvasivetechnique.

Efectividad del cálculo del poder dióptrico de la lente intraocular con interferometría parcialmente coherente / Effectiveness of the intraocular lens power calculation using the partial coherent interferometry

OBJETIVO: Comparar la efectividad del cálculo del poder dióptrico de la lente intraocular con IOL Master y el método de biometría por aplanación convencional. MÉTODOS: Se seleccionó una muestra de 100 ojos (pacientes) mediante un muestreo simple aleatorio, en el Servicio de Catarata del Centro de Microcirugía Ocular, con diagnóstico de catarata unilateral o bilateral en la consulta preoperatorio, desde marzo hasta septiembre de 2006. Se clasificaron en dos grupos según el método utilizado para el cálculo de la lente intraocular. Se analizaron las variables: longitud axial media preoperatoria, promedio queratométrico preoperatorio, componente esférico esperado y obtenido, agudeza visual sin corrección y mejor agudeza visual corregida preoperatoria y posoperatoria. El análisis estadístico de los resultados se realizó mediante un análisis de varianza, la prueba t de Student de comparación de medias para datos pareados y chi cuadrado. Se utilizó un nivel de confiabilidad de 95 por ciento. RESULTADOS: Entre los principales resultados se encontró que la diferencia de las longitudes axiales entre los métodos IOL Master y biometría por aplanación A-Scan fue estadísticamente significativa. La agudeza visual sin corrección aumentó cuatro líneas y la mejor agudeza visual corregida seis líneas en el posoperatorio de los pacientes del grupo I. El 90 por ciento de los pacientes del grupo I, o sea, los calculados con IOL Master quedaron en la emetropía en cuanto al componente esférico. CONCLUSIONES: Se evidenció una diferencia significativa e inferior a la encontrada en estudios internacionales entre las longitudes axiales preoperatorias halladas mediante los métodos IOL Master y biometría por aplanación; resultaron superiores las calculadas por IOL Master. Se obtuvo ganancia en las líneas de la Cartilla de Snellen tanto de la agudeza visual sin corrección como la mejor agudeza visual corregida en ambos grupos (superior en el grupo II). Predomina ron los resultados refrac...

OBJECTIVE: to compare the effectiveness of the intraocular lens dioptric power calculation using IOL Master and the conventional applanation biometry. METHODS: A sample of 100 eyes (patients), diagnosed with unilateral or bilateral cataract in the preoperative consultation service, was selected through simple random sampling in the Ocular Microsurgery Center in the period from March to September, 2006. They were divided into two groups based on the method for intraocular lens calculation. The variables were preoperative mean axial length, preoperative keratometric average, expected and obtained spheral component, visual acuity without correction and better corrected visual acuity preoperatively and postoperatively. The statistical analysis of the results was made by variance analysis, Student's t test for paired mean comparisons and Chi square. The confidence level of 95 percent was used. RESULTS: Among the main results, it was found that the axial length differences between IOL Master and A-Scan applanation biometry was statistically significant. Visual acuity without correction increased 4 lines and the best corrected visual acuity increased 6 lines in the postoperative period of the group I patients. Ninety percent of the group I patients, whose visual acuity was calculated with IOL Master, reached emetropia in terms of the spheral component. CONCLUSIONS: A significant difference but lower than that found in the international studies among the preoperative axial lengths calculated through ILO Master and applanation biometry were evinced. The differences were higher in the lenghts calculated by IOL Master. There was improvement in the number of lines of Snellen´s chart both in the visual acuity without correction and the better corrected visual acuity in the two groups; being better in group II. The refractive results tending to emetropy prevailed, taking into consideration the spheral component reached in both groups, which were also higher in group I

Evaluación del equipo de interferometia óptica de coherencia parcial Lenstar en la biometría ocular / Evaluation of Lenstar partial coherente optical interferometry device in the ocular biometry

OBJETIVOS: Comparar y evaluar la biometría ocular con el nuevo equipo de interferometría óptica de coherencia parcial (Lenstar) con el equipo de interferometría óptica de baja coherencia IOL Master y también con los sistemas topográficos Galilei y Pentacam. MÉTODOS: Se realizó un estudio descriptivo, transversal, en 120 ojos de 60 pacientes. Para el cálculo del lente intraocular se tomaron mediciones con un nuevo biómetro Lenstar LS 900 (Haag Streit AG) y con el IOL Master V.5 (Carl Zeiss Meditec AG). Se compararon mediante el análisis de regresión lineal y correlación de Pearson. También se compararon las medidas con las obtenidas por los equipos topógrafos Galilei y Pentacam. RESULTADOS: Existe una alta correspondencia en los valores biómetricos de longitud axial, queratometría y profundidad de la cámara anterior entre los equipos Lenstar e IOL Master. También se encontró una buena correspondencia entre las medidas de profundidad de cámara posterior y queratometría entre Lenstar y los topógrafos Galilei y Pentacam. CONCLUSIONES: El nuevo biómetro Lenstar, provee resultados que se correlacionan muy bien con aquellos obtenidos con los equipos IOL Master, Pentacam y Galilei. El equipo Lenstar es un equipo preciso que brinda información adicional por lo que es útil en la cirugía de catarata y la cirugía refractiva(AU)

OBJECTIVES: To compare and to evaluate the ocular biometry taken by a new optical partial coherence interferometry device (Lenstar),the low coherence optical interferometry equipment (ILO Master) and the topographic systems Pentacam y Galilei. METHODS: A descriptive cross-sectional study was conducted in 120 eyes from 60 patients. For the IOL calculation, the necessary measurements were taken with the new optical biometer Lenstar LS 900 (Haig Streit AG) and with the IOL Master V5 (Carl Zeiss Meditec AG). The results were evaluated using the linear regression analysis and Pearson´s correlation. The measures were then compared to those taken by topographic devices Galilei and Pentacam. RESULTS: There existed high correlation in biometric measurements of axial length, keratometry and anterior chamber depth between the Lenstar and the IOL Master. Good correlation was also found for the Keratometry and anterior chamber depth between the Lenstar and the topographs Pentacam and Galilei. CONCLUSION: The new biometer LENSTAR provided results that correlated very well with those of the IOL Master, Pentacam and Galilei systems. Lenstar is a precise device offering additional features that will be helpful for any cataract or refractive surgery(AU)

Evaluación del equipo de interferometia óptica de coherencia parcial Lenstar en la biometría ocular / Evaluation of Lenstar partial coherente optical interferometry device in the ocular biometry

OBJETIVOS: Comparar y evaluar la biometría ocular con el nuevo equipo de interferometría óptica de coherencia parcial (Lenstar) con el equipo de interferometría óptica de baja coherencia IOL Master y también con los sistemas topográficos Galilei y Pentacam. MÉTODOS: Se realizó un estudio descriptivo, transversal, en 120 ojos de 60 pacientes. Para el cálculo del lente intraocular se tomaron mediciones con un nuevo biómetro Lenstar LS 900 (Haag Streit AG) y con el IOL Master V.5 (Carl Zeiss Meditec AG). Se compararon mediante el análisis de regresión lineal y correlación de Pearson. También se compararon las medidas con las obtenidas por los equipos topógrafos Galilei y Pentacam. RESULTADOS: Existe una alta correspondencia en los valores biómetricos de longitud axial, queratometría y profundidad de la cámara anterior entre los equipos Lenstar e IOL Master. También se encontró una buena correspondencia entre las medidas de profundidad de cámara posterior y queratometría entre Lenstar y los topógrafos Galilei y Pentacam. CONCLUSIONES: El nuevo biómetro Lenstar, provee resultados que se correlacionan muy bien con aquellos obtenidos con los equipos IOL Master, Pentacam y Galilei. El equipo Lenstar es un equipo preciso que brinda información adicional por lo que es útil en la cirugía de catarata y la cirugía refractiva

OBJECTIVES: To compare and to evaluate the ocular biometry taken by a new optical partial coherence interferometry device (Lenstar),the low coherence optical interferometry equipment (ILO Master) and the topographic systems Pentacam y Galilei. METHODS: A descriptive cross-sectional study was conducted in 120 eyes from 60 patients. For the IOL calculation, the necessary measurements were taken with the new optical biometer Lenstar LS 900 (Haig Streit AG) and with the IOL Master V5 (Carl Zeiss Meditec AG). The results were evaluated using the linear regression analysis and Pearson´s correlation. The measures were then compared to those taken by topographic devices Galilei and Pentacam. RESULTS: There existed high correlation in biometric measurements of axial length, keratometry and anterior chamber depth between the Lenstar and the IOL Master. Good correlation was also found for the Keratometry and anterior chamber depth between the Lenstar and the topographs Pentacam and Galilei. CONCLUSION: The new biometer LENSTAR provided results that correlated very well with those of the IOL Master, Pentacam and Galilei systems. Lenstar is a precise device offering additional features that will be helpful for any cataract or refractive surgery