Estudo tridimensional da oclusão normal na população brasileira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da correlação entre a angulação (mesiodistal) dos caninos e a inclinação (vestibulolingual) dos incisivos

OBJETIVO: avaliar o nível de correlação entre a angulação dos caninos e a inclinação dos incisivos. MÉTODOS: a angulação mesiodistal dos caninos e a inclinação vestibulolingual dos incisivos foram obtidas em um programa digital gráfico (Imagetool®), a partir de fotografias padronizadas dos modelos de 60 pacientes. A inclinação dos incisivos foi, ainda, avaliada pela cefalometria lateral. RESULTADOS: o erro casual mostrou uma variação em torno de 2° nas medidas feitas nos modelos (1,8–2,5º), enquanto o erro sistemático, avaliado pela teste de correlação intraclasse, revelou uma excelente reprodutibilidade para ambos os métodos empregados (p<0,001, r=0,84–0,96). Testes de correlação linear revelaram uma correlação positiva significativa entre a angulação dos caninos e a inclinação dos incisivos para a arcada superior (r=0,3, p<0,05), e mais significativa para a arcada inferior (r=0,46–0,51, p<0,001), quando ambas foram mensuradas nos modelos. Entretanto, quando a inclinação dos incisivos foi examinada pela cefalometria, o nível de correlação foi estatisticamente insignificante para os incisivos superiores (r=-0,06–0,21, p>0,05) e variou bastante na arcada inferior (r=0,14–0,50), dependendo da grandeza correlacionada. CONCLUSÃO: ratifica-se a introdução de mudanças na angulação dos caninos com o intuito de acompanhar as compensações observadas na inclinação dos incisivos, principalmente na arcada inferior.

Angulação dos caninos em indivíduos portadores de má oclusão de Classe I e de Classe III: análise comparativa através de um novo método utilizando imagens digitalizadas

OBJETIVO: determinar as angulações mesiodistais das coroas dos caninos em indivíduos portadores de má oclusão de Classe III, comparando-os a indivíduos Classe I. MÉTODOS: foram empregadas medidas tomadas em fotografias digitalizadas de modelos de gesso e transportadas para um programa gráfico para leitura das medidas (Image Tool). Tais procedimentos foram repetidos para avaliação do erro do método casual (fórmula de Dahlberg) e para a análise da reprodutibilidade através da Correlação intraclasse. A amostra constituiu-se de 57 pacientes com dentição permanente completa e não tratados ortodonticamente, dividida em dois grupos, de acordo com a má oclusão apresentada: o grupo I foi constituído por 33 pacientes portadores de má oclusão de Classe I, sendo 16 do sexo masculino e 17 do feminino, com média de idades de 27 anos; o grupo II era representado por 24 pacientes portadores de má oclusão de Classe III, 20 do sexo masculino e 4 do feminino, com média de idades de 22 anos. RESULTADOS: o erro casual mostrou-se com uma variação de 1,54 a 1,96 graus para a angulação dos caninos. A análise estatística revelou que o método apresenta uma excelente reprodutibilidade (p<0,01). Os resultados obtidos na angulação da coroa dos caninos não mostraram diferença estatisticamente significativa entre os caninos superiores nos grupos Classe I e Classe III, embora esse dente mostrasse, em média, uma angulação 2 graus maior nos indivíduos Classe III. Entretanto, para os caninos inferiores, foi observada uma diferença estatisticamente significativa em ambos os lados (p=0,0009 e p=0,0074) entre os grupos Classe I e Classe III. Os pacientes Classe III apresentaram uma menor angulação nos caninos inferiores em comparação aos pacientes Classe I, tendendo a acompanhar a compensação natural dos incisivos, descrita rotineiramente na literatura. CONCLUSÃO: os resultados permitem concluir que as compensações dentárias, frequentemente observadas na literatura para a região de incisivos, se estendem também à angulação dos caninos, principalmente no que se refere à arcada inferior.

Evaluation of a photographic method to measure dental angulation

Objetivo: analisar a confiabilidade e reprodutibilidade de um método simplificado para análise da angulação dentária que faz uso de fotografias digitalizadas de modelos de gesso. Métodos: foram realizadas fotografias digitalizadas e padronizadas de modelos de gesso, posteriormente transportadas para um programa gráfico de leitura de ângulos, para a obtenção das medidas. Tais procedimentos foram repetidos para avaliação do erro do método casual e para a análise da reprodutibilidade por meio da Correlação Intraclasse. A amostra constituiu-se de 12 indivíduos com dentição permanente completa e não tratados ortodonticamente, sendo seis do sexo masculino e seis do feminino. As análises foram feitas bilateralmente, gerando 24 medidas. Resultados: o erro casual mostrou uma variação de 0,77 a 2,55º para a angulação dos dentes. A análise estatística revelou que o método apresenta uma excelente reprodutibilidade (r = 0,65 - 0,91; p < 0,0001) para todos os dentes, exceto para os pré-molares superiores, mas ainda assim estatisticamente significativa (p < 0,001). Conclusão: o método proposto apresenta confiabilidade suficiente para justificar seu uso no desenvolvimento de pesquisas científicas, bem como na prática clínica.

Estudo das tensões em próteses sobre implantes esplintadas: análise pelo método da fotoelasticidade

Pós-graduação em Odontologia - FOA

A new sampling strategy for the Shewhart control chart monitoring a process with wandering mean

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Association between ACTA1 candidate gene and performance, organs and carcass traits in broilers

This study investigates the genetic association of the SNP present in the ACTA1 gene with performance traits, organs and carcass of broilers to help marker-assisted selection of a paternal broiler line (TT) from EMBRAPA Swine and Poultry, Brazil. Genetic and phenotypic data of 1,400 broilers for 68 traits related to body performance, organ weights, weight of carcass parts, and yields as a percentage of organs and carcass parts were used. The maximum likelihood method, considering 4 analytical models, was used to analyze the genetic association between the SNP and these important economic traits. The association analysis was performed using a mixed animal model including the random effect of the animal (polygenic), and the fixed effects of sex (2 levels), hatch (5 levels) and SNP (3 levels), besides the random error. The traits significantly associated (P < 0.05) with the SNP were analyzed, along with body weight at 42 days of age (BW42), by the restricted maximum likelihood method using the multi-trait animal model to estimate genetic parameters. The analysis included the residual and additive genetic random effects and the sex-hatch fixed effect. The additive effects of the SNP were associated with breast meat (BMY), liver yield (LIVY), body weight at 35 days of age (BW35); drumstick skin (DSW), drumstick (DW) and breast (BW) weights. The heritability estimates for these traits, in addition to BW42, ranged from 0.24 ± 0.06 to 0.45 ± 0.08 for LIVY and BW35, respectively. The genetic correlation ranged from 0.02 ± 0.18 for LIVY and BMY to 0.97 ± 0.01 for BW35 and BW42. Based on the results of this study, it can be concluded that ACTA1 gene is associated with performance traits BW35, LIV and BMY, DW, BW and DW adjusted for body weight at 42 days of age. Therefore, the ACTA1 gene is an important molecular marker that could be used together with others already described to increase the economically important traits in broilers.

Valutazione dell'accuratezza e della precisione di un algoritmo di correlazione digitale di volumi applicato a vertebre naturali e trattate

La Digital Volume Correlation (DVC) è una tecnica di misura a tutto campo, non invasiva, che permette di misurare spostamenti e deformazioni all’interno della struttura ossea in esame. Mediante la comparazione d’immagini con provino scarico e con provino carico, ottenute attraverso sistemi di tomografia computerizzata, si può ottenere la mappa degli spostamenti per ogni direzione e la mappa di deformazione per ogni componente di deformazione. L’obiettivo di questo lavoro di tesi è la validazione della DVC, attraverso la determinazione dell’errore sistematico (accuratezza) e dell’errore casuale (precisione), in modo da poter valutare il livello di affidabilità della strumentazione. La valutazione si effettua su provini di vertebre di maiale, aumentate e non, sia a livello d’organo, sia a livello di tessuto. The Digital Volume Correlation (DVC) is a full field and contact less measurement technique that allowed estimating displacement and strain inside bone specimen. Images of the unloaded and loaded specimen were obtained from micro-CT and compared in order to obtain the displacement map and, differentiating, the strain map. The aim of this work is the validation of the approach, estimating the lack of accuracy (systematic error) and the lack of precision (random error) on different kinds of porcine vertebra, augmented and not, analysing the specimen on tissue level and on organ level.

Validation of middle-atmospheric campaign-based water vapour measured by the ground-based microwave radiometer MIAWARA-C

Middle atmospheric water vapour can be used as a tracer for dynamical processes. It is mainly measured by satellite instruments and ground-based microwave radiometers. Ground-based instruments capable of measuring middle-atmospheric water vapour are sparse but valuable as they complement satellite measurements, are relatively easy to maintain and have a long lifetime. MIAWARA-C is a ground-based microwave radiometer for middle-atmospheric water vapour designed for use on measurement campaigns for both atmospheric case studies and instrument intercomparisons. MIAWARA-C's retrieval version 1.1 (v1.1) is set up in a such way as to provide a consistent data set even if the instrument is operated from different locations on a campaign basis. The sensitive altitude range for v1.1 extends from 4 hPa (37 km) to 0.017 hPa (75 km). For v1.1 the estimated systematic error is approximately 10% for all altitudes. At lower altitudes it is dominated by uncertainties in the calibration, with altitude the influence of spectroscopic and temperature uncertainties increases. The estimated random error increases with altitude from 5 to 25%. MIAWARA-C measures two polarisations of the incident radiation in separate receiver channels, and can therefore provide two measurements of the same air mass with independent instrumental noise. The standard deviation of the difference between the profiles obtained from the two polarisations is in excellent agreement with the estimated random measurement error of v1.1. In this paper, the quality of v1.1 data is assessed for measurements obtained at two different locations: (1) a total of 25 months of measurements in the Arctic (Sodankylä, 67.37° N, 26.63° E) and (2) nine months of measurements at mid-latitudes (Zimmerwald, 46.88° N, 7.46° E). For both locations MIAWARA-C's profiles are compared to measurements from the satellite experiments Aura MLS and MIPAS. In addition, comparisons to ACE-FTS and SOFIE are presented for the Arctic and to the ground-based radiometer MIAWARA for the mid-latitude campaigns. In general, all intercomparisons show high correlation coefficients, confirming the ability of MIAWARA-C to monitor temporal variations of the order of days. The biases are generally below 13% and within the estimated systematic uncertainty of MIAWARA-C. No consistent wet or dry bias is identified for MIAWARA-C. In addition, comparisons to the reference instruments indicate the estimated random error of v1.1 to be a realistic measure of the random variation on the retrieved profile between 45 and 70 km.

Evaluation of 3-dimensional superimposition techniques on various skeletal structures of the head using surface models.

OBJECTIVES To test the applicability, accuracy, precision, and reproducibility of various 3D superimposition techniques for radiographic data, transformed to triangulated surface data. METHODS Five superimposition techniques (3P: three-point registration; AC: anterior cranial base; AC + F: anterior cranial base + foramen magnum; BZ: both zygomatic arches; 1Z: one zygomatic arch) were tested using eight pairs of pre-existing CT data (pre- and post-treatment). These were obtained from non-growing orthodontic patients treated with rapid maxillary expansion. All datasets were superimposed by three operators independently, who repeated the whole procedure one month later. Accuracy was assessed by the distance (D) between superimposed datasets on three form-stable anatomical areas, located on the anterior cranial base and the foramen magnum. Precision and reproducibility were assessed using the distances between models at four specific landmarks. Non parametric multivariate models and Bland-Altman difference plots were used for analyses. RESULTS There was no difference among operators or between time points on the accuracy of each superimposition technique (p>0.05). The AC + F technique was the most accurate (D<0.17 mm), as expected, followed by AC and BZ superimpositions that presented similar level of accuracy (D<0.5 mm). 3P and 1Z were the least accurate superimpositions (0.790.05), the detected structural changes differed significantly between different techniques (p<0.05). Bland-Altman difference plots showed that BZ superimposition was comparable to AC, though it presented slightly higher random error. CONCLUSIONS Superimposition of 3D datasets using surface models created from voxel data can provide accurate, precise, and reproducible results, offering also high efficiency and increased post-processing capabilities. In the present study population, the BZ superimposition was comparable to AC, with the added advantage of being applicable to scans with a smaller field of view.

Information bias and lifetime mortality risks of radiation-induced cancer

Additive and multiplicative models of relative risk were used to measure the effect of cancer misclassification and DS86 random errors on lifetime risk projections in the Life Span Study (LSS) of Hiroshima and Nagasaki atomic bomb survivors. The true number of cancer deaths in each stratum of the cancer mortality cross-classification was estimated using sufficient statistics from the EM algorithm. Average survivor doses in the strata were corrected for DS86 random error ($\sigma$ = 0.45) by use of reduction factors. Poisson regression was used to model the corrected and uncorrected mortality rates with covariates for age at-time-of-bombing, age at-time-of-death and gender. Excess risks were in good agreement with risks in RERF Report 11 (Part 2) and the BEIR-V report. Bias due to DS86 random error typically ranged from $-$15% to $-$30% for both sexes, and all sites and models. The total bias, including diagnostic misclassification, of excess risk of nonleukemia for exposure to 1 Sv from age 18 to 65 under the non-constant relative projection model was $-$37.1% for males and $-$23.3% for females. Total excess risks of leukemia under the relative projection model were biased $-$27.1% for males and $-$43.4% for females. Thus, nonleukemia risks for 1 Sv from ages 18 to 85 (DRREF = 2) increased from 1.91%/Sv to 2.68%/Sv among males and from 3.23%/Sv to 4.02%/Sv among females. Leukemia excess risks increased from 0.87%/Sv to 1.10%/Sv among males and from 0.73%/Sv to 1.04%/Sv among females. Bias was dependent on the gender, site, correction method, exposure profile and projection model considered. Future studies that use LSS data for U.S. nuclear workers may be downwardly biased if lifetime risk projections are not adjusted for random and systematic errors. (Supported by U.S. NRC Grant NRC-04-091-02.) ^

Validação do protocolo de avaliação do frênulo da língua em bebês

Este estudo teve por objetivo validar o Protocolo de avaliação do frênulo da língua em bebês. Para isso, a partir do cálculo amostral, foi aplicado o protocolo em 100 bebês saudáveis, nascidos a termo, com 30 dias de vida, em amamentação exclusiva. O processo de validação consistiu da análise da validade de conteúdo, de critério e de construto, bem como da confiabilidade, sensibilidade, especificidade, valor preditivo positivo e negativo. A validade de conteúdo foi realizada por três examinadores, por meio da classificação de cada item quanto à clareza e posterior aplicação do Índice de Validação do Conteúdo. As avaliadoras sugeriram modificações no protocolo, por consenso, possibilitando obter a versão final. Para a validade de critério, comparou-se o Protocolo de avaliação do frênulo da língua em bebês com o instrumento Bristol Tongue Assessment Tool (BTAT). A validade de construto foi analisada a partir da comparação dos escores do protocolo aplicado nos bebês com 30 e 75 dias. As avaliações foram realizadas por duas fonoaudiólogas especialistas em Motricidade Orofacial (denominadas A1 e A2), devidamente treinadas e calibradas, por meio da análise das filmagens realizadas durante a aplicação do protocolo, para verificação da concordância entre examinadores, bem como definição dos valores de sensibilidade, especificidade e valores preditivos. Para a análise da concordância intra-avaliador foi realizado o teste/reteste de 20% da amostra pela A2. Quanto ao tratamento estatístico, para a análise de concordância intra e entre avaliadores, foram utilizados o Coeficiente de Correlação Intraclasse e o cálculo do erro do método. Para análise da validade de construto foram aplicados os testes de Wilcoxon e Mann-Whitney. O nível de significância adotado em todos os testes foi de 5%. Houve 100% de concordância na validação do conteúdo. A validade de critério apresentou correlações fortes dos itens correspondentes do Protocolo de avaliação do frênulo da língua em bebês e do instrumento BTAT, sendo o valor do coeficiente de correlação de Spearman igual a -0,997. Os resultados obtidos evidenciaram uma concordância muito boa intra e entre avaliadores, com valores baixos de erro casual e valores de p>0,05 (evidenciando que não há diferença entre a análise dos avaliadores) e Coeficiente de Correlação Intraclasse maior que 0,75; mostrando ainda, uma capacidade significativa do protocolo em mensurar as mudanças resultantes da frenotomia lingual, pela história clínica, avaliação anatomofuncional e avaliação da sucção não nutritiva e nutritiva (p<0,05). Quando comparados os resultados dos bebês com alteração do frênulo lingual (grupo experimental) e sem alteração (grupo controle), com 30 e 75 dias, houve diferença nos escores parciais e no escore total do exame clínico e do protocolo completo. Os índices de sensibilidade, especificidade e valores preditivos positivo e negativo foram 100%. A ocorrência das alterações do frênulo lingual nesse estudo foi de 21%. Concluiu-se, com este estudo, que o Protocolo de avaliação do frênulo da língua em bebês mostrou ser um instrumento válido e confiável de avaliação, assegurando acurácia em diagnosticar as alterações do frênulo lingual dentro dos parâmetros investigados, podendo ser aplicado por diferentes avaliadores, desde que os mesmos sejam capacitados e treinados para sua aplicação.

Toward better outcomes with tacrolimus therapy: Population pharmacokinetics and individualized dosage prediction in adult liver transplantation

Patient outcomes in transplantation would improve if dosing of immunosuppressive agents was individualized. The aim of this study is to develop a population pharmacokinetic model of tacrolimus in adult liver transplant recipients and test this model in individualizing therapy. Population analysis was performed on data from 68 patients. Estimates were sought for apparent clearance (CL/F) and apparent volume of distribution (V/F) using the nonlinear mixed effects model program (NONMEM). Factors screened for influence on these parameters were weight, age, sex, transplant type, biliary reconstructive procedure, postoperative day, days of therapy, liver function test results, creatinine clearance, hematocrit, corticosteroid dose, and interacting drugs. The predictive performance of the developed model was evaluated through Bayesian forecasting in an independent cohort of 36 patients. No linear correlation existed between tacrolimus dosage and trough concentration (r(2) = 0.005). Mean individual Bayesian estimates for CL/F and V/F were 26.5 8.2 (SD) L/hr and 399 +/- 185 L, respectively. CL/F was greater in patients with normal liver function. V/F increased with patient weight. CL/F decreased with increasing hematocrit. Based on the derived model, a 70-kg patient with an aspartate aminotransferase (AST) level less than 70 U/L would require a tacrolimus dose of 4.7 mg twice daily to achieve a steady-state trough concentration of 10 ng/mL. A 50-kg patient with an AST level greater than 70 U/L would require a dose of 2.6 mg. Marked interindividual variability (43% to 93%) and residual random error (3.3 ng/mL) were observed. Predictions made using the final model were reasonably nonbiased (0.56 ng/mL), but imprecise (4.8 ng/mL). Pharmacokinetic information obtained will assist in tacrolimus dosing; however, further investigation into reasons for the pharmacokinetic variability of tacrolimus is required.

Are diagnosis specific outcome indicators based on administrative data useful in assessing quality of hospital care?

Background: Hospital performance reports based on administrative data should distinguish differences in quality of care between hospitals from case mix related variation and random error effects. A study was undertaken to determine which of 12 diagnosis-outcome indicators measured across all hospitals in one state had significant risk adjusted systematic ( or special cause) variation (SV) suggesting differences in quality of care. For those that did, we determined whether SV persists within hospital peer groups, whether indicator results correlate at the individual hospital level, and how many adverse outcomes would be avoided if all hospitals achieved indicator values equal to the best performing 20% of hospitals. Methods: All patients admitted during a 12 month period to 180 acute care hospitals in Queensland, Australia with heart failure (n = 5745), acute myocardial infarction ( AMI) ( n = 3427), or stroke ( n = 2955) were entered into the study. Outcomes comprised in-hospital deaths, long hospital stays, and 30 day readmissions. Regression models produced standardised, risk adjusted diagnosis specific outcome event ratios for each hospital. Systematic and random variation in ratio distributions for each indicator were then apportioned using hierarchical statistical models. Results: Only five of 12 (42%) diagnosis-outcome indicators showed significant SV across all hospitals ( long stays and same diagnosis readmissions for heart failure; in-hospital deaths and same diagnosis readmissions for AMI; and in-hospital deaths for stroke). Significant SV was only seen for two indicators within hospital peer groups ( same diagnosis readmissions for heart failure in tertiary hospitals and inhospital mortality for AMI in community hospitals). Only two pairs of indicators showed significant correlation. If all hospitals emulated the best performers, at least 20% of AMI and stroke deaths, heart failure long stays, and heart failure and AMI readmissions could be avoided. Conclusions: Diagnosis-outcome indicators based on administrative data require validation as markers of significant risk adjusted SV. Validated indicators allow quantification of realisable outcome benefits if all hospitals achieved best performer levels. The overall level of quality of care within single institutions cannot be inferred from the results of one or a few indicators.

Assembly accuracy analysis for small components with a planar surface in large-scale metrology

Large-scale mechanical products, such as aircraft and rockets, consist of large numbers of small components, which introduce additional difficulty for assembly accuracy and error estimation. Planar surfaces as key product characteristics are usually utilised for positioning small components in the assembly process. This paper focuses on assembly accuracy analysis of small components with planar surfaces in large-scale volume products. To evaluate the accuracy of the assembly system, an error propagation model for measurement error and fixture error is proposed, based on the assumption that all errors are normally distributed. In this model, the general coordinate vector is adopted to represent the position of the components. The error transmission functions are simplified into a linear model, and the coordinates of the reference points are composed by theoretical value and random error. The installation of a Head-Up Display is taken as an example to analyse the assembly error of small components based on the propagation model. The result shows that the final coordination accuracy is mainly determined by measurement error of the planar surface in small components. To reduce the uncertainty of the plane measurement, an evaluation index of measurement strategy is presented. This index reflects the distribution of the sampling point set and can be calculated by an inertia moment matrix. Finally, a practical application is introduced for validating the evaluation index.