Son confiables las fotografías para el análisis facial en ortodoncia? / Are photos for facial analysis in orthodontics reliable?

RESUMEN: Introducción: Antropometría facial es la medición de distancias del rostro. Un método indirecto es a través de fotografías estandarizadas, conocido como fotogrametría. Este trabajo busca estandarizar una técnica fotográfica y estudiar la fiabilidad de la fotogrametría facial, comparando mediciones antropométricas directas y fotogramétricas con tres objetivos fotográficos distintos. Objetivo: Estandarizar parámetros de la cámara fotográfica y encuadre de la imagen para fotogrametría facial. Materiales y métodos: A una muestra de 50 sujetos se les midieron directa e indirectamente seis distancias faciales. Para las fotografías se utilizaron objetivos fotográficos fijos de 35mm, 50mm y 100mm. Se tomaron seis fotografías a cada uno de los voluntarios; tres de frente y tres de perfil, una con cada lente. La distancia entre la cámara y el sujeto fue variable, siempre con un encuadre de 30cm. Se compararon las diferencias estadísticamente. Resultados: Con el lente de 100mm fue el único con el que todas las distancias medidas en fotografías fueron iguales y sin diferencia estadística respecto a las medidas obtenidas directamente. Conclusión: De los tres objetivos fotográficos utilizados uno de 100mm es el que permite la fotografía más fiel a la realidad, con una diferencia promedio de 0,5mm con las medidas directas.

ABSTRACT: Introduction: Facial anthropometry is the measurement of distances of the face. It can be performed directly in the subject present or indirectly. Among the indirect methods is photogrammetry: measuring facial distances in photographs. In order to perform the facial photographic registration, a standardized photographic technique is required, that is, the parameters of the camera, the photographic set and the parameters of the subject must be previously established. This work aims to standardize a photographic technique and to study the reliability of facial photogrammetry, comparing direct anthropometric measurements and photogrammetry with three different photographic lenses, in order to determine which one has the highest fidelity. Objective: To standardize camera parameters and image framing for facial photogrammetry. Materials and Methods: Six facial distances were measured directly and indirectly on a sample of 50 subjects. The indirect measurements were taken on photographs of the subjects using fixed photographic lenses of 35mm, 50mm and 100mm. Six photographs were taken from each volunteer; three of front and three of profile, one with each lens. The distances between the camera and the subjects was variable, so that the image frame was always 30 cm. The differences were statistically compared. Results: With a 35mm lens, only one of the six distances measured in photographs was equal to the measurement obtained directly. With a 50mm lens, three of the six distances obtained were equal to the direct measurements. With a 100mm lens, all distances measured in photographs were equal and without statistical difference in relation to the measurements obtained directly. Conclusion: Of the three photographic lenses, the 100mm lens is the one that allows the photograph more faithful to the reality, where the photogrammetric measures of the face have a difference of 0,5mm or less with the direct measurements.

Análise do perfil facial masculino adulto jovem, esteticamente agradável, em fotografias padronizadas: comparação da medição manual com a computadorizada / Facial profile analysis of esthetically harmonious young male adults in standardized photographs: comparison of manual versus computerized measurements

OBJETIVO: analisar o perfil facial masculino adulto jovem, através de fotografias padronizadas e comparar a medição manual com a medição computadorizada por meio do software Cef X (CDT). MÉTODOS: a amostra consistiu de 40 indivíduos brasileiros brancos, com média de idade de 21,9 anos, que possuíam perfis agradáveis, oclusão normal, sem histórico de tratamento ortodôntico prévio. As fotografias coloridas de 10cm x 15cm foram obtidas de forma padronizada, com o indivíduo na posição natural da cabeça. As fotografias foram medidas manualmente, utilizando-se paquímetro digital e transferidor, e também através de computador, utilizando-se o programa Cef X (CDT). Trinta e seis variáveis faciais foram analisadas por meio de medidas lineares, angulares e proporcionais. RESULTADOS: as médias da medição manual e da medição por computador foram diferentes estatisticamente para 24 variáveis. No método por computador, somente uma medida mostrou diferença significativa entre a primeira e a segunda medição, enquanto na manual oito mostraram diferença. CONCLUSÕES: considerando-se que houve diferença entre as medições manual e por computador, deve-se utilizar as médias respectivas para cada tipo de medição. Os dois tipos de medição são confiáveis, entretanto a medição por computador é mais precisa. Devido à praticidade e agilidade da medição por computador, esta seria a mais indicada.

Aim: To analyze the young male adult facial profile using standardized photographs and compare manual measuring procedures to the measuring procedures with the software Cef X (CDT). METHODS: The sample consisted of 40 Brazilian Caucasian individuals, with an average age of 21.9 years, who possessed pleasant profiles, normal occlusion, and no history of previous orthodontic treatment. Colored photographs measuring 10cm x 15cm were taken in a standard way with the subject in natural head position. The photographs were measured manually, using dial caliper and a protractor, as well as using the Cef X (CDT) computer program. Thirty six facial variables were analyzed with linear, angular, and proportional measurements. RESULTS: Manual and computerized measurement scores presented different statistics to 24 variables. In the computerized method only one measurement showed significant difference between the first and the second measuring whereas in the manual method eight measurements presented differences. CONCLUSION: Considering that there were differences in manual and computerized measurements, one must use respective mean values for each type of measuring procedure. Both types of measurement are reliable although the computerized one is more accurate. Due to the convenience and swiftness of the computerized measuring, it is best recommended.