Revista de Odontologia da UNESP
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Revista de Odontologia da UNESP
Original Article

Effect of digitization parameters on periapical radiographic image quality with regard to anatomic landmarks

Efeitos dos parâmetros de digitalização na qualidade da imagem radiográfica periapical com relação a reparos anatômicos

Gonçalves, Andréa; Nicoli, Giovanni Antonio; Zamperini, Camila Andrade; Hebling, Josimeri; Gonçalves, Marcelo

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Abstract

The aim of this study was to evaluate the influence of digitization parameters on periapical radiographic image quality, with regard to anatomic landmarks. Digitized images (n = 160) were obtained using a flatbed scanner with resolutions of 300, 600 and 2400 dpi. The radiographs of 2400 dpi were decreased to 300 and 600 dpi before storage. Digitizations were performed with and without black masking using 8-bit and 16-bit grayscale and saved in TIFF format. Four anatomic landmarks were classified by two observers (very good, good, moderate, regular, poor), in two random sessions. Intraobserver and interobserver agreements were evaluated by Kappa statistics. Inter and intraobserver agreements ranged according to the anatomic landmarks and resolution used. The results obtained demonstrated that the cement enamel junction was the anatomic landmark that presented the poorest concordance. The use of black masking provided better results in the digitized image. The use of a mask to cover radiographs during digitization is necessary. Therefore, the concordance ranged from regular to moderate for the intraobserver evaluation and concordance ranged from regular to poor for interobserver evaluation.

Keywords

Radiography, dental, radiographic image enhancement, image processing, computer-assisted

Resumo

O objetivo deste estudo foi avaliar a influência dos parâmetros de digitalização na qualidade da imagem radiográfica digital, com relação a reparos anatômicos. Para isso, imagens radiográficas foram digitalizadas por meio de um scanner (n = 160) com resoluções de 300, 600 e 2400 dpi. As imagens de 2400 dpi foram ainda diminuídas para 300 e 600 dpi antes do armazenamento. As digitalizações foram realizadas com e sem máscaras pretas utilizando-se escalas de cinza de 8-bit e 16-bit e salvas em formato TIFF. Para avaliar a influência dos parâmetros de digitalização na qualidade da imagem radiográfica digitalizada, quatro reparos anatômicos foram classificados por dois observadores (muito boa, boa, moderada, regular, pobre) em duas ocasiões diferentes. As concordâncias intra e inter-observadores foram avaliadas por meio do teste Kappa. Os resultados obtidos demonstraram que as concordâncias intra e inter-observadores variaram em função dos reparos anatômicos e da resolução utilizada. A junção cemento esmalte foi o reparo anatômico que apresentou a mais pobre concordância. A utilização da máscara preta favoreceu a qualidade da imagem digitalizada e seu uso é necessário para cobrir a radiografia durante o processo de digitalização. Portanto, a concordância variou de regular a moderada para a avaliação intra-observador e de regular a pobre para a concordância inter-observador.

Palavras-chave

Radiografia dentária, radiografia digital, processamento de imagem assistida por computador

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