RESUMO

The reproducibility of measurements of alveolar bone loss on radiographs may be a problem on epidemiologic studies, as they are based on comparisons of the diagnosis of various examiners. The aim of the present research paper was to assess the inter- and intra-examiner reproducibility of measurements of the interproximal alveolar bone loss on non-manipulated digital radiographs and after the application of image filters. Five Oral Radiologists measured the distance between the cementoenamel junction (CEJ) to the alveolar crest or to the deepest point of the bony defect on 12 interproximal digital radiographs of molars and bicuspids of a dry human skull. The digital manipulation and the linear measurements were obtained with the Trophy Windows software (Throphy®). For each image, six different versions were created: 1) non-manipulated; 2) bright-contrast adjustment; 3) negative; 4) negative with brightness-contrast adjustment; 5) pseudo-colored; 6) pseudo-colored with brightness-contrast adjustment. In order to prevent interpretation bias because of the repetition of measurements, the examiners measured the radiographs in a random sequence. The two-way ANOVA test at 5 percent level of significance to compare the means of readings of the same operator with each filter indicated p<0.05 for the majority of operators, while the comparison between the mean values of operators using the same filter indicated p>0.05 for all filters. Based on the results, we concluded that linear measurements of interproximal alveolar bone loss on digital radiographs are highly reproducible among examiners. Nevertheless, the application of image filters significantly influenced the degree of intra-examiner reproducibility. Some filters even reduced the reproducibility of intra-examiner readings.

A reprodutibilidade de medidas da perda óssea alveolar em radiografias pode se tornar um problema em levantamentos epidemiológicos, que são baseados em comparações de diagnóstico de vários observadores. O objetivo neste estudo foi avaliar a reprodutibilidade intra e inter-examinador de medidas da perda óssea interproximal, em radiografias digitais não manipuladas e após a aplicação de diferentes filtros de imagem. Cinco radiologistas avaliaram a distância da junção cemento-esmalte até a crista óssea alveolar ou ponto mais apical do defeito ósseo em 12 radiografias digitais interproximais da região de molares e pré-molares de crânio humano macerado. As manipulações digitais e as medidas lineares foram realizadas no programa de computador do sistema radiográfico (Throphy®). Para cada imagem foram criadas seis diferentes versões: 1) não manipulada digitalmente; 2) manipulada por ajuste de brilho e contraste; 3) negativo; 4) negativo com ajuste de brilho e contraste; 5) pseudo-colorida; 6) pseudo-colorida com ajuste de brilho e contraste. Para prevenir tendências da mesma leitura pela avaliação repetida das radiografias, determinou-se uma ordem para a interpretação das imagens. O teste ANOVA fator duplo sem repetição, com nível de significância de 5 por cento, realizado para comparação das médias de um mesmo examinador nas diferentes versões de imagem revelou p<0,05 para a maioria dos examinadores, enquanto para análise entre os examinadores, com cada ferramenta, p>0,05. A análise dos resultados nos permite concluir que medidas lineares da perda óssea alveolar interproximal em radiografias digitais apresentam alto grau de reprodutibilidade inter-examinadores, entretanto a aplicação de filtros de imagem não influenciou significativamente no grau de reprodutibilidade dessas medidas. Ao contrário, certas ferramentas reduziram a reprodutibilidade das medidas intra-examinador.

Assuntos

RESUMO

The reproducibility of measurements of alveolar bone loss on radiographs may be a problem on epidemiologic studies, as they are based on comparisons of the diagnosis of various examiners. The aim of the present research paper was to assess the inter- and intra-examiner reproducibility of measurements of the interproximal alveolar bone loss on non-manipulated digital radiographs and after the application of image filters. Five Oral Radiologists measured the distance between the cementoenamel junction (CEJ) to the alveolar crest or to the deepest point of the bony defect on 12 interproximal digital radiographs of molars and bicuspids of a dry human skull. The digital manipulation and the linear measurements were obtained with the Trophy Windows software (Throphy). For each image, six different versions were created: 1) non-manipulated; 2) bright-contrast adjustment; 3) negative; 4) negative with brightness-contrast adjustment; 5) pseudo-colored; 6) pseudo-colored with brightness-contrast adjustment. In order to prevent interpretation bias because of the repetition of measurements, the examiners measured the radiographs in a random sequence. The two-way ANOVA test at 5% level of significance to compare the means of readings of the same operator with each filter indicated p<0.05 for the majority of operators, while the comparison between the mean values of operators using the same filter indicated p>0.05 for all filters. Based on the results, we concluded that linear measurements of interproximal alveolar bone loss on digital radiographs are highly reproducible among examiners. Nevertheless, the application of image filters significantly influenced the degree of intra-examiner reproducibility. Some filters even reduced the reproducibility of intra-examiner readings.