Influence of image filters on the reproducibility measurements of alveolar bone loss

Wivian Eiras Garcia Wong Alves,Evelise Ono,Jefferson Luis Oshiro Tanaka,Edmundo Medici Filho,Mari Eli Leonelli De Moraes,Luiz César De Moraes,Julio Cezar De Melo Castilho

doi:10.1590/s1678-77572006000600006

Wivian Eiras Garcia Wong Alves, Evelise Ono + Show 5 more

Open Access

https://doi.org/10.1590/s1678-77572006000600006

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Abstract

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.

Highlights

Periodontal disease may present a wide variation of its appearance, which brings lack of uniformity on the criteria that define its aspects
Despite the fact that progresses on the standardization of radiographs have been achieved, their use to qualify the periodontal disease still depends on subjective interpretation
Measurements of alveolar bone loss have a low level of reproducibility, mainly because of the difficulty to visualize the cementoenamel junctions (CEJs) and alveolar crests (AC)[1,4,6,16,17]

Summary

Introduction

Periodontal disease may present a wide variation of its appearance, which brings lack of uniformity on the criteria that define its aspects. This is a problem for epidemiologic researches, since they require reliable information[17]. Measurements of alveolar bone loss have a low level of reproducibility, mainly because of the difficulty to visualize the cementoenamel junctions (CEJs) and alveolar crests (AC)[1,4,6,16,17]. Once the radiographs are digitalized, filters may be readily applied to enhance visualization of the bone architecture for the measurements of bone loss. Researches on density, contrast and edge enhancement have already proved their usefulness to the diagnosis of caries and alterations of the alveolar bone[15,18]

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