Digital radiography of interproximal caries: Effect of different filters

The aim of this study was to compare the effect of different image processi ng modes (filters) on reproducibility and validity of the assessment of int erproximal carious lesions on digitized radiographic images. Standardized r adiographs of 34 extracted teeth exhibiting interproximal caries were obtai ned. All radiographs were digitized and using the FRIACOM-software the cent ral depth (CD) of each carious lesion was measured on the unchanged radiogr aphic image and after use of five different filters with 7fold and 18fold m agnification. All measurements were repeated after 1 week to estimate repro ducibility. Histometric CD assessments provided a gold standard for compari son with the radiographic measurements (validity). Neither reproducibility nor validity of CD measurements were improved by one of the filters. Measur ements of dentinal lesions showed a statistically higher variability than t hose of enamel lesions (p<0.001). 18fold magnification provided more va lid CD measurements than 7fold magnification (p<0.001). In this study digital manipulations of radiographic images failed to result in statistically sign ificantly improved reproducibility or validity of CD measurements.