The efficiency of films from different speed groups at the determination of the remaining dentin thickness between carious lesion and pulp tissue

The aim of this study was to assess the efficiency of films from differentspeed groups (Ultraspeed, Ektaspeed Plus, Insight) and their indirect digital imagesat detecting the remaining sound dentin thickness between carious lesion and pulptissue.Ninety-one extracted human teeth, having various degrees ofdemineralization and cavitation on their approximal surfaces, were used in this study.The teeth were embedded into methyl methacrylate blocks, as one block consisted onetooth, and conventional radiographs were taken with Ultraspeed, Ektaspeed Plus andInsight films. Subsequently, indirect digital images were obtained by scanning theconventional radiographs at 600 dpi resolution. The remaining dentin thickness wasmeasured both on conventional and indirect digital images from the teeth which thelesion and pulp boundaries were clearly visible.After all measurements were completed, the teeth blocks weresubjected to progressive grinding at buccolingual direction. The images of thesections were taken with an operating microscope and histologic remaining sounddentin thickness was measured.Pearson correlation coefficients, t-test, concordance correlationcoefficients and 95% confidence intervals were calculated for the statistical analysisof the data.There was a high concordance and agreement level between the threefilms, their indirect digital images and histology and between all receptors.No significant difference was found between the six imaging modalitiesand histology, and between all receptors according to the 95% confidence intervals ofeach concordance correlation coefficient (p>0.05).As there was no significant difference between Insight, Ultraspeed andEktaspeed Plus films, the use of Insight films, which provides a benefit in radiationdose, will be an advantage.