The use of digital image in the diagnosis of microleakage

Objective: The aim of this study was to determinate the ideal resolution and magnification for digital images used in the diagnosis of microleakage of composite restorations. Methods: Sixty one bovine tooth where used and it was prepared 61 class V cavities at the enamel/cement junction, which were restored with Single Bond and Z100 composite. After finished the restorations, they were polished with Sof-lex discs and thermo cycled 500 times with baths of 30 seconds at 5C and 55ºC of temperature. Then they were cutted with a rotating diamond disc and the tooth fragments were digitalized with 200 dpi, 400 dpi and 600 dpi of resolution and in each resolution with 100%, 200%, 300% and 400% of magnification using Image Tool software. Two examiners classified the images according to microleakage, in scores, by consensus. It was applied Kruskal Wallis test (H) at 5% of significance. Results: The 600 dpi resolution was the best one because of the quality image provided by it. At 600 dpi, the magnifications produced significant differences in the effects of the microleakage classification (H= 32.83; p<0.05), and the statistical contrasts showed that the 200% and 300% of magnification were similar for the microleakage diagnosis, and, indeed, the limits were well defined. Conclusion:The magnifications of 200% and 300% are indicated in the microleakage diagnosis using digital image, so that, the researches could choose any one of them to clinical tasks.