Measuring the Radiopacity of Flowable Resin Composites Using Scanned Radiograph Images

Abstract

Radiopacity is a requirement for dental restorative materials that permits evaluation of the integrity and adaptation over time to the restoration of the tooth structure. This work was to investigate amount of fillers and radiopacity of flowable resin composites using scanned radiograph images. Radiographs of samples (8 mm diameter and 1 mm thickness) were taken with a dental x-ray at 60 kv, 7 mA, for 0.32 sec. exposure time, with a target-film distance at 40 cm. After development, dental films (Kodak D-Speed) were scanned for digitalisation and average gray value was recorded for every sample using Image J software. Percentage of filler by weight and volume were assessed by combustion analysis. The filler percentages of the flowable composites determined was ranged from 52.26 to 69.74 wt%. All materials investigated were more radiopaque than dentin and two materials were more radiopaque than enamel. The usage of low radiopaque materials should be avoided because it may lead to incorrect diagnosis. Future flowable resin composites are recommended to have higher radiopacity than dentin and perhaps ideally similar to or slightly higher than that of enamel for improved clinical detection. Digital imaging could be an alternative to transmission densitometry for the evaluation of the radiopacity of dental composites.