Objectives: The purpose of this study was to compare the radiopacity of polymeric materials with dentin, enamel and amalgam. Methods: Disks measuring 5.0 mm in diameter and 2.9 mm in thickness were prepared from several polymeric materials (Table) using a stainless steel ring molds (N=6 per material). They were radiographed (Spectro, 70Kv-10 MA/Dabi-Atlante, Brazil) using Insight dental film (Kodak) with a exposure time of 1 second. Each radiograph contained 2 disks of each material, one disk of amalgam and two disks of intact human teeth with the same thickness. The optical density of the images was evaluated by digital transmission photodensitometer (MRA, Brazil), with five measurements of each sample. Results: ANOVA and Tukey test were used to determine differences in optical density among materials and between materials and dentin, enamel and amalgam. Values are mean optical density (SD).

	Permite C SDI	Z-100 3M	Prodigy Kerr	Freedom SDI	Fill-Magic Vigodent	ArtGlass Kulzer	Enamel	Dentin	Durafill VS/ Kulzer
Mean S.D	0.029 (0.001) A	0.473 (0.008) B	0.577 (0.145) C	0.707 (0.137) D	0.870 (0.018) E	0.898 (0.034) E	0.995 (0.048) F	1.244 (0.027) G	2.012 (0.021) H

 There were statistically significantly differences among materials and substrates (p<0.05). Durafill VS was the only resin with optical density lower than enamel and dentin (p<0.05). Conclusions: Radiopacity varied significantly among all the polymeric materials evaluated. Most of them are more radiopaque than enamel and dentin and all are less radiopaque than amalgam. Supported by CNPq 300481/95-0.