Radiopacity Of Dental Adhesives: A Comparative Study

Objectives: To evaluate the radiopacity of 10 popular adhesive systems and compare them with healthy and decayed human enamel and dentin. Methods: Samples of 10 adhesives (A.R.T.Bond (ART), One Coat^TMBond (OCB), One Coat^TM7.0 (OC7) and One Coat^TMSelf-etching Bond (OCS) from Coltène Whaledent; Adper^TMScotchbond^TMMulti-purpose Adhesive (ASM), Adper^TMScotchbond^TM 1XT Adhesive (AS1XT), Adper^TMScotchbond^TMSE (ASSE) and Adper^TMEasy Bond (AEB) from 3M-ESPE; Optibond^TMFL (OFL) and Optibond^TMAll-in-One (OAO) from Kerr), (n=30) (10 mm in diameter and 2 mm in thickness) were prepared and compared to slices (2 mm thickness) of human healthy and decayed enamel and dentin (n=12). An x-ray was taken per specimen and 9 measurements of the radiodensity were obtained per sample using a transmission densitometer (X-Rite). Radiodensity data (optical density unit - ODU) were statistically analyzed using Kruskal-Wallis test followed by post-hoc paired comparisons. Results: Radiopacity varied between adhesives (range: 0.27±0.03 to 1.82±0.06 ODU). Only OFL (0.29±0.05 ODU) and ASSE (0.27±0.03 ODU) showed a radiopacity significantly higher than healthy enamel (0.42±0.03 ODU) and dentin (1.08±0.05 ODU) (p<0,05). ART (1.82±0.06 ODU) and OCS (1.63±0.03 ODU) showed no significant difference to decayed dentin (2.29±0.32 ODU)(p>0,05). All other adhesives were less radiopaque than healthy enamel and dentin. Conclusion: Popular adhesive systems vary considerably in radiopacity. Some adhesives present a radiolucency similar to decayed dentin which is critical for an accurate differential diagnosis and subsequent clinical treatment procedure.