Radiopacity of an Experimental Universal Adhesive

Objectives: Objectives: Aim of this study was to assess the radiopacity of an experimental universal adhesive (ADH-XTE, 3M) versus commonly used adhesives.
Methods: Methods: Solvents were evaporated from adhesives (ADH-XTE, 3M; Scotchbond^TM Universal, SBU, 3M, AdheSE^TM Universal, ADU, Ivoclar-Vivadent; Prime&Bond^TM NT, PBNT, Dentsply-Sirona; Prime&Bond Active^TM, PBA, Dentsply-Sirona; Clearfil^TM SE Bond, CSE, Kuraray-Noritake; Optibond^TM Solo Plus^TM, OSP, Kerr). The remaining liquid was cured in polytetrafluoroethylene moulds (10mm diameter, 1mm height) using an Elipar S10 curing light (3M) to produce disks (n=3). 1mm thick disks of mid-coronal dentin of human molars were prepared using a circular saw (Accutom, Struers, n=3). Radiopacity was determined according to ISO13116:2014, using a Heliodent Plus device (Dentsply-Sirona) and VistaScan digital imaging equipment (Dürr Dental), voltage 60kV.
Class I cavities (4mm deep) were prepared in extracted human molars. Adhesives were applied using a fully saturated disposable applicator according to manufacturers’ instructions, and gently air dried to provoke pooling at the cavity bottom. Cavities were restored with Filtek^TM One (3M). Radiographs of teeth were taken using above equipment and examined for radiolucent areas underneath the fillings.
Results: Results: The table shows the radiopacity in % of aluminium, and the occurrence of radiolucent areas under the restorations. Standard deviations (SD) are given in parentheses. Radiopacity data were analyzed by ANOVA and multiple comparisons using the Tukey test (p<0.05). Means with the same letters are statistically the same.
Conclusions: Conclusion: ADH-XTE and human mid-coronal dentin had statistically the same radiopacity. All other adhesives tested had significantly lower radiopacity. Radiopacity of the adhesive may reduce the occurrence of doubtful X-ray images, where a radiolucent thicker adhesive layer under a restoration might be misinterpreted as caries, gap or void resulting in unnecessary treatment.