Die Dentinhaftfestigkeit eines experimentellen Universaladhäsivs unter Anwendung verschiedener Applikationsverfahren

Aim of the study Aim of the present study was to investigate dentin bond strength of an experimental universal adhesive in comparison to the well-suited ScotchbondTM Universal (3M Oral Care, Seefeld, Germany) and to evaluate the influence of both self-etch and etch-and-rinse technique on bonding performance in high C-factor cavities. Materials and methods Fifty caries-free human third molars received Class-I cavities measuring 4 x 4 x 4 mm, and were randomly assigned to 10 experimental groups (n=5). Cavities were filled with resin composite using various adhesive techniques and exposure times. The uni-versal adhesive EXP19 investigated in this study was used in both self-etch and etch-and-rinse techniques. Duration of application of the adhesive varied between 0 s and 30 s. As a control, ScotchbondTM Universal was also applied using the self-etch and etch-and-rinse technique according to the manufacturer's instructions. Cavities were filled with the resin composite FiltekTM One Bulk Fill Restorative. After cutting com-posite-dentin beams with a cross-sectional area of 1.0 x 1.0 mm, bond strength be-tween dentin and resin composite was determined in a micro tensile test. Finally, the failed resin-dentin interfaces were examined under a scanning electron microscope at up to 1000x magnification. Results The experimental adhesive EXP19 did not exhibit sufficient adhesive performance for clinical use in the self-etch approach (ES1: 1.2 ± 3.5 MPa; ES2: 4.2 ± 5.0 MPa; ES3: 5.0 ± 4.2 MPa; ES4: 5.3 ± 3.9). Using the etch-and-rinse technique, low adhesion val-ues were achieved after 0 s or 10 s exposure time (EE1: 0.6 ± 3.0; EE2: 3.9 ± 3.5 MPa). Only in the groups EE3 (7.6 ± 4.2 MPa) and EE4 (9.3 ± 3.6 MPa), the experimental ad-hesive showed sufficient or comparable adhesion values to the control groups (12.4 ± 5.0 MPa) and SCE (8.2 ± 3.9 MPa). The use of the etch-and-rinse technique leads to improved adhesion values after 20 s or 30 s exposure time when EXP19 was used. With ScotchbondTM Universal, slightly higher bond strengths were observed in the self-etch process. Conclusion Within the limits of this in-vitro study, the investigated experimental universal adhe-sive has not been tested suitable for everyday clinical practice. Shortening applica-tion time lead to lower adhesion values. Further research is therefore required into new universal adhesives whose effectiveness is already apparent after shorter appli-cation time in order to accelerate the restorative process.