In vitro study on nonthermal argon atmospheric plasma improving the bonding interface between dentin and self-etch adhesive

To study the effect of nonthermal argon atmospheric pressure plasma (NTAPP) treatment on the bonding strength between dentine and self-etch adhesive and the wettability of dentine surfaces under different treatment times.

The plasma jet was operated at an input power of 9 W. Argon was used as the operating gas at a flow rate of 5 L/min. The dentin surface was exposed to the plasma jet (n=6) for various times (0, 5, 10, 15, 20 s). After a one-step self-etch adhesive (S3 Bond) was applied to the treated dentine surface, microtensile bonding specimens were made, and the microtensile bonding strength was tested. Then, the dentine surface contact angles were measured after NTAPP treatment for 5, 10, 15, and 20 s with the same gas flow rate and input power described above.

Along with the NTAPP treatment time, the dentin immediate bonding strength was significantly increased. The 15 s group showed significantly elevated bonding strength (31.82±2.80 MPa) in contrast to the other groups. The contact angles of each experimental group significantly decreased compared with the contact angles of the negative control group (75.57°± 1.45°). The contact angles decreased the most to 33.56°±2.14° with NTAPP treatment for 15 s, and its wettability was the highest.

NTAPP treatment can significantly increase the wettability of the dentin surface and improve the adhesive strength of the adhesive interface with self-etching adhesive, which is also related to the treatment time.