The effect of surface treatments on the adhesive bond in all-ceramic dental crowns using four-point bending and dynamic loading tests

The aim of this study was to determine the effect of sandblasting, grinding and plasma treatment on the adhesive bond strength between framework ceramic (Y-TZP) and veneering ceramic (feldspar ceramic). Therefore, four-point bending specimens (n = 180) were cut from densely sintered 3Y-TZP blanks. Subsequently, 80 of these samples received surface treatment by sandblasting and 80 samples by grinding. A reference group (20 samples) was not processed. Half of the specimens that received a surface treatment were additionally exposed to an oxygen plasma treatment. After processing, all specimens were manually veneered with feldspar ceramic and examined with a four-point bending test to evaluate the strain energy release rate G. The surface treatment parameters that achieved the highest and lowest G were transferred to real geometries of a posterior crown (n = 45). The crowns' ceramic framework was sandblasted and veneered by hand. The all-ceramic crowns were tested in a dynamic loading test and Wohler curves were evaluated. Four-point bending samples blasted at an angle of 90 degrees at 6 bar and a working distance of 1.5 cm without plasma treatment achieved the highest energy release rate. Samples blasted at an angle of 90 degrees at 2 bar and a working distance of 1 cm with plasma treatment achieved the lowest energy release rate. Overall, plasma treatment did not improve bond strength. In the dynamic loading test, the group blasted with 2 bar showed the best results.

Automated summary

The aim of this study was to investigate the effect of different surface treatments on the bond strength between framework ceramic and veneering ceramic. Sandblasting and grinding were carried out on samples, with and without plasma treatment. The results showed that the highest bond strength was achieved in the group with sandblasting at 90 degrees, 6 bar, and a working distance of 1.5 cm without plasma treatment, while the lowest bond strength was observed in the group with sandblasting at 90 degrees, 2 bar, and a working distance of 1 cm with plasma treatment. Overall, plasma treatment did not improve bond strength.