Effect of polymerization mode and LED light-curing units on the shear bond strength of an alkasite restorative...

This in vitro study evaluated the effects of different polymerization approaches and LED light-curing units on the shear bond strength (SBS) of a bioactive alkasite restorative material to dentin and compared the results with those of a resin-modified glass ionomer cement (RMGIC). Fifty extracted human premolars were randomly assigned to five groups according to the polymerization protocol. The alkasite material was polymerized either by self-curing or with two different LED light-curing units (VALO Cordless and Bluephase), while the RMGIC was light-cured using the same devices. All specimens were subjected to 5,000 thermal cycles between 5 °C and 55 °C before SBS testing using a universal testing machine. Failure modes were evaluated using stereomicroscopy, and representative specimens were examined by scanning electron microscopy. The mean SBS values were 15.77 ± 5.66 MPa, 15.51 ± 3.16 MPa, and 16.11 ± 4.37 MPa for the self-cured, VALO-cured, and Bluephase-cured alkasite groups, respectively, whereas the corresponding values for the RMGIC groups were 8.97 ± 2.80 MPa and 8.20 ± 2.51 MPa. No significant differences were observed among the alkasite groups or between the RMGIC groups (p > 0.05). However, all alkasite groups demonstrated significantly higher SBS values than the RMGIC groups (p ≤ 0.004). The findings of the present study demonstrate that the bioactive alkasite restorative material provides higher dentin bond strength than the RMGIC, regardless of the polymerization mode or LED light-curing unit used. Furthermore, neither self-curing nor light-curing with different LED devices significantly affected its shear bond strength.