Flexural strength of dental adhesives with different photoinitiator systems.

Background: The aim of this study was to investigate the flexural strength of dental adhesives containing different combinations of photoinitiators systems.

Material and methods: The organic matrix of the experimental adhesives was created using a blend of monomers: 50% by weight bisphenol-A glycidyl methacrylate (BisGMA) and 50% triethylene glycol dimethacrylate (TEGDMA). The photoinitiators utilized were camphorquinone (CQ) and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), with diphenyliodonium hexafluorophosphate (DPIHFP) and 2-(Dimethylamino)ethyl methacrylate (DMAEMA) as co-initiators. These photoinitiators and co-initiators were integrated into the organic matrix at a concentration of 0.5% by mass, resulting in the formation of 6 groups (n=12): CQ/DMAEMA (control); CQ/DMAEMA/DPIHFP; BAPO; BAPO/DMAEMA; BAPO/DPIHFP and BAPO/DMAEMA/DPIHFP. Samples measuring 7 mm in length, 2 mm in width, and 1 mm in height were prepared and subjected to a three-point flexural test. Data were analyzed using one-way ANOVA with Tukey's post-hoc test (α=0.05).

Results: Results indicated that groups incorporating BAPO and DPIHFP exhibited higher flexural strength compared to those with CQ and DMAEMA. The BAPO/DPIHFP group achieved the highest mean flexural strength values (p<0.001).

Conclusions: These findings suggest that using adhesive systems with alternative photoinitiators and co-initiators can lead to superior flexural strength compared to conventional systems. Key words:Photoinitiators, Dentin-bonding agents, Light-curing.