Method: Experimental hydrophobic adhesive resins containing BisGMA/HEMA as organic matrix were manipulated, with different photoinitiator content: G1- CQ/amine, G2- PPD/amine, G3- CQ/PPD/amine, G4- BAPO/Amine, G5- BAPO, G6- CQ/BAPO/Amine, G7- PPD and G8- the hydrophobic resin of Adper Scotchbond Multi-Purpose as control. 3µl of each adhesive was dispensed on the zinc selenide cristal of the FTIR device and cured with a polywave LED (Bluephase G2) for 20s, using 24J of energy dose. After 3 min, the DC was measured by FTIR. For the cytotoxicity assessment, mouse immortalized fibroblasts were exposed to the experimental resin extracts. An MTT assay was used to evaluate cell viability. Data were submitted to one-way ANOVA and Tukey’s test at a preset alpha of 0.05.
Result: The BAPO, BAPO/amine and the control adhesives showed higher DC values compared to the other resins (66%, 65.1% and 62.2%, respectively). The PPD alone presented the lowest DC (2.9%). The adhesives containing PPD/amine or CQ/amine showed similar monomer conversion. Moreover, for the cytotoxicity, the adhesives containing BAPO or BAPO/amine showed the highest cell viability (92.7% and 93.8%, respectively), compared to the PPD, CQ and control resins. Also, the PPD/amine presented lower cytotoxicity, in comparison to the CQ adhesives.
Conclusion: CQ can be replaced by BAPO and PPD in hydrophobic adhesive resins, since it can increase the degree of conversion and reduce the cell cytotoxicity of these restorative materials.