# Flexural strength of dental adhesives with different photoinitiator systems

## TL;DR

This study compares the strength of dental adhesives using different photoinitiator systems to find the most effective combination.

## Contribution

The study introduces a new combination of photoinitiators and co-initiators that significantly improves the flexural strength of dental adhesives.

## Key findings

- Groups with BAPO and DPIHFP showed higher flexural strength than those with CQ and DMAEMA.
- The BAPO/DPIHFP group had the highest mean flexural strength (p<0.001).

## Abstract

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

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 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).

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.