Table 1.

Summary of sample composition and corresponding sample codes.

Bis-GMA (wt%)	TEGDMA (wt%)	Photo-initiator	Resin/filler (wt%)	Sample code
70	30	CQ	50/50	70/30 CQ
70	30	TPO	50/50	70/30 TPO
60	40	CQ	50/50	60/40 CQ
60	40	TPO	50/50	60/40 TPO
60	40	CQ	40/60	60/40 CQ HF
60	40	TPO	40/60	60/40 TPO HF

Weight percentage (wt%) mixing ratios of Bis-GMA and TEGDMA monomers used to formulate each resin blend. Each mixing ratio was combined with a photo-initiator as either 0.2 wt% camphorquinone (CQ) with 0.8 wt% of its tertiary amine N,N-dimethylaminoethyl-methacrylate (DMAEMA) or 1 wt% Lucirin-TPO (TPO) photo-initiator. Silica filler particles were added in higher (HF) (40/60) and lower (50/50) wt% loadings to form composites.