Table 3. Means and standard deviations of transverse strength of the control and copolymer groups/MPa.

Test groups	Acrylic resins
	QC-20	Acron MC
Control (100% PMMA)	106.05±7.68	98.07±2.95
5% copolymer (5% AAm+95% PMMA)	109.42±6.83	99.11±3.54
10% copolymer (10% AAm+90% PMMA)	108.95±4.92	106.61±1.95*
15% copolymer (15% AAm+85% PMMA)	114.56±3.05*	111.76±4.60*
20% copolymer (20% AAm+80% PMMA)	106.91±6.53	100.42±4.21

AAm, acrylamide monomer; PMMA, poly(methyl methacrylate).

*Symbol indicates significant differences between control and copolymer groups in each column (P<0.01).