Table 3. Mean values (MPa) and SD for the polymerization shrinkage stress (PSS) considering both compliances (Classes I and II) and heating conditions.

	Class I		Class II
	No preheating	Preheating	No preheating	Preheating
Universal Restorative	5.57 (1.02)	4.18 (1.31)	1.04 (0.18)	0.85 (0.13)
Filtek Supreme Ultra	4.83 (1.15)	4.22 (1.08)	1.00 (0.16)	1.08 (0.17)

Tukey’s post-hoc test: no significant differences between materials and heating conditions. Standard deviation in parentheses.