Effect of Laser and Conventional Office Bleaching and Polishing on the Color Change of Stained Nanohybrid and Microhybrid Composite Resin

Table 5

Two way ANOVA test of mean color change after stain-removal procedures compared with after staining (ΔE₂).

Source	Type III sum of squares	df	Mean square	F	Sig.
Corrected model	49.826^a	5	9.965	1.941	0.108
Intercept	960.806	1	960.806	187.170	0.000
Composite	37.647	1	37.647	7.334	0.010
Method	2.550	2	1.275	0.248	0.781
Composite method	10.678	2	5.339	1.040	0.363
Error	210.467	41	5.133
Total	1,210.185	47
Corrected total	260.293	46

^aR² = 0.191 (adjusted R² = 0.093). Interacion between composite and method and its effect on ΔE. ANOVA, analysis of variance.