Table 5.

Statistical analysis for mean ± St. deviation for the effect of bleaching protocol on colour change in shade guide units (SGU)

	Before bleaching	Post-bleaching	P-value
High light intensity	5.9 ± 3.1	2.8 ± 1.5	0.001*
Descending light intensities	6.6 ± 1.3	2.9 ± 1.6	0.002*

^*: significant (p ≤ 0.05); NS: non-significant (p > 0.05).