Table 5. National Bureau of Standards (NBS) interpretation of calculated ΔE values.

Beverages	Groups	ΔE values	NBS units	Clinical interpretation
Artificial saliva	NGB	0.83	0.76	Slight change
	GB	1.73	1.59	Perceivable
Coffee	NGB	2.96	2.72	Perceivable
	GB	4.47	4.11	Marked change
Red Bull	NGB	1.83	1.68	Perceivable
	GB	2.47	2.27	Perceivable
Coca-Cola	NGB	1.85	1.70	Perceivable
	GB	2.55	2.34	Perceivable