Table 2.

Total concentrations of selected metals in the enamel samples of Experiments #1, #2 and #3

Experiment		Group	Metal concentration (µg/g)												pH cycles applied	Presence of appliance
			Fe			Cr			Ni			Cu
			Median	IQR	Sig	Median	IQR	Sig	Median	IQR	Sig	Median	IQR	Sig
Experiment #1	Main	1A	41.63	30.58	b	1.13	0.87	b	3.05	1.99	b	0.94	0.46	ab	+	+
	Control	1B	12.56	6.68	a	0.31	0.29	a	1.33	0.79	a	1.33	0.96	a	+	−
Experiment #2	Main	2A’	8.28	5.53	a	0.12	0.07	a	0.77	1.28	a	1.20	0.64	ab	+	−
	control	2B’	10.32	4.00	a	0.31	0.34	a	2.47	1.52	ab	0.60	0.41	b	−	−
Experiment #3	main	3A’’	9.17	2.54	a	0.27	0.06	a	0.74	0.12	a	0.55	0.35	b	−	−
	control	3B’’	8.45	1.30	a	0.26	0.05	a	0.67	0.35	ac	0.69	0.35	b	−	−
			p < 0.0006*			p < 0.002*			p < 0.002*			p < 0.003*

IQR interquartile range, Sig. significance

Exact p value for particular groups are available in Supplementary Materials Table S1a–d.

*Values within a median column followed by different letters in a significance (sig) column differ significantly at given p.