Table 2.

Intergroup comparison of cell viability between hydrogen water-treated periodontally healthy fibroblasts and chronic periodontitis fibroblasts after 24 h and 48 h

	Groups	n	Mean	SD	Median	Mann-Whitney-U value	Z	P*
Absorbance (nm) at 24 h	Hydrogen water-treated periodontally HF	13	0.256	0.013	0.254	0.000	−4.337	0.000
	Hydrogen water-treated fibroblasts from chronic periodontitis patients (CF)	13	0.290	0.005	0.292
Absorbance (nm) at 48 h	Hydrogen water-treated periodontally HF	13	0.434	0.008	0.435	0.000	−4.345	0.000
	Hydrogen water-treated fibroblasts from chronic periodontitis patients (CF)	13	0.275	0.004	0.276

*Statistically highly significant difference (P<0.01). n – Number of samples; Z – Number of standard deviations from mean; P – Level of significance; SD – Standard deviation; nm – Nanometers; HF – Healthy fibroblasts; CF – Fibroblasts from patients with chronic periodontitis