Table 2. Half-maximal inhibitory concentration (IC₅₀: Concentration for inhibition of 50% of the cells) and confidence interval (%) after 1-h and 24-h exposure of HaCaT cells to articaine formulations.

Formulations	IC50 (%)		IC50 confidence interval (%)
	1-h	24-h	1-h	24-h
ATC	0.3597	0.1176	0.3034 to 0.4265	0.1082 to 0.1277
ATCepi	0.5786	0.2467	0.5469 to 0.6122	0.1770 to 0.3439
ATCnano	0.7692	0.1639	0.7272 to 0.8137	0.1490 to 0.1803
ATCnanoepi	0.9582	0.3487	0.8538 to 1.075	0.3220 to 0.3776

P<0.0001 for all formulations. Different exposure times were analyzed separately.