Table 1: Experimental question.

Aggregate samples	Instruments design effect (IG file K-NiTI) on apical gauging
	Operator experience effect on apical gauging correct measurement
	Exceeding or lacking apex gauging (IG file EO Vs UO)
	Exceeding or lacking apex gauging (K-NiTI EO Vs UO)
With or without canal curvature	Measurements accuracy (IG file Vs K-NiTi file)
	Exceeding or lacking apex gauging (IG file -NiTi file)
	Operator experience effect on apical gauging correct measurement
	Instruments design effect (IG file K-NiTI) on apical gauging