Table 2.

Displacement (mm) of tissue (median ± quartiles) in all groups

Irrigant	Position	CNI groups	PIPS groups	p-value
Saline	coronal 1/3	−0.00 ± 0.03a	−0.65 ± 0.80a	< 0.05
	middle 1/3	0.00 ± 0.00a	−1.45 ± 0.95b	< 0.05
	apical 1/3	0.00 ± 0.00a	−1.90 ± 0.72c	< 0.05
1%NaOCl	coronal 1/3	−0.00 ± 0.03a	−0.80 ± 0.98a	< 0.05
	middle 1/3	0.00 ± 0.00a	−1.80 ± 0.98b	< 0.05
	apical 1/3	0.00 ± 0.00a	−2.80 ± 0.97c	< 0.05
2.5%NaOCl	coronal 1/3	0.00 ± 0.00a	−0.85 ± 0.48a	< 0.05
	middle 1/3	0.00 ± 0.00a	−1.40 ± 0.53b	< 0.05
	apical 1/3	0.00 ± 0.00a	ND	ND
5.25%NaOCl	coronal 1/3	0.10 ± 0.43a	0.00 ± 0.55	> 0.05
	middle 1/3	0.00 ± 0.38a	ND	ND
	apical 1/3	0.00 ± 1.53a	ND	ND

Lower-case letters in a columns are for the comparison of displacement between different positions using the same irrigation protocol. Same lower-case letters follow means that do not differ statistically (p >.05). Displacement >0 refers to moving towards apical direction, <0 refers to moving towards coronal direction. ND denotes that displacement could not be measured as the tissue sample was completely dissolved

Abbreviations: CNI conventional needle irrigation, PIPS photon-initiated photoacoustic streaming, NaOCl sodium hypochlorite, ND not detected