In vitro effects of laser-activated irrigation methods on apical extrusion of indocyanine green mediated photodynamic...

This study aimed to compare the effects of different laser-activated irrigation (LAI) methods on apical extrusion of indocyanine green (ICG).

In this in vitro study, 40 extracted single-canal premolars were instrumented and randomly assigned to 4 groups (n = 10) of (I) ICG (1 mg/mL) + photon-induced photoacoustic streaming (PIPS) with 2940 nm erbium laser, 20 mJ energy, and 50 µs pulse width for 30 s, (II) ICG + shockwave enhanced emission photoacoustic streaming (SWEEPS) with 2940 nm erbium laser with 20 mJ energy, and 50 µs pulse width (two 25 µs pulse widths) for 30 s, (III) ICG + 810 nm diode laser with 250 mW power for 30 s, and (IV) ICG without activation. Photoluminescence (PL) was used to quantify the ICG volume extruded through the apex, and determine the excitation wavelength of the ICG samples. To calibrate the PL results, one random ICG sample underwent inductively-coupled plasma (ICP) test to quantify the sulfur content of the extruded ICG. Considering the chemical formulation of ICG, the concentration of extruded ICG was calculated accordingly. Data were analyzed by one-way ANOVA (alpha=0.05).

The best spectrum was obtained at 390 nm excitation wavelength with 700 V voltage and slit number=10. The study groups had no significant difference in the concentration of apically extruded ICG (P = 0.611).

The tested LAI protocols had no significant difference with each other or with the no activation protocol regarding the apical extrusion of ICG.