Cleaning efficacy and apical pressure in sonically-activated irrigation systems: Impact of tip vertical stroke

A newly developed sonic device for root canal irrigation, the SmartLite Pro EndoActivator, features modified vibration frequencies and behaviors. This study aimed to examine the cleaning efficacy and periapical pressure generation of sonically-activated irrigation (SAI) with different number of vertical strokes.

Seventy-two human anterior teeth were instrumented to a #25/0.07 taper. Experiment 1: 36 teeth were irrigated using: (1) EndoActivator (SAI-1), (2) SmartLitePro EndoActivator (SAI-2), and (3) syringe irrigation (SI) (n = 12, each). Experiment 2: 36 teeth were irrigated with SAI-2, varying the number of vertical strokes applied (0, 10, and 40 times; n = 12, each). Debris and smear layer scores were assessed using scanning electron microscopy. Experiment 3: Periapical pressures were measured during irrigation of plastic root canal models (#40/0.06 taper) with SAI-2 using 0, 10, or 40 strokes. Data were analyzed with the Kruskal Wallis and Mann-Whitney U tests (P < 0.05).

In Experiment 1, the SAI-2 group showed significantly better smear layer scores than the SAI-1 and SI groups (P < 0.05). In Experiment 2, the 40-stroke group had significantly superior debris and smear layer scores than the 0-stroke group (P < 0.05), with similar scores to those of the 10-stroke group. In Experiment 3, the 40-stroke group generated significantly higher periapical pressure than the other groups (P < 0.05).

The SmartLite Pro EndoActivator outperformed EndoActivator and syringe irrigation regarding cleaning efficacy. Increasing the number of vertical strokes improved the cleaning efficacy but also resulted in higher apical pressures.