The PAD and EndoActivator system were more successful in reducing the root canal infection than the diode laser and NaOCl syringe irrigation alone.

The present study indicates that, compared to SRP alone, multiple adjunctive applications of a 980-nm diode laser with SRP showed PD improvements only in moderate periodontal pockets (4 to 6 mm).

The aim of the study was to evaluate the efficacy of photon-initiated photoacoustic streaming (PIPS) in the removal of filling remnants from root canals after rotary phase of retreatment and to examine the difference in the amount of residual material considering the type of sealer. Thirty-six extracted single-rooted human teeth were instrumented and randomly divided into three groups according to the filling material used: group 1: EndoSequence BC Sealer (Brassler, USA), group 2: MTA Fillapex (Angelus Solucoes Odontologicas, Londrina, Brasil), and group 3: AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). Cold lateral condensation technique was used. After 2 weeks, the root canals were retreated with a rotary phase retreatment system (ProTaper Universal Retreatment, Maillefer, Ballaigues, Switzerland), followed by Er:YAG laser-activated irrigation (photon-initiated photoacoustic streaming, PIPS). The specimens were scanned in a micro-computed tomographic (micro-CT) device after root canal filling, after the rotary retreatment, and after the PIPS. There was significant reduction in the amount of filling material after the rotary phase of retreatment in all groups (p < 0.05), the highest in the MTA Fillapex group (p < 0.001) and no difference between the EndoSequence BC and the AH Plus (p = 0.608). There was significant reduction of the filling remnants after the PIPS in all groups (p < 0.05). The MTA Fillapex was the most easily removed during rotary phase of the retreatment, and there were no differences in the amount of the remaining filling material between EndoSequence BC and the AH Plus groups after rotary phase of the retreatment. The PIPS improved the removal of filling remnants in all groups.

The aim of the study was to assess the antibacterial efficacy of photon-initiated photoacoustic streaming (PIPS) using an Er:YAG laser and sonic-activated irrigation combined with QMiX irrigant or sodium hypochlorite against Enterococcus faecalis intracanal biofilm. Root canals of 91 human extracted single-canal teeth were instrumented, sterilized, contaminated with E. faecalis and incubated for 15 days. The infected teeth were then randomly distributed into six experimental groups: G1: PIPS/Er:YAG laser (wavelength 2940 nm, pulse energy 20 mJ, 15 Hz, pulse duration 50 μs, energy density 2.06 J/cm(2), 3 × 20 s) with the QMiX irrigant; G2: PIPS/Er:YAG laser-activated 2.5 % NaOCl; G3 sonic-activated irrigation (EndoActivator system) for 60 s with the QMiX irrigant; G4 sonic-activated irrigation for 60 s with 2.5 % NaOCl; G5 30-gauge needle irrigation with the QMiX irrigant; G6 30-gauge needle irrigation with 2.5 % NaOCl. The positive control group was rinsed with sterile saline solution. The root canals were sampled by flushing with saline solution at baseline and after the treatments, serially diluted and cultured. The number of bacteria in each canal was determined by plate count. The presence and the absence of E. faecalis in root canals were demonstrated by polymerase chain reaction (PCR), and the pattern of the bacteria colonization was visualized by scanning electron microscopy. There was significant reduction in the bacterial population for all groups (p < 0.001). The best antibacterial efficacy was recorded after sonic-activated irrigation with both NaOCl (99.999 %) and QMiX (99.999 %) and after PIPS with QMiX (99.999 %), which were more effective than conventional irrigation with NaOCl (99.998 %) and the PIPS with the NaOCl (99.966 %). Also, the PIPS with QMiX solution provided the highest number of sterile samples (five). There was no difference in the bacteria reduction between the active irrigation techniques, regardless of the irrigant used. Although the laser activation did not improve the antimicrobial action of the NaOCl nor QMiX, the fact that it generated the greatest number of sterile samples warrants further investigation.

The Reciproc system was more effective than the Reciproc Blue and ProTaper Universal Retreatment systems during the removal of filling material from oval, straight canals, although none of the systems completely removed the filling material.