Antimicrobial efficacy of a high-power diode laser, photo-activated disinfection, conventional and sonic activated irrigation during root canal treatment.

AIM: To evaluate the antimicrobial effect of a diode laser irradiation, photo-activated disinfection (PAD), conventional and sonic activated irrigation with 2.5% sodium hypochlorite (NaOCl) on Enterococcus faecalis. METHODOLOGY: Root canals of 120 human extracted teeth with single straight canals were prepared with ProTaper files, sterilized, contaminated with an E. faecalis suspension and incubated for 7 days. They were then randomly distributed into six groups: G1, diode laser irradiation (2 W, 3 × 20 s); G2, PAD (100 mW, 60 s); G3, PAD with 3D Endoprobe (100 mW, 60 s); G4, 30-gauge syringe irrigation with NaOCl (60 s); G5, sonic agitation of NaOCl with the EndoActivator system (60 s); G6, 30-gauge syringe irrigation with NaCl (60 s). The pattern of colonization was visualized by scanning electron microscopy. The root canals were sampled by flushing with saline solution at baseline and after the treatments. The number of bacteria in each canal was determined by plate count. The presence and the absence of E. faecalis in root canals were also demonstrated by polymerase chain reaction (PCR). RESULTS: There was a significant reduction in the bacterial population after all treatments (P < 0.001). The PAD, using both laser systems, and the sonic activated NaOCl irrigation were significantly more effective than diode irradiation and single NaOCl irrigation in reducing CFUs (P < 0.05). High-power diode laser and single NaOCl irrigation had an equal antibacterial effect (P > 0.05). CONCLUSIONS: The PAD and EndoActivator system were more successful in reducing the root canal infection than the diode laser and NaOCl syringe irrigation alone.

Hydroxyapatite formation from cuttlefish bones: kinetics.

Highly porous hydroxyapatite (Ca(10)(PO(4))(6)·(OH)(2), HA) was prepared through hydrothermal transformation of aragonitic cuttlefish bones (Sepia officinalis L. Adriatic Sea) in the temperature range from 140 to 220°C for 20 min to 48 h. The phase composition of converted hydroxyapatite was examined by quantitative X-ray diffraction (XRD) using Rietveld structure refinement and Fourier transform infrared spectroscopy (FTIR). Johnson-Mehl-Avrami (JMA) approach was used to follow the kinetics and mechanism of transformation. Diffusion controlled one dimensional growth of HA, predominantly along the a-axis, could be defined. FTIR spectroscopy determined B-type substitutions of CO(3) (2-) groups. The morphology and microstructure of converted HA was examined by scanning electron microscopy. The general architecture of cuttlefish bones was preserved after hydrothermal treatment and the cuttlefish bones retained its form with the same channel size (~80 × 300 µm). The formation of dandelion-like HA spheres with diameter from 3 to 8 µm were observed on the surface of lamellae, which further transformed into various radially oriented nanoplates and nanorods with an average diameter of about 200-300 nm and an average length of about 8-10 µm.