Over the last two decades, calcium silicate-based materials have grown in popularity. As root canal sealers, these formulations have been extensively investigated and compared with conventional sealers, such as zinc oxide–eugenol and epoxy resin-based sealers, in in vitro studies that showed their promising properties, especially their biocompatibility, antimicrobial properties, and certain bioactivity. However, the consequence of their higher solubility is a matter of debate and still needs to be clarified, because it may affect their long-term sealing ability. Unlike conventional sealers, those sealers are hydraulic, and their setting is conditioned by the presence of humidity. Current evidence reveals that the properties of calcium silicate-based sealers vary depending on their formulation. To date, only a few short-term investigations addressed the clinical outcome of calcium silicate-based root canal sealers. Their use has been showed to be mainly based on practitioners’ clinical habits rather than manufacturers’ recommendations or available evidence. However, their particular behavior implies modifications of the clinical protocol used for conventional sealers. This narrative review aimed to discuss the properties of calcium silicate-based sealers and their clinical implications, and to propose rational indications for these sealers based on the current knowledge.

Activation techniques are essential for root canal disinfection but may result in incomplete removal of bacteria. The aim of our study was to assess the antibacterial action of sonically, ultrasonically and laser-activated irrigation and 5.25% sodium hypochlorite (NaOCl) on Enterococcus faecalis in an infected tooth. Forty-four extracted mandibular premolars were mechanically prepared, sterilized, and inoculated with E. faecalis for 1 week. Bacterial counts after inoculation were evaluated in 4 randomly chosen teeth, remaining root canals were divided into 4 groups. Group A: laser-activated irrigation by photon-induced photoacoustic streaming, Group B: the sonic irrigation by EDDY, Group C: ultrasonic irrigation by EndoUltra, and Group D: 5.25% NaOCl. Colony forming unit (CFU) counts were measured and Kolmogorov–Smirnov, Wilcoxon, Kruskal–Wallis and Mann–Whitney tests were used to determine differences. The mean of CFU was found to significantly decrease in group D, 2110 ± 1015.93 (p < 0.001). Changes in measurement levels followed the same trend over time in groups A 27.40 ± 30.15, B 81.3 ± 85.68 and C 44.40 ± 67.12 (p = 0.141). The average CFU after irrigation in all groups was significantly greater than 0. Within the limitations of this study, all activation techniques were superior to NaOCl 5.25% in reducing E. faecalis from the infected tooth model.

Objective: The aim of this randomized clinical study was to evaluate the effect of laser-activated irrigation using a photon-induced photoacoustic streaming (PIPS) technique on postoperative pain following completion of root canal obturation. Methods: Fifty-six patients were enrolled in this randomized clinical trial. Fifty-six healthy premolars or molars with asymptomatic irreversible pulpitis, symptomatic irreversible pulpitis, or symptomatic pulpal necrosis, with or without apical periodontitis, were mechanically prepared for endodontic treatment and divided into two groups. Patients were randomly allocated to treatment groups. In the positive control group G1, the final irrigation with 2 cc of 5.25% sodium hypochlorite (NaOCl) was achieved using a 27G needle, introduced into the canal to a distance of 5 mm from the predetermined working length. In the experimental group G2, the root canals were irrigated with 17% ethyldiamine tetric acid (EDTA) and 5.25% NaOCl following the PIPS protocol, using an Er:YAG 2940 nm laser (LightWalker ATS^®; Fotona, Slovenia) with a 600 μm diameter tip and operating parameters of 20 mJ per pulse, 15 Hz frequency, 0.3 W average power, and a 50-μs pulse duration. Postoperatively, the patients were advised to take a minor analgesic (ibuprofen 400 mg) in the event of pain perception. Postoperative pain levels were assessed after 24, 48, and 72 h and 7 days through the use of a Visual Analogue Scale questionnaire, completed by each patient. Data were analyzed using Kolmogorov–Smirnov, Fisher Exact, Chi square, Mann–Whitney test, and Friedman's test. The level of significance was set at α = 0.05. Results: There was no significant difference between the laser-irradiated group and the control group (p < 0.5). Laser activation of irrigating solutions did not increase postoperative pain. Conclusions: The outcome of this investigation indicated that PIPS was as effective as conventional irrigation in relation to postoperative pain, making this activation technique interesting to use for supplementary root canal disinfection.

The aim of this in vitro study was to evaluate the dentinal tubule penetration of two calcium silicate-based sealers used in warm vertical compaction (WVC) obturation technique in comparison with the single cone (SC) technique by confocal laser scanning microscopy (CLSM). The null hypothesis was that both obturation techniques produced similar sealer penetration depths at 1 and 5 mm from the apex. Forty-four mandibular single-rooted premolars were randomly divided into four equally experimental groups (n = 10) and two control groups (n = 2) according to the type of sealer (Bio-C Angelus, Londrína, PR, Brazil or HiFlow Brasseler, Savannah, GA, USA) with either SC or WVC. The sealers were mixed with a fluorescent dye Rhodamine B (0.1%) to enable the assessment under the CLSM. All the specimens were sectioned horizontally at 1 and 5 mm from the apex. The maximum penetration depth was calculated using the ImageJ Software (ImageJ, NIH). Data were analyzed by Mann–Whitney U and Kruskal–Wallis tests (p < 0.05). A significant difference was shown between the four groups at 1 mm (p = 0.0116), whereas similar results were observed at 5 mm (p = 0.20). WVC allowed better diffusion for both sealers at 1 mm (p = 0.01) and 5 mm (p = 0.034). The maximum penetration of the Bio-C and HiFlow sealers was more important at 5 mm with the two obturation techniques. Within the limitations of this study, WVC enhanced the penetration of calcium silicate-based sealers into the dentinal tubules in comparison with the SC technique at both levels.