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:Minimal invasive endodontics preserve coronal and radicular tooth structure to increase the fracture resistance of teeth. The aim of this study was to assess the influence of final preparation taper on the fracture resistance of maxillary premolars.Materials and Methods:Sixty maxillary premolars were selected and divided into 2 groups: 30 were shaped with a final apical diameter 30 and a 4% taper and 30 with 6% taper using iRaCe® instrument (FKG dentaire, Switzerland). All root canals were irrigated with sodium hypochlorite and final rinse with ethylenediaminetetraacetic acid. All canals were filled with gutta-percha single-cone filling technique and AHPlus® sealer (Dentsply- Maillefer, Baillagues, Switzerland) and access cavity restored with resin composite. Roots were wax coated, placed in an acrylic mold and loaded to compressive strength fracture in a mechanical material testing machine recording the maximum load at fracture and fracture pattern (favorable/restorable or unfavorable/unrestorable). Fracture loads were compared statistically, and data examined with Student t-test with a level of significance set at P ≤ 0.05.Results:No statistically significant difference was registered between the 4% taper of preparation (270.47 ± 90.9 N) and 6% taper of preparation (244.73 ± 120.3 N) regarding the fracture resistance of the endodontically treated premolars tested (P = 0.541), while more favorable restorable fractures were registered in the 4% taper group.Conclusions:Continuous 4% preparation taper did not enhance the fracture resistance of endodontically treated maxillary premolars when compared to a 6% taper root canal preparation. More fractures were registered in the 4% taper group.

Objective: The objective of this ex vivo study was to evaluate canal transportation and centring ability of Reciproc and Reciproc blue systems in curved root canals with or without prior use of PathFile rotary system (PF) using Cone Beam Computed Tomography (CBCT). Methods: One hundred and twenty curved root canals from maxillary and mandibular premolars were selected. Canals were divided randomly into 4 groups (n=30): Reciproc 25 (R25), (PF+R25), Reciproc Blue 25 (RB25), (PF+RB 25). Specimens were scanned before and after root canal preparation. Using CBCT, root canal transportation and centring ability was assessed by measuring the shortest distance from the edge of uninstrumented canal to the periphery of the root (mesial and distal) before and after preparation. Data were analysed using a one-way analysis of variance and Tukey test. The p value was set at 0.05. Results: Less transportation and better centring ability occurred when PF was used before R25 or RB25 (P<0.0001). There was no significant difference between R25 and RB25 groups. Conclusion: Using PF before R25 and RB25 resulted in less root canal transportation and better centring ability. The specific thermo-mechanical treatment of RB25 did not provide better results when compared to R25.

The conservative preparations in AH4 and TF4 did not induce less voids compared with more enlarged tapers (6%) in AH6 and TF4 groups.