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The aim was to compare the shaping ability of different rotary nickel–titanium instruments in simulated S-shaped canals. One hundred S-shaped canals in resin blocks were prepared to an apical size 25 using F6 SkyTaper (Komet), Silk Files.04, Silk Files.06, Prototypes.04, and Prototypes.06 (all Mani) (20 canals/group). Material removal was measured at 20 measuring points, beginning 1 mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, and instrument failures were also recorded. Statistical analyses were performed using ANOVA, Student–Newman–Keuls and Chi-square test. Pooled data of all measuring points revealed that canals instrumented with Prototypes.04 were significantly better centered than those prepared with all other instruments, while Prototypes.06 and both Silk Files performed significantly better than F6 SkyTaper (p < 0.05). The preparation time differed significantly between all groups and Prototypes.04 allowed the fastest preparation (p < 0.05). There was no statistically significant association between type of instrument and incidence of aberrations (p > 0.05). The cross-sectional design had a marked impact on the shaping ability of the instruments, and less tapered instruments maintained the original canal curvature better than instruments having greater tapers. [ABSTRACT FROM AUTHOR]

Recently, sealers based on calcium silicates were developed as a new class of endodontic sealers. Inspired by the excellent sealing ability and biocompatibility of calcium silicate-based cements, these sealers establish a biological point of view on the obturation of root canals. No longer, the bacteria-tight seal against reinfection of the root canal is the only goal of root canal obturation. Antibacterial properties as well as bioactive inducement of periapical healing and hard tissue formation are added to the portfolio of sealers. Ready-to-use sealers consisting of only one component with a need for external water supply from, e.g., body fluid and two components sealers with internal water supply were introduced to the market. Both of these material types have the same setting reactions in common whereby a hydration reaction of the calcium silicate is followed by a precipitation reaction of calcium phosphate. Though the available sealers are all based on calcium silicates, they consist of different compositions. Due to this aspect, differences in their physical and chemical properties as well as in their in vitro characteristics were described. Studies addressing the clinical impact of calcium silicate-based sealers on outcome are still sparse. The bioactive potential of sealers based on calcium silicates is a consequence of the slight solubility of these materials even after setting, but solubility of the sealer might also compromise the quality of sealing a root canal against regrowth and reinfection. Further clinical investigations are required to evaluate the clinical relevance of the gulf between bioactivity and solubility. [ABSTRACT FROM AUTHOR]

The aim was to compare the canal straightening of M-wire [Reciproc (VDW, Munich, Germany) and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland)] and gold- and blue-wire heat-treated [Reciproc blue (VDW) and WaveOne Gold (Dentsply Maillefer)] instruments in severely curved root canals. A total of 80 root canals in extracted human teeth with angles of curvatures ranging between 25° and 35° and radii ranging between 3.1 and 8.5 mm were divided into four groups (n = 20). Based on radiographs taken prior to instrumentation, the groups were balanced with respect to the angle and the radius of canal curvature (P = 1.0 and P = 1.0, respectively). All canals were prepared to an apical size 25 according to the manufacturers' instructions. Pre- and post-instrumentation radiographs were superimposed and canal straightening was analysed using a computer imaging programme. Preparation time and instrument failure were also recorded. Data were analysed statistically using ANOVA and Student-Newman-Keuls test. During preparation no instrument fractured. All instruments maintained the original canal curvature well with no significant differences between the instruments (P = 0.278). Regarding preparation time, no significant differences between the four instruments were obtained (P > 0.05). Under the conditions of this study, all instruments respected the original canal curvature well. Instruments were safe to use. The use of the gold- and blue-wire heat-treated instruments was not associated with an improved shaping ability. [ABSTRACT FROM AUTHOR]

The aim of this laboratory study was to assess selected physicochemical properties of three root canal sealers. The solubility, setting time and radiopacity of AH Plus, EndoREZ and RealSeal SE were evaluated. The solubility was determined by weight loss of specimens in water over a period of 28 days. Setting time and radiopacity were assessed according to ANSI/ADA and ISO specifications using an aluminum step wedge calibrated in millimeters and the intendention test using a Gilmore needle. Data were analyzed using ANOVA and the Student-Newman-Keuls test for pairwise comparisons. AH Plus was significantly less soluble, showed the significantly highest radiopacity and displayed the significantly longest setting time of all sealers ( P < 0.01). At all exposure times, EndoREZ was significantly more soluble than the other sealers ( P < 0.01) and displayed the significantly lowest values regarding radiopacity ( P < 0.01). Analysis showed that setting time and radiopacity for all sealers met the ANSI/ADA and ISO standards. Solubility of AH Plus and RealSeal confirmed the ANSI/ADA and ISO specification, while EndoREZ clearly exceeded the proposed solubility value. Out of all sealers tested, AH Plus obtained the best values for all properties. [ABSTRACT FROM AUTHOR]