Many types of endodontic root canal sealers have been employed for the purpose of filling voids and irregularities in root canals, as well as reducing/removing bacterial remnants/remains. Sealers are available in various formulations, and research work to find the most appropriate ones is still ongoing. Recently, many kinds of novel root canal sealers have been introduced under various commercial names. However, most sealers are known to exhibit different levels of cytotoxicity on tissues which would result in prolonged wound healing, inflammation, and bone resorption. Preferably, sealers need to have tolerable biological and physico-chemical properties along with biocompatibility. Additives promoting the biocompatibility and bioactivity of sealers are of major concern in clinical applications. The aim of this review was to compare, evaluate, and analyze comparatively the cytotoxic effects, biocompatibility, and antimicrobial properties of recently used root canal sealers. A comprehensive literature search was made to identify their properties involving biocompatibility and cytotoxicity. In general, the sealers reported in recent literature exhibited favorable biological features in comparison to conventional ones. They promoted better cell viability and biocompatibility. The incorporation of additives influences favorably the potential negative effects. However, it has been highlighted that there is a lack of well-designed long-term clinical applications, and more in vitro and in vivo research work would be helpful to confirm the sustainability of the sealers for further clinical practice.

The impact of nano-based technologies in endodontics for the identification and treatment of various dental infections is showing fast progress. Studies show that nanoparticles could serve as useful agents with many beneficial results and continue to be promising in the field of endodontics. To ensure progress and improvements on novel nanomaterials in relation to their physicochemical and biological properties, nano-identification methods for the detection and evaluation of diseases need to be further highlighted. This study aims to review the current technological progress and recent research outcomes as well as possible prospective applications of nano-based technologies in endodontics. A comprehensive literature survey has been carried out on the utilizations of nanomaterials and nano-characterization techniques in endodontics. The current status and recent applications in endodontics are discussed with illustrative examples. The results have shown that the progress and improved accuracy of nano-identification techniques enabled a better characterization, evaluation and selection of appropriate treatment plans for endodontics-related diseases. The results have been inspiring for further clinical investigations. Nano-endodontics is still a developing field with a strong potential for revolutions of novel materials and techniques in the diagnosis and treatment of dental diseases. Further improvements in nanoparticles properties will pave the way for the development of many beneficial endodontic therapeutic agents. The future looks encouraging for sustainable products and testing methods for clinical endodontic applications.

Background. This study aimed to compare the cyclic fatigue resistance of ProTaper Next, Hyflex CM, 2Shape, and TF-Adaptive nickel-titanium endodontic file systems with various alloy properties and production methods and investigate the fractured cross-sectional surface of files due to cyclic fatigue by scanning electron microscopy (SEM). Methods. A total of 120 instruments were used (n=30). For standardization, #25/.06 apical diameter and taper angle were selected for each file system. The experiment of files was subjected to a static cyclic fatigue model. The time for files’ failure was recorded with a digital chronometer and multiplied by the rotation speed to calculate the number of cycles. Kolmogorov-Smirnov, one-way ANOVA, and post hoc Bonferroni analysis were used for statistical analysis. Statistical significance was set at P<0.05. Results. The number of cycles for the failure of files was compared between the groups, and significant differences were found (P<0.05). The number of cycles for instrument failure was recorded from the highest to the lowest as follows: Hyflex CM, TF-Adaptive, ProTaper Next, and 2Shape. Conclusion. The files were fractured at different average numbers of cycles in an artificial canal in all the groups. The Hyflex CM demonstrated better cyclic fatigue resistance than TF Adaptive, ProTaper Next, and 2Shape file systems. Factors such as production patterns, alloy properties, and the phase in which the files were produced might affect the lifespan of file systems.