BackgroundPropolis is a unique natural adhesive product collected by honeybees. It contains a diversity of bioactive compounds with reported functional properties such as antioxidants, antibacterial, antifungal, anti-inflammatory, antiviral and anticancer activity. Dental caries is a worldwide problem that caused by microbial growth usually progress from tooth enamel to the underlying pulpal tissues and root canal. This situation could be controlled by a sequence of steps to remove microorganisms and fill root canal with a suitable long-lasting root canal sealer. Unfortunately, leachable and degradation products of the currently used sealers compromised their antimicrobial activity by inflammatory modulation associated with irritation and toxicity of periapical tissues.Materials and methodsHence, propolis was selected to be designed as a natural root canal sealer due to its amazing functional properties. Moreover, its handling properties were enhanced and potentiated by its incorporation in polymeric nanoparticles (NPs). Frist, propolis was collected, extracted and analyzed for its bioactive compounds. After that, propolis-loaded NPs of PLGA (ProE-loaded NPs) were developed and fully characterized regarding physicochemical properties, in vitro release and in vitro cytotoxicity. Then, root canal sealers were fabricated and assayed for their antimicrobial activity. Both cytotoxicity and antimicrobial activity were compared to those of a model sealer; AH Plus®.ResultsThe results revealed that spherical nanoscopic NPs with narrow size distribution were obtained. ProE-loaded NPs exhibited accepted entrapment efficiency (>80) and prolonged release. In vitro cytotoxicity study confirmed the safety of ProE-loaded NPs. Also, the developed sealers showed antimicrobial activity versus bacterial strains of Enterococcus faecalis and Streptococcus mutans and antifungal activity against Candida albicans.ConclusionProE-loaded NPs could be incorporated in and represented as a root canal sealer with prolonged release and enhanced cytocompatibility as well as antimicrobial activities.

Background: Successful endodontic therapy is mainly governed by the satisfactory sealing ability of the applied root canal sealer. Also, tolerability of root canal structure to accommodate the presence of a sealer participates in the efficiency of the treatment. Hence, this study was aimed to extrapolate our previous one that was concerned with the preparation and evaluation of novel nature-based root canal sealers. Our current work is focused on the evaluation of sealing ability and in vivo biocompatibility. Materials and Methods: Egyptian propolis was extracted (ProE) and encapsulated in polymeric nanoparticles (ProE-loaded NPs). Two root sealers, PE sealer and PE nanosealer, were fabricated by incorporating ProE and ProE-loaded NPs, respectively. The sealing ability of the developed sealers was tested by a dye extraction method. An in vivo biocompatibility study was conducted using a subcutaneous implantation method for two and four weeks. At the same time, a model sealer (AH Plus®) was subjected to the same procedures to enable accurate and equitable results. Results: The teeth treated with PE sealer exhibited weak sealing ability which did not differ from that of unfilled teeth. PE nanosealer enhanced the sealing ability similarly to the model sealer with minimal apical microleakage. Studying in vivo biocompatibility indicated the capability of the three tested sealers to induce cell proliferation and tissue healing. However, PE nanosealer had superior biocompatibility, with higher potential for cell regeneration and tissue proliferation. Conclusion: PE nanosealer can be presented as an innovative root canal sealer, with enhanced sealing ability as well as in vivo biocompatibility. It can be applied as a substitute for the currently available sealers that demonstrate hazardous effects.