Evaluation of dental pulp stem cells response to flowable nano-hybrid dental composites: A comparative analysis.

BACKGROUND: Flowable resin composites (FRC) are tooth-colored restorative materials that contain a lower filler particle content, and lower viscosity than their bulk counterparts, making them useful for specific clinical applications. Yet, their chemical makeup may impact the cellular population of the tooth pulp. This in-vitro study assessed the cytocompatibility and odontogenic differentiation capacity of dental pulp stem cells (DPSCs) in response to two recent FRC material extracts. METHODS: Extracts of the FRC Aura easyflow (AEF) and Polofil NHT Flow (PNF) were applied to DPSCs isolated from extracted human teeth. Cell viability of DPSCs was assessed using MTT assay on days 1, 3 and 7. Cell migration was assessed using the wound healing assay. DPSCs' capacity for osteo/odontogenic differentiation was assessed by measuring the degree of mineralization by Alizarin Red S staining, alkaline phosphatase enzyme (ALP) activity, and monitoring the expression of osteoprotegerin (OPG), RUNX Family Transcription Factor 2 (RUNX2), and the odontogenic marker dentin sialophosphoprotein (DSPP) by RT-PCR. Monomer release from the FRC was also assessed by High-performance liquid chromatography analysis (HPLC). RESULTS: DPSCs exposed to PNF extracts showed significantly higher cell viability, faster wound closure, and superior odontogenic differentiation. This was apparent through Alizarin Red staining of calcified nodules, elevated alkaline phosphatase activity, and increased expression of osteo/odontogenic markers. Moreover, HPLC analysis revealed a higher release of TEDGMA, UDMA, and BISGMA from AEF. CONCLUSIONS: PNF showed better cytocompatibility and enhancement of odontogenic differentiation than AEF.

Biocompatibility assessment of different root-end filling materials implanted subcutaneously in rats: An in vivo study.

BACKGROUND: Root-end filling materials are used in surgical endodontic treatment to seal the teeth periapically. Ideally, these materials should prevent bacterial leakage by tightly sealing the canal, be biocompatible with the periapical tissues, and preferably stimulate the regeneration of dentin, contributing to the success of treatment. OBJECTIVES: The purpose of this study was to evaluate and compare the biocompatibility of the GuttaFlow® Bioseal cement in relation to MTA Angelus® and Zical® after implantation into the subcutaneous tissue of rats. MATERIAL AND METHODS: Eighteen male albino rats were used in the study. Four polyethylene tubes were implanted in the backs of the rats (3 tubes containing the test materials and 1 empty tube as a control). Nine animals were sacrificed at each interval of 7 and 30 days, and the implants were removed with the surrounding tissue. The samples were evaluated for stromal inflammatory response, fibrous tissue formation, vascular reactivity, and the presence of multinucleated giant cells (MNGCs). RESULTS: On day 7, the capsules in all subgroups revealed moderate to severe inflammatory reactions with the presence of inflammatory cells, multiple irregular collagen fibers, dilated blood vessels, and MNGCs. However, on day 30, tissue organization was more evident with a reduction in the inflammatory response. In this time interval, the tissue in contact with GuttaFlow Bioseal showed progressive healing with a wellformed fibrous capsule. Conversely, the tissue close to MTA Angelus revealed a fibrous capsule of limited organization with mild pericapsular fibrosis and vascular congestion. Zical showed a mild to moderate persistent inflammatory reaction and vascular reactivity. CONCLUSIONS: The 3 cements demonstrated more severe irritation at the beginning that became milder with time. GuttaFlow Bioseal yielded better tissue organization than MTA Angelus and Zical. Thus, these findings strongly suggest that GuttaFlow Bioseal is a promising material for root-end filling.

Bond strength and solubility of a novel polydimethylsiloxane-gutta-percha calcium silicate-containing root canal sealer.

BACKGROUND: Endodontic sealers are essential for sealing gutta-percha to the dentin walls. They help to ensure that the canal remains free of microorganisms which might lead to infection. In order to perform their intended function, the sealers should properly adhere to the dentin walls and remain insoluble when set in the canal. OBJECTIVES: The purpose of this study was to evaluate the bond strength and solubility of a novel polydimethylsiloxane-gutta-percha calcium silicate-containing root canal sealer (GuttaFlow® bioseal) and compare it with the zinc oxide and eugenol sealer (Zical®). MATERIAL AND METHODS: The endodontic sealers used in this study were GuttaFlow bioseal and Zical. The bond strength was assessed using push-out bond strength test in 3 root segments: coronal, middle and apical. The solubility was tested according to the American National Standards Institute / American Dental Association (ANSI/ADA) specification No. 57 at 3 different time intervals: 1, 7 and 14 days. RESULTS: The push-out bond strength in all root segments was significantly higher in Zical compared to GuttaFlow bioseal. The solubility was significantly higher on day 1 and 7 in Zical compared to GuttaFlow bioseal, and on day 14, the difference between them was not significant. CONCLUSIONS: Within the limitations of this study, the endodontic sealer GuttaFlow bioseal showed low bond strength values compared to Zical. The solubility of the set GuttaFlow bioseal and Zical were both within the recommended ANSI/ADA levels.