Organic Eluates Derived from Intermediate Restorative Dental Materials.

A great number of different types of materials have been used in dentistry as intermediate restoratives. Among them, new resin-based bases have been released in the dental market. The present study focuses on the identification of the organic eluates released from such materials and the study of their surface microstructure in combination with their corresponding elemental composition. For this purpose, the following materials were used:ACTIVA™BioACTIVE-BASE/LINER™, Ketac™Bond Glass Ionomer, SDR™ and Vitrebond™Light Cure Glass Ionomer Liner/Base. Methanolic leachates derived from polymerized materials were analyzed by means of gas chromatography-mass spectrometry (GC-MS). Scanning electron microscopy(SEM) was used for the surface monitoring of suitably prepared specimens. The GC-MS analysis revealed the elution of twenty different substances from the three resin-based materials, while none was eluted from the glass ionomer base. The SEM analysis for Vitrebond™ presented small pits, the one for Ketac™Bond presented elongated cracks, while no voids were present for ACTIVA™BioACTIVE-BASE/LINER™ and SDR™. Moreover, the resin matrix of some dental materials may inhibit elements' accumulation on the surface layers. Particularly, the detected organic eluents may be related to potential toxic effects.

Pit and fissure nanocomposite sealants reinforced with organically modified montmorillonite: A study of their mechanical properties, surface roughness and color stability.

The aim of the present work was to investigate the effect of the different organically modified nanoclays on clinically significant properties of new synthesized dental pit and fissure nanocomposite sealants. Their morphological characteristics were examined by means of X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). A universal testing machine was used to conduct the flexural and compression tests. Surface roughness measurements were taken by using a 3D-optical profilometer. Color changes after aging in black tea were determined by recording UV-visible spectra. XRD plots depicted possible structures governed by intercalated regions along with some "tactoids" nanoparticles. SEM images revealed a better dispersion for the methacrylated clay nanofiller. Flexural modulus and microhardness were found to be higher for sealants reinforced with such polymerizable nanoclays. These specific nanocomposites yielded smoother surfaces, as well as clinically accepted color changes even after 1 week aging in black tea.

Cytotoxicity of a New Calcium Silicate Endodontic Sealer.

INTRODUCTION: Resin sealers with biocompatible and bioactive additives have been used in clinical practice. Recently, a calcium silicate root canal sealer was introduced under the name BioRoot RCS (Septodont, Saint Maur-des-Fossés, France). The aim of this study was to evaluate the effects of BioRoot RCS on cell survival and proliferation of cultured cells in parallel with an epoxy resin sealer with calcium phosphate and calcium oxide and a salicylate resin sealer with mineral trioxide aggregate filler. The tested hypothesis was that BioRoot RCS is significantly less cytotoxic than the other tested sealers. METHODS: The experiments were performed on NIH/3T3 cells (American Type Culture Collection, Manassas, VA) grown as monolayer cultures at 37°C in atmosphere containing 5% CO2 in air and 100% relative humidity. The sealers' extracts (24 hours and 1 week) were applied to cells at 1:1 and 1:2 dilutions. The effect was assessed by a modified sulforhodamine B staining assay in reference to controls after 24 and 72 hours of exposure. All experiments were performed at least twice in 6 replicates. Analysis of variance and post hoc comparison tests were used to evaluate the statistical significance of the results at a level of significance of P = .05. RESULTS: BioRoot RCS was significantly less cytotoxic than the other 2 sealers. MTA-Fillapex (Angelus, Londrina, Brazil) and SimpliSeal (Discuss Dental, LLC, Calver City, CA) exhibited a similar antiproliferative profile with no statistically significant differences in all settings. CONCLUSIONS: BioRoot RCS showed quite a positive biological behavior. Further investigation is needed in order to clarify the mechanism and the components that contribute to the beneficial results observed.