Effect of a hyperbaric environment (diving conditions) on adhesive restorations: an in vitro study

International audienceObjectives No recent study has addressed the effect of diving conditions (pressure increase) on adhesive restorations. We evaluated the impact of a simulated hyperbaric environment on microleakage of the dentine-composite resin interface. The ultimate aim was to propose recommendations for restorative dentistry for patients who are divers to limit barodontalgia (dental pain caused by pressure variations of the environment) and may lead to dangerous sequelae.Methods We bonded 20 dentine disks by using an adhesive system (Scothbond Universal) to ten intact composite cylinders and ten composite cylinders with porosity (Ceram X mono). For each group, the samples were divided into two subgroups, one submitted to a simulated hyperbaric environment and the other to an ambient environment. All samples were immersed in a silver nitrate solution to evaluate microleakage at the interface after analysis with a camera.Results Dye percolation for groups in the hyperbaric environment was greater than groups in ambient environment. For each subgroup, dye percolation was greater for samples with than without porosity.Conclusions High percolation percentages demonstrate that our simulated hyperbaric condition led to loss of sealing at the dentine-composite resin interface, especially with porous composites.Clinical significance Respect of the protocol and the quality of condensation for adhesive restorations are important in all clinical situations, especially for patients who are divers. A more interventionist approach must be adopted with these patients

In vitro biocompatibility of a dentine substitute cement on human MG63 osteoblasts cells: Biodentine™ versus MTA ®

The authors also wish to express their appreciation to Beatrice Burdin, PhD, at the Microstructures Technology Center of University Claude Bernard Lyon1 for assistance with the SEM study. The AFM study was supported by the Characterization of Interactions Platform of the Nanobio Program, Grenoble University. We gratefully acknowledge the assistance on the English checking from Dr Huw Jones BSc PhD MRSC, Senior Lecturer in Chemistry for Environmental Science and Public Health, Middlesex University (UK).International audienceAimTo compare the in vitro biocompatibility of Biodentine and White ProRoot((R)) mineral trioxide aggregate (MTA((R))) with MG63 osteoblast-like cells and to characterize the cement surface. MethodologyA direct contact model for MG63 osteoblast-like cells with cements was used for 1, 3 and 5days. Four end-points were investigated: (i) cement surface characterization by atomic force microscopy (AFM), (ii) cell viability by MTT assay, (iii) protein amount quantification by Bradford assay and (iv) cell morphology by SEM. Statistical analyses were performed by analysis of variance (anova) with a repetition test method. ResultsThe roughness of the cements was comparable as revealed by AFM analysis. The MTT test for Biodentine was similar to that of MTA((R)). Biodentine and MTA((R)) induced a similar but slight decrease in metabolic activity. The amount of total protein was significantly enhanced at day three (P<0.05) but slightly decreased at day five for both tested samples. Biodentine was tolerated as well as MTA((R)) in all cytotoxicity assays. SEM observations showed improvement of cell attachment and proliferation on both material surfaces following the three incubation periods. ConclusionThe biocompatibility of Biodentine to bone cells was comparable to MTA((R))

Nanocomposites from mesoporous silica and dimethacrylic resin

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