A critical review of dental biomaterials with an emphasis on biocompatibility.

This paper presents the major achievements in the field of biomaterials in restorative dentistry and tissue regeneration reported over the past 3 years. The review aims to summarize the knowledge on important biomaterials and the emerging modification strategies to improve their biointegration, biological activity, mechanical properties, and resistance to the harsh oral environment. We also discuss the main opportunities and challenges associated with the use of biomaterials in dentistry.Much contemporary research focuses on the interactions between biomaterials and the surrounding tissues in the oral environment regarding adhesion, associated stresses and strains, and the durability of dental restoration materials. Dental biomaterials should support cell adhesion and activity, leading to dental tissue regeneration, and are also expected to effectively prevent bacterial infections and inhibit material corrosion in saliva. The degradation, dissolution or corrosion of restorative materials due to exposure to body fluids can alter the structure and mechanical properties of the material, causing various adverse effects.Another aspect addressed in recent literature is the improvement of the mechanical properties and esthetics of restorative materials. The surfaces of biomaterials are usually modified with polymers or nanomaterials to reduce friction while maintaining biocompatibility.Although all modern biomaterials are promising, there is an urgent need for more in vivo and clinical studies to investigate their biological advantages and disadvantages in detail. The computational techniques used to assess the properties of modern dental materials, particularly the mechanical ones, could assist in the development of the materials. Such an approach can help bring new biomaterials to the market by reducing complicated, tedious and expensive experimentation.

Nanofiltration, bipolar electrodialysis and reactive extraction hybrid system for separation of fumaric acid from fermentation broth.

A novel approach based on a hybrid system allowing nanofiltration, bipolar electrodialysis and reactive extraction, was proposed to remove fumaric acid from fermentation broth left after bioconversion of glycerol. The fumaric salts can be concentrated in the nanofiltration process to a high yield (80-95% depending on pressure), fumaric acid can be selectively separated from other fermentation components, as well as sodium fumarate can be conversed into the acid form in bipolar electrodialysis process (stack consists of bipolar and anion-exchange membranes). Reactive extraction with quaternary ammonium chloride (Aliquat 336) or alkylphosphine oxides (Cyanex 923) solutions (yield between 60% and 98%) was applied as the final step for fumaric acid recovery from aqueous streams after the membrane techniques. The hybrid system permitting nanofiltration, bipolar electrodialysis and reactive extraction was found effective for recovery of fumaric acid from the fermentation broth.