Acids with an equivalent taste lead to different erosion of human dental enamel.

Objectives: The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste.

Methods: Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste.

Pectin, alginate and gum arabic polymers reduce citric acid erosion effects on human enamel.

Objectives: Consumption of acidic soft drinks may lead to the dissolution and softening of human enamel, known as erosion. The first aim of this in vitro study was to test the hypothesis that food-approved polymers added to citric acid solutions (CAS) decrease the erosion of human dental enamel compared to citric acid solutions without these polymers. The second aim was to test the hypothesis that these polymers added to CAS form a polymer layer directly on the eroded enamel surface.

Quantification of dental erosion--a comparison of stylus profilometry and confocal laser scanning microscopy (CLSM).

Objectives: Since stylus profilometry applies a force on the sample surface, it is logical to hypothesize that the profilometer penetrates the surface of the enamel softened by acid solutions. The aims of the present study were, therefore, to test the hypothesis that surface profilometry measurements of eroded enamel alter the surface of the enamel, to quantify the potential effect of the surface alteration (scratches) on the measured values of enamel erosion by atomic force microscopy and to compare the values of enamel loss caused by erosion as measured by profilometry and non-contact confocal laser scanning microscopy (CLSM).

Methods: Enamel samples, cut from unerupted human third molars were treated with Volvic Mineral Water and citric acid solutions of different pH values.

Micro-structured smart hydrogels with enhanced protein loading and release efficiency.

A series of temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels with highly porous microstructures were successfully prepared by using hydrophobic polydimethylsiloxane (PDMS) and sodium dodecyl sulfate as liquid template and stabilizer, respectively. These newly prepared hydrogels possess highly porous structures. In contrast to the conventional PNIPAAm hydrogel, the swelling ratios of the porous gels at room temperature were higher, and their response rates were significantly faster as the temperature was raised above the lower critical solution temperature.

Future perspectives of resin-based dental materials.

Objective: This concise review and outlook paper gives a view of selected potential future developments in the area of resin-based biomaterials with an emphasis on dental composites.

Methods: A selection of key publications (1 book, 35 scientific original publications and 1 website source) covering the areas nanotechnology, antimicrobial materials, stimuli responsive materials, self-repairing materials and materials for tissue engineering with direct or indirect relations and/or implications to resin-based dental materials is critically reviewed and discussed. Connections between these fields and their potential for resin-based dental materials are highlighted and put in perspective.

Temperature-sensitive PVA/PNIPAAm semi-IPN hydrogels with enhanced responsive properties.

A series of temperature-sensitive hydrogels of semi-interpenetrating polymeric networks (semi-IPN) composed of poly(N-isopropylacrylamide) (PNIPAAm) and poly(vinyl alcohol) (PVA) were prepared by radical polymerization. The PNIPAAm networks were cross-linked by N,N'-methylenebisacrylamide in the presence of linear PVA. The reaction processes were investigated by rheometry using oscillatory deformation tests.

Surface functionalized titanium thin films: zeta-potential, protein adsorption and cell proliferation.

The relationship between electric charge at a material surface and protein adsorption is essential to understand the mechanism of biological integration of materials with tissues. This study investigated the influence of titanium thin films' surface chemistry and surface electric charge (zeta-potential) properties on protein adsorption and cell proliferation. Titanium thin films were surface functionalized with different functional end groups, such as -CH=CH2, -NH2 and -COOH groups in order to produce surfaces with a variety of electric charge properties.

Does the nanometre scale topography of titanium influence protein adsorption and cell proliferation?

To investigate the influence of titanium films with nanometre scale topography on protein adsorption and cell growth, three different model titanium films were utilized in the present study. The chemical compositions, surface topographies and wettability were investigated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurement, respectively. The films share the same surface chemistry but exhibit different topographies on a nanometre scale.

Time dependence of composite shrinkage using halogen and LED light curing.

Objectives: The polymerization shrinkage of light cured dental composites presents the major drawback for these aesthetically adaptable restorative materials. LED based light curing technology has recently become commercially available. Therefore, the aim of the present study was to investigate if there was a statistically significant difference in linear and volumetric composite shrinkage strain if a LED LCU is used for the light curing process rather than a conventional halogen LCU.

Second generation LEDs for the polymerization of oral biomaterials.

Objectives: New blue, so called second generation light emitting diodes (LEDs) are now available with a high optical power output. These LEDs will potentially find widespread application in commercially available light curing units (LCUs). This study, therefore, investigated the curing performance of a prototype LCU containing one high power LED and a conventional halogen LCU (Polofil).

The influence of storage and indenter load on the Knoop hardness of dental composites polymerized with LED and halogen technologies.

Objectives: The mechanical properties of light cured dental composites are greatly influenced by the light curing unit (LCU) used for the polymerization. Previous studies have shown that for some composites lower mechanical properties were obtained if light emitting diode (LED) LCUs were used for the polymerization instead of halogen LCUs. Previous studies have also shown that light cured composites improve their mechanical properties through a post-curing process after the initial illumination with the LCUs.