Search results for "Minerali"

Epidemiologic study of molar-incisor hypomineralization in 8-year-old Spanish children

2013

Aim To find the prevalence of molar-incisor hypomineralization (MIH) in a random sample of Spanish children, and to investigate the gender influence, distribution of defects, the treatment need associated and the relation between this disorder and dental caries. Design A cross-sectional study was carried out to determine MIH and caries prevalence in a randomly selected sample of 840 children from the 8-year-old population of the Valencia region of Spain. The examinations were carried out in the children's schools by one examiner who had previously been calibrated with the MIH diagnostic criteria of the European Academy of Paediatric Dentistry (EAPD). Results The percentage of children with …

Blueberry Muffin Baby Associated with Bone Demineralization Due to Congenital Transient Neonatal Hyperparathyroidism

2014

Enzyme-based biosilica and biocalcite: biomaterials for the future in regenerative medicine

2013

The oldest animals on Earth, sponges, form both the calcareous and the siliceous matrices of their spicules enzymatically. Until recently, it has been neglected that enzymes play crucial roles during formation of these biominerals. This paradigm shift occurred after the discovery that the enzyme silicatein, which catalyzes the polycondensation of silica, and the enzyme carbonic anhydrase (CA), which catalyzes the formation of bicarbonate (HCO3(-)/CaCO3), produce solid amorphous bioglass or biocalcite. This suggests that in mammals, biosilica and biocalcite can act anabolically during hydroxyapatite (HA) synthesis and bone formation. Biosilica and biocalcite are thus promising candidates for…

Bioinspired synthesis of multifunctional inorganic and bio-organic hybrid materials

2012

Owing to their physical and chemical properties, inorganic functional materials have tremendous impacts on key technologies such as energy generation and storage, information, medicine, and automotive engineering. Nature, on the other hand, provides evolution-optimized processes, which lead to multifunctional inorganic–bio-organic materials with complex structures. Their formation occurs under physiological conditions, and is goverened by a combination of highly regulated biological processes and intrinsic chemical properties. Nevertheless, insights into the molecular mechanisms of biomineralization open up promising perspectives for bioinspired and biomimetic design and the development of …

The formation of silica high temperature polymorphs from quartz: Influence of grain size and mineralising agents

2015

Abstract The formation of high-temperature silica polymorphs in presence of Na and K has been studied at various temperatures and soaking times, starting from quartzes of different grain size, ex situ as well as in situ. The results show that cristobalite and tridymite formation is strongly influenced by the nature and the amount of mineraliser added. In particular, K seems to discriminate more between the two structures, as it produces the largest observed amount of cristobalite. The disappearance of quartz can be controlled by the proper combination of mineraliser/temperature/time, which in turn control the amount and the type of polymorph formed, together with the amount of amorphous mat…

Osteogenic potential of a biosilica-coated P(UDMA-co-MPS) copolymer

2020

A P(UDMA-co-MPS) copolymer was surface-functionalized through the polycondensation activity of the enzyme silicatein. The resulting biosilica coating significantly enhanced mineralization of osteoblastic cells, thereby revealing its osteogenic potential. Consequently, the functionalized copolymer may be explored as an alternative to conventionally used acrylics in applications where stable bone-material interfaces are required.

Strukturelle Veränderungen in säuregeätztem Schmelz im konfokalen Laser-Scanning-Mikroskop

1996

The aim of the present investigation was to elucidate structural alternations in enamel subjected to acid etch technique and treatment under remineralizing conditions by means of a new microscopy technique known as confocal laser scanning microscopy (CLSM). Blocks of enamel were treated with 37% phosphoric acid and exposed for 3 weeks to an oral environment. Tomographic CLSM images were subsequently obtained and compared with controls. CLSM proved to be a reliable, highly reproducible and simple method of qualitative assessment of structural changes occurring on the surface of enamel and in areas below the surface as deep as 100 microns or more. Structural alterations associated with acid a…

Nanoscale assembly processes revealed in the nacroprismatic transition zone of Pinna nobilis mollusc shells

2015

Intricate biomineralization processes in molluscs engineer hierarchical structures with meso-, nano-, and atomic architectures that give the final composite material exceptional mechanical strength and optical iridescence on the macroscale. This multiscale biological assembly inspires new synthetic routes to complex materials. Our investigation of the prism-nacre interface reveals nanoscale details governing the onset of nacre formation using high-resolution scanning transmission electron microscopy. A wedge polishing technique provides unprecedented, large-area specimens required to span the entire interface. Within this region, we find a transition from nanofibrillar aggregation to irregu…

Influence of saline and pH on collagen type I fibrillogenesis in vitro: Fibril polymorphism and colloidal gold labelling

2007

We have produced different collagen type I fibrils by in vitro fibrillogenesis of acetic acid-soluble collagen within the pH range 2.5-9.0, in the presence and absence of 150 mM NaCl. The varying relatively stable molecular assemblies and polymorphic fibrillar end-products produced after 24 h incubation have been assessed and compared by the TEM study of specimens negatively stained with uranyl acetate. In the presence of 150 mM NaCl, the assembly of collagen at low pH (2.5) leads to the formation of initial molecular aggregates that progressively link together at slightly higher pH (5.0) to form sub-fibrils and spindle-shaped D-banded bundles of sub-fibrils. At pH 6.0 these D-banded bundle…

The effect of combining laser and nanohydroxy-apatite on the surface properties of enamel with initial defects

2017

Background The aim of this study was to evaluate the effect of combining fractional CO2 LASER and nanohydroxy apatite on surface microhardness and color of enamel with initial defects. Material and Methods Two types of nano hydroxylapatite (nHAP) was prepared; Pure hydroxyapatite (nHA) and Fluoro hydroxyapatite (nFHA), Sixty extracted premolar teeth without visible caries or structural defects on enamel surface were used, immersed in 10 ml of a demineralizing solution for 2 weeks to create artificial white spot lesions, they were randomly allocated into two groups; Group 1: nHA, Group 2: nFHA, each group is then subdivided into 2 subgroups (A and B) where two different in vitroremineralizat…