A new method for altered enamel surface remineralization has been proposed . To this aim carbonate‐hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical‐physical properties have been used. The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate‐hydroxyapatite consists in a deposition of a new apatitic mineral into the eroded enamel surface scratches. A new biomimetic mineral coating, which progressively fills and shadows surface scratches, covers and safeguards the enamel structure by contrasting the acid and bacteria attacks.

Maxillofacial, orthopedic, oral, and plastic surgery require materials for tissue augmentation, guided regeneration, and tissue engineering approaches. In this study, the aim was to develop and characterize a new extrudable hydrogel, based on agarose gel (AG; 1.5% wt) and to evaluate the local effects after subcutaneous implantation in comparison with collagen and hyaluronic acid. AG chemical–physical properties were ascertained through Fourier transform infrared (FT-IR) spectroscopy and rheological analysis. In vivo subcutaneous implants were performed, and histological and histomorphometric evaluations were done at 1, 4, 12, and 16 weeks. FT-IR confirmed that spectroscopic properties were the same for the baseline agarose and rheological characterization established that AG is a weak hydrogel. Subcutaneous AG implants induced new vessels and fibrous tissue formation rich in neutrophils; the capsule thickness around AG increased until the 12th week but remained thinner than those around hyaluronic acid and collagen. At 16 weeks, the thickness of the capsule significantly decreased around all materials. This study confirmed that 1.5% wt AG possesses some of the most important features of the ideal biocompatible material: safety, effectiveness, costless, and easily obtained with specific chemical and geometrical characters; the AG can represent a finely controllable and biodegradable polymeric system for cells and drug delivery applications.

This study widens the role of biomimetic hydroxyapatite (HA) nanocrystals as bone substitutes and describes how they can be used as bone-specific drug delivery devices for in situ treatment of bone tumors upon local implantation. The adsorption and release kinetics of bis-{ethylenediamineplatinum(II)}-2-amino-1-hydroxyethane-1,1-diyl-bisphosphonate and bis-{ethylenediamineplatinum(II)}medronate on two kinds of HA nanocrystals having different morphologies, crystallinity degrees and surface areas have been investigated. The different chemical structures of the two Pt complexes appreciably affect not only the affinity towards the two kinds of HA, but also their release. The Pt complex loading is slightly greater for the HA characterized by lower crystallinity and higher surface area, with respect to the more crystalline one. The cytotoxicity of Pt complexes released from the HA were tested against human cervix carcinoma cells and, interestingly, were found to be more cytotoxic than the unmodified complexes. The released Pt species are therefore the active dichloridoethylenediamineplatinum(II) or related solvato species formed by Pt-bisphosphonate bond breaking.