2010

This article compares most of the three-dimensional (3D) morphometric methods currently proposed by the technical literature to evaluate their morphological informative value, while applying them to a case study of five patients affected by the malocclusion pathology. The compared methods are: conventional cephalometric analysis (CCA), generalised Procrustes superimposition (GPS) with principal-components analysis (PCA), thin-plate spline analysis (TPS), multisectional spline (MS) and clearance vector mapping (CVM).

To obtain the best surgical results in orthognathic surgery, treatment planning and evaluation of results should be performed. In these operations it is necessary to provide the physician with powerful tools that can underline the behavior of soft tissue. For this reason, considering the improvements provided by the use of 3D scanners in medical diagnosis, we propose a methodology for analyzing facial morphology working with geometrical features. The methodology has been tested on patients with malocclusion in order to analyze the reliability and efficiency of the provided diagnostic results.

An innovative gel-casting process was developed in order to obtain macro porous ceramics scaffolds of hydroxyapatite to be used in regenerative medicine for bone tissue reconstruction. Mechanical investigation was carried out on different formulations of dense hydroxyapatite samples in order to evaluate the effect of the gel casting process parameters on the density, the elastic modulus, the tensile and the compressive strength. The fracture critical stress intensity factor (KIC) was also evaluated by means of microhardness measurements.

Two different alumina powders were dispersed in low-density polyethylene (LDPE) to evaluate if any role can be ascribed to the crystalline phase, size and morphology of the alumina filler. In particular a submicrometric α-alumina and a nanocrystalline transition (γ/δ) alumina were added to the polymer at 5 wt% concentration, using a Brabender mixing unit. Both the neat inorganic fillers showed a good dispersibility in the polyolefin. The thermal and mechanical properties of the composites obtained were evaluated.

Biocompatible and biodegradable scaffolds can provide a convenient support for stem cell differentiation leading to tissue formation. Porous hydroxyapatite (HAp) scaffolds are clinically used for applications such as spinal fusions, bone tumors, fractures, and in the replacement of failed or loose joint prostheses. The incorporation of small amounts of silicon within hydroxyapatite lattice significantly improves HAp solubility and rate of bone apposition, as well as the proliferation of human osteoblasts in vitro.

This article reports the study of a transition nanometric alumina both as such and after prolonged magnetic stirring in bi-distilled water. Stirring was effective in inducing a significant reduction of starting particles agglomeration and modification of the surface properties of the material. The formation of an Al(OH)3 (gibbsite) phase after magnetic stirring in water was detected by means of XRD on powdered samples. Correspondingly, Infra Red spectrum of magnetically stirred alumina outgassed at 150 °C showed a band at ca.

Here we report how thermal treatments of a surface modified α-alumina powder on which a zirconium oxide precursor was grafted can be tailored so as to obtain an alumina-zirconia composite powder with well-controlled phase distribution and size.

Fluorine-substituted hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted hydroxyapatite (F-HAp, Ca10(PO4)6OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry.

The laser surface remelting (LSR) process was successfully applied to restore localized corrosion resistance in sensitized stainless steel and also as a useful method to improve passivity of some martensitic stainless steels. The LSR process can be successfully applied to repair cracks and defects at the surface of highly thermo-mechanically loaded parts of stainless steel. The purpose of presented study was to evaluate the microstructure and properties of laser remelted surface of stainless steels. The wrought austenitic stainless steel and sintered in vacuum 316L type were studied.