891 research outputs found
Biomechanically Active Hybrid nano composite for early osteointegration implants
No full textA biomimetic approach has been applied to design and realize new odontostomatological Titanium (Ti) implants using a multifunctional bioactive ceramopolymeric hybrid material. The proposed biomimetic/biomechanical approach consists in combining mechanical and physical characterization of the hybrid nanocomposite to biosolid mechanics Finite Element Analysis of the new design implants. Hybrid ceramopolymeric nanocomposites based on Hydroxyl-Ethyl-Methacrylate polymer (pHEMA) filled with nanosilica particles are presented as biomimetic-scaffolding materials. Cytotoxicity and Osteoblast cells adhesion tests have shown good material biocompatibility and osteoconductivity [1]. Dynamic Mechanical Analysis (DMA) confirmed the hybrid mechanical behaviour of these nanocomposites. Moreover, this class of material swells in presence of aqueous physiological solution according to limiting Case II sorption mode turning from glassy and rigid to soft and rubbery while presenting a mechanical behaviour, at 5 to 10 % nanosilica volume loadings, that is comparable with that of bone (when glassy) and to that of the cartilage and Ligaments (when rubbery). Materials swelling behaviour and mechanical characterizations are presented. Design criteria and FEM simulation are discussed. The use of mechanically compatible hybrid hydrogels as scaffolding materials are expected to increase prosthesis adaptation mechanisms introducing active interfaces that improve implant biomimetics while reproducing cartilage and ligaments biomechanical functions.
[1] C Schiraldi, A D'Agostino, A Oliva, ... R Aversa, M De Rosa, Biomaterials, 25 (17), 3645-3653 (2004).
[2] R Aversa, D Apicella, L Perillo, R Sorrentino, F Zarone, M Ferrari, A Apicella, Dental Materials, 25(5), 678-690 (2009).
[3] D Apicella, R Aversa, F Ferro, D Ianniello, A Apicella, J. of Biomedical Material Research: Part B, Applied Biomaterials, vol-93(1), 150-163 (2010)
Un riparo nella valle dei templi di Agrigento
No full textIl volume è l’esito di alcune riflessioni dei professori titolari delle cattedre dei corsi di Laboratorio di composizione architettonica e urbana, prof. R. Capozzi, prof.ssa P. Scala, prof.ssa V. Pezza, Prof. G. Szaniszlò, e delle relative esperienze didattiche svolte nei corsi di laboratorio al primo anno del CdL ARC5UE, a.a. 2020/2021, presso il Dip. di Architettura dell’Università degli studi di Napoli Federico II; ed infine restituisce le lectiones di docenti esterni al DiARC invitati al ciclo di seminari svolto a corsi congiunti.
Il volume si suddivide in tre parti: Parte I - Il progetto didattico tra teoria e laboratori, Parte II - Le esperienze di laboratorio, Parte III - Architettura, città e archeologia.
A curare il volume sono stati l’arch. Francesca Spacagna, referente del corso 1 A; l’arch. phd candidate Maria Fierro, referente del corso 1 B; l’arch. Davide Apicella, referente del corso 1 C; l’arch. Pasquale Abbagnale, referente del corso 1 D
Hybrid Ceramo-Polymeric Scaffolds with Biomimetic Characteristics
No full textThe research develops and tests new hybrid biomimetic materials that work as mechanically stimulating "scaffolds" to promote early regeneration in implanted bone healing phases. A biomimetic nanostructured osteoconductive material coated apparatus is presented. Bioinspired approaches to materials and templated growth of hybrid networks using self-assembled hybrid organic-inorganic interfaces is finalized to extend the use of hybrids in the medical field. Combined in vivo, in vitro and computeraided simulations have been carried out. A new experimental methodology for the identification of design criteria for new innovative prosthetic implant systems is presented. The new implant design minimizes the invasiveness of treatments while improving implant functional integration [1]. A new bioactive ceramo-polymeric hybrid material was used to modify odontostomatological Titanium implants in order to promote early fixation, biomechanical stimulation for improved scaffold mineralization and ossification. It is a hybrid ceramo-polymeric nanocomposites based on Hydroxyl-Ethyl- Methacrylate polymer (pHEMA) filled with nanosilica particles that have shown biomimetic characteristics [2,3]. This material swells in presence of aqueous physiological solution leading to the achievement of two biomechanical functions: prosthesis early fixation after and bone growth stimulation. Such multidisciplinary approach explores novel ideas in modelling, design and fabrication of new nanostructured biomaterials with enhanced functionality and improved interaction with OB cells.
[1] R Aversa, D Apicella, L Perillo, R Sorrentino, F Zarone, M Ferrari, A Apicella, Dental Materials, 25(5), 678-690 (2009).
[2] C Schiraldi, A D'Agostino, A Oliva, ... R Aversa, M De Rosa, Biomaterials, 25 (17), 3645-3653 (2004).
[3] G R. Beck, Shin-Woo Ha, C E Camalier, M Yamaguchi, Y Li, J K Lee, M. N Weitzmann, Nanomedicine, 8(6), 793-803 (2012)
Nota dei curatori
No full textIl volume è l’esito di alcune riflessioni dei professori titolari delle cattedre dei corsi di Laboratorio di composizione architettonica e urbana, prof. R. Capozzi, prof.ssa P. Scala, prof.ssa V. Pezza, Prof. G. Szaniszlò, e delle relative esperienze didattiche svolte nei corsi di laboratorio al primo anno del CdL ARC5UE, a.a. 2020/2021, presso il Dip. di Architettura dell’Università degli studi di Napoli Federico II; ed infine restituisce le lectiones di docenti esterni al DiARC invitati al ciclo di seminari svolto a corsi congiunti.
Il volume si suddivide in tre parti: Parte I - Il progetto didattico tra teoria e laboratori, Parte II - Le esperienze di laboratorio, Parte III - Architettura, città e archeologia.
A curare il volume sono stati l’arch. Francesca Spacagna, referente del corso 1 A; l’arch. phd candidate Maria Fierro, referente del corso 1 B; l’arch. Davide Apicella, referente del corso 1 C; l’arch. Pasquale Abbagnale, referente del corso 1 D
Biomeccanica e biomimetica dei sistemi adesiviOdontoiatria Conservatrice fra presente e futuro
No full textThe importance of cortical bone orthotropicity, maximum stiffness direction and thickness on the reliability of mandible numerical models
No full textAim: To identify mechanical and geometrical variables affecting the biofidelity of numerical models of human mandible. Computed results sensibility to cortical bone orthotropy and thicknesses is investigated. Methods: Two mandible numerical models of different bone complexities are setup. In the low-complexity model, cortical bone is coupled with isotropic materials properties; constant thickness for cortical bone is adopted along the mandible structure. In the higher complexity model, the cortical bone is considered as an orthotropic material according to an independent mechanical characterization performed on fresh human dentate mandibles. Cortical thickness distribution, the values of the principal elastic moduli and principal directions of orthotropy are considered as piecewise heterogeneous. Forces for masseter (10 N), medial pterigoid (6 N), anterior (4 N) and posterior (4 N) temporalis muscles are applied to the models. Computed strains fields are compared with those experimentally measured in an independent test performed on a real human mandible in the same loading conditions. Results: Under closure muscles forces both models shows similar strain distribution. On the contrary, strain fields values are significantly different between the presented models. Conclusions: The mandible structure is sensible to compact bone orthotropy and thickness at the facial side of condylar neck, retro molar area and at the lingual side of middle portion of the corpus in molars area, anterior margin of the ramus. In these areas, it is advisable to use orthotropic properties for cortical bone to accurately describe the strain state. © 2010 Wiley Periodicals, Inc
Influence of abutment material on the fracture strength and failure modes of abutment-fixture assemblies when loaded in a bio-faithful simulation
No full textOBJECTIVES: The aim of the present study was to evaluate differences in the ultimate fracture resistance of titanium and zirconia abutments.
MATERIAL AND METHODS: Twenty titanium fixtures were embedded in 20 resin mandible section simulators to mimic osseointegrated implants in the premolar area. The embedded implants were then randomly divided into two groups. Afterwards, specimens in group A (n=10) were connected to titanium abutments (TiDesignTM 3.5/4.0, 5.5, 1.5 mm), while specimens in group B (n=10) were connected to zirconia abutments (ZirDesign TM 3.5/4.0, 5.5, 1.5 mm). Both groups were loaded to failure in a dynamometric testing machine. Fractured samples were then analyzed by scanning electron microscopy (SEM).
RESULTS: Group A showed a significantly higher fracture strength than that observed in group B. Group A failures were observed at the screw that connects the abutment with the implant while the abutment connection hexagons were plastically bent by the applied load. Group B failures were a result of abutment fractures. SEM analysis showed that in group A the screw failure was driven by crack nucleation, coalescence and propagation, while in group B, the SEM analysis of failed surfaces showed the conchoidal fracture profile characteristic of brittle materials.
CONCLUSIONS: The strength of both tested systems is adequate to resist physiologic chewing forces in the premolar area. Conversely, the titanium and zirconia failure modes evaluated here occurred at unphysiological loads. In addition, because the abutments were tested without crowns, the presented data have limited direct transfer to the clinical situation
Light shielding effect of overlaying resin composite on the photopolymerization cure kinetics of a resin composite and a dentin adhesive
No full textThickness shading effect on the photopolymerization kinetics of dental composite materials
No full textLight shielding effect of overlaying resin composite on the photopolymerization cure kinetics of a resin composite and a dentin adhesive.
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