s of the Titanium implant to integrate within the bone seems to be whether or not the bone adequately remodels at the periphery of the implant (Aversa et al 2016b).
Figure 1 reports the result of the “in vivo” experiments carried out on dental implants placed in white rabbit femour. In particular Zach Gentry Steelers Jersey , the experiment described in Aversa et al (2016b) consisted in the evaluation of osteoinductivity and osteoconductivity of the surfaces of Ti implants without and with a 100 microns thin coating of our ceramo-polymeric hybrid material.
The bone implant apposition or bone ingrowth (Comeron 1986), which is defined as the percentage of osteointegrated implant length for the biomimetically coated and uncoated implants in the six months in vivo test show a significant improvement of about 100% increase in the first two months and of the 30% after 6 months.
Micro-CT bone reconstruction of the bone ingrowth around the implant was validated by the use of FEA calculated physiological strain distributions. The colored strain maps around in the bone surrounding the implant confirmed the critical role of the bioactive Ti-Bone interface.
The Osteoblast proliferation and bone growth in the implanted rabbit femur is clearly favoured and accelerated by the presence of the hybrid nanostructured coating. The biomechanical approach using the adaptive properties of bone well describes the biomimetic behaviour of the proposed perimplantar hybrid scaffold since it can predict areas of bone reabsorption (FEA model elements with strains below the physiological lower limits have been removed in the image), as it occurs in the in vivo tests at the neck of the implant (Micro CT reconstruction on the right side of figure 1).
Research has shown that mechanical stimulation can have a profound effect on the differentiation and development of mesenchymal tissues.
Figure 2 illustrates the adaptive properties and strain threshold values for healthy bone growth.
According to Frost (1990), who quantified the observations of Wolff (1892) Benny Snell Jr. Steelers Jersey , above (>3000 microepsilon) and below (<50 microepsilon) critical strain levels, bone growth is impaired. In the mild range of strains, healthy bone growth and regeneration is favoured. In fact, in order too maintain the stability of implants under load Justin Layne Steelers Jersey , it is of major importance for the bone-forming osteoblast to promote extra-cellular matrix in the vicinity of the implant.
Osseointegration mechanisms to account for in the biofidel models
The osseointegration of the implants is essential for the attainment of prosthetic rehabilitations. The accomplishment and the maintenance of a stable functional anchilosis show the following morpho-structural features, namely:
Direct contact between bone and implant, in absence at the interface of idoneous tissues; the existence of primary bone in contact with the surface of the biomaterial; deposition, externally to the primary bone layer Diontae Johnson Steelers Jersey , of lamellar secondary bone in contact with the titanium surface; total increase of the perimplantar osseous density compared to the normal bone architecture of the region; growth of medullar spaces, which is necessary to exhaust the metabolic requirement of the tissue in the region less involved in the loading dissipation; Condensation of compact bone, which can be linked to the loading propagation patterns determined by the specific implant morphology; Organization of strong trabecular structure departing radiallly from compact perimplantar bone; Presence of a osseous crestal wall at level of the subepitelial connective, which can allow junctional trophism of and sulcular epithelium formation.
The mature mineralised matrix that has been described to occur in dental and orthopaedic clinical studies Devin Bush Steelers Jersey , is expected to assure the mechanical stability of the implant even in the early osseointegration phase (primary stability). In fact, due to the hydrophilic nature of the hybrid material, high levels of fluids are absorbed from the liquid external environment leading to significant swelling and volume increase of the initially glassy hybrid material (figure 3).
The biomimetic and bio-mechanically active scaffold is, therefore James Conner Steelers Jersey , accomplishing two biomechanical functions, the first is strictly related to the prosthetic system stabilization after implantation (the prosthesis can be early loaded one hour after implantation), while the second function is associated to the bone growth stimulus exerted bone area surrounding the implantation.
The volumetric expansion of the scaffolds may be effective in improving the primary stability of the implants, confirming the high bioactive performance of the tested nanocomposite material (figure 4).
The presence of the swellable implant component contiguous the upper the Ti core of the implant increases its removal torque after implantation when the system is in presence of organic fluids.
聽The removal torque measured at different times after implantation JuJu Smith-Schuster Steelers Jersey , in fact, increased of more than 100% at 24. Moreover, even just after one hrs, the removal torque already raised from 43 to 62 N (about 25% improvement). It has been described in a previous paper (Aversa et al 2016b) that the retention improvement was directly following the swelling kinetic of the hybrid material scaffold (lower part of figure 4).
This increase of the implant stability is due to the strong compressive strains generated in the swollen rubbery hybrid scaffold as it can be inferred from the colored strains map reported in the right side of figure 3 (red color of the hybrid insert of the implant). The implant is then constrained in its socket by the external bone T. J. Watt Steelers Jersey , which then increases the retention and stability of the implant. The application of a higher removal torque for explanting is therefore needed at increasing swelling levels, as indeed it has been experimentally measured.