Journal of Composites and Compounds
Volume:2 Issue: 2, Mar 2020

Carbon nanotubes (CNTs)-reinforced Al composites have attracted attention due to their high specific strength and low density, which makes them suitable for the use in aerospace and automobile industries. In this review, preparation methods of Al/CNTs composites for achieving a homogeneous desperation of the CNT in the Al matrix are summarized. In addition, the effect of processing methods on carbon nanotube distribution and enhancement of mechanical properties such as toughness, wear behavior and hardness of the nanocomposites are reviewed. Improvement of mechanical characteristics was observed by the incorporation of carbon nanotubes into aluminum matrix. The strengthening factors gained by the carbon nanotubes addition are the interface of metal and CNTs and the chemical and structural stability of CNTs.

Nowadays, zirconia has been favored greatly for dental implants; however its disadvantages such as poor mechanical properties and brittleness makes it unsuitable. On the other hand, bioactive glasses coating have been utilized on tougher substrates such as zirconia. Bioactive glass coatings can decrease the healing time and hence accelerate the formation of the bond between bone and implant. Hence, in this study, we introduce the novel zirconia/ bioactive glass composites with high mechanical strength and bioactivity to achieve the ideal implant in dentistry. Furthermore, a review of bioactive glass coatings (i.e., 45S5 and 58S) on zirconia as well as surface modification methods (i.e., sol-gel, laser cladding, plasma spraying, etc.) is provided.

Currently, dental implants are considered useful alternatives to missing teeth, although they may suffer from failure. In this study, the current scientific literature has been reviewed to highlight the risk factors affecting dental implant failure. Radiotherapy in the neck and head cancers, diabetes, smoking, osteoporosis, and HIV can increase the occurrence of risk factors for the failure of a dental implant. As a result of negative impacts on osseointegration, osteoporosis, smoking, and head, neck radiotherapy causes a higher risk of dental implant failure. The irradiation target volume during radiotherapy is the main cause of implant failure, especially due to the increment of marginal bone resorption. Additionally, the healing of bones around dental implants is negatively affected by heavy smoking due to the reduction of the healing speed. Moreover, diabetic patients have some complications (e.g., delayed wound healing of soft tissues, periodontitis, impaired response to infection, tooth loss, and microvascular disease) affecting therapyial preliminary considerations of dental implant treatment. However, in case of HIV-positive patients, the dental implant failure rate would not increase due to affective factors (e.g., prophylactic antibiotic treatment, the administration of active antiretroviral therapy, and control of the CD4+ T lymphocyte counts). Therefore, these patients have no clinical signs of mobility or infection in this treatment and much more attention should be paid to these patients and they should be treated with controlled oral surgical procedures.

Zirconia has garnered significant attention as a new ceramic material for dental implant due to its excellent biocompatibility, strength, and promoting the oral rehabilitation with high aesthetic, biological and mechanical properties. It also expedites the amelioration of bone minerals surface by its bio-integrative ingredients which are naturally close to ceramic intrinsic of bone. Alternatively, hydroxyapatite (HAp) has prevalently been used in dental implant due to its high biocompatibility. However, it generally shows weak strength and mechanical properties. Consequently, incorporating zirconia and HAp produces appropriate composites for dental implant having improved physiochemical properties. This review provides discussions addressing the methodologies and exemplars for the designed composites used in dental implant applications. The representative methods for surface modification of zirconia incorporating HAp (i.e. sol-gel, hot isostatic pressing, plasma spraying, electrophoretic deposition, etc.) is highlighted. The advantages, disadvantages, biocompatibility, strength, and osseointergration and biointegration properties of the presented composites are explored.

Numerical simulation is a powerful tool to predict the physical behavior of the designed devices. This method provides detailed information about the investigated phenomenon for each point of the device, which is generally challenging by experiments. Comsol Multiphysics can be utilized in a wide range of engineering fields. This software employs the finite element method (FEM) to solve the physical governing equations. Due to the importance of the heat transfer in advanced ceramics and the potential of the numerical methods to solve the related problems, the present article aims to provide a comprehensive review of the performed numerical research works using Comsol Multiphysics.

Bio-ceramics are a set of ceramic materials that possess an important feature called biocompatibility. Bioglass is one of the most applicable ceramic materials contributing to bioactivity improvement due to the presence of Si as an ossification material. Besides, PCL polymer supported by bioglass nanoparticles was used to improve the mechanical properties. In this study, we combined Tricalciumphosphate (TCP) with nano-bioglass (NBG) with four different amounts (10%, 20%, 30%, and 0%) to produce composite scaffolds (lost sponge foam method); then, we coated these composites by Polycaprolactone (PCL) biopolymer, and eventually, evaluated its bioactivity, biodegradability, and mechanical properties. Scanning electron microscopy (SEM) and EDS methods were employed to investigate the morphology and bioactivity of scaffolds. The results of the ion concentration measurement test and SEM and EDS analysis showed the formation of Apatite on the scaffold’s surface. The results from SEM indicate that the most bioactivity was observed for composite scaffold containing 20%wt of nano-bioglass presenting it as the preferable sample, in terms of mechanical properties and bioactivity.

There has been an extensive investigation in the field of optical applications of nanocomposite materials. To prepare photosensitive nanocomposites, an optically functional phase is embedded in a transparent, processable matrix. This provides the opportunity to utilize the optical properties in other forms including fibers and films, which are more technologically important. Due to expansion of optical materials applications, novel transparent materials and optically functional are required. Recent optical nanocomposites and their applications in different areas especially catalysis and drug delivery have been addressed in this paper.