Masfueh Razali

Surface Modifications and Their Effects on Titanium Dental Implants

This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effective surface for bone implant contact, cell proliferation, and removal torque, despite having good mechanical properties. Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness. Thus, a combination of a good surface roughness and mechanical properties of titanium could lead to successful dental implants.

Effects of Surface Treatment on Titanium Alloys Substrate by Acid Etching for Dental Implant

Many studies were carried out to investigate the ability of titanium alloys for dental implant. Surface treatment is one of the famous methods to increase the titanium surface properties. The purpose of this paper is to investigate the effects of acid etching on the surface topography and roughness of titanium alloys (Ti6Al4V ASTM 1472-99). Acid etchings were carried out by using different type of acids with same time exposures. All etched surface were characterized by using an X-ray diffraction (XRD), a scanning electron microscope (SEM) and a roughness tester. Acid etched and pure surface were comparatively analysed. Results obtained show that the type of acids influenced the surface topography as well as roughness properties. The microstructure of the surface is highly modified after acid etching. Further we can confirm that, the experimental etched titanium alloys had features of a roughened surface with micro-roughness. In general, the experimental surface (0.137 μm – 3.986 μm) was significantly rougher than control surface (0.124 μm).

Influence of Polyvinylalcohol on the Size of Calcium Ferrite Nanoparticles Synthesized Using a Sol-gel Technique

In this study calcium ferrite nanoparticles are synthesized using a sol-gel method and the magnetic properties of these nanoparticles are characterized. The influence of process parameters, namely molar ratio of starting materials, calcination temperature and effect of polyvinylalcohol (PVA) on particles size is also investigated. These parameters are also necessary to produce nano-sized calcium ferrite particles with a superparamagnetic behavior for drug delivery systems. In the synthesis a PVA polymer is initially mixed with calcium nitrate and ferric nitrate by using a magnetic stirrer. Citric acid is then used to increase the chelation to produce calcium ferrite nanoparticles. The prepared samples are calcined at 550 °C for 2 h in a vacuum oven, and a furnace. The morphological features of the calcium ferrite nanoparticles examined using scanning electron microscopy. The structure and magnetic properties of these materials are also characterized through X-ray diffraction and vibrating sample magnetometry. SEM images reveal spherical calcium ferrite nanoparticles. These nanoparticles also exhibit an orthorhombic structure with a crystal size of 16.8 nm. The magnetic properties of the sample measured using a vibrating sample magnetometer of the sample measured using vibration sample magnetometer are as follows: superparamagnetic with a coercivity of 43.35 G and a magnetic saturation of 59.3 emu/g. This study will contribute to the development of superparamagnetic nanoparticles for targeted drug delivery systems.

The Translucency of Yttria-Stabilized Zirconia in Dental Crowns: A Review

Ceramics are increasingly popular in dental restoration after metal restoration has been found to be less esthetic. One such example is yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP). However, one of the challenges of this application is its insufficient translucency to ensure high esthetic restoration. This study reviews the effect of sintering parameters, primary particle size, microstructure homogeneity, and thickness of zirconia on its translucency. Several studies remarked that the thickness of the framework had the greatest effect on zirconia translucency. Thus, a rigorous thickness control is necessary. The consideration for optimal sintering parameters (sintering temperature and holding time) and the use of smaller particle sizes help in the densification and elimination of porosity in zirconia, which, consequently, improve its translucency. Finally, a homogeneous microstructure can reduce the light scattering effect in zirconia and increase its translucency. Identifying the factors that influence zirconia translucency can contribute to future research in improving the esthetic dental restoration.

A Review: Effect of Sintering Method on the Decomposition of Hydroxyapatite and Density of Hydroxyapatite Zirconia Composites

Hydroxyapatite (HA) is a biomaterial with excellent biocompatibility. However, the brittleness and low fracture toughness of HA have limited its biomedical applications. As such, HA has been incorporated with zirconia (ZrO2) to enhance its mechanical strength. However, ZrO2 addition decreases the phase stability of HA. HA decomposition is not favored because it decreases the mechanical strength of HA/ZrO2. In this paper, the effect of sintering on HA decomposition is reviewed. Experimental results show that hot isostatic pressing of HA/ZrO2 is one of the most effective methods to suppress HA decomposition, yielding the highest relative density compared with other sintering methods.