An increase in the world population and its life expectancy, as well as the ongoing concern about our physical appearance, have elevated the relevance of dental implantology in recent decades. Engineering strategies to improve the survival rate of dental implants have been widely investigated, focusing on implant material composition, geometry (usually guided to reduce stiffness), and interface surrounding tissues. Although efforts to develop different implant surface modifications are being applied in commercial dental prostheses today, the inclusion of surface coatings has gained special interest, as they can be tailored to efficiently enhance osseointegration, as well as to reduce bacterial-related infection, minimizing peri-implantitis appearance and its associated risks. The use of biomaterials to replace teeth has highlighted the need for the development of reliable analytical methods to assess the therapeutic benefits of implants. This literature review considers the state-of-the-art strategies for surface modification or coating and analytical methodologies for increasing the survival rate for teeth restoration.

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Latest Trends in Surface Modification for Dental Implantology: Innovative Developments and Analytical Applications

https://eprints.whiterose.ac.uk/188754/1/1-s2.0-S0042207X22004225-main.pdf

Thermal based surface modification techniques for enhancing the corrosion and wear resistance of metallic implants: A review

The development of new β-Ti alloys has been extensively studied in the medical field in recent times due to their more suitable mechanical properties, such as a relatively low Young’s modulus. This paper analyzes the influence of heat treatments (homogenization and annealing) and hot rolling on the microstructure, phase composition, and some mechanical properties of ternary alloys of the Ti-xNb-5Mo system, with an amount of Nb varying between 0 and 30 wt%. The samples are produced by argon arc melting. After melting, the samples are homogenized at 1000 °C for 24 h and are hot rolled and annealed at 1000 °C for 6 h with slow cooling. Structural and microstructural analyses are made using X-ray diffraction and optical and scanning electron microscopy. Mechanical properties are evaluated by Vickers microhardness and Young’s modulus. The amount of β phase increases after heat treatment and reduces after hot rolling. The microhardness and Young’s modulus of all heat-treated samples decrease when compared with the hot rolled ones. Some samples exhibit atypical Young’s modulus and microhardness values, such as 515 HV for the as-cast Ti-10Nb-5Mo sample, indicating the possible presence of ω phase in the microstructure. The Ti-30Nb-5Mo sample suffers less variation in its phase composition with thermomechanical treatments due to the β-stabilizing effect of the alloying elements. The studied mechanical properties indicate that the annealed Ti-30Nb-5Mo sample has potential for biomedical applications, exhibiting a Young’s modulus value of 69 GPa and a microhardness of 236 HV.

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Effect of Thermomechanical Treatments on Microstructure, Phase Composition, Vickers Microhardness, and Young’s Modulus of Ti-xNb-5Mo Alloys for Biomedical Applications

We used the soft sparking mode to fabricate microarc oxidation coatings containing micro/nano-scale pores and bioactive Ca/P components on Ti6Al4V alloy samples formed by selective laser melting. The effect of soft sparking on the microstructure and corrosion resistance of the coatings and the codeposition mechanism of the electrolyte anions in the soft sparking layer were investigated using different negative/positive charge ratios. The results showed that the negative charge significantly decreased the intensity of microarc discharge, resuling in the soft sparking phenomenon, which promotes the formation of a thin amorphous TiO2 layer at the barrier layer/substrate interface. In turn, this interface facilitated the electron tunneling and aggregation of the electrolyte anions, which leads to soft sparking at voltages significantly lower than the breakdown voltage of the anodic oxide film on the selective laser melted Ti alloys. Soft sparking promoted the codeposition of the electrolyte anions, including PO43− and Ca2+ ions, in the form of bulk amorphous phases in the coating formed by soft sparking. The soft sparking layer contained amorphous phases, which were corroded more readily than that the outer ceramic layer. However, the submicro/nano-scale pores in the soft sparking layer improved its corrosion resistance. With an increase in negative/positive charge ratio, the effect of soft sparking on the surface morphology of the MAO coating weakened, and the amounts of Ca and P codeposited in the soft sparking layer increased. Finally, the corrosion resistance of the coating was found to first increase and then decrease, reaching the maximum at the 1.1 ratio. 

Effects of soft sparking on micro/nano structure and bioactive components of microarc oxidation coatings on selective laser melted Ti6Al4V alloy

Effects of Soft Sparking on Micro/Nano Structure and Bioactive Components of Microarc Oxidation Coatings on Selective Laser Melted Ti6al4v Alloy

Ti and Ti alloys have charming comprehensive properties (high specific strength, strong corrosion resistance, and excellent biocompatibility) that make them the ideal choice in orthopedic and dental applications, especially in the particular fabrication of orthopedic and dental implants. However, these alloys present some shortcomings, specifically elastic modulus, wear, corrosion, and biological performance. Beta-titanium (β-Ti) alloys have been studied as low elastic modulus and low toxic or non-toxic elements. The present work summarizes the improvements of the properties systematically (elastic modulus, hardness, wear resistance, corrosion resistance, antibacterial property, and bone regeneration) for β-Ti alloys via surface modification to address these shortcomings. Additionally, the shortcomings and prospects of the present research are put forward. β-Ti alloys have potential regarding implants in biomedical fields.

Kun Dai

Papers

β-Ti Alloys for Orthopedic and Dental Applications: A Review of Progress on Improvement of Properties through Surface Modification