Osteogenic and Antibacterial Activity of a Plasma-Sprayed CeO2 Coating on a Titanium (Ti)-Based Dental Implant

Abstract

Peri-implantitis, often induced by oral pathogens, is one of the main reasons for the clinical failure of dental implants. The aim of this study was to investigate the biocompatibility, osteogeneic, and antibacterial properties of a cerium oxide (CeO2) coating containing high proportions of Ce4+ valences on a titanium-based dental implant biomaterial, Ti-6Al-4V. MC3T3-E1 cells or bone marrow stem cells (BMSCs) were seeded onto Ti-6Al-4V disks with or without CeO2 coating. Compared to the control, the plasma-sprayed CeO2 coating showed enhanced cell viability based on cell counting kit-8 (CCK-8) and flow cytometry assays. CCK-8, colony-forming unit test (CFU), and live-dead staining illustrated the antibacterial activity of CeO2 coating. Additionally, CeO2 coating upregulated the gene expression levels of osteogenic markers ALP, Bsp and Ocn, with a similar increase in protein expression levels of OCN and Smad 1 in both MC3T3-E1 cells and BMSCs. More importantly, the viability and proliferation of Enterococcus faecalis, Prevotella intermedia, and Porphyromonas gingivalis were significantly decreased on the CeO2-coated Ti-6Al-4V surfaces compared to non-treated Ti-6Al-4V. In conclusion, the plasma-sprayed CeO2 coating on the surface of Ti-6Al-4V exhibited strong biocompatibility, antibacterial, and osteogenic characteristics, with potential for usage in coated dental implant biomaterials for prevention of peri-implantitis.

Histologic and Histomorphometric Evaluation of a New Bioactive Liquid BBL on Implant Surface: A Preclinical Study in Foxhound Dogs

“…Graphene-chitosan hybrid dental implants were reported to promote osteoblast proliferation while reducing biofilm formation and bacterial activity [ 15 ]. Similar observations were also reported for titanium implants treated with zinc-containing tricalcium phosphate (Zn-TCP), poly-ε-caprolactone/titania (PCL/TiO 2 ), or plasma-sprayed cerium oxide (CeO 2 ) [ 16 , 17 , 18 , 19 ]. Other titanium implant-coating materials, such as nano-Ag and poly-ethylene oxide (PEO), possess notable antibacterial properties [ 20 , 21 ].…”

Preventing Peri-implantitis: The Quest for a Next Generation of Titanium Dental Implants

“…Processing of titanium and its alloys has been done through several approaches. These include, but are not limited to, new alloy formation, laser or UV treatment, antimicrobial peptides, plasma spraying, anodization, silanization, antimicrobial coatings, and photolithography. ,− Most of these studies have reported comparisons of the attachment behavior of multiple species on the modified and control surfaces. The bacterial species tested in several studies have been categorized under the yellow (early), orange (intermediate), or red complexes (late colonizers), Table .…”

Cerium Ion-Incorporated Titanium Metal Implants of Enhanced Bioactivity for Biomedical Applications

“…Surface modification techniques adopted for metals and alloys can be mechanical (grinding, polishing, blasting), chemical (alkali/acid treatment, anodization), or physical (spraying, PVD). ,, These surface modification approaches are mainly aimed at making the implant surface more rough and porous. Enhanced surface roughness as well as the porous nature of the implant will lead to enriched protein adsorption that promotes better cell adhesion and their ingrowth into the porous layers of the surface. , A bioactive surface with a porous nanonetwork structure can be generated onto a Ti/Ti alloy-based implant by a simple alkaline treatment with a high concentration of NaOH. − It is also reported that elements with antimicrobial properties (Ag, Zn, Ce, etc. ), as well as enhancement of osseointegration (Ca, Mg, Zr, Se, Ce etc.…”

“…), as well as enhancement of osseointegration (Ca, Mg, Zr, Se, Ce etc. ), can be incorporated into the thus-formed nanonetwork structure by subsequent treatment with a respective elemental solution. ,,, These elements will be decorated over the nanonetwork structure over the surface to promote biocompatibility and add biofunctions to the Ti/Ti alloy-based implants. A similar approach for the incorporation of beneficial elements such as Ag, Zn, Ca, and Sr to Ti/Ti alloys was attempted by our research group, and it resulted in an implant with enhanced surface properties with good biocompatibility, which will help fasten the healing process. ,,,, …”

“…Recently, Ce or cerium oxide nanoparticles (CeO 2 NPs) have been widely used in biomaterials, as it shows similar physiological and biochemical effects like calcium (Ca) . The similar ionic radius of bivalent calcium (1.00 Å) and trivalent cerium (1.01 Å) enables Ce to replace Ca in many biomolecules. − In the biological context, Ce shows affinity toward the mineral bone matrix and induces local soft-tissue calcification by the formation of crystallization nuclei, on which calcium and phosphate accumulate to form apatite. , Nanoceria has been verified to possess the potential to serve as an effective and long-lasting biocide for preventing bacterial infections, due to its lower toxicity to mammalian cells and unique antibacterial mechanism compared to other metal ions. ,− …”