Tribocorrosion Behavior of Calcium- and Phosphorous-Enriched Titanium Oxide Films and Study of Osteoblast Interactions for Dental Implants

Abstract

Titanium (Ti) dental implants are frequently exposed simultaneously to a corrosive environment and cyclic micromovements at implant/abutment and implant/ bone interfaces, becoming part of a tribocorrosion system. Thus, wear debris and corrosion products/ions can be released to peri-implant tissues and induce inflammatory reactions leading to implant failure. Moreover, the poor osseointegration is also one of the main problems affecting dental implants lifetime. Surface modification strategies have been proposed to design novel Ti oxide-based multifunctional surfaces that are able to simultaneously improve cellular functions and provide enhanced tribocorrosion resistance. Hence, the main objective of this work was the synthesis of Calcium (Ca)-and Phosphorous (P)-enriched Ti oxide films aimed to display superior wear/corrosion performance and simultaneously, to enhance osteoblast-material interactions. Ca-and P-enriched films were synthesized by plasma electrolytic oxidation (PEO) and their characteristics were assessed by Field emission scanning electron microscopy, profilometry, energy-dispersive X-ray spectroscopy, X-ray diffraction, and water contact angle measurements. PEO-treated samples were subjected to pin-on-disk reciprocating sliding tests in artificial saliva at 37°C. The viability of MG63 cells cultured on PEO-treated samples was investigated by MTT assay, and their adhesion ability by SEM and confocal laser scanning microscopy. The wear/corrosion behavior of Ti was improved after PEO treatments and the electrolyte composition appeared to play a crucial role both on its corrosion tendency and mechanical wear resistance. It is believed that this improvement is related to the higher rutile/anatase ratio exhibited by Ca-and P-enriched surfaces. Osteoblasts were well spread on these surfaces displaying improved viability/proliferation compared to Ti.

Corrosion mechanisms in titanium oxide-based films produced by anodic treatment

“…Anyway, even without HA precipitation, samples investigated in this work showed enhanced human osteoblast adhesion when tested in vitro [43,46,47].…”

“…During this process, specific ions as Ca and P can be retained in the porous oxide layer [19,20,22]. This is one advantage of this anodic treatment, as the presence of these ions may improve osteointegration [43,46,47].…”

Influence of macroporosity on NIH/3T3 adhesion, proliferation, and osteogenic differentiation of MC3T3‐E1 over bio‐functionalized highly porous titanium implant material

“…Several studies had shown that MAO treatment on Ti surfaces enhanced its biological response. Alves et al performed PEO on commercial pure Ti and studied the biological properties of Ca‐and P‐enriched layers assessed for osteoblastic cell viability/proliferation ability. The authors concluded that cell viability/proliferation was improved on PEO treated samples.…”

Electrochemical coating of dental implants with anodic porous titania for enhanced osteointegration

“…In fact, one may explore the possibility to add different chemical species to the APT coating from those naturally resulting in the dissolved acid electrolyte. Interesting candidate elements are F, Ca and Mg and P, as demonstrated by recent loading carried out on implants coated with nanoporous titania by means of different techniques [22,32–33]. We selected Mg, which is essential to all living cells for its interaction with polyphosphate compounds such as ATP, DNA and RNA, required by many enzymes for their functioning, and present in many pharmaceutical products.…”