Peek dental implants coated with boron-doped nano-hydroxyapatites: Investigation of in-vitro osteogenic activity

Background: PEEK is a high-performance thermoplastic that has many potential uses in orthopaedics and dentistry, and it has been shown to be a substitute for titanium (Ti) implants. However, PEEK is an inherently inert material, and that characteristic limits its cellular adhesion and bone integration. The aim of this study is to determine a suitable surface modification method for increasing the osteogenic potential of polyetheretherketone (PEEK) implants used in periodontal applications. Methods: In this work, a nanostructured porous surface is created on PEEK material by sulfonation, in sulfuric acid at room temperature for 20 min, and thus SPEEK samples were obtained. Then, PEEK and SPEEK samples were coated with boron (B) doped hydroxyapatite (HAp) nanoparticles (B-nHAp) precipitated from concentrated synthetic body fluid (10xSBF) by a microwave-assisted method conducted at 600 W. In vitro cell culture studies were carried out with periodontal ligament cells (PDL) on the samples. Osteogenic differentiation of PDL cells on PEEK, SPEEK and SPEEK-B-nHAp was evaluated using ALP activity assay, hydroxyproline assay, and RT-qPCR. Results: In vitro cell culture studies disclosed improved adhesion and proliferation of PDL cells on the SPEEK and B-nHAp coated SPEEK surfaces (SPEEK-B-nHAp). Results of these assays confirmed that treated PEEK surfaces, especially SPEEK-B-nHAp, significantly enhanced osteogenic differentiation of PDL cells in vitro compared with untreated PEEK surfaces. Conclusion: Here a simple, easy to-use, and efficient modification method based on the properties of boron is proposed for increasing osteogenic potential of PEEK implants.