In recent years, extensive studies have been continuously undertaken on the design of bioactive and biomimetic dental implant surfaces due to the need for improvement of the implant–bone interface properties. In this paper, the titanium dental implant surface was modified by bioactive vitamin D3 molecules by a self-assembly process in order to form an improved anticorrosion coating. Surface characterization of the modified implant was performed by field emission scanning electron microscopy (FE-SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurements (CA). The implant’s electrochemical stability during exposure to an artificial saliva solution was monitored in situ by electrochemical impedance spectroscopy (EIS). The experimental results obtained were corroborated by means of quantum chemical calculations at the density functional theory level (DFT). The formation mechanism of the coating onto the titanium implant surface was proposed. During a prolonged immersion period, the bioactive coating effectively prevented a corrosive attack on the underlying titanium (polarization resistance in order of 10⁷ Ω cm²) with ~95% protection effectiveness.

Organophosphorus compounds, like bisphosphonates, drugs for treatment and prevention of bone diseases, have been successfully applied in recent years as bioactive and osseoinductive coatings on dental implants. An integrated experimental-theoretical approach was utilized in this study to clarify the mechanism of bisphosphonate-based coating formation on dental implant surfaces. Experimental validation of the alendronate coating formation on the titanium dental implant surface was carried out by X-ray photoelectron spectroscopy and contact angle measurements. Detailed theoretical simulations of all probable molecular implant surface/alendronate interactions were performed employing quantum chemical calculations at the density functional theory level. The calculated Gibbs free energies of (TiO₂)₁₀–alendronate interaction indicate a more spontaneous exergonic process when alendronate molecules interact directly with the titanium surface via two strong bonds, Ti–N and Ti–O, through simultaneous participation common to both phosphonate and amine branches. Additionally, the stability of the alendronate-modified implant during 7 day-immersion in a simulated saliva solution has been investigated by using electrochemical impedance spectroscopy. The alendronate coating was stable during immersion in the artificial saliva solution and acted as an additional barrier on the implant with overall resistivity, R ~ 5.9 MΩ cm².

The effects of various organic additives, such as diethanolamine (DEA) and ethanolamine (EA), and variations in aging times on the formation and stability mechanisms of spherical aggregates of ZnO nanoparticles (NPs) prepared by using solvothermal synthesis were studied. The experimental results of the structural, morphological and optical properties monitored by using X-ray diffraction, field-emission scanning electron microscopy (FE-SEM) and UV-Vis spectroscopy were supported by quantum chemical calculations at the level of density functional theory (DFT). Understanding the mechanism of spherical ZnO aggregate formation and its stability by mimicking the processes at the computer level was achieved through theoretical simulations of the ZnO surface/additive interactions using (ZnO)₃₆–DEA and (ZnO)₃₆–EA models. The fine-tuned spherical aggregation of ZnO nanoparticles was driven by various interactions, in particular, strong O–H∙∙∙O and weak N–H∙∙∙O hydrogen bonds as controlling interactions. The calculated negative free release energy, ∆G*_INT, indicates that the ZnO surface/additive interaction in diethanolamine media is a spontaneous exergonic process (∆G*_INT = −7.73 kcal mol⁻¹), whereas, in ethanolamine media, it is an unfavorable, slightly endergonic process (∆G*_INT > 0). The presence of two strong O–H∙∙∙O hydrogen bonds and, at the same time, a weaker N–H∙∙∙O hydrogen bond is the key factor for the very good and long-term aggregate stability of ZnO NPs in DEA media. This integrated experimental–theoretical study highlights the stability and compactness of spherical ZnO aggregates of ZnO NPs, prepared in the presence of diethanolamine compared to ethanolamine media, and provides a promising method and flexible design of ZnO nanomaterials to improve their adsorptive and optical properties.

The success of the osseointegration process depends on the surface characteristics and chemical composition of dental implants. Therefore, the titanium dental implant was functionalised with a composite coating of alendronate and hydrolysed collagen, which are molecules with a positive influence on the bone formation. The results of the quantum chemical calculations at the density functional theory level confirm a spontaneous formation of the composite coating on the titanium implant, ∆G*_INT = −8.25 kcal mol⁻¹. The combination of the results of X-ray photoelectron spectroscopy and quantum chemical calculations reveals the structure of the coating. The alendronate molecules dominate in the outer part, while collagen tripeptides prevail in the inner part of the coating. The electrochemical stability and resistivity of the implant modified with the composite coating in a contact with the saliva depend on the chemical nature of alendronate and collagen molecules, as well as their inter- and intramolecular interactions. The formed composite coating provides a 98% protection to the implant after the 7-day immersion in the artificial saliva. From an application point of view, the composite coating could effectively promote osseointegration and improve the implant’s resistivity in contact with an aggressive environment such as saliva.