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Dental implants are used in dentistry to replace missing tooth roots, and their stable osseointegration with surrounding bone tissue is key to clinical success. The surface characteristics of the implant directly influence the efficiency of osseointegration and resistance to infection.
This study investigates the efficacy of plasma treatment in enhancing the biological properties of titanium surfaces. Titanium samples, including commercially pure smooth titanium and sandblasted acid-etched (SLA) titanium, were treated using a plasma system driven by nanosecond-pulsed power supply with a 95% N2 and 5% H2 gas mixture at 200 Pa. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the morphology and chemical features of the treated titanium surfaces. The biological properties of modified titanium surfaces were evaluated through water contact angle measurements, antibacterial effect against Streptococcus mutans assays, adhesion effect on mouse pre-osteoblastic cell line and cytotoxicity tests.
Results indicated that the plasma treatment induced a significant transition from hydrophobicity to hydrophilicity without altering surface morphology (as confirmed by SEM). Specifically, the water contact angle of SLA Ti decreased dramatically from 76.5° to 7.9°, while that of smooth Ti dropped from 78.3° to 16°. XPS analysis confirmed the removal of organic carbon contaminants and the successful introduction of nitrogen-containing functional groups (-NH3+), which are crucial for bioactivity.
Biologically, the N2-H2 plasma-treated surfaces demonstrated superior dual functionality. The modified surface significantly inhibited bacterial adhesion, achieving a reduction over 4 orders of magnitude, which vastly outperformed the untreated controls (smooth Ti: 1.81 logs, SLA Ti: 2.19 logs). Simultaneously, cells adhesion rate improved markedly to 70%, compared to baseline rates of 20% for untreated smooth Ti and 51% for untreated SLA Ti. Furthermore, cell viability assays (CCK-8) confirmed that the modified surfaces exhibited no cytotoxicity (Grade 0).
In conclusion, nanosecond pulsed N2-H2 plasma treatment is a highly effective, low-cost surface modification technique. It successfully transforms inert titanium into a hydrophilic, antibacterial, and biocompatible surface. Notably, the treated smooth titanium achieved an optimal balance between economic cost and biological performance, suggesting a promising alternative for reducing implant infection risks while promoting osseointegration.