Effect of Secondary Non-Thermal Plasma Decontamination on Ethanol-Treated Endosteal Implant Surfaces: An In Vivo Study of Osseointegration

Abstract

Effective surface treatment of implants is essential for enhancing osseointegration outcomes. This study assessed the influence of alcohol decontamination both with and without secondary argon-based non-thermal plasma (NTP) treatment on osseointegration of endosteal implants in a large translational (sheep) model. Ti6Al4V dental implants were utilized either as received (CTRL), or subjected to ethanol cleaning (for 60 s) followed by NTP (for 60 s) (Clean+Plasma); or treated with NTP alone (Plasma) for 60 s. X-ray photoelectron spectroscopy was used for surface elemental analysis, followed by interferometry and sessile drop tests to measure changes in surface roughness and surface energy, respectively. Twelve sheep received implants (one implant per group per sheep) in the iliac crest, and bone healing was evaluated after 3 and 12 weeks using histomorphometric analysis (six sheep/time point). No significant differences in surface roughness (arithmetic mean (Sa) and root mean square (Sq) height: p > 0.161 and p > 0.173, respectively) or topographies were detected between implant surfaces. However, both NTP treated groups presented higher surface energies and lower water contact angle values relative to CTRL surface (p < 0.001). Compared to the CTRL, both NTP-treated groups exhibited reduced levels of Carbon and elevated levels of Oxygen. No significant differences in Bone-to-Implant Contact (BIC) or Bone Area Fractional Occupancy (BAFO) were observed among groups at 3 weeks. At the 12-week time point, Plasma implants demonstrated significantly higher BAFO (p = 0.014) compared to the CTRL group, as well as an increase in both BIC and BAFO over time (3 vs. 12 weeks in vivo) (p = 0.041 and p = 0.043, respectively). Building on the existing literature, the current study suggests that NTP treatment alone may be adequate to successfully enhance osseointegration while minimizing contamination risks, thereby eliminating the need for additional cleaning protocols.