Purpose: A hydrophilic surface can favor the osseointegration of Titanium (Ti) dental implants. We aimed to determine the minimum time required to reach a hydrophilic surface using different working gases in a novel chairside plasma activation technique of encapsulated Ti implants.
Material and Methods: Ti Grade V alloy rods (2.98mm diameter) and glass tubes were ultrasonically cleaned with a sequential ethanol–Hellmanex–Millipore water protocol. Each Ti sample was encapsulated in a glass tube at a pressure of 0.3mbar using a working gas (either Argon, Oxygen or atmospheric Air). Plasma was generated inside each capsule by induction using a chairside device for either 10s, 20s, 60s, or 10min. Corresponding control samples of each working gas received no plasma treatment. Changes in wettability were evaluated in triplicate using dynamic contact angle analysis by tensiometric Wilhelmy experiments (3 cycles, 10mm/min immersion speed) and statistically analyzed (ANOVA, Tukey’s test, p<0.05).
Results: Control samples exhibited contact angles ranging from 57° to 105°. We found a statistical difference between controls and 10s-plasma treatment in all gases (p<0.05). Argon- and air-plasma did not statistically differ in 10s treatment (contact angle 18.3±4.2° vs. 24.3±3.2°, respectively) but, Argon-plasma allowed a more uniform change towards hydrophilicity when considering all immersion cycles. Oxygen-plasma required at least 20s to assure hydrophilicity. At 60s-plasma treatment, all working gases switched Ti samples towards superhydrophilicity (contact angles 0°) as also 10min treatments did.
Conclusion: After plasma activation, all working gases rendered the surface of encapsulated Ti implants hydrophilic. However, the time required varied among them, being Argon-plasma the fastest treatment that increased the wettability of Ti implants uniformly within 10s. These findings suggest that chairside plasma activation can be a promising technique to induce hydrophilicity of Ti implants at dentists' offices with a minimum of time.