Atmospheric plasma enhances wettability and cell spreading on dental implant metals

OBJECTIVES

Treatment regimens, which predictably support re-osseointegration of implants with peri-implantitis, are needed. Increased wettability may be an important factor for re-osseointegration. In this study, a cold atmospheric pressure gas-discharge plasma was applied to reduce water contact angles on titanium discs with different surface topography and to improve the spreading of osteoblastic cells.

MATERIAL AND METHODS

An argon plasma jet with different oxygen admixtures was used to treat titanium discs with different topologies, i.e. machined, SLA(®) , SLActive(®) , diamond bur-treated or Airflow(®) -treated. Water contact angles were measured before and after plasma treatment. The spreading behaviour of human osteoblastic cells was investigated.

RESULTS

Contact angle of titanium discs (baseline values: 68°-117°) were significantly reduced close to 0° irrespective of surface topography after the application of argon plasma with 1.0% oxygen admixture for 60 s or 120 s. The cell size of osteoblastic cells grown on argon-oxygen-plasma-treated titanium discs was significantly larger than on non-treated surfaces (p < 0.001) irrespective of surface topography.

CONCLUSIONS

Plasma treatment reduced contact angle and supported spreading of osteoblastic cells. The application of cold plasma may be supportive in the treatment of peri-implant lesions and may improve the process of re-osseointegration.

Influence of age and sex in exhaled breath samples investigated by means of infrared laser absorption spectroscopy

Breath gas analysis provides insight into human metabolism of healthy and ill individuals. As an innovative and non-invasive method, it opens up options to improve diagnostics, monitoring and treatment decisions. Mid-infrared laser absorption spectroscopy is utilized to detect CH(4), H(2)O, CO(2), NH(3) and CH(3)OH in exhaled human breath. An off-line approach using breath sampling by means of Tedlar bags is applied. The breath gas samples are measured within the population-based epidemiological Study of Health in Pomerania (SHIP-TREND) performed at the University of Greifswald. The study covers about 5000 adult subjects aged 20-79 years within 3 years. Besides breath gas analysis many other examinations are conducted. It is expected to find associations between distinct concentration levels of species in the exhaled breath and diseases assessed in this study. The study will establish reference values for exhaled breath components and serve as background population for case-control studies. In the long run, morbidity and mortality follow-ups will be conducted, which will answer the question whether end-expiratory breath gas components predict future diseases and death. As first results, we present data from 45 dialysis patients (23 males, 22 females) which were recruited in a preliminary study in preparation for SHIP-TREND.

Spatiotemporal laser perturbation of competing ionization waves in a neon glow discharge

The experimental verification of spatiotemporal periodic pulling, a specific but universal phenomenon associated with driven, nonlinear, spatiotemporal systems, is reported as part of a study characterizing the ability of dc and chopped laser light to induce periodic pulling in ionization waves propagating in a neon glow-discharge plasma. The degree to which a single-mode laser beam at a metastable transition of 6401 A (1s(5)-2p(9)) influences the discharge is found to depend on the location and magnitude of the perturbation. Cases of ac (chopping the light) and dc perturbation are presented. In a range of chopping frequencies above and below the ionization wave's undriven frequency, the wave can become synchronized to the perturbation. This entrainment range is shown to depend on the frequency difference between the wave and the perturbation, as well as on the perturbation distance from the cathode. Hysteresis is found in the value of the perturbation frequency associated with transitions into and out of entrainment. Outside of entrainment, periodic pulling of a self-excited, propagating, ionization wave by the laser perturbation is observed. This is a case of frequency pulling, or temporal periodic pulling. Inside of entrainment, the chopped laser light controls the frequency and amplitude of the mode. By properly adjusting the frequency and amplitude of one mode with respect to a second mode, periodic pulling of one ionization wave by the mode-locked, propagating, original ionization wave is demonstrated. This is a case of spatiotemporal pulling, involving both wavelength pulling and frequency pulling. Under proper conditions, competition between temporal and spatiotemporal periodic pulling results in a modulation in the dynamics of the system, a process referred to as dynamics modulation.