Effect of Plasma-Glow Discharge as a Sterilization of Titanium Surfaces

Effect of Plasma-Glow Discharge as a Sterilization of Titanium Surfaces
March 2003
Youngblood, T. DDS*; Ong, J. L. PhD**
Implant Dentistry: Volume 12(1) March 2003 pp 54-60
Lippincott Williams & Wilkins
*Private Practice.
**Associate Professor, The University of Texas Health Science Center at San Antonio, Department of Restorative Dentistry, Division of Biomaterials, San Antonio, TX.
Reprint requests and correspondence to:
Dr. Joo L. Ong
University of Texas Health Science Center at San Antonio
Department of Restorative Dentistry
Division of Biomaterials, MSC 7890
7703 Floyd Curl Drive
San Antonio, TX 78229-3900
Phone: 210-567-3658
Fax: 210-567-3669
E-mail: ong@uthscsa.edu
The authors claim to have no financial interest in any company or any of the products mentioned in this article.
Abstract
In this study, in vitro osteoblast responses to glow-discharged, commercially pure titanium (Ti) surfaces were investigated. It was hypothesized that the glow-discharge treatment would be an effective sterilization procedure for Ti implantations before implantation. The Ti surfaces were prepared by grinding to 600 grits followed by cleaning. These were then divided into two groups, with one group being the control and the other group undergoing glow-discharge treatment using oxygen. Human embryonic palatal mesenchyme cells, an osteoblast precursor, were used to evaluate the cell responses to glow-discharged and control Ti surfaces. It was observed from this study that protein production and osteocalcin production on both surfaces exhibited no significant differences during the 10-day study. Similarly, no significant differences were observed for alkaline phosphatase (ALP) specific activity during the first 7 days of incubation. However, at day 10, the ALP specific activity for control Ti surfaces was significantly higher than the ALP activity for the glow-discharged surface. Overall, this study suggested that the use of glow discharge as an alternative sterilization procedure for medical and dental implants did not inhibit osteoblast phenotypic expression.
Titanium (Ti) has been a material of choice for many orthopaedic and dental implant devices. The surface is known to be protected by Ti oxide. It has been described as passivated and highly biocompatible, with an ability to establish close bone apposition. 1-4 However, biomaterials-tissue interactions are dependent, in part, upon the surface characteristics of the implant material, surface composition and structure, oxide thickness, and surface contaminants. 5-9 It must be emphasized that the characteristics of the implant surfaces are also governed by the sterilization procedures. As a final surface preparation before implant placement, the use of a particular sterilization procedure is one of the most important criteria governing implant surface changes, thereby resulting in alterations in cellular responses.
Common sterilization procedures have included autoclaving, radiation, and dry heat treatment. 10-12 Glow discharge has also been proposed as an alternative means for the sterilization of medical devices. The glow-discharge procedure, using either air, oxygen, nitrogen, chlorine, helium, or argon, has been reported to clean the implant surface, thereby resulting in high surface energy. 13-16 It was reported that implants treated with glow discharge demonstrated the thinnest Ti oxide layer and the cleanest surface. 17 No toxic residues on the surfaces were reported when the glow-discharge process was used as a means for rapid sterilization. 18 In this study, it was hypothesized that the glow-discharge treatment would be an effective sterilization procedure for Ti implantations before implantation. As such, in vitro osteoblast responses to glow-discharged, commercially pure Ti surfaces were investigated.
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