Journal of Oral Implantology February 2014 - (Page 3)

RESEARCH Electrochemical Behavior of Titanium in Artificial Saliva: Influence of pH Savithri Abey, DDS1 Mathew T. Mathew, PhD2 Damian J. Lee, DDS, MS3 Kent L. Knoernschild, DMD, MS3 Markus A. Wimmer, PhD2 Cortino Sukotjo, DDS, PhD3* Titanium is the most common material chosen for dental implants because it is highly corrosion resistant because it constantly reforms a protective passive film layer. The formation and composition of the passive film layer is dependent on the environmental conditions. If the stable oxide layer is damaged, the titanium surface underneath can corrode. The purpose of this study was to determine if basic corrosion of commercially pure titanium (CpTi) alloy in artificial saliva was affected by pH and to understand the corrosion kinetics/mechanisms of CpTi as a function of pH. In this study, titanium alloy discs were subjected to corrosion tests. Before the tests, all samples were cleaned and polished using standard metallographic preparation methods. Artificial saliva was used as the testing medium. The following pH values were tested: 3.0, 4.5, 6.0, 6.5, 7.5, and 9.0. Different pH values were achieved by adding lactic acid (acidic) or NaOH (basic) in appropriate amounts. Potentiodynamic curves indicated behavior change at each pH. In addition, the corrosion current density value determined from the potentiodynamic curve exhibited the poorest corrosion resistance for pH 7.5. The Nyquist plot (from the electrochemical impedance spectroscopy results) indicated that pH 7.5 had the poorest resistance. Scanning electron microscopy images indicated that pH levels of 6.5, 7.5, and 9.0 had considerable surface corrosion. The results showed that the media's pH significantly influenced the corrosion behavior of CpTi. The poor corrosion behavior at the neutral pHs invites some concerns and highlights the need for further study. Key Words: titanium, corrosion, biocompatibility, artificial saliva, electrochemical impedance spectroscopy INTRODUCTION 1 Department of Restorative Dentistry, School of Dentistry, Indiana University, Indianapolis, Ind. 2 Department of Orthopedics, Rush University Medical Center, Chicago, Ill. 3 Department of Restorative Dentistry, Comprehensive Dental Implant Center, University of Illinois at Chicago, College of Dentistry, Chicago, Ill. * Corresponding author, e-mail: csukotjo@uic.edu DOI: 10.1563/AAID-JOI-D-11-00054 T itanium (Ti) is the most widespread material used for dental implants because of its mechanical properties, exceptional corrosion resistance, and biocompatibility.1-3 Although Ti alloys are highly corrosion resistant because of the stability of the TiO2 oxide layer, they are not inert to corrosive attack. When the stable oxide layer is broken down Journal of Oral Implantology 3

Table of Contents for the Digital Edition of Journal of Oral Implantology February 2014

Evolution of Bone Grafting for Improved Predictability
Electrochemical Behavior of Titanium in Artificial Saliva: Influence of pH
Efficacy of Antibacterial Sealing Gel and O-Ring to Prevent Microleakage at the Implant
Wired/Classic and Wireless/Periotest ‘‘M’’ Instruments: An In Vitro Assessment of
Altered Position of the Medial Lingual Nutritional Foramina at Different Stages of Alveolar
Genotoxicity of Endosseous Implants Using Two Cellular Lineages In Vitro
Implants With Internal Hexagon and Conical Implant-Abutment Connections: An In Vitro
Stress Distribution Around Maxillary Anterior Implants as a Factor of Labial Bone Thickness
Peri-Implant Biomechanical Responses to Standard, Short-Wide, and Mini Implants
Removal Torque Analysis of Implants in Rabbit Tibia After Topical Application of
Nonprocessed Adipose Tissue Graft in the Treatment of Peri-Implant Osseous Defects in
Assessment of the Effect of Two Occlusal Concepts for Implant-Supported Fixed
Nerve Damage Assessment Following Implant Placement in Human Cadaver Jaws:
Dental Implants: Early Versus Standard Two-Stage Loading (Animal Study)
Intravenous Sedation for Implant Surgery: Midazolam, Butorphanol, and
Nanocrystalline Hydroxyapatite-Based Material Already Contributes to Implant Stability
Two Neglected Biologic Risk Factors in Bone Grafting and Implantology: High Low-Density

Journal of Oral Implantology February 2014