Biocorrosion study of titanium-nickel alloys

A classification of the mechanisms producing pathological tissue changes

The objectives are to present a classification of mechanisms which can produce pathological changes in body tissues and fluids, as well as to clarify and define the term biocorrosion, which has had a singular use in engineering. Considering the emerging field of biomedical engineering, it is essential to use precise definitions in the lexicons of engineering, bioengineering and related sciences such as medicine, dentistry and veterinary medicine. The mechanisms of stress, friction and biocorrosion and their pathological effects on tissues are described. Biocorrosion refers to the chemical, biochemical and electrochemical changes by degradation or induced growth of living body tissues and fluids. Various agents which can affect living tissues causing biocorrosion are enumerated which support the necessity and justify the use of this encompassing and more precise definition of biocorrosion. A distinction is made between the mechanisms of corrosion and biocorrosion.

Evaluation of titanium in oral conditions and its electrochemical corrosion behaviour

Due to its excellent biocompatibility and good mechanical properties, titanium has been used successfully in dentistry for many years. In this study, complete dentures with titanium palatal plates were applied to 10 patients who were in need of upper dentures. The clinical performance of cast titanium palatal plates was determined over a period of 6 months. No increase in accumulation of denture plaque nor mucosa irritation was observed. After the above period, the electrochemical corrosion behaviour of cast titanium and chromium-cobalt palatal plates were compared with the titanium plates that were not left in an oral environment after casting. For the electrochemical corrosion tests, a corrosion cell was designed and artificial saliva with lactic acid was used, with the temperature during the tests being about 37 degrees C. The potential difference between the test sample and the saturated calomel electrode was measured, and after the determination of the rest potentials, the anodic potentiodynamic polarization curves were traced at a rate of 1 mV/s. From the standpoint of corrosion, the titanium plates used by the patients for a 6-month period corroded more than the titanium not used by the patients. This may be due to the casting and processing conditions and the effect of the oral environment.

Dental materials: 1996 literature review

This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.