Atomic and nuclear surface analysis methods for dental materials: A review

Abstract

The development of dental biomaterials is now on the rise, with new materials created at a high rate and in large variety. Yet, considerable effort is needed to improve their physical–chemical characteristics as well as their biotolerance, biocompatibility and osseointegration, and to extend their longevity. Foremost, the new dental biomaterials are confronted with surface phenomena occuring at their interface with the oral tissues and environment, which produce degradation by corrosion, dissolution and wear. To control them, nondestructive instrumental methods for the investigation of surface chemistry and physics are needed. A comprehensive insight requires also the mapping of elemental, chemical and structural information. Appropriate methods can be among other electron probe microanalysis, laser Raman spectromicroscopy, confocal fluorescence and atomic force microscopy. However, atomic and nuclear surface analysis methods qualify chiefly. They reach unsurpassed sensitivity in elemental analysis and are unique by depth profiling capabilities of layers 1 nm–100 µm thick and by surface mapping. Some techniques can provide also chemical and electronic information. Here we treat the most widely used ion beam analysis (IBA) and X-ray spectrometry (XRS) methods and some related techniques; all make use of incident and emergent beams of radiation and particles to analyze the specimen. Basic principles, practical aspects and applications in dental biomaterials’ research are reviewed comparatively for each technique, with its highlights and limitations. Noteworthy, new microprobe low energy heavy ions accelerators and electron synchrotrons are now commissioned; thus proton and X-ray microbeams are available for surface mapping at micrometer resolution. The reviewed applications cover ceramics, calcium phosphates, glasses, polymers, adhesives, composites, glass ionomers, endodontic materials, silver amalgam, alloys, titanium implants and their coatings, and oral tissues contamination with released elements (sometimes cytotoxic). The present survey is expected to be a representative sampling of a mature topic, typified by the sustainably high dynamics of publications.