PIXE and PIGE assessment of in vivo elemental and physical changes of a composite from a dental filling

Abstract

Simultaneous particle‐induced x‐ray emission (PIXE) and particle‐induced gamma‐ray emission (PIGE) measurements in the 0–270 keV range with a low‐energy hyperpure Ge detector have been performed on the outer surface and on an inner section of a dental composite filling extracted from a patient. The biomaterial has been identified as the fluorine‐releasing Tetric Ceram dental composite. Compared to the native material, the dental filling evidenced changes occurring during the in vivo oral use. These included mainly Cl and K accumulation and loss of Zr, Ba, Yb (by PIXE), and F (in the PIGE region). The changes were similar at the surface and inside of the dental filling for most of the above elements, indicating an unexpectedly high permeability of the material, maybe due to microscopic bulk fracture of the dental composite filling throughout its use. The PIGE spectra detected also Al and traces of Hf and Sm possibly associated with Zr and Yb. Changes in the ratio of the L lines of Yb and in the ratio of the 110‐ and 197‐keV lines of F evidenced alterations in the matrix physical properties of the composite, associated with factors such as surface roughening by wear, grain size decrease by slow dissolution, and compositional variations. Further studies are needed to gain a deeper insight into the complex changes taking place in a dental composite filling. Copyright © 2009 John Wiley & Sons, Ltd.

Proton µ‐PIXE mapping, AFM imaging and size statistics of mineral granules in a dental composite

“…2010, 39, 208-215 simple model, and thus favoring the onset of secondary caries. Similar effects -which may be expected to have more important dental consequences -may be involved in the protection by F − ions released slowly from the weakly soluble particles of YbF 3 and Ba fluoroaluminosilicate glass. Hence, µ-PIXE mapping of mineral granules and AFM imaging of surface, which examined the specimen at different spatial resolutions, offered complementary information and brought convergent insight on certain possible limits of tooth protection by Ca and F released from composites.…”

“…The relatively close dimensions may lead to a rather homogeneous local mixing of Ba-and Ca-rich particles, although opposite effects due to segregation could not be excluded; these conflicting trends may explain in this way the perceptible but low (r = 0.57) Ba-Ca correlation found from the µ-PIXE maps. Lack of information from the producer [23] about the chemical form of the Ca granules [3] prevents us to make any supposition about a possible role played by the chemical similarity of Ba and Ca in the correlation of these two elements. We shall finally refer to an outcome of major importance from the AFM findings, namely the images of the 20 × 20 µm 2 areas ( Fig.…”

“…The PIXE analysis of Ba and Yb was intended to provide indirect information relevant to the F bonded with them in weakly soluble compounds, while Zr is possibly contained in the form of ZrO2 or other chemically inert compound with a role in the mechanical strength of the composite. [3] Because the structure and properties of dental restoratives are known to fluctuate even within small samples of dimensions comparable to a dental filling (V. Fano, Institute of Physical Sciences, Parma, Italy, personal communication), particular attention is paid to the size statistics of Ca-rich grains in different areas. To correlate the µ-PIXE maps to the specimen's topography, atomic force microscopy (AFM) [22] imaging of the surface landscape was performed.…”

Estudio de los cambios de la composición química de un ionómero vítreo mediante la técnica de PIXE

“…El efecto de estas bebidas en el color y la microdureza de los materiales de restauración varía en función de las características intrínsecas de dicho material, tales como su composición química [16,18,20]. Se ha encontrado que la alteración química lenta de las restauraciones dentales puede ir acompañada por la liberación de elementos quimicos, y estos pueden producir ciertos efectos biológicos [21,22]. Por otro lado, los espacios pequeños entre la restauración y la estructura dental pueden llevar a la colonización por bacterias y al desarrollo de caries secundaria, una de las principales causas de fracaso de la restauración [2].…”

“…En general, los daños superficiales, la liberación y la absorción de iones inorgánicos y la acción bacteriana alteran las propiedades de los ionómeros de vidrio y limitan la longevidad de una restauración dental. Estos procesos requieren el estudio de la química y la física de superficies, que son fenómenos diferentes de los del volumen interno, y su estudio por consiguiente, requiere de métodos específicos [21][22][23]. La técnica de PIXE es adecuada para acercarse a este tipo de problemas debido a su capacidad para el análisis de elementos traza en una capa fina de material [21][22][23][24][25].…”