Morphological and compositional alterations of in vivo aged prefabricated pediatric metal crowns (PMCs)

Objectives The purpose of the present study was to assess the morphological and elemental alterations of retrieved prefabricated metal crowns (PMCs) after intraoral exposure. Methods Seventeen in vivo aged stainless steel crowns (3M ESPE) were collected. The intraoral exposure time varied from 3 to 101 months. For every retrieved crown one new crown of the same type was used as a reference. The reference and in vivo aged crowns were examined by high-vacuum scanning electron microscopy and energy-dispersive X-ray microanalysis. The elemental composition between the as-received and in vivo aged crowns was statistically analyzed by t-test (a = 0.05). Results In vivo aged crown surfaces demonstrated significantly morphological alterations with accumulation of amorphous intraoral integuments, biting imprints, wear and occlusal perforations. The results of microanalysis showed that there were no statistically significant differences in the elemental composition of the stainless steel crowns between the two conditions. Significance Under the conditions of the present study, retrieved prefabricated pediatric stainless steel crowns exhibit morphological changes mainly due to plastic deformation, without changes in elemental composition.