In vitro microscopic changes of dental amalgam test bodies subjected to high temperatures observed by scanning electron microscopy

Abstract

Objective: describe the in vitro microscopic changes of dental amalgam test bodies subjected to high temperatures observed by scanning electron microscopy. Materials and methods: descriptive observational cross-sectional study of pseudo-experimental nature that analyzed by scanning electron microscopy (SEM) the in vitro behavior of 27 test bodies elaborated in three brands of dental amalgam (Contour® Kerr®, Admix® SDI® and Nu Alloy® Newstethic®) subjected to high temperatures (200ºC, 400ºC, 600ºC). Results: the three trademarks of dental amalgam used in this study had a similar behavior, except for the behavior of silver nodules. These appeared to 200ºC in the test bodies of Admix® SDI® and 400ºC in the test bodies of Contour® Kerr® and Nu Alloy® Newstethic®. The analysis of scanning electron microscopy and spectrophotometry at the surface of the test bodies showed the statistically significant increase (p<0.05) the percentage of atomic weight of mercury, copper and tin. Conclusions: the test bodies of the three trademarks of dental amalgam undergo changes in their microstructure so long as the temperature increases. The formation of silver nodules was explained as a consequence of the behavior of the gamma 1 phase silver-mercury with increasing temperature, which begins to dissociate at 200ºC in the test bodies of Admix® SDI® and 400ºC in the test bodies of Contour® Kerr® and Nu Alloy® Newstethic®.