Avaliação da influência da agitação ultrassônica no tempo de presa, estabilidade volumétrica e na capacidade de formação de apatita de três cimentos reparadores endodônticos

Abstract

This study investigated the influence of ultrasonic agitation (UA) on the curing time, volumetric stability, and capacity of hydroxyapatite formation of three endodontic cements: White MTA-Angelus (MTA), MTA Repair HP (MTAHP), and Biotine (BIO). Six experimental groups were evaluated, being them divided according to the material to be tested and to the use or not of UA. The curing time assay was performed according to the ISO 6876/2012. The volumetric stability (mm3) was analyzed through microtomography by comparing the volume of the retrograde cavities filled with the cements submitted or not to UA. This analysis was made before and after a seven-day period during which the specimens remained immersed into water. The morphological and chemical analyses of the surface of the materials tested were made using energy dispersion X-ray stereoscopy (EDX) after 28 days of immersion in Hank’s balanced salt solution (HBSS). The results show that the ultrasonic agitation influenced differently the curing time of the different cements tested. The initial setting time of the MTA was increased (40.8/64.6), while for the BIO, it was decreased (35.6/22.4). The final setting time of the BIO (64.4/42.4) and MTAHP (154.4/114.6) was decreased (P<.05). All the groups exhibited volumetric reduction, and the volumetric stability was not affected by the ultrasonic agitation (P>.05). All the cements tested presented favorable Ca/P proportion on their surface after 28 days of immersion in HBSS. The ultrasonic agitation fragmented and dispersed homogeneously the particles. Given the exposed, it can be concluded that the ultrasonic agitation differently influenced the materials tested. Also, all the cements remained volumetrically stable during the experiment and presented the capacity to form calcium and phosphate deposits on their surfaces, which was intensified by the ultrasonic agitation.