INFLUÊNCIA DO MEIO DE ARMAZENAMENTO SOBRE AS PROPRIEDADES FÍSICO QUIMICAS E BIOATIVIDADE DE CIMENTOS ENDODÔNTICOS

Abstract

Bioceramic sealers were introduced in endodontics in order to overcome the biological limitations that conventional endodontic sealers present. Current literature shows that bioceramic endodontic sealers have good radiopacity, fluidity, working time, pH alkalinization capacity, antibacterial activity and biocompatibility. However, it has as a disadvantage, solubility higher than the required standard ISO 6876/2012, which determines that an endodontic sealer must not exceed 3% of mass loss after immersion in distilled water. However, criticisms have been made of this methodology since distilled water does not represent the medium to which these materials are actually exposed. Therefore, modifications in the sorption and solubility tests have been carried out using a phosphate saline solution (PBS) as a storage medium, concluding that bioceramic sealers are less soluble when immersed in PBS. It is speculated that the lower solubility is justified by the deposition of a layer of hydroxyapatite that fills the voids generated by the solubility. The present study proposed to evaluate the influence of a high concentrated storage medium (SBF) on the properties of sorption, solubility, fluid absorption, bioactivity and pH alkalinization capacity of a bioceramic sealer (BioRoot RCS) and a resin-based cement epoxy (AH Plus). 24 samples were made for each sealer tested, which were subsequently randomly divided into 3 experimental groups (n = 8). The samples were desiccated for 30 days, weighed and stored in containers containing 5ml of distilled water, PBS or SBF. The pH readings and weighings were performed after 24 hours, 48 hours, 7, 30, 60 and 90 days. To analyze the formation of precipitates, 2 specimens from each group were selected and taken for observation using scanning electron microscopy (SEM) and composition reading by dispersive energy spectroscopy (EDS). The data of sorption / solubility / fluid absorption were found in TwoWay Analysis of Variance (Solution vs. Cement) and Holm-Sidak test ( = 0.05) for contrast medium. An analysis of pH, SEM and EDS, were performed descriptively. The AH Plus was not influenced by the storage solution, for all evaluated properties (p> 0.05). BioRoot presents greater solubility when immersed in SBF, followed by water and PBS, which are not differentiating between themselves. There was formation of precipitates on the surface of the BioRoot sample only in PBS and SBF. AH Plus maintained a neutral pH, while BioRoot was able to alkalinize the medium. Therefore, the storage medium influenced by physicalchemical properties and the bioactive potential of bioceramic sealer. However, conventional tests of sorption, solubility and fluid absorption performed in distilled water should not be indicated for bioceramic sealers, since they do not present evidence on in vivo behavior and still mask their bioactivity, which is the main differential material.