PROPRIEDADES MECÂNICAS DE RESINA COMPOSTA ORTODÔNTICA EXPERIMENTAL CONTENDO SILICATO DOPADO DE PRATA

Abstract

Introduction: Bracket detachment during orthodontic treatment is a situation that can lead to delays in orthodontic mechanics, increased costs and patient dissatisfaction in relation to the total treatment time. To investigate new materials for the purpose of bonding orthodontic accessories, it is necessary to evaluate their mechanical properties through the strength of bond strength, surface microhardness and roughness to observe whether they will be suitable for the use of the appliance, guaranteeing the survival of the bracket throughout the entire treatment period. The incorporation of antimicrobial agents into adhesive systems and resins can affect their mechanical properties, making them unsuitable for clinical practice. Thus, the objective of this study was to compare the mechanical properties of an experimental orthodontic composite resin with silver(Ag)- doped silicate with commercial orthodontic adhesive systems, to evaluate whether the addition of Ag has an influence on the mechanical properties of the orthodontics adhesive systems. Methods: 36 bovine incisor teeth, enamel defects and cracks free, were selected and randomly divided by simple draw into 3 groups (n=12), Transbond group, Biofix group and Exp Ag group. A bracket was attached to the central portion of the buccal surface of each tooth using the same bonding protocol, only varying the resin according to each group, the teeth were stored for 24 hours in distilled water in an stove at 36.5°C then subjected to the shear test for bracket detachment, the shear bond strenght (SBS) was calculated using the formula SBS(Mpa) = Force (N)/A(mm2), then the tooth was taken to the scanning electron microscope (SEM) at 50x magnification to assesss the adhesive remnant index (ARI) score, 5 discs were crafted of each resin tested for surface microhardness and roughness analyses. Results: It was observed that the Transbond group presented higher SBS than the other study groups (P <0.001). There were significant differences in the ARI score between the groups (P = 0.041). Roughness was higher in the Transbond group (P <0.001), the Exp Ag group presented intermediate values. The microhardness variable was higher in the Transbond group than the other two groups (P <0.001), while the Biofix and Exp Ag groups did not show significant differences between them. Conclusion: The findings suggest that the experimental resin with Ag- doped silicate has mechanical properties suitable for orthodontic clinical practice and the addition of Ag did not influence the mechanical properties of the resin. Future studies are required to assess the antimicrobial properties of the experimental composite resin with Ag-doped silicate studied.