Evaluation of the physical-mechanical and antimicrobial performance of a glass ionomer cement modified by phosphate nanoparticles and phosphorylated chitosan used to bond orthodontic brackets: an in vitro study

Abstract

The aim of this study is to evaluate the effect of incorporating sodium trimetaphosphate nanoparticles (TMPnano) and phosphorylated chitosan (Qui-Ph) in resin-modified glass ionomer cement (RIMC) used for cementation of orthodontic brackets, on the physical-mechanical and antimicrobial properties. Specimens of each material will be made: 1) CIVMR without TMPnano/Qui-Ph (Positive Control-Fuji Ortho LC); 2) CIVMR with 14% TMPnano (CIVMR-TMPnano); 3) CIVMR with 0.25% Qui-Ph (CIVMR-0.25%Chi-Ph; 4) CIVMR with 0.5% of Qui-Ph (CIVMR-0.25%Chi-Ph; 5) CIVMR with 14% of TMPnano and 0.25% of Qui-Ph (CIVMR-TMPnano-0.25%Qui-Ph) and 6) CIVMR with 14% of TMPnano and 0.5% of Qui-Ph (CIVMR-TMPnano-0.5%Qui-Ph). The physical-mechanical properties of the CIVMRs will be determined: diametrical tensile strength (RTD), compressive strength (CR), hardness (D), and shear strength (RC). The antimicrobial and antibiofilm activity will be evaluated by means of the Streptococcus Mutans adhesion test and biofilm assay. For statistical analysis, the values of the physical-mechanical and microbiological tests will be considered as variables (resistance to diametrical traction - kgF/cm2, compression - MPa and hardness of materials - KHN; shear strength - RC and CFU/ml); and as a variation factor the type of CIVMR. The statistical program SigmaPlot for Windows version 12.0 will be used, with significance at 5% level to submit the data to normality and homoscedasticity tests. After the analysis, if there is no normal distribution, the Kruskal-Wallis test will be used for non-parametric tests. If the data distribution presents normality criteria, the ANOVA variance test will be performed, with the variance factor being the type of MICR followed by the Student-Newman-Keuls test to verify the differences between the groups.(AU)