In vitro assessment of solvent evaporation from commercial adhesive systems compared to experimental systems

ABSTRACT

Solvents should be properly evaporated after application to dental substrates. The aim of this study was to assess the evaporation of commercial, experimental and neat solvents. The tested null hypotheses were that there are no differences in solvent evaporation regardless of its formulation and over time. Evaporation from commercial adhesive systems (Scotchbond Multipurpose Primer, Scotchbond Multipurpose Adhesive, Prime & Bond NT, Multi Bond, Excite, Single Bond 2, Adhese Primer, Adhese Bond, Xeno III A and Xeno III B) and experimental primers (35 percent HEMA plus 65 percent acetone or ethanol or water v/v) were compared to neat solvents (acetone, ethanol and water). Samples (10 µL) of these products were dripped into glass containers placed on a digital precision balance. Evaporation was assessed at 0, 5, 10, 15, 30, 60, 120, 300 and 600 s times to calculate mass loss. Data were analyzed statistically by ANOVA and Bonferroni's correction (a=0.05). Acetone-based products exhibited a remarkable capacity to evaporate spontaneously over time. Neat acetone evaporated significantly more than the HEMA-mixtures and the commercial formulations (p<0.05). The incorporation of monomers and other ingredients in the commercial formulations seem to reduce the evaporation capacity. Solvent evaporation was time and material-dependent.

RESUMO

O solvente deve ser adequadamente evaporado após aplicação ao substratos dentários. O objetivo deste estudo foi avaliar a evaporação de formulações comerciais, primers experimentais e solventes puros. As hipóteses nulas testadas foram de que não há diferenças da quantidade evaporada independentemente do material e tempo. Evaporação dos sistemas adesivos comerciais (Scotchbond multipurpose primer, Scotchbond multipurpose adhesive, Prime & Bond NT, Multi Bond, Excite, Single Bond 2, Adhese Primer, Adhese Bond, Xeno III A e Xeno III B) e primers experimentais (35 por cento HEMA associado com 65 por cento acetona, etanol ou água v/v) foram comparadas a solventes puros (acetona, etanol e água). Amostras (10 µL) de cada produto foram dispensadas em balança de precisão digital. As massas nos tempos 0, 5, 10, 15, 30, 60, 120, 300 e 600 s foram registradas. Os dados foram analisados estatisticamente por ANOVA e Bonferroni (a=0,05). Produtos a base de acetona exibiram maior capacidade de evaporação espontânea ao longo do tempo. Acetona pura evaporou significantemente mais que as misturas de HEMA e formulações comerciais (p<0,05). A incorporação de monômeros e outros ingredientes nas formulações comerciais reduzem a capacidade de evaporação. A evaporação é dependente do produto e do tempo.