A comparison of microhardness of indirect composite restorative materials

Abstract

The purpose of this study was to compare the microhardness of four indirect composite resins. Forty cylindrical samples were prepared according to the manufacturer’s recommendations using a Teflon mold. Ten specimens were produced from each tested material, constituting four groups (n=10) as follows: G1 - Artglass; G2 - Sinfony; G3 - Solidex; G4 - Targis. Microhardness was determined by the Vickers indentation technique with a load of 300g for 10 seconds. Four indentations were made on each sample, determining the mean microhardness values for each specimen. Descriptive statistics data for the experimental conditions were: G1 - Artglass (mean ±standard deviation: 55.26 ± 1.15HVN; median: 52.6); G2 - Sinfony (31.22 ± 0.65HVN; 31.30); G3 - Solidex (52.25 ± 1.55HVN; 52.60); G4 - Targis (72.14 ± 2.82HVN; 73.30). An exploratory data analysis was performed to determine the most appropriate statistical test through: (I) Levene's for homogeneity of variances; (II) ANOVA on ranks (Kruskal-Wallis); (III) Dunn's multiple comparison test (0.05). Targis presented the highest microhardness values while Sinfony presented the lowest. Artglass and Solidex were found as intermediate materials. These results indicate that distinct mechanical properties may be observed at specific materials. The composition of each material as well as variations on polymerization methods are possibly responsibles for the difference found in microhardness. Therefore, indirect composite resin materials that guarantee both good esthetics and adequate mechanical properties may be considered as substitutes of natural teeth.

Effects of simulated gastric juice on color stability, surface roughness and microhardness of laboratory-processed composites

“…Despite the high microhardness value of SOL prior to its exposure to gastric juice, it was the most affected material with the largest ΔVHN value. Its chemical composition influenced the degree of conversion during polymerization, resulting in lower resistance to indentation 33) . The material least affected by gastric juice was SIN, whereby its polymerizable monomer had no hydrophilic group.…”

Avaliação da microdureza e da rugosidade de compósitos resinosos de uso direto e indireto

“…As restaurações confeccionadas com resinas compostas que apresentem menor microdureza são supostamente menos resistentes aos esforços mastigatórios e apresentam menor longevidade clínica 21,22 . As propriedades dos compósitos são influenciadas pelo tamanho, tipo e volume das partículas de carga e pela proporção com que essa carga é aderida à sua matriz resinosa 23 . Alguns autores evidenciaram que quanto maior a quantidade de carga de um compósito maior será a sua microdureza 24,25 .…”

Avaliação Comparativa da Resistência à Compressão Entre uma Resina Composta Direta e Duas Resinas Laboratoriais

“…As propriedades dos compósitos são influenciadas pelo tamanho, tipo e volume das partículas de carga, e pela proporção que essa carga é aderida à sua matriz resinosa (MIRANDA et al, 2003). O conhecimento da composição do material nos possibilita uma estimativa de seu comportamento mecânico.…”