Influence of pulse-delay curing on sorption and solubility of a composite resin

Abstract

The purpose of this study was to evaluate the sorption and solubility of a composite resin (TPH3; Dentsply) cured with halogen light due to different storage media and curing modes. The methodology was based on the ISO 4049 standard. Two independent groups were established according to the storage time (7 days-G1; 60 days-G2). A stainless steel mould (2 mm x 8 mm ø) was used. The selected curing modes were: I (Conventional - C): 40s - 600 mW/cm2; II (Pulse I - PD): 3 s - 200 mW/cm2 + 2 min (delay) + 39 s - 600 mW/cm2; III (Pulse II): 10 s - 200 mW/cm2 + 2 min (delay) + 37 s - 600 mW/cm2; IV (Pulse III): 3 s- 600 mW/cm2 + 2 min (delay) + 37 s -600 mW/cm2. The media used were: distilled water, 75% ethanol and 100% chlorophorm. Five repetitions were made for each group. The specimens were placed in a desiccator at 37°C for 24 h and, after that, at 23°C for 1 h to be weighed until a constant mass (m1) was obtained. The discs were immersed separately into the 3 media for 7 days (G1) and 60 days (G2), and thereafter reweighed (m2). The reconditioning in the desiccator was done until a constant mass (m3) was obtained. Sorption and solubility were calculated and the data of G1 and the sorption data of G2 were subjected to two-way ANOVA and Tukey's tests (p=0.05). The solubility data of G2 were analyzed by Kruskal-Wallis test (p=0.05). For G1 and G2, no statistically significant differences were found in sorption among curing techniques (p>0.05). The solubility values were negative, which means that there was mass gain. Regarding the storage media, in G2 chlorophorm had the highest sorption values. It may be concluded that the curing modes (C and PD I, II and III) did not affect the sorption of the tested composite resin. However, different storage media influenced sorption behavior. The solubility test demonstrated negative data, masking the real solubility.

Water sorption and solubility of bulk-fill composites polymerized with a third generation LED LCU

“…18 In other studies, it has been suggested that negative values may be the result of hydrogen bonds connecting the absorbed water molecules to polar groups of the polymer chains, which cannot be removed entirely. 31,32 As a result, Filtek Z250 showed higher water sorption values in all curing modes when compared with bulkfill composites. In terms of water solubility, the SonicFill bulk-fill composite showed the highest value among the groups, so that the null hypothesis was rejected.…”

“…Negative solubility results have also been reported in other studies. 18,31,32 In some studies, these negative values have been explained by possible hydrolytic chemical reactions that result in the formation of metal hydroxides on the filler surface. 18 In other studies, it has been suggested that negative values may be the result of hydrogen bonds connecting the absorbed water molecules to polar groups of the polymer chains, which cannot be removed entirely.…”

Changes in Water Sorption and Solubility of Dental Adhesive Systems after Cigarette Smoke

“…Two possible explanations for the negative solubility values are assumed. The first one was that the absorbed water during storage period may have not been completely eliminated, and consequently mass gain was obtained [27, 30, 32]. Secondly, the volatile smoke compounds may be linked to the adhesive systems specimens and led to increase the mass values.…”

“…Previous studies of water sorption and solubility have mainly been conducted in water [18, 19, 22, 24], artificial saliva [25], lactic acid [26], different pH beverages [23], ethanol, and chloroform [27]. To date, the ability of volatile compounds released during the cigarette combustion to affect the water sorption and solubility of resin-based materials is not yet described.…”

Comparação das propriedades de sorção e solubilidade de cimentos submetidos a diferentes soluções e tempos de armazenagem

“…Este fato também está de acordo com o trabalho de Lopes et al (2008), que também encontraram valores de solubilidade negativos, o que indica que o cimento é mais sensível à sorção de água levando ao ganho de massa, que poderia mascarar a solubilidade real. Isso não significa que não ocorreu solubilidade, mas que a sorção de água foi maior que a solubilidade [22] . Tanto a sorção quanto a solubilidade são dependentes da composição química dos materiais resinosos.…”