Evaluation of microhardness, sorption, solubility, and color stability of bulk fill resins: a comparative study

• Luís-Felipe Espíndola-Castro ^[1] ; Márcia-de Almeida Durão ^[1] ; Tacyandra-Victória-Gomes Pereira ^[1] ; Ayanne-Karine-de Barros Cordeiro ^[1] ; Gabriela-Queiroz-de Melo Monteiro ^[1]
  1. [1] Universidade de Pernambuco

     Universidade de Pernambuco

     Brasil

     
• Localización: Journal of Clinical and Experimental Dentistry, ISSN-e 1989-5488, Vol. 12, Nº. 11 (November), 2020, págs. 1033-1038
• Idioma: inglés
• Enlaces
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• Resumen

  • Due to the increasing popularity of bulk fill resins, there is a concern that their components can be leached; this is because these are inserted in a single 4-5 mm increment. This in vitro study evaluated the microhardness, sorption, solubility, and color stability of three restorative bulk fill resins, namely: Filtek Bulk Fill (FBF), Tetric N-Ceram Bulk Fill (TNC), and Opus Bulk Fill (OBF).

    Cylindrical samples were fabricated to be 15 mm in diameter and 1 mm thick (n = 10). For the microhardness test, three random indentations were formulated on the samples using a micro-durometer with a load of 300 gf for 15 s. Sorption and solubility were then evaluated (ISO 4049: 2009). Color stability was analyzed with a digital spectrophotometer three times (initially, after 24 h, and after 7 d) during immersion in coffee and distilled water (control). The Shapiro-Wilk test was applied to analyze normality. The Mann-Whitney and Kruskal-Wallis tests were used to compare the groups and the immersion solution, with a significance level of 5%.

    There were a significant difference in microhardness (p<0.001), with the FBF group showing a higher value compared to the other groups (56.38). The highest average of sorption scores was observed in the OBF group (16.9 µg / mm3), followed by FBF (16.8 µg / mm3) and TNC (11.3 µg / mm3). Solubility was lowest in the OBF group (-2.83 µg / mm3), with a significant difference (p = 0.031). There was also a significant difference after 24 h in the mean ∆E score of all groups (p<0.005). After one week of immersion, the group that pigmented most was OBF (p = 0.008).

    The three bulk fill resins had acceptable hardness, sorption, and solubility values. However, all groups showed a high pigmentation rate after 7 d of immersion in coffee.