Physical properties of two bis-acryl interim materials: color stability, flexural strength and shear bond strength to flowable composite resin as add-on material

摘要

Aims: The objective of this study was to evaluate the mecha- nical properties of two bis-acryl interim resin materials, such as color stability, exural strength and shear bond strength to owable composite resin, simulating clinical situations when this material has to be used for repair as add-on. Two shades of two bis-acryl interim resin materials [Structur 2 SC (shades Bleach and A2); Protemp 4 (shades A1 and A2)] were evaluated. Discs (5 x 1 mm) were fabricated and ba- seline color was determined after 1 h. Ten specimens were immersed at 37oC in solutions of distilled water (control) and cola-based soft drink (Coca-Cola). Color measurements were performed with a spectrophotometer using CIELab pa- rameters. Color readings were again measured after 2 hours, 4 hours, 24 hours and 7 days. Flexural strength was deter- mined using the three-point bending test (10 x 1 x 2 mm) on a universal testing machine (0.5 mm/min) (n = 10). Discs of bis-acryl resin were embedded in acrylic resin, planned and distributed in 2 groups: G1 - Filtek Z350 Flow/Protemp4 and G2 - Grandio SO Flow/Structure 3 (n = 15). Cylinders (3.5 x 2 mm) were made with the owable composite resins and polymerized for 20 s. The specimens were stored in distilled water at 37oC for 24 h and subjected to shear bond strength test. Data were analyzed using one-way ANOVA and Tukeya€?s test (?± = 0.05). ?”E values were higher for Structur Bleach (3.08)a compared with Protemp 4 (shade A1, 2.22)b (shade A2, 2.25)b. There were no signi cant differences between Structur Bleach and Structur A2 (2.62)ab. Coca-Cola presen- ted higher ?”E values (3.08)a than (2.00)b. Regarding time, ?”E values increased from 1.84a after 2 h to 2.31b after 4 h. The higher values were observed after 24 h and 7 days (2.93c and 3.09d, respectively). No signi cant differences were observed for the exural strength of Structur (22.05 MPa)a and Protemp 4 (19.01 MPa)a. The repairs executed with Structur/Grandio ow (9.21 MPa)a were similar to those performed with Pro- temp 4/Z350XT ow (10.71 MPa)a. It can be concluded that the two bis-acyl resins evaluated showed similar physical and mechanical properties.