ABSTRACT
OBJECTIVES: To evaluate the effect of post-curing times on the color change, flexural strength (FS), modulus (FM) and microhardness at different depths of four 3D printed resins. MATERIALS AND METHODS: A characterization of the light emitted by 3D-resin post-curing unit (Wash and Cure 2.0, Anycubic) was performed. The tested 3D printed resins were Cosmos Temp3D (COS), SmartPrint BioTemp (SM) Resilab3D Temp (RES) and Prizma3D BioProv (PRI) were evaluated under five different post-curing conditions (no post-curing or 5-, 10-, 15, and 20 min of post-curing). For color change analysis, 10 mm diameter x 1 mm thick discs (n = 7) were printed, and the luminosity, color and translucency were measured before post-curing as control, and repeatedly after 5 min cycles of post-curing until a total of 20 min was reached for ΔE00 [CIED2000 (1:1:1)] calculation. For FS and FM, 25 × 2×2 mm (n = 10, for each post-curing time) 3D printed bars were subjected to a 3-point being test. Knoop microhardness (KHN) was measured transversally on 5 × 5×5 mm blocks (n = 10, for each post-curing time). Color results were analyzed by one-way repeated measures ANOVA (factor: color change). FS and FM were analyzed by two-way ANOVA (factors: Material*Post-Curing Time). KHN was analyzed individually for each material by two-way ANOVA (factors: Depth*Post-Curing Time). RESULTS: The post-curing time significantly influenced the ΔE00, FS, FM and KHN of all the evaluated materials. COS and SMA presented ΔE00 values above the acceptability threshold after 5 and 10 min of post-curing, respectively. The FS of RES reached a plateau after 5 min of post-curing, and for PRI and SMA, the FS stabilized after 10 min of post-curing. The post-curing process improved the KHN of the tested materials, and longer exposure periods were associated to higher KHN values at all the evaluated depths. SIGNIFICANCE: A fine adjustment of the post-curing time is crucial to produce adequate mechanical properties in 3D-printed restorative resins, while minimizing the color alterations on the restorations. For the evaluated resins, 5-10 min of post-curing will result in adequate mechanical properties, without affecting the acceptability in the color of the material. However, the results are material-dependent, and evaluation of each specific resin is advised.
Subject(s)
Composite Resins , Flexural Strength , Materials Testing , Printing, Three-Dimensional , Surface PropertiesABSTRACT
OBJECTIVE: To evaluate coating materials regarding color and roughness changes when applied over a composite resin. MATERIALS AND METHODS: Specimens were made using Filtek Supreme Ultra. Coating materials were applied over the specimens' surface: Control (CTRL); Adper Single Bond Plus (SB); Scotchbond Universal (US); Clearfil SE (CL); Ambar APS (APS); Bioforty (BF); Fortify (FF); PermaSeal (PS); G-CoatPlus (GC). Specimens were evaluated regarding color changes (∆E00 ) using spectrophotometer (n = 10); surface roughness (Ra), using optical profilometer (n = 10); surface topography, using scanning electron microscopy (n = 1); and thickness of material, using optical microscopy (n = 1). Analyses were made before and after 24, 72, and 168 hours of storage in wine, used as a staining solution. Data was statistically analyzed using analysis of variance, Tukey and Pearson tests (α:.05). RESULTS: None of the materials presented color stability. ∆E00 increased with increasing storage time at red wine, until 72 hours. BF, FF, PS, SB, and CTRL presented the lowest ∆E00 after 24 hours. APS presented the highest ∆E00 (32.59; P < .05). Regarding roughness, initially, surface sealants and APS presented the lowest values. After 168 hours, GC presented the lowest Ra (0.60; P < .05). CONCLUSIONS: All the materials presented color and roughness changes after storage in red wine. CLINICAL RELEVANCE: Some coating materials can be applied over the surface of RBC restorations without changing its color stability or surface roughness.
