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This short report evaluated the differences in stress concentration and the load to fracture of multilayered and monolayer glass ceramic discs. Using a static structural analysis, the 3D model of the discs received a load of 150N and results in maximum principal stress were obtained. For the in vitro analysis, the samples (ø 12 mm) were submitted to a compressive test (100kgf, 1mm/min). The data was analyzed using one-way analysis of variance and Tukey test (α=5%). The monolayer group showed a lower stress peak (129.24 MPa) and higher load to fracture (118.38N) than the multilayered group with 211.04MPa and 48.34N, respectively. All samples presented catastrophic failure with its origin on the tensile surface. Therefore, the monolayer ceramic group showed superior mechanical behavior than the multilayered group.

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Objetives: this study aimed to fabricate electrospun-based polyetherimide (PEI) fibers, under controlled parameters, and to perform a diameter analysis for potential mechanical improvement of dental materials. Material and Methods: PEI pallets (0.75 g) were dissolved in 2 mL of chloroform and then processed by electrospinning, under a flow rate of 1mLh1 , three different electrical voltages (10kV, 15kV and 20kV) and three distances (10 cm, 15 cm and 18 cm) between the needle tip and collector. These parameter combinations resulted in nine experimental groups that were analyzed using scanning electron microscopy (SEM) and image processing program for diameter measurement. Statistical analysis was performed using two-way ANOVA with post-hoc Tukey (5% significance). Results: from SEM images it was possible to observe formation of solid, misaligned and flawless defect-free fibers. And from the statistical analysis, distance (p = 0,0026) and the electric tension (p = 0,0012) showed a significant difference, but not for interaction between then (p = 0,4486). Conclusion: thus, it can be concluded that there is a possibility of the morphology control of PEI electrospun fibers, such as diameter, that can be used for a variety of applications such as incorporation in dental materials in order to improve its properties. Keywords Electrospinning technique; Fibers; Polyetherimide; Polymer.

<p><strong>Objective: </strong>The aim of this study was to evaluate the effect of different surface clinical treatments on the roughness (Ra) of a lithium disilicate ceramic veneer. <strong>Material and Methods: </strong>Forty-eight lithium disilicate discs with ceramic veneer and glaze layer were manufactured and distributed into six groups (n=8) according to the surface treatment performed: G1, glaze layer (control group); G2, diamond bur 4138F; G3, diamond bur 4138F + 4138FF; G4, diamond bur 4138F + new glaze layer; G5, diamond bur 4138F + ceramic polishing kit; G6, diamond bur 4138F + rubber cup with diamond paste + felt with diamond paste. Surface Ra measurement (µm) was performed using a profilometer before and after surface treatments, and one specimen from each group was subjected to Scanning Electron Microscopy (SEM) after treatment. Two-way ANOVA and Tukey's test (5%) were used for data analysis. <strong>Results: </strong>Group 2 (3,00 ± 0,61)^b showed higher values of Ra, followed by Group 3 (1,93 ± 0,45)^c, Group 6 (1,56 ± 0,22)^ac, Group 5 (1,14 ± 0,68)^a and Group 4 (0,90 ± 0,26)^a. G4, G5 and G6 were not different between each other and control group (1,11 ± 0,21)^a. SEM imaging revealed surface smoothness in G1, G4 and G5, and presence of irregularities in G2, G3 and G6. <strong>Conclusion: </strong>it is possible to conclude that different surface clinical treatments influences the roughness of a lithium disilicate ceramic veneer.</p><p> </p><p><strong>Keywords</strong><strong>:</strong> Ceramics; Dental porcelain; Dental polishing.</p>