Abstract Borosilicate glass was developed to enhance the mechanical behavior and smoothness of dental zirconia as an alternative to conventional glaze. This study assessed the mechanical and optical properties of 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) coated with borosilicate glass or a commercial glaze fired for an extended period of time. Disc-shaped 3Y-TZP zirconia specimens (Zpex, Tosoh) were sintered at 1550°C for 2 hours. The specimens were divided into three groups: as-sintered (control, C); commercial glaze (G); and borosilicate glass (SL). The glaze and borosilicate glass were applied over the zirconia and fired for 20 minutes at 950°C and 1200°C, respectively. Biaxial flexural strength, fractography, X-ray diffraction (XRD), roughness (Ra and Rz), fracture toughness (Vickers indentation method), color difference (∆E00), and translucency (TP00) analyses were conducted. The t-test or the one-way ANOVA and Tukey’s tests were used to analyze the data (α = 0.05). Flexural strength data were subjected to the Weibull analysis. The SL group exhibited the highest flexural strength (1025.8 MPa), whereas the C (859.41 MPa) and G (816.0 MPa) groups exhibited similar values. The SL group also had the highest characteristic strength. The fracture origin in all groups was on the zirconia surface. XRD analysis revealed that the specimens from the SL group contained tetragonal, cubic, and monoclinic phases. The SL group presented the lowest surface roughness. Fracture toughness in the SL group was lower than in the C group, but similar to that observed in the G group. The translucency and color differences observed in the G and SL groups were similar. Borosilicate glass enhanced the flexural strength of 3Y-TZP, promoted the smoothest surface, and exhibited optical properties similar to those of the glaze. mol yttriastabilized yttria stabilized 3YTZP YTZP 3Y TZP Y (3Y-TZP time Discshaped Disc shaped Zpex, Zpex (Zpex Tosoh 1550C 1550 hours assintered control, control (control C) (G) SL. . (SL) 950C 950 1200C 1200 1200°C respectively fractography Xray X ray XRD, , (XRD) Ra Rz, Rz Rz) Vickers method, method method) ∆E00, E00 E ∆E00 (∆E00) TP00 TP (TP00 conducted ttest t test oneway one way Tukeys Tukey s α 0.05. 005 0.05 0 05 0.05) 1025.8 10258 1025 8 (1025. MPa, MPa 859.41 85941 859 41 (859.4 816.0 8160 816 (816. values cubic phases 3YTZP, TZP, 155 (G (SL 95 120 (XRD E0 ∆E0 (∆E00 TP0 (TP0 00 0.0 1025. 102 (1025 859.4 8594 85 4 (859. 816. 81 (816 15 9 12 ∆E (∆E0 (TP 0. 10 (102 859. (859 (81 1 (∆E (10 (85 (8 (1 (

Aim The aim of this study was to investigate the influence of the quantity and positioning of feldspathic ceramic specimens inside the furnace on their flexural strength and translucency. The tested hypotheses were that the arrangement of specimens in the furnance would not influence 1) the translucency or 2) the biaxial strength of the porcelain. Methods Ninety porcelain specimens were made (1.2 mm thickness and 13.5 mm diameter) and assigned into two main groups (n=15): G1 group - 15 firing cycles containing only one specimen each, always at the center of the refractory; and G5 group - 15 firing cycles containing five specimen each, where one specimen was at the center of the refractory and four specimens positioned equidistantly on the periphery. The translucency test was performed using a spectrophotometer, followed by the flexural strength test, according to ISO 6872:2015. T-student test was performed for both the mechanical and optical obtained data. Results The flexural strength of the porcelain was not affected by the positioning (center x periphery) of the specimens inside the furnace (p =0.08), but the translucency was affected (periphery > center; p =0.009). Regarding to the number of feldspathic ceramic specimens, the biaxial flexural strength was affected (p =0.025), as well as the translucency (p <0.05). Conclusion A higher quantity of feldspathic ceramic specimens for each firing cycle decreased its biaxial flexural strength and translucency. Also, specimens positioned at the center of the refractory became less translucent than those positioned at the periphery. 1 2 1.2 12 (1. 135 13 5 13. diameter n=15 n15 n (n=15) G periphery spectrophotometer 68722015. 68722015 6872 2015. 2015 6872:2015 Tstudent T student data =0.08, 008 =0.08 , 0 08 =0.08) =0.009. 0009 =0.009 . 009 =0.009) =0.025, 0025 =0.025 025 =0.025) <0.05. 005 <0.05 05 <0.05) Also 1. (1 n=1 n1 (n=15 6872201 687 201 6872:201 00 =0.0 000 =0.00 002 =0.02 02 <0.0 ( n= (n=1 687220 68 20 6872:20 =0. <0. (n= 68722 6 6872:2 =0 <0 (n 6872: = <

Aim This study assessed the color and translucency stability of a polymer infiltrated ceramic network (PICN) and compared it with a resin composite (RC) and a feldspathic ceramic (FEL). Methods Disc-shaped samples of a PICN (Vita Enamic), a feldspathic ceramic (Vitablocks Mark II), and a resin composite (Brava block) were prepared from CAD/CAM blocks. PICN and RC surfaces were finished with a sequence of polishing discs and diamond paste. FEL samples received a glaze layer. The samples were subjected to 30-min immersions in red wine twice a day for 30 days. CIE L*a*b* coordinates were assessed with a spectrophotometer at baseline and after 15 and 30 days of immersion. Color alteration (∆E 00 ) and translucency parameter (TP 00 ) were calculated with CIEDE2000. Average roughness was measured before the staining procedures. Color difference and translucency data were analyzed with repeated-measures ANOVA and Tukey’s tests. Roughness was analyzed with the Kruskal-Wallis test. Results Roughness was similar among the experimental groups. All materials had their color alteration significantly increased from 15 to 30 days of staining. PICN reached an intermediate ∆E 00 between FEL and RC at 15 days. PICN revealed a color alteration as high as the composite after 30 days. No statistical difference was observed regarding translucency. Conclusion PICN was not as color stable as the feldspathic ceramic at the end of the study. Its color alteration was comparable to the resin composite when exposed to red wine. However, the translucency of the tested materials was stable throughout the 30-day staining.