Monolithic zirconia restorations may require adjustments to their structure prior to cementation. Several methods of finishing and polishing are suggested in the literature, however they may promote changes in the surface characteristics of the zirconia, which may affect the mechanical strength of the material in the long term. The aim of this study was to investigate in vitro the effect of degradation at low temperatures and different finishing and polishing regimes on the flexural strength and surface topography of two types of zirconia. Methods: 300 zirconia bars (zirkon ice translucent / Conventional and Prettau Anterior / Ultratranluzent, Zirkonzahn, Gais, Italy) were made in sizes 1,9-1,3x 2,5x10mm, sanded and sintered, presenting final dimensions of 1,5 -1 x 2 x 8mm. The bars were divided into 20 groups (n = 15) according to three factors "type of ceramic - 2 levels", "Degradation" - (with: autoclave at 127 ° C, 1,7 bar / 24h; "Polishing" - (C- Control, B- Polishing, P- grinding with burs, PB- grinding with burs + polishing, PG- burs + glaze). The bars were submitted to the miniflexural test (3 points). Two samples from each group were prepared for the topographic analyzes in SEM. Data were analyzed statistically by means of ANOVA (3 factors) and Tukey (5%). Results: ANOVA revealed that the factors "Degradation" (p=0.01, 1007.4 MPa^A> 919.1MPa^B), "Polishing" (p=0.0000, 1183.4MPa^A >1066.4MPa^B > 1012.4MPa^BC> 933.2MPa^C > 620.9MPa^D) and "Zirconia" (p = 0.0000; 1398.4 MPa^A> 528.1 MPa^B) were statistically significant. The ZPB_D (1670.2 ± 252.7)^A, ZB_D (1663.5 ± 216.8)^A and ZB (1654.7 ± 367.7^A) groups had the highest mean flexural strength. The groups of the ultratranslucent zirconia had lower averages of flexural strength, standing out the group UTPG (372.1 ± 56.2) G, which obtained the lowest one among the others (Tukey).