Banca de QUALIFICAÇÃO: ISABELLE HELENA GURGEL DE CARVALHO
Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.DISCENTE : ISABELLE HELENA GURGEL DE CARVALHO
DATA : 23/04/2019
HORA: 14:00
LOCAL: DEPARTAMENTO DE ODONTOLOGIA
TÍTULO:
INFLUENCE OF DIFERENTE FINISHING AND POLISHING TECHNIQUES ON FLEXURAL STRENGTH OF ULTRATRANSLUCENT ZIRCONIA AFTER IN SITU AGING.
PALAVRAS-CHAVES:
Y-TZP zirconia; thickness; flexural strength; polishing.
PÁGINAS: 48
GRANDE ÁREA: Ciências da Saúde
ÁREA: Odontologia
SUBÁREA: Clínica Odontológica
RESUMO:
Introduction: monolithic zirconia based restorations might require some adjustments in its structure before cementation. Even though zirconia is thickly sintered with minimal empty spaces, the alteration of tetragonal phase for monolithic phase (te > mo) may occur with application of external stresses or aging, which might modify the mechanical strength of the material. In this way, the aim of this study was to investigate the influence of different protocols of finishing and aging in situ on flexural strength and surface topography of ultra-translucent zirconia. Methodology: 240 zirconia bars (UT: Prettau Anterior/Ultratranslucent, zirkonzahn, Gais, Italy) were manufactured with dimensions of 1,3x 2,5x10mm, and 0,9x 2,5x10mm. They were polished and sintered, presenting final dimensions of 1,0 x 2 x 8mm, and 0,5 x 2 x 8mm. The bars were divided among 16 groups (n=15) in accordance to three factors “in situ aging”– 2 levels (With and Withouth “E”), “thickness” – 2 levels (1- 1 mm or 05- 0,5mm) and “Finishing and Polishing” – 4 levels (C- Control, B- Polishing; P- grinding with burs; PB- grinding with burs + polishing;). The bars were submitted to miniflexure test (three points test) on universal testing machine (1mm/min, load cell 100 kgf). Two samples of each group were prepared to the topographical analysis on SEM. The data was analyzed statistically through ANOVA (three factors) and Tukey (5%). Results: ANOVA (three factors) revealed that the factors “Thickness” (p=0.0599) e “in situ aging” (p= 0.5040) did not present significant statistical difference. On the other hand, “Finishing and Polishing” (p=0,0000; B: 476.40A Mpa > C: 420.92B MPa,> PB: 329.33c Mpa > P: 269.88D), presented results statistically significant. On Tukey’s test, B1 (449.07±100.30ABCD), B0,5(513.53±101.49A), BE1 (455.87±93.160ABC) and BE0,5 (487.13±118.05A ) revealed higher values of flexural strength. The groups treated with diamond bur P1 (257.13±47.872G), P0,5 (269.60±55.01FG), PE1 (292.93±58.676FG) and PE0,5 (259.87±43.388G) presented the lowest means of flexural strength.
MEMBROS DA BANCA:
Interna - 1678126 - PATRICIA DOS SANTOS CALDERON
Interno - 1640419 - RODRIGO OTHAVIO DE ASSUNCAO E SOUZA
Externa ao Programa - 2492886 - SAMIRA ALBUQUERQUE DE SOUSA