Banca de DEFESA: ISABELLE HELENA GURGEL DE CARVALHO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ISABELLE HELENA GURGEL DE CARVALHO
DATA : 25/06/2019
HORA: 08:30
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: 70
GRANDE ÁREA: Ciências da Saúde
ÁREA: Odontologia
SUBÁREA: Clínica Odontológica
RESUMO:

Introduction: 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 ultratranslucent zirconia. Methodology: 240 zirconia bars (UT: Prettau Anterior/Ultratranslucent, zirkonzahn, Gais, Italy) were cut, 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- Rubber polishing; P- grinding with burs; PB- grinding with burs + polishing;). The bars were submitted to mini flexure three points test (1mm/min, load cell 100 kgf). Two samples of each group were prepared to the topographical analysis on Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and surface roughness. For the cell adhesion assay, six blocks of ultratranslucent zirconia (2.5 x 2.5 mm), of each group were contaminated with the C. albicans (ATCC 90028) for counting the colony forming units (CFU / mL). The mechanical test results were analyzed using ANOVA (3 factors) and Tukey (5%); and the cell adhesion assay data by the Kruskal Wallis test (5%. Results: ANOVA (3 factors) revealed that only the "Finishing and Polishing" factor was statistically significant for mini-flexure strength (p = 0.0001). The finishing and polishing with rubber polishers improved the mini-flexure strength in relation to the control group and was superior to the other techniques tested. On the other hand, grindind only with a diamond burs produced the smallest mini-flexure strength (B: 476.40A Mpa> C: 420.92B Mpa> PB: 329.33C Mpa> P: 269.88D). Conclusion: The adjustment of ultratranslucent zirconia monolithic should preferably be performed with rubber polishers. Grinding with diamonds burs should be avoided or be followed by rubber polishers to minimize the mechanical properties damages.

MEMBROS DA BANCA:
Presidente - 1640419 - RODRIGO OTHAVIO DE ASSUNCAO E SOUZA
Interna - 1678126 - PATRICIA DOS SANTOS CALDERON
Externa à Instituição - RENATA MARQUES DE MELO - UNESP