Banca de DEFESA: JOÃO VITOR DO NASCIMENTO SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOÃO VITOR DO NASCIMENTO SANTOS
DATE: 21/07/2025
TIME: 08:30
LOCAL: DEPARTAMENTO DE ODONTOLOGIA - SALA 07
TITLE:

EFFECT OF A BOROSILICATE GLASS AND DIFFERENT SURFACE TREATMENTS ON THE BIAXIAL FLEXURAL STRENGTH OF 4Y-PSZ AND MULTILAYER ZIRCONIAS SUBJECTED TO MECHANICAL FATIGUE

KEY WORDS:

Dental prosthesis; Dental materials; 4Y-PSZ zircônia; Multilayer zirconia; Mechanical properties.

PAGES: 70
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUBÁREA: Materiais Odontológicos
SUMMARY:

Objective: To evaluate the effect of applying a borosilicate-based glass as a surface treatment on the biaxial flexural strength, surface roughness and chemical characteristics of a multilayer zirconia, compared to a 4Y-PSZ zirconia, after mechanical fatigue. Materials and Methods: Eighty ceramic discs (Ø 12 mm × 1.5 mm – ISO 6872) were fabricated, including 40 4Y-PSZ zirconia specimens (UT) (Nexx Zr+ White, Sagemax Bioceramics) and 40 multilayer zirconia specimens (ML) (Nexx Zr+ Multi, Sagemax Bioceramics). After sintering, the specimens were randomized into eight groups (n=10), according to the surface treatment: Control (application of Monobond N primer) (C), airborne-particle abrasion with 50 µm Al2O3 + primer (AL), silica coating + primer (SI), and borosilicate glass infiltration + HF etching + primer (BG). After surface treatments, surface roughness was analyzed by optical profilometry (CCI MP, Taylor Hobson, UK). A layer of dual-cure resin cement (Variolink Esthetic DC) was then applied and light-cured for 40 seconds. All groups were subjected to mechanical fatigue (6 bar, 1,200,000 cycles, 4 Hz). Subsequently, biaxial flexural strength testing (Instron 3365, 1 mm/min, 5,000 kgf) and fractographic analysis by SEM were performed. Chemical characterizations were conducted using EDS and XRD analyses. Data were statistically analyzed using tow-way ANOVA and Tukey's test (5%).Results: All studied factors showed statistically significant effects (p < 0.05). The BG group exhibited the highest strength values (758.51A MPa). ML zirconia demonstrated superior performance (714.62A MPa) compared to UT (609.63B MPa). Within UT, BG (769.63A MPa) outperformed all other groups except SI (683.70AB MPa); within ML, AL (754.41A MPa) and SI (696.57AB MPa) were statistically similar to BG (747.39AB MPa). Regarding surface roughness, BG presented the lowest mean value, SI was similar to the control, and AL resulted in the roughest surface. Conclusion:
The application of borosilicate glass as a surface treatment improved the mechanical strength of both multilayer and 4Y-PSZ zirconias, representing a promising alternative to conventional methods.

 

COMMITTEE MEMBERS:
Presidente - 1640419 - RODRIGO OTHAVIO DE ASSUNCAO E SOUZA
Interna - 1678126 - PATRICIA DOS SANTOS CALDERON
Externa à Instituição - RENALLY BEZERRA WANDERLEY E LIMA - UFPB