Banca de QUALIFICAÇÃO: SABRINA BARTH DE ANDRADE LUZ

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : SABRINA BARTH DE ANDRADE LUZ
DATE: 25/11/2025
TIME: 16:30
LOCAL: Departamento de Odontologia - Natal-RN - REMOTO (GOOGLE MEET)
TITLE:

Influence of Manufacturing Methods and Surface Treatments on the Mechanical, Optical, and Adhesive Performance of Zirconias Produced by Additive and Subtractive Manufacturing

KEY WORDS:

Dental prosthesis; Zirconia; Additive manufacturing; Mechanical performance; In situ aging; Adhesion.

PAGES: 41
BIG AREA: Ciências da Saúde
AREA: Odontologia
SUMMARY:

The advancement of manufacturing technologies has driven the development of dental ceramics, particularly zirconia, with the introduction of additive manufacturing (AM) as an alternative to conventional subtractive manufacturing (SM) based on CAD/CAM milling. However, the standardization of printing parameters and the understanding of how build orientation, surface finishing, and aging influence the mechanical and optical properties of zirconia remain significant challenges. In this context, this study aims to investigate the influence of manufacturing methods, printing orientations, and finishing and polishing protocols on the mechanical, optical, and microstructural performance of zirconia produced by additive and subtractive manufacturing, as well as to evaluate the behavior of these ceramics after in situ aging under oral conditions and different repair techniques. The research will be divided into two complementary stages. In Stage 1 (in vitro), disc-shaped specimens (Ø 12 mm × 1.5 mm – ISO 6872) of zirconia (3Y-TZP) will be fabricated by additive and subtractive (CAD/CAM) manufacturing. The specimens will be printed at two build orientations (0° and 90°) and subjected to four surface finishing protocols: control (no treatment), polishing, glazing, and polishing + glazing. Flexural fatigue tests will be conducted in water (1,200,000 cycles at 4 Hz), and roughness, microhardness, and translucency will be evaluated before and after fatigue testing. Fractured surfaces will be examined using scanning electron microscopy (SEM), and data will be statistically analyzed using three-way ANOVA and Tukey’s post-hoc test (α = 0.05). In Stage 2 (in situ), block specimens (6 × 5 × 2.5 mm) of 3Y-TZP zirconia obtained by additive and subtractive manufacturing will be attached to the buccal surface of complete or partial dentures of patients for a period of 60 days, simulating clinical aging in the oral environment. After intraoral exposure, specimens will undergo different surface treatment protocols (control, airborne-particle abrasion with Al₂O₃, airborne-particle abrasion + MDP, and primer + MDP), followed by the fabrication of composite resin cylinders (2.5 × 3 mm) for the repair protocol. Half of the samples will be subjected to thermocycling (10,000 cycles / 5°–55°C). Shear bond strength will be tested using a universal testing machine (INSTRON 3365, USA) at a crosshead speed of 1 mm/min. After fracture, all samples will be analyzed under a stereomicroscope for failure mode evaluation. Additional specimens from each restorative material will be examined using SEM for surface characterization and an optical profilometer (CCI MP, Taylor Hobson, UK) for surface roughness analysis. Statistical evaluation will be performed using three-way ANOVA and Tukey’s test (α = 0.05). The expected results aim to establish correlations between manufacturing methods, surface treatments, and the adhesive behavior of 3D-printed zirconia under both controlled and clinically simulated conditions. This study is expected to contribute to the development of optimized fabrication, finishing, polishing, and repair protocols, supporting the predictable and safe clinical application of additively manufactured zirconia in contemporary restorative dentistry.

COMMITTEE MEMBERS:
Presidente - 1640419 - RODRIGO OTHAVIO DE ASSUNCAO E SOUZA
Interno - 1031499 - LAERCIO ALMEIDA DE MELO
Externa ao Programa - 2492886 - SAMIRA ALBUQUERQUE DE SOUSA - UFRN