In vitro analysis of cytotoxicity and production of inflammatory mediators by keratinocytes stimulated by a denture base resin obtained by 3D printing under different angulations and post-curing light exposure time

• Grant number: 25/00923-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2025
• End date: February 28, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Ana Carolina Pero
• Grantee: Sabrina Romão Gonçalves Coelho
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

3D printing for dental prostheses is a highly advantageous process compared to conventional techniques. By eliminating steps, reducing costs, increasing precision and speed, and reducing waste, additive manufacturing brings numerous improvements to the field. Recently, LCD (liquid crystal display) printers have been introduced at much lower costs than more established technologies, such as DLP (digital light processing). LCD printers are capable of operating with the same resins used for DLP, achieving good properties in some applications, such as orthodontic aligners. However, little is known about their results when used for the manufacture of complete dentures. For example, there are no studies on the interaction between oral mucosa cells and denture base resins obtained by LCD. Parameters such as the printing angle also deserve to be studied for LCD, since they can influence the polymerization process, directly interfering with the physical, mechanical, and biological properties of the materials. The main objective of this project is to evaluate the cytotoxicity of a denture base resin printed on LCD, varying the printing angles and post-curing light times. Circular specimens (10 x 1.2 mm) of the denture base resin (priZma 3D Bio Denture) will be printed at three angles (0º, 45º or 90º) and subjected to post-polymerization in UV light for 10, 20 and 30 minutes. The cytotoxicity of the resins will be tested in human gingival keratinocytes (NOK-SI) by MTT and analysis of membrane integrity. Extracts will be obtained after 24 hours of exposure of the samples in DMEM culture medium, in addition to negative controls (DMEM medium and 1% ethanol solvent) and positive control (DMSO 100%). NOKsi cells will be cultured in vitro and exposed for 24 hours to the extracts. After this period, the cytotoxicity of the extracts will be evaluated by the MTT assay and analysis of membrane integrity (test with the CytoTox-One reagent) and by analysis of cell viability (live/dead) by fluorescence microscopy. The production of cytokines IL-1¿, IL-6 and TNF-¿ will be evaluated using the ELISA assay. In the different experimental conditions, the specimens will be characterized using Fourier Transform Infrared Spectroscopy (FTIR) tests to analyze the degree of conversion. Statistical analysis of the data, according to the assumptions of normality and homoscedasticity, will be performed with ¿=0.05. Results of this project may support the use of LCD printers to obtain complete dentures, or point out limitations to be overcome.