Effect of incorporating graphene oxide nanoparticles into experimental varnish in controlling artificial dental caries lesions.

• Grant number: 24/09268-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2024
• End date: September 30, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Marilia Mattar de Amoêdo Campos Velo
• Grantee: Guilherme José Drigo
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The establishment of strategies to arrest the progression of caries lesions is necessary through the development of new products providing more effective and stable remineralization. The modification of a varnish with graphene oxide can be an excellent strategy for more effective remineralization in the control of dental caries, since graphene has an antimicrobial mechanism of action and is also capable of promoting nucleation and crystallization for the rapid growth of hydroxyapatite under biomimetic conditions. Thus, the objective of the present in vitro study is to evaluate the efficacy of an experimental varnish modified with graphene oxide in the remineralization of artificial caries lesions in bovine tooth enamel. An in vitro study will be conducted using previously demineralized bovine tooth enamel, simulating an initial white spot situation, following the protocol: [Ca(NO3)2.4H2O 1.3mM; Na2HPO4.2H2O 0.78mM; glacial acetic acid 0.05M; 0.0315 ppm F, 16h, pH 5.0; 37°C]. Blocks (6×4×2 mm3) will be selected for their initial surface hardness (SD) and, after caries induction, the SH of the blocks will be determined again. The blocks will then be treated according to the following groups: group 1 (experimental varnish - 2.71% F, as NaF); group 2 (experimental varnish + 10% graphene oxide nanoparticles); group 3 (experimental varnish + 20% graphene oxide nanoparticles), group 4 (experimental varnish + 5.63% F, being 2.71% F, as NaF and 2.92% F, as CaF2) and group 5 (commercial varnish - Duraphat®, being 2.26% F, as NaF). The blocks will then be subjected to a dynamic pH cycling model, for 6 h in demineralizing solution and 18 h in remineralizing solution, for 7 days at 37 °C. The percentage of surface hardness loss (%SHL) and surface hardness recovery (%SHR) will be calculated from the SH analysis. The percentage composition analysis of the enamel components will be evaluated by energy dispersive X-ray spectroscopy (EDX) after each condition and Cross-Sectional Microradiography will be performed to evaluate the mineral loss. The relative amounts of calcium (Ca) and phosphorus (P) by volume percentage in the specimens will be evaluated before and after caries induction and after cycling for comparisons. After verifying the normality of the tests, appropriate statistical tests will be conducted. For all analyses, a significance level of 5% will be considered.