Evaluation of the potential antimicrobial effect of experimental primers containing flavonoids on cavity disinfection and mechanical properties of dentin affected by caries using a microcosm biofilm model

• Grant number: 21/11972-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): July 01, 2022
• Effective date (End): February 28, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Marcelo Giannini
• Grantee: Beatriz Ometto Sahadi
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

This study will evaluate the effect of experimental flavonoid-based primers on antimicrobial potential, cavity disinfection, adhesion and mechanical properties of affected demineralized dentin from a microcosm biofilm model. Primers based on compounds of natural origin (Baicalein, Naringin and Kaempferol) will be manipulated at a concentration of 20 mM and applied to demineralized dentin substrate affected by caries for 60 sec as cavity disinfection agents, prior to restoration. The dentin-adhesive bonding area formed by the experimental primers will be analyzed mechanically, chemically and morphologically by the methods of bond strength to dentin by microtensile, with the evaluation of the types of fracture, nanoindentation, micro-raman spectroscopy and by Scanning Electron Microscopy (SEM). In the evaluations of antimicrobial activity, dentin affected by caries followed by the application of primers will be analyzed by counting Colony Forming Units (CFU), cell viability (CLSM) and morphological analysis of the microcosm biofilm in dentin (in SEM). In addition to the experimental primers, 2% chlorhexidine gluconate (CHX) will be used as a positive control at the same time of application. Etching with 35% phosphoric acid without primer application after etching will be used as a negative control. The dentin of all groups will be etched with 35% phosphoric acid (Ultra-Etch, Ultradent) for 15 sec and for the experimental groups 15 ¼L of each experimental primer will be applied for the specified time and the excess of the primer will be removed with absorbent paper. In the test of bond strength of the composite to dentin, with description of the types of fractures obtained (n=12), in the evaluation of nanoindentation (n=7) and in the description of the morphology of the structures of this bond (n=3), an adhesive simplified commercial will be used according to the manufacturer's recommendations, with evaluations after 24 h and after storing the specimens in water for 1 and 2 years. For micro-raman spectroscopy analysis (n=5) the specimens will be evaluated after 24 h. The bond strength and nanoindentation data will be analyzed by two-way analysis of variance and micro-raman and CFU spectroscopy tests will be analyzed by one-way variance, followed by Tukey's test. The other results will be analyzed qualitatively. (AU)