Dentin remineralization with the use of composite containing calcium orthophosphate particles associated with a Polymer-Induced Liquid Precursor (PILP): material development, in vitro and randomized clinical studies

• Grant number: 19/04737-4
• Support type: Research Projects - Thematic Grants
• Duration: October 01, 2020 - September 30, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Roberto Ruggiero Braga
• Grantee: Roberto Ruggiero Braga
• Home Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Co-Principal Investigators: Daniela Rios Honório ; Marcelo Giannini
• Assoc. researchers: Bruna Marin Fronza ; Marília Afonso Rabelo Buzalaf ; Stefan Habelitz

Abstract

The objective of this project is to develop a resin-based composite containing DCPD particles (dicalcium phosphate dihydrate, CaHPO4.2H2O) to be used in minimally invasive restorations, and evaluate its efficacy in the functional (or biomimetic) remineralization of artificially demineralized human dentin, combined or not with the PILP process. DCPD particles will be synthesized by co-precipitation, characterized and used in resin composite formulations associating DCPD particles and reinforcing particles at different ratios. Composites will be tested for degree of conversion, fracture toughness and ion release up to 14 days. The material with the most favorable relation between KIc and ion release will be used in the remineralization studies. For the in vitro phase, dentin blocks (previously immersed for 66 hours in acetate buffer, pH 5.0) will receive a layer of composite, combined or not to a pre-treatment with the PILP solution. After 14 days of immersion in simulated body fluid, dentin remineralization at the interface with the restorative material will be evaluated by attenuated total reflectance mid-infrared spectroscopy (ATR-FTIR). The recovery of mechanical properties will be evaluated by nanoindentation. Additionally, cross-section of dentin subject to the different treatments will be observed under transmission electron microscopy. For the randomized clinical phase, children with mixed dentition presenting carious lesions in primary molars (ICDAS 5 or 6) will be ascribed to one of the four treatments described in the in vitro phase after selective caries removal. After exfoliation, teeth will be analyzed according to the same methods used for the in vitro specimens. Statistical treatment of the data will be defined after preliminary testing for normality and homogeneity of variance. (AU)