Enzymatically-driven biomineralization potential of an experimental bleaching gel containing calcium-polyphosphate particles (CaPP)

• Grant number: 21/10175-9
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: May 15, 2022
• End date: December 14, 2022
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Debora Alves Nunes Leite Lima
• Grantee: Mariangela Ivette Guanipa Ortiz
• Supervisor: Klaus Rischka
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Institution abroad: Fraunhofer-Gesellschaft, Germany
• Associated to the scholarship: 19/20272-1 - Development of a hydrogen peroxide bleaching agent with the addition of calcium polyphosphate nanoparticles and its effect on the whitening and mineralization of dental enamel, BP.DR

Abstract

Recently calcium-polyphosphate nano/microparticles (CaPP) have been developed through a co-precipitation method by adjusting the Ca:P ratio (2:1). CaPP can integrate to the tooth surface and release Ca2+ and PO43- to achieve bioinspired mineralization of the dental tissues, and this process is biologically upregulated by the enzymatic activity of Alkaline Phosphatase (ALP). Considering this, the present project aims to assess the effect of incorporating ALP in the chemical and physical properties of an experimental bleaching gel containing hydrogen peroxide (HP) - 35% and calcium-polyphosphate particles (HP-CaPP). Based on the experimental bleaching formula developed by our research team, the following groups will be formulated and assessed: G1 - HP (without CaPP or ALP); G2 - HP + CaPP (2% w/t); G3 - HP + CaPP (2% w/t) + ALP (x% w/t); G4 - HP + CaPP (2% w/t) + ALP (y% w/t); G5 - Control group (distilled water). After achieving the optimal conditions in the bleaching formula with the ALP incorporation, the ALP activity will be assessed with a colorimetric endpoint assay through spectrophotometric methods. Two sets of samples will be prepared to compare the effect of pH levels and hydrogen peroxide concentration on ALP activity. To calculate the orthophosphate production (with and without the ALP in the bleaching gel formula) the same groups will be assessed by spectrophotometric methods using a phosphate assay kit. Qualitative inspection of the CaPP within the bleaching gel formula will be done by scanning electron microscopy with an electron-ion dual beam (SEM-FIB). The statistical analysis will be carried out in the SPSS software, considering a significance level of 5%, if normally or abnormally distributed an ANOVA mixed or Friedman test, respectively, will be performed. (AU)