Effect of Temperature and pH on Calcium Phosphate Precipitation

Author(s)

Vilela, Handially Santos ^[1] ; Rodrigues, Marcela Charantola ^[2] ; Fronza, Bruna Marin ^[1] ; Trinca, Rafael Bergamo ^[1] ; Vichi, Flavio Maron ^[3] ; Braga, Roberto Ruggiero ^[1]

Affiliation

^[1] Univ Sao Paulo, Sch Dent, Dept Biomat & Oral Biol, Av Prof Lineu Prestes 2227, BR-05508000 Sao Paulo, SP - Brazil

^[2] Municipal Univ Sao Caetano Do Sul USCS, Rua Santo Antonio 50, BR-09521160 Sao Caetano do Sul, SP - Brazil

^[3] Univ Sao Paulo, Inst Chem, Dept Fundamental Chem, Av Prof Lineu Prestes 748, BR-05508900 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Crystal Research and Technology; v. 56, n. 12 OCT 2021.
• Web of Science Citations: 0

Abstract

Calcium orthophosphates (CaP) synthesis involves several chemical equilibria that define the phases present in the final product. From the biomaterials standpoint, it is important to gain knowledge on how synthesis parameters affect phase formation and particle size. This study evaluates the interaction between temperature (24 or 45 degrees C) and pH conditions (4.5, 6.5, or drifting) on CaP precipitation in terms of yield, phase formation, density, morphology, and size distribution. Calcium and phosphate solutions (Ca/P = 1.0) are mixed and kept under stirring for 3 h. The precipitate is freeze-dried and characterized. Under drifting pH and pH 4.5, dicalcium phosphate dihydrate (DCPD, CaHPO4 x 2H(2)O) is the predominant phase at both temperatures; however, some samples also present peaks ascribed to dicalcium phosphate anhydrous (DCPA, CaHPO4). At pH 6.5, diffractograms reveal a mixture of low-crystallinity DCPD and DCPA (24 degrees C) or low crystallinity hydroxyapatite {[}HAP, Ca-10(OH)(2)(PO4)(6)] (45 degrees C). In spite of the different morphologies (plates or aggregates), particle size remains within a relatively narrow range (D-50 = 12-28 mu m). DCPD precipitation is favored under more acidic or drifting pH, while HAP is formed under nearly neutral pH 6.5. (AU)

• FAPESP's process: 20/13983-6 - Effect of temperature, pH and precursors concentrations on the synthesis of DCPD particles and its application on a remineralizing resin composite
• Grantee: Rafael Bergamo Trinca
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/21023-2 - Influence of temperature and drip rate on the synthesis of dicalcium phosphate dihydrate particles
• Grantee: Handially dos Santos Vilela
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 19/04737-4 - 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
• Grantee: Roberto Ruggiero Braga
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/01701-9 - Development of functionalized calcium phosphate particles for use in remineralizing restorative composites
• Grantee: Bruna Marin Fronza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral