Sodium trimetaphosphate (TMP) action on hydroxyapatite (HA) submitted to pH-cycling conditions: infrared spectroscopy, X-ray diffraction and biochemistry analysis

• Grant number: 09/09757-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2009
• End date: September 30, 2010
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Alberto Carlos Botazzo Delbem
• Grantee: José Antonio Santos Souza
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

The use of fluoride dentifrices by children under six years old has been pointed as a risk factor for dental fluorosis. The reduction of fluoride (F) concentration in dentifrices is considered to be an alternative to avoid this problem; however the anticariogenic effect presented by commercially available dentifrices (1100 µg F/g) must be maintained. Studies have showed the action of phosphates in the dental enamel demineralization mainly when associated the low concentration fluoride, but the mechanism is uncertain. The aim of the study will be analyser the effect of inorganic phosphate (sodium trimetaphosphate) on hydroxyapatite (HA) associated or not to fluoride (F). Syntetic hydroxyapatite (0.5 g) will be suspense in TMP solutions (100 mL) with concentrations of 1.0 e 3.0% associated or not to F (500 µg/g). After 18 hours (pH 7.0), the suspensions will get slow decrease pH still 4.0 using 1 mol L-1 nitric acid. After 30 minutes, the pH will be rise to 7.0 by adding 1 mol L-1 sodium hydroxyl. The pH-cycling will be repeated 3 times at 37º C. To precipitates aged the suspensions will be keeping for one day at 37º C. They will be filtrated and washed with deionized water and dried in an oven at 70o C for 24 hours. The precipitates will be ground into a fine power (53 µm) to analysis of X-ray diffraction, Fourier transform infrared spectroscopy and fluoride, calcium and phosphorus analysis. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ALBERTO CARLOS BOTAZZO DELBEM; JOSÉ ANTONIO SANTOS SOUZA; ANA CAROLINA SOARES FRAGA ZAZE; ELIANA MITSUE TAKESHITA; KIKUE TAKEBAYASHI SASSAKI; JOÃO CARLOS SILOS MORAES. Effect of Trimetaphosphate and Fluoride Association on Hydroxyapatite Dissolution and Precipitation In Vitro. Brazilian Dental Journal, v. 25, n. 6, p. 479-484, 2014-12-00. (09/09757-1)