Influence of the chitosan, zirconia and hydroxyapatite additives on the bioactivity of the calcium aluminate cement to the root-end cavity when in contact with phosphate based solution

• Grant number: 16/24432-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2017
• End date: December 31, 2017
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Walter Raucci Neto
• Grantee: Fernanda Mara Saltareli
• Host Institution: Universidade de Ribeirão Preto (UNAERP). Campus Ribeirão Preto. Ribeirão Preto , SP, Brazil

Abstract

This study aims to evaluate the influence of additives chitosan, zirconia and hydroxyapatite on bioactivity and bond strength of calcium aluminate cement (CAC) to the retrograde cavity. A hundred bovine incisors will be selected and instrumented up to F5 Protaper Universal system and adapted to a device to perform the apicectomy and root-end preparation (1.5 mm in diameter and 2 mm deep). The teeth will be divided into five groups, according to the cements used for root-end filling: MTA, CAC, CAC + chitosan (CACq) + CAC zirconia (CACz) + CAC hydroxyapatite (CACH); and two subgroups, according to the contact with the phosphate buffer solution (PBS): PBS and without PBS. The roots will be kept in an incubator (37°C) for 3 hours. Ten roots of each filling material will be adapted to a microtube containing gauze moistened with distilled water (changed every third day) and kept in an incubator (37oC) for 14 days (group A). Ten roots of each filling material will be adapted to a microtube containing PBS (changed every third day) and kept in an incubator (37oC) for 14 days (group B). The roots will be sectioned perpendicular to the long axis to obtain 2 mm slices of the apical portion. For the bioactivity evaluation, 10 disks of group A and 10 discs of the group B of each cement will be evaluated as the precipitate formed on the cement by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS-X) and infrared spectroscopy by Fourier transform (FTIR) and the solutions evaluated for pH and release of Ca2+ by atomic absorption spectrometry with flame (AAS). The EDS-X, FTIR and AAS data will be analyzed quantitatively according to the most appropriate statistical test. The images obtained in SEM will be analyzed qualitatively. The results of this study will contribute to identify the physico-chemical alterations of the new formulations of calcium aluminate cement, simulating the physiological conditions. (AU)