Influence of the chitosan, zirconia and hydroxyapatite additives on the bond strength of the calcium aluminate cement to the retrograde cavity in contact with phosphate-based solution

• Grant number: 17/07419-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2017
• End date: May 31, 2018
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Walter Raucci Neto
• Grantee: Elen Mayara Theodoro da Silva
• 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 bond strength of calcium aluminate cement (CAC) to the root-end filling. A hundred bovine incisors will be selected and instrumented up size 120 K file 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): without PBS (A) and PBS (B). 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. 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. The roots will be sectioned perpendicular to the long axis to obtain 2 mm slices of the apical portion. Ten disks of subgroup A and ten discs of the subgroup B of each cement will be submitted to the push-out test in a universal testing machine. The analysis of the failure type will be performed with the aid of a stereomicroscope. The data obtained in the push-out test were quantitatively analyzed according to the most appropriate statistical test. The results of this study will help to identify the relationship of the physical and chemical changes of the new formulations of the calcium aluminate cement with the bond strength of endodontic cement to root dentin in retrograde cavity, simulating the physiological conditions. (AU)