Influence of cervical cap position on chromatic change and diffusion of H2O2 to the periodontal region in teeth submitted to internal bleaching

• Grant number: 22/05318-8
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): August 01, 2022
• Effective date (End): July 31, 2023
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal researcher: André Luiz Fraga Briso
• Grantee: Monara Marie Rodrigues Pereira
• Home Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

The aim of the study will be to evaluate the influence of cervical sealing on the chromatic alteration and diffusion of H2O2 in bovine teeth submitted to internal bleaching. For that, 80 bovine incisors will have their roots cut 3mm from the cementoenamel junction (CEJ) and the coronal opening will be performed. In the first phase of the experiment, 40 specimens will be pigmented with equine blood, being randomly divided into 2 groups, according to the positioning of the cervical patch (n=20): GI- below the JCE and; GII- in addition to the JCE. The cervical plug will be made with resin-modified glass ionomer cement and will be 2 mm thick. Then, 60µL of 35% hydrogen peroxide inside the pulp chamber for 45 minutes, and the endodontic access will be restored with composite resin. Four bleaching sessions will be performed with an interval of 7 days, with the color reading being performed 24 hours after each session, as well as 15 days after the end of the last session. For the color readings, individual trays of acetate plates will be made with three perforations (in the root, in the cervical region, and in the incisal third of the vestibular face), where the active tip of the portable spectrophotometer will be positioned. For the analysis of H2O2 diffusion, the remaining 40 specimens will be randomly divided into the same groups previously described. After the preparation and preparation of the tampons, the specimens will be waterproofed with black nail polish, leaving only the surface cavo angle and the 2 mm contiguous to the endodontic access uncovered. The bleaching treatment and sealing of the endodontic access will be carried out as already described, however, only one bleaching session will be held for 45 minutes. The teeth will be positioned inside cell culture plates containing 1mL of acetate buffer solution, in such a way that the entire root surface maintains contact with this solution. The solution will be collected, added to the leucocrystal solution, and to the peroxidation enzyme. Subsequently, it will be analyzed in a Visible Ultraviolet Reflection Spectrophotometer to quantify the diffused peroxide. After data collection, appropriate statistical tests will be performed.(AU)