In vitro evaluation of intra-chamber pulp temperature variation during bleaching with high and low concentration gels activated with different light sources

• Grant number: 17/19161-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): March 01, 2018
• Effective date (End): November 30, 2018
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Rafael Francisco Lia Mondelli
• Grantee: Larissa Fernanda de Santis
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

This in vitro study aims to evaluate the intra-chamber temperature variation during the photoactivation of bleaching agents with and without nanosized titanium dioxide particles by three light sources (blue LED, blue LED hybrid light / diode laser, hybrid light LED violet / laser diode). For the bleaching protocol it will be selected one human upper central incisor and one human bottom central incisor, extracted due to periodontal reasons, free of caries, restorations or visible cracks. This tooth will be cut 3mm beyond the cementoenamel junction. The pulp chamber will be filled with thermal paste together with the K-type thermocouple sensor and the position will be checked by X-Ray. The set will be inserted in a temperature controlled camera at 37 ° C. The bleaching agente, at concentrations of 6% (Lase Peroxide Lite), 15% (Lase Peroxide Flex) and 35% (Lase Peroxide Flex / Whiteness HP Maxx), will be applied to the vestibular face of the tooth in a uniform layer. Then, the light source (TF Premier (MMOptics), Whitening Plus (DMC)) will be fixed at a distance of 10 mm from the tooth surface. Distributed in 15 groups, the photoactivation protocol will consist of three applications of light for 2 minutes, with intervals of 30s (7min 30s by application of the whitening gel, and the temperature will be measured). At the end of each protocol, the bleaching gel will be removed with water and there will be a pause between the groups until the return of the intra-chamber temperature at 37 ° C ± 1, completing 5 replicates for each evaluated group. The null hypotheses tested will be: the absence of bleaching gel, the different light sources and the different concentrations of the bleaching gel will not determine an increase of the intra-chamber temperature. (AU)