Low level laser therapy influence on the inflammation of the pulp tissue by bleaching procedure

• Grant number: 16/20271-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: February 01, 2017
• End date until: November 30, 2019
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Luciano Tavares Angelo Cintra
• Grantee: Amanda Miyuki Terayama
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

It is known that hydrogen peroxide (H2O2), the active substance of dental bleaching gel can cause damage to the pulp tissue. The low level laser therapy (LLLT) shows analgesic efficacy, anti-inflammatory and biostimulant capacity on tissues.  However, there is controversy about its effect on pulp cells after contact with these hydrogen peroxide contained in the bleaching gel. Objective: To evaluate the in vivo effects of LLLT using infrared laser (IRL) and red laser (RL) on the pulp tissue of rat molars submitted to the bleaching procedure, checking its mechanism of action in reducing the damage caused to the tissue. Methods: 80 Wistar rats will be randomly divided into 8 groups of 10 hemi-jaws: Control group - no treatment; Ble group - 30 minutes of bleaching gel 35% H2O2; Ble-1IRL group - immediately after the application of H2O2, an application of IRL (808 nm, 30 seconds, 3J); Ble-3IRL group - after application of H2O2, three applications IRL: Immediately after, 24 hours after, and 48 hours after dental bleaching (before euthanasia); Ble-1RL group - immediately after the application of H2O2, an application of RL (660 nm, 15 sec, 1.5 J); Ble-3RL group - after application of H2O2, three applications RL: immediately after, 24 hours after, and 48 hours after dental bleaching (before euthanasia); 3IRL group - only three IRL applications, as described in Ble-3IRL group; 3RL group - only three applications of the RL, as described in Ble-3RL group. After 2 and 30 days, the rats will be killed and the jaws removed and processed for histological evaluation (H.E.). Analysis method: The tissue sections stained with H.E. will be evaluated by pre-established criteria by assigning scores to microscopic events. They will be performed statistical tests of Kruskal Wallis and Dunn (p<0.05). (AU)