The Number of Bleaching Sessions Influences Pulp Tissue Damage in Rat Teeth

Author(s)

Angelo Cintra, Luciano Tavares ^[1] ; Benetti, Francine ^[1] ; da Silva Facundo, Aguinaldo Candido ^[1] ; Ferreira, Luciana Louzada ^[1] ; Gomes-Filho, Joao Eduardo ^[1] ; Ervolino, Edilson ^[2] ; Rahal, Vanessa ^[3] ; Fraga Briso, Andre Luiz ^[3]

Affiliation

^[1] UNESP Univ Estadual Paulista, Aracatuba Dent Sch, Dept Endodont, Sao Paulo - Brazil

^[2] UNESP Univ Estadual Paulista, Aracatuba Dent Sch, Dept Basic Sci, Sao Paulo - Brazil

^[3] UNESP Univ Estadual Paulista, Aracatuba Dent Sch, Dept Restorat Dent, Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF ENDODONTICS; v. 39, n. 12, p. 1576-1580, DEC 2013.
• Web of Science Citations: 26

Abstract

Introduction: Hydrogen peroxide tooth bleaching is claimed to cause alterations in dental tissue structures. This study investigated the influence of the number of bleaching sessions on pulp tissue in rats. Methods: Male Wistar rats were studied in 5 groups (groups 15-55) of 10 each, which differed by the number (1-5) of bleaching sessions. In each session, the animals were anesthetized, and 35% hydrogen peroxide gel was applied to 3 upper right molars. Two days after the experimental period, the animals were killed, and their jaws were processed for light microscope evaluation. Pulp tissue reactions were scored as follows: 1, no or few inflammatory cells and no reaction; 2, <25 cells and a mild reaction; 3, between 25 and 125 cells and a moderate reaction; and 4, 125 or more cells and a severe reaction. Results from each experimental group were compared between groups and within groups to the corresponding unbleached upper left molars and analyzed for significant differences using the Kruskal-Wallis test (P < .05). Results: All tissue sections showed significant bleaching-induced changes in the dental pulp. After 1 bleaching session, necrotic tissue in the pulp horns and underlying inflammatory changes were observed. The extent and intensity of these changes increased with the number of bleaching sessions. After 5 sessions, the changes included necrotic areas in the pulp tissue involving the second third of the radicular pulp and intense inflammation in the apical third. Conclusions: The number of bleaching sessions directly influenced the extent of pulp damage. (AU)

• FAPESP's process: 11/13709-2 - Influence of the number of sessions dental bleaching on the pulp of Wistar rats
• Grantee: Francine Benetti
• Support Opportunities: Scholarships in Brazil - Scientific Initiation