Antimicrobial photodynamic therapy in the treatment of apical periodontitis induced experimentally in dogs\' teeth

Author(s)

Lidia Regina da Costa Hidalgo

• Document type: Doctoral Thesis
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2016-09-16

Examining board members

Arthur Belem Novaes Junior; Paulo Sérgio Cerri; Paulo Nelson Filho; Lívio de Barros Silveira; Manoel Damião de Sousa Neto

• Advisor: Arthur Belem Novaes Junior; Léa Assed Bezerra da Silva

Abstract

To evaluate one-session endodontic treatment with aPDT and two-session treatment with calcium-hydroxide (CH)-based dressing in dog\'s teeth with apical periodontitis. Methods: After experimental induction of apical periodontitis, 48 teeth were randomly assigned to the following groups: Group I (one-session treatment with aPDT 120 days); Group II (one-session treatment with aPDT 180 days); Group III (two-session treatment with CH-based dressing -120 days) and Group IV (two-session treatment with CH-based dressing -180 days). The animals were euthanized after 120 and 180 days. After histotechnical processing, microscopic and radiographic analyses were performed. Data were analyzed by Kruskal-Wallis and Fishers exact tests (=0.05). Results: In the microscopical analysis, Groups I and III presented repaired cemental areas, with various colagen bundles in the periodontal ligament and mild presence of inflamatory cells. In the groups III and IV the present resorbed cemental areas were not repired, with reduced number of cells and fibers and the presence of inflamatory cells. The semi-quantitative analysis of the apical clousure, there was a significant difference (p<0.0001) between groups I and II; and between groups III and IV (p<0.0001). In the fluorescence microscopy analysis, there was a significant difference between groups, aftter 120 days (p=0.0004) and after 180 days (p=0.0081). The groups I and III presented smaller periapical lesions. The percentage of radiographic reduction of lesions demonstrated a significant difference between groups (p<0.05) with a higher reducton in group I and II. Regarding the immunohistochemistry analysis, in the groups I, II and IV, RANK, RANKL and OPG staining indicated pro-resorption signaling; although the RANKL immunostaining in the group I were not intense. In the group III, the immunostaining demonstrated the occurrence of bone neoformation. Conclusion: Two-session treatment with CH based promoted more reduction in the periapical lesion size and more repair advanced stage, highlighting better histopathological, immunostaining and radiographic results in comparison with one-session treatment with aPDT protocol used. (AU)

• FAPESP's process: 12/10238-1 - Antimicrobial photodynamic therapy in the treatment of experimentally induced apical periodontitis.
• Grantee: Lidia Regina da Costa Hidalgo
• Support Opportunities: Scholarships in Brazil - Doctorate