Antimicrobial photodynamic therapy in the treatment of experimentally induced apical periodontitis

• Grant number: 12/14505-4
• Support Opportunities: Regular Research Grants
• Duration: March 01, 2013 - February 28, 2015
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Léa Assed Bezerra da Silva
• Grantee: Léa Assed Bezerra da Silva
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Arthur Belem Novaes Junior

Abstract

The objective of this project will be assessed quantitatively in vivo the effects of antimicrobial photodynamic therapy in the treatment of experimentally induced periapical periodontitis. Will be used premolars of 70 dogs (140 roots) which, after periapical lesion induction, will be divided into eight groups: group I and V (20 roots each) - after the biomechanical preparation, the canals are filled with the folder Calen ® for 15 days, followed by filling with AH Plus; group II and VI (20 roots each): after the biomechanical preparation, the canals will be conditioned with fotosensitizador the basis of phenothiazine for 1 min, followed by laser irradiation diode with a wavelength of 670 nm for 1 minute and filling with AH Plus; group III and VII (20 roots each) after biomechanical root canals will be filled in the same session with the AH Plus group IV and VIII (10 roots each) after biomechanical preparation channels remain empty. Then, the teeth of all groups are restored to amalgam of silver, based on a glass ionomer. After the experimental periods of 28 ± 3 days (Groups I, II, III and IV) and 90 ± 5 days (Groups V and VIII), the animals will be killed, the mandibles and maxillae were removed and the teeth subjected to processing and histotechnical subsequently be deparaffinized and hydrated for immunohistochemical analysis. Longitudinal sections of 5 mm will be obtained and stained with hematoxylin and eosin, Mallory trichrome and Brown & Brenn. For the microscopic evaluation by quantitative method is recorded full description of the characteristics of the apical and periapical tissues and made to quantify the number of inflammatory cells and the lengths of the areas of apical periodontitis, bone resorption, the apical resorption (dentin and cementum) and edema in mm2. Immunohistochemical analysis will be conducted to identify and locate the factors involved in osteoclastogenesis and the cuts will be subjected to immunohistochemistry by using primary antibodies to RANK, RANKL and OPG. The immunoblots are evaluated throughout the length of the tooth root, periodontal ligament, alveolar bone and pulp and the results are expressed in a qualitative manner. Evaluations shall be performed Axio Imager.M1 microscope (Zeiss) coupled to an AxioCam MRC5 camera (Zeiss). The values obtained are evaluated for the type of distribution of groups and compared by analysis of variance (ANOVA) or nonparametric Kruskal-Wallis test with a significance level of 5%. (AU)