Wagner Gomes-Silva1, Ana Carolina Prado Ribeiro1, Gilberto de Castro Junior2, João Victor Salvajoli3, Natalia Rangel Palmier4, Marcio Ajudarte Lopes4, Marcelo Marques Rocha5, Mario Fernando de Goes6, Thais Bianca Brandão1, Alan Roger Santos-Silva7. 1. Oral Diagnosis Department, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil; Dental Oncology Service, Instituto do Câncer do Estado de São Paulo, Faculdade de Medicina da Universidade de São Paulo, Sao Paulo, Brazil. 2. Clinical Oncology Department, Instituto do Câncer do Estado de São Paulo, Faculdade de Medicina da Universidade de São Paulo, Sao Paulo, Brazil. 3. Radiotherapy Service, Instituto do Câncer do Estado de São Paulo (ICESP), Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. 4. Oral Diagnosis Department, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil. 5. Department of Morphology, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil. 6. Restorative Dentistry Department, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil. 7. Oral Diagnosis Department, Piracicaba Dental School, University of Campinas, Piracicaba, Sao Paulo, Brazil; Dental Oncology Service, Instituto do Câncer do Estado de São Paulo, Faculdade de Medicina da Universidade de São Paulo, Sao Paulo, Brazil. Electronic address: Alanroger@fop.unicamp.br.
Abstract
OBJECTIVE: Recent studies suggested that head and neck radiotherapy increases active forms of matrix metalloproteinases (MMPs) in the dentin-enamel junction (DEJ), leading to enamel delamination and radiation-related caries. This study aimed to assess the expression and activity of the gelatinases MMP-2 and MMP-9 in the DEJ and dentin-pulp complex tissues of teeth irradiated in vivo. STUDY DESIGN: Thirty-six teeth were studied, including 19 irradiated and 17 non-irradiated controls. In situ zymography was used to investigate the gelatinolytic activity in the micromorphologic components of enamel, DEJ, dentin-pulp complex, and caries. Immunohistochemical analysis was conducted on the demineralized samples to assess MMP-2 and MMP-9 expression levels in the DEJ, dentin-pulp complex components, and caries. RESULTS: No statistically significant differences were detected between groups in gelatinolytic activity or in MMP-2 expression levels (P > .05). Odontoblast MMP-9 expression was reduced in the irradiated group (P = .02). CONCLUSIONS: The study rejected the hypothesis that MMP-2 and MMP-9 would be overexpressed or more activated in the DEJ and dentin-pulp complex of irradiated teeth. Direct effects of radiation should not be regarded as an independent factor for explaining radiation-related caries onset and progression.
OBJECTIVE: Recent studies suggested that head and neck radiotherapy increases active forms of matrix metalloproteinases (MMPs) in the dentin-enamel junction (DEJ), leading to enamel delamination and radiation-related caries. This study aimed to assess the expression and activity of the gelatinases MMP-2 and MMP-9 in the DEJ and dentin-pulp complex tissues of teeth irradiated in vivo. STUDY DESIGN: Thirty-six teeth were studied, including 19 irradiated and 17 non-irradiated controls. In situ zymography was used to investigate the gelatinolytic activity in the micromorphologic components of enamel, DEJ, dentin-pulp complex, and caries. Immunohistochemical analysis was conducted on the demineralized samples to assess MMP-2 and MMP-9 expression levels in the DEJ, dentin-pulp complex components, and caries. RESULTS: No statistically significant differences were detected between groups in gelatinolytic activity or in MMP-2 expression levels (P > .05). Odontoblast MMP-9 expression was reduced in the irradiated group (P = .02). CONCLUSIONS: The study rejected the hypothesis that MMP-2 and MMP-9 would be overexpressed or more activated in the DEJ and dentin-pulp complex of irradiated teeth. Direct effects of radiation should not be regarded as an independent factor for explaining radiation-related caries onset and progression.