Head and neck radiotherapy may not increase gelatinase (metalloproteinase-2 and -9) expression or activity in teeth irradiated in vivo

Publication date: Available online 25 April 2017
Source:Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Author(s): Wagner Gomes-Silva, Ana Carolina Prado Ribeiro, Gilberto de Castro Junior, João Victor Salvajoli, Natalia Rangel Palmier, Marcio Ajudarte Lopes, Marcelo Marques Rocha, Mario Fernando de Goes, Thais Bianca Brandão, Alan Roger Santos-Silva
ObjectivesRecent 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 (RRC). 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 designThirty-six teeth were studied including 19 irradiated and 17 non-irradiated controls. In situ zymography was used to investigate the gelatinolytic activity in the micromorphological 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.ResultsNo statistically significant differences were detected in MMP-2 expression levels or in gelatinolytic activity (p > 0.05) between groups. Odontoblast MMP-9 expression was reduced in the irradiated group (p = 0.02).ConclusionsThe 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 shouldn't be regarded as an independent factor for explaining RRC onset and progression.



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