title: Postradiation Matrix Metalloproteinase-20 Expression and Its Impact on Dental Micromorphology and Radiation-Related Caries.
abstract: Recent evidence suggests that head-and-neck radiotherapy (HNRT) increases active forms of matrix metalloproteinase-20 (MMP-20) in human tooth crowns, degrading the dentin-enamel junction (DEJ) and leading to enamel delamination, which is a pivotal step in the formation of radiation-related caries (RRC). Additional participation of enzymatic degradation of organic matrix components in caries progression was attributed to MMP-20 in dentin. Therefore, the current study tested the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes to the enamel and dentin. Thirty-six teeth were studied, including 19 post-HNRT specimens and 17 nonirradiated controls. Optical light microscopy was used to investigate the micromorphological components of the DEJ, dentin-pulp complex components, and carious dentin. The samples were divided into 2 subgroups: nondemineralized ground sections (n = 20) and demineralized histological sections (n = 16). In addition, immunohistochemical analysis using the immunoperoxidase technique was conducted to semiquantitatively assess MMP-20 expression in the DEJ, dentin-pulp complex components, and carious dentin. No apparent damage to the DEJ microstructure or other dentin-pulp complex components was observed and no statistically significant differences were detected in MMP-20 expression (p > 0.05) between the irradiated and control groups. This study rejected the hypothesis that MMP-20 is overexpressed in the DEJ, dentin-pulp complex components, and carious dentin of post-HNRT patients, leading to detectable micromorphological changes. Hence, direct effects of radiation may not be regarded as an independent factor to explain aggressive clinical patterns of RRC.
authors.affiliation: Oral Diagnosis Department, Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
authors.forename: Wagner
authors.initials: W
authors.lastname: Gomes-Silva
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Prado-Ribeiro
authors.forename: Thaís Bianca
authors.initials: TB
authors.lastname: Brandão
authors.forename: Karina
authors.initials: K
authors.lastname: Morais-Faria
authors.forename: Gilberto
authors.initials: G
authors.lastname: de Castro Junior
authors.forename: Milena Perez
authors.initials: MP
authors.lastname: Mak
authors.forename: Marcio Ajudarte
authors.initials: MA
authors.lastname: Lopes
authors.forename: Marcelo Marques
authors.initials: MM
authors.lastname: Rocha
authors.forename: Tuula
authors.initials: T
authors.lastname: Salo
authors.forename: Leo
authors.initials: L
authors.lastname: Tjäderhane
authors.forename: Mario Fernando
authors.initials: MF
authors.lastname: de Goes
authors.forename: Alan Roger
authors.initials: AR
authors.lastname: Santos-Silva
mesh_terms: D000328:Adult; D000368:Aged; D003731:Dental Caries / Q000201:enzymology / Q000209:etiology*; D003782:Dental Pulp / Q000201:enzymology / Q000528:radiation effects*; D003804:Dentin / Q000201:enzymology / Q000528:radiation effects*; D018450:Disease Progression; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D053519:Matrix Metalloproteinase 20 / Q000378:metabolism*; D008875:Middle Aged; D012307:Risk Factors; D019237:Tooth Cervix / Q000201:enzymology / Q000528:radiation effects*
chemical_list: D053519:Matrix Metalloproteinase 20
keywords: Caries; Dental tissues; Dentin-enamel junction; Head-and-neck cancer; Matrix metalloproteinase-20; Radiotherapy