: Evaluation of the sealing provided by resin-based endodontic filling materials and analysis of the expression of metalloproteinases in human and bovine dentin matrix / Avaliação do selamento do conduto radicular por materiais obturadores endodonticos resinosos e analise da expressão de metaloproteinases na matriz dentinaria humana e bovina

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Restorative strategies involving dentin bonding have been increasingly applied to endodontics. The first study evaluated the immediate and long-term sealing ability of adhesive versus conventional endodontic filling materials and investigated the influence of a coronal seal on leakage rates. After chemo-mechanical preparation/irrigation, human roots were filled with either AH Plus/gutta-percha or Epiphany/Resilon. Coronal sealing was performed with Coltosol or Clearfil SE Bond/Filtek Z250, and some samples received no material. The quality of root canal sealing was assessed by a fluid transport method, performed after sealer setting and 180 days of storage. Specimens filled with Epiphany/Resilon exhibited higher leakage than specimens filled with AH Plus/gutta-percha regardless of experimental condition. Coronal sealing reduced leakage significantly, but no difference was detected between Coltosol and Clearfil/Filtek Z250. After storage, significant decrease in leakage was observed in roots filled with AH Plus/gutta-percha either without coronal sealing or sealed with Coltosol, as well as in roots filled with Epiphany/Resilon without coronal sealing. It was concluded that adhesive filling materials did not provide better sealing than the conventional materials and that this sealing was not disturbed by storage of root filled specimens The presence of a coronary seal contributed to reduce leakage. Matrix metalloproteinases (MMPs) found in coronary dentin may play a role in the loss of stability of bonded restorations. The second study aimed to investigate whether these enzymes can also be detected in root dentin. Crown and root sections of human teeth were pulverized into powder and dentin proteins were extracted by using guanidine-HCl and EDTA. Zymography revealed gelatinolytic activity in both crown and root dentin samples, with bands corresponding to MMP-2 and MMP-9. MMP-2 activity was more evident in demineralized root dentin whereas MMP-9 was mostly extracted from the mineralized compartment of dentin. Western Blot analysis was able to detect MMP-8 equally distributed in crown and root dentin. In conclusion, MMPs are expressed in radicular dentin similarly to crown dentin. Using the same methodology, the third study assessed whether metalloproteinases are expressed in bovine dentin since this substrate has been frequently used as a substitute to human dentin in bond strength evaluations. Protein extracts obtained from bovine crown dentin exhibited gelatinolytic activity in zymography corresponding to MMP-2 and MMP-9. A similar pattern could be observed in root dentin proteins regarding the expression of MMP-2 isoforms, but no gelatinolytic activity was observed in the molecular weight area corresponding to MMP-9. It could be concluded that bovine sound dentin can express MMPs with gelatinolytic activity, but differences may occur in the expression profile of crown and root dentin substrates

ASSUNTO(S)

root canal obturation resinas obturação do canal radicular dentina resins dentin metaloproteinases da matriz matrix metalloproteinases

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