Metalloproteinases and their role in the degradation of bonding systems. Part 2

The stability of the hybrid layer is crucial for ensuring the durability of fillings made of composite materials. Factors which weaken the bond strength are related to, among others, the presence of bacteria and their enzymes in the structure of the bacterial biofilm. Chronic damage the hybrid layer is also a result of hydrolysis and leaching of adhesive monomers which infiltrated the demineralised dentin matrix. Nanoleakage is also among the factors contributing to degradation. Many studies examine the effect of endogenous proteases on the degradation of the hybrid layer. Endogenous collagenolytic enzymes: metalloproteinases (MMPs) and cysteine cathepsins, are responsible for the degradation of the collagen matrix in the hybrid layer. Inhibition of endogenous proteases is therefore necessary to slow the degradation of fillings. The enzyme activity in dentine and in the hybrid layer can be regulated by endo- and exogenous inhibitors. The paper is a review of the available literature published in the PubMed medical database, as well as in Polish dental journals in the years 2002-2017. Its aim is to assess the role of metalloproteinases and cysteine cathepsins in the degradation of the hybrid layer and to review the compounds with inhibitory properties in relation to these enzyme groups.