Polymer based adhesives for tooth restorations : monomer leakage and degradation

Abstract

Bonding materials are essential for modern restorative dentistry (i.e composite restorations and composite cements). Leakage from composite resin-based materials has been investigated and it is shown that 5-10 % of the residual monomers are released within the first seven days from the moment the restauration is made. Studies has also stated that monomer leakage can be a problem for patients and dental personal, and allergies can occur. Only a few studies have been focused on the degradation and erosion process of bonding materials. Since bonding agents are insufficiently studied concerning leakage of monomers, the aim of this study was to investigate leakage of monomers from bonding materials after light curing by using Gas Chromatography - Mass Spectrophotometry (GC-MS). The MS-instrument was equipped with an Electron Ionization (EI) and a Chemical Ionisation (CI) ion source that enabled to choose the most sensitive and selective method for the different compounds. Compounds with polar functional groups (i.e. –OH groups) were derivatized and analysed as their trimethyl silyl ethers. The light cured materials were immersed in water and in ethanol. In both cases the analysis demonstrated the leakage of several different compounds, even compounds that were not listed in the Material Safety Data Sheets (MSDS) of the actual bonding material.