Novel Fluoro-carbon Functional Monomer for Dental Bonding

Abstract

Among several functional monomers, 10-methacryloxydecyl dihydrogen phosphate (10-MDP) bonded most effectively to hydroxyapatite (HAp). However, more hydrolysis-resistant functional monomers are needed to improve bond durability. Here, we investigated the adhesive potential of the novel fluoro-carbon functional monomer 6-methacryloxy-2,2,3,3,4,4,5,5-octafluorohexyl dihydrogen phosphate (MF8P; Kuraray Noritake Dental Inc., Tokyo, Japan) by studying its molecular interaction with powder HAp using solid-state nuclear magnetic resonance ((1)H MAS NMR) and with dentin using x-ray diffraction (XRD) and by characterizing its interface ultrastructure at dentin using transmission electron microscopy (TEM). We further determined the dissolution rate of the MF8P_Ca salt, the hydrophobicity of MF8P, and the bond strength of an experimental MF8P-based adhesive to dentin. NMR confirmed chemical adsorption of MF8P onto HAp. XRD and TEM revealed MF8P_Ca salt formation and nano-layering at dentin. The MF8P_Ca salt was as stable as that of 10-MDP; MF8P was as hydrophobic as 10-MDP; a significantly higher bond strength was recorded for MF8P than for 10-MDP. In conclusion, MF8P chemically bonded to HAp. Despite its shorter size, MF8P possesses characteristics similar to those of 10-MDP, most likely to be associated with the strong chemical bond between fluorine and carbon. Since favorable bond strength to dentin was recorded, MF8P can be considered a good candidate functional monomer for bonding.

Dentin bond optimization using the dimethyl sulfoxide-wet bonding strategy: A 2-year in vitro study

“…Alternatively, or in addition, it may be due to the increased chemical interactions between CF monomers and hydroxyapatite. In mineralized tissues, hydroxyapatite crystal has a hydration layer water adsorbed onto the crystal particle surface [25,26]. If DMSO affects the behavior of this water layer, it might allow more interaction between hydroxyapatite and functional monomers, such as 10-MDP.…”

Adsorption behavior of methacryloyloxydecyl dihydrogen phosphate on an apatite surface at neutral pH

“…Many investigations thus far have emphasized two chemical phenomena: chemical adsorption of 10-MDP onto the HA surface; and confirmation and characterization of the 10-MDP-Ca salt that precipitates on the mineral surface. Both phenomena have been studied by methods such as X-ray diffraction (3,7,8,(10)(11)(12)(13), transmission electron microscopy (3,9,12), X-ray photoelectron spectroscopy (5), nuclear magnetic resonance imaging (9,11,14), infrared spectroscopy (10), solubility testing of 10-MDP-Ca (1,6,9,10,15), and the adsorption of 10-MDP onto HA monitored by solidstate 31 P cross polarization magic angle spinning nuclear magnetic resonance (CP-MAS NMR) spectroscopy (3,11), when 10-MDP-H 2 was applied onto HA.…”

Impact of hydrophilicity and length of spacer chains on the bonding of functional monomers

“…Besides etching, thereby providing micro-retention, specific functional monomers have also shown to interact chemically (ionically) with calcium and hydroxyapatite of enamel and dentin [11,19]. Moreover, phosphate monomers like 10-MDP [20], 6-MHP [9] and MF8P [21], were documented to self-assemble into nanolayers, being dense monomer-calcium salt structures that are thought to provide stability to the interface. In addition to micro-mechanical interlocking, chemical interaction, potentially complemented with nano-layering, is presumed to improve bond durability and thus clinically to contribute to the longevity of composite restorations [7,8].…”