Effect of Four Silane Coupling Agents on Bonding of Two Resin-modified Glass Ionomer Cements to a Machinable Ceramic

Effect of the type of acidic monomer on the bond durability of two-bottle type ceramic primer

Ceramic primers consisting of γ-methacryloxypropyl trimethoxysilane (γ-MPS) and either 4-methacryloyloxyethyl trimellitate (4-MET) or 10-methacryloyloxydecyl dihydrogen phosphate (MDP) are useful for facilitating bonding of resin cement to silica-based ceramic surfaces. However, bond stability at the resin-ceramic interface differs among commercial ceramic primers. To determine the ability of 4-MET or MDP to hydrolyze the methoxy group in γ-MPS, the author designed two-bottle experimental ceramic primers comprising γ-MPS solution and an activator solution of 4-MET or MDP. The effects of the type of acidic monomer on contact angle and ceramic bond durability of resin were investigated. MDP and 4-MET promoted chemisorption of γ-MPS on the ceramic surface and enhanced the ceramic bond strength of the resin. However, thermocycling decreased ceramic bond strengths, as reflected by the increased number of bonded specimens that exhibited interfacial resin failure. Bond strength was greater for 4-MET-activated ceramic primer than for the MDP-activated ceramic primer, although most bonded specimens exhibited interfacial resin failure. Degradation behavior differed between the 4-MET-activated and MDP-activated ceramic primers.

Morphological analysis of flowable resins after long-term storage or surface polishing with a mini-brush

This study evaluated the surface roughness and morphological changes of various flowable resins after long-term storage in a phosphate-buffered saline (PBS) or surface polishing with a mini-brush. The tested products were Beautifil Flow BF02 and BF10, Clearfil Majesty LV, Filtek Supreme XT, and UniFil LoFlo Plus. A paste-type resin composite, Filtek Supreme, was used as a control. The prepared specimens were 10 mm in diameter and 1 mm in height. The standard surfaces were polished with #600-1200 diamond disks and kept in deionized water for 24 hours. Surface roughness was detected after storage in PBS (pH 7.4) for either 2 weeks or 6 months, or after polishing with a mini-brush. Results of this study demonstrated that the surface roughness of the standard specimens had a lower value as compared to those after storage in PBS for 2 weeks and 6 months, or after polishing with a mini-brush.