Shear Bond Strength of Bioactive Amorphous Calcium Phosphate Composites
Gary E. Schumacher, Joseph M. Antonucci, Justin N. O'Donnell, Drago Skrtic
Bioactive, amorphous calcium phosphate (ACP)-filled polymeric composites in aqueous environments release significant amounts of Ca and PO4 ions leading to deposition of an apatitic mineral that is similar to that found in enamel. These materials are potentially effective anti-demineralizing/remineralizing agents with foreseeable clinical applications as adhesives, protective liners and bases, orthodontic cements and pit and fissure sealants. The objective of this study was to evaluate the shear bond strength to dentin (SBS) of ACP basing-composites after various periods of water-aging. Two photo-activated, experimental matrix resinmatrices were employed in this study: one comprising a blend of 2,2-bis[p-(2 -hydroxy-3 -methacryloxypropoxy)phenyl]propane (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA) and zirconyl dimethacrylate (BTHZ matrix) and the other consisting of TEGDMA and pyromellitic glycerol dimethacrylate (PMGDMA) (TP matrix). Different composites were formulated with three types of filler: 1) silica- (Si-ACP), 2) zirconia-hybridized ACP (Zr-ACP; as-synthesized and milled) and 3) commercial strontium ion-leachable glass, all at 40 % by mass loading. Flat dentin surfaces were acid-etched, primed with N-phenylglycine glyceryl methacrylate and PMGDMA, and photo-polymerized. The ACP composites were then applied and photo-polymerized. The bonded specimens were completed by adding a final layer of light-cured resin composite and the final specimens were then de-bonded in shear after various times (24 h, 3 weeks, 1 mo, 3 mo and 6 mo) of storage in water at 37 oC. The average SBS of ACP composites, regardless of the type of the filler, resin composition and water aging interval, was (18.3 3.5) MPa. 91 % of debonded surfaces after 24 h aqueous exposure showed the adhesive failure. After 2 weeks of water aging adhesive/cohesive failures were predominantly observed in unmilled and milled ACP composites (up to 75 % in combined the adhesive layer and
, Antonucci, J.
, O'Donnell, J.
and Skrtic, D.
Shear Bond Strength of Bioactive Amorphous Calcium Phosphate Composites, Journal of the American Dental Association, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852737
(Accessed October 2, 2023)