Light-Cured Dimethacrylate-Based Resins and Their Composites: Comparative Study of Mechanical Strength, Water Sorption, and Ion Release

Abstract

This study explored how resin type affects selected physicochemical properties of complex methacrylate copolymers and their amorphous calcium phosphate (ACP)-filled and glass-filled composites. Two series of photo-polymerizable resin matrices were formulated employing 2,2-bis [p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) or an ethoxylated bisphenol A dimethacrylate (EBPADMA) as the base monomer, Unfilled copolymers and composites filled with a mass fraction with 40 %, 35 % and 30 %, respectively, of ACP or the un-silanized glass were assessed for biaxial flexure strength (BFS), water sorption (WS) and mineral ion release upon immersion in HEPES-buffered saline solution for up to six months. Substituting EBPADMA for Bis-GMA significantly reduced the WS while only marginally affected the BFS of both dry and wet copolymers. Independent of the filler level, both dry and wet ACP composites formulated with either BTHM or ETHM resins were mechanically weaker than the corresponding copolymers. The BFS of ACP composite specimens after 1 month in saline did not further decrease with further aqueous exposure. The BFS of glass-filled composites decreased with the increased level of the glass filler and the time of aqueous exposure. After 6 months of immersion, the BFS of glass-filled BTHM and ETHM composites, respectively, remained 58 % and 41 % higher than the BFS of the corresponding ACP composites. Ion release data indicated that a minimum mass fraction of 35 % ACP was required to attain the desired solution supersaturation with respect to hydroxyapatite for both the BTHM and ETHM derived composites.

In vitro remineralization of enamel by polymeric amorphous calcium phosphate composite: Quantitative microradiographic study

“…Zirconia hybridized ACP (Zr-ACP) was prepared according to our previously published protocol [19, 20]. The amorphous state of the filler was verified by X-ray diffractometry (Rigaku DMAX 2000 X-ray diffractometer, Rigaku/USA Inc., Danvers, MA, USA) and Fourier-transform infrared spectroscopy (Nicolet Magna-IR FTIR 550 spectrophotometer, Nicolet Instrumentations Inc., Madison, WI, USA).…”

“…In the case of ACP sealants, solution solubility of ACP [18] enabled the release of supersaturating levels of calcium and phosphate ions intralesionally and shifted the solution thermodynamic driving forces toward the formation of apatite. ACP can sustain these supersaturation conditions over extended periods of time [19, 20]. …”

Ultra‐small‐angle X‐ray scattering–X‐ray photon correlation spectroscopy studies of incipient structural changes in amorphous calcium phosphate‐based dental composites

“…Despite these advantages, ACP composites trail behind conventional glass-based dental composites in terms of mechanical strength. 10 Many treatments, such as filler hybridization 13,14 or milling, [15][16][17] surface treatment of the filler, 9 and use of various methacrylic polymer matrices, [18][19][20][21] have been explored for optimizing the mechanical properties of the ACP-based dental composites for potential clinical applications. Notably, a comparison of wet and dry ACP composites showed that the biaxial flexure strength of the composites is strongly related to the uptake of water in these composites -more water, less strength, and vice versa.…”

Effect of Food Stimulated Liquids and Thermocycling on the Monomer Elution from a Nanofilled Composite

“…There is a very limited number of studies evaluating the effects of organic acids on the leaching of monomers [20], but there are several reports regarding the effects of organic acids on the mechanical and surface characteristics of composite resins [5, 21]. Asmussen has reported that the hardness of resin composite significantly decreased after 1 d of immersing in ethanol, acetic acid, propionic acid, and lactic acid [8].…”