Monomer/Solvent Solubility Interaction Parameter Comparisons

Objectives: Currently, solvent dissolution methods are being employed to remove excess of uncured dental composite when performing depth of cure testing, instead of the conventional manual hand-scraping with a spatula. However, the choice of solvent has yet to be standardized in order to be effective for a range of common dental monomers. Thus, this study compared Hoy’s total solubility parameters of selected solvents to solubility parameters of commonly used dental monomers to identify possible candidates for uncured monomer dissolution.
Methods: Software (Hoy Solubility Parameter Calculation, Computer Chemistry Consultancy, Thal, Austria) was used to determine the total Hoy’s solubility coefficient (δt) from contributions of individual parameters of dispersive (δd), polar (δp), and hydrogen bonding (δh) of major dental monomers (Bis-GMA, ethoxylated Bis-GMA, TEGDMA) and common organic solvents (chloroform, acetone, tetrahydrofuran, acetonitrile, ethanol, and methanol), by inputting the composition of each compound into the software. If the calculated total parameter of the monomer fell within ±5 (MPa)^½ units from the calculated value for the solvent (a typical method for assessing solubility compatibility found in the literature), the potential for solubility of a monomer in a specific solvent was accepted (“YES”). If monomer δt exceeded ±5 (MPa)½ units of the solvent value, the potential for solvation was not accepted (“NO”).
Results: The table presents study findings.
Conclusions: Three of the solvents (chloroform, acetone, and tetrahydrofuran) proved to be potentially good solvents for the common dental monomers evaluated, while other solvents (acetonitrile, ethanol, and methanol) did not.