ボールミリング法で改質したβ-TCPセメントの諸特性への粉液比の影響

The authors have developed a β-tricalcium-phosphate (β-TCP) powder modified mechano-chemically through the application of a ball-milling process (mβ-TCP). The resulting powder can be used in a calcium-phosphate-cement (CPC). In this study, the effects of the powder-to-liquid ratio (P/L ratio) on the properties of the CPCs were investigated, and an appropriate P/L ratio that would simultaneously improve injectability and strength was clarified. The mβ-TCP cement mixed at a P/L ratio of 2.5 and set in air exhibited sufficient injectability until 20 min after mixing, and strength similar to or higher than that mixed at a P/L ratio of 2.0 and 2.78. Although the mβ-TCP cements set in vivo and in SBF were found to exhibit a lower strength than those set in air, it did have an appropriate setting time and strength for clinical applications. In conclusion, P/L ratio optimization successfully improved the strength of injectable mβ-TCP cement

Clinical Key Points of Class II Direct Composite Restoration

Direct composite restorations have been widely accepted as a reliable bonded restorative option to achieve minimal intervention with improved physical properties of resin composite and advancement of adhesive systems. Recently, relatively complicated Class II composite restorations have been more frequently performed because they are esthetically pleasing and easily accepted by patients. In these years, auxiliary instruments such as matrix retainers and wedges for restoring Class II cavities have been enhanced. Using these instruments appropriately brings a promising clinical outcome restoring functions and esthetics of even posterior teeth in Class II cavities. This article will introduce instruments and techniques that can be easily incorporated into daily practice for Class II direct composite restorations, where it is difficult to restore the contact tightness and the anatomy of the proximal surfaces