Consequently, in cavity preparation for an adhesive restoration after removal of caries-infected

dentin, large areas of the cavity floor are composed of caries-affected dentin. Therefore, in clinical settings, bonding substrate is commonly caries-affected dentin, not normal dentin. Many studies on dentin bonding have used normal dentin as bonding substrate, which have contributed to the dramatic development of dentin adhesive systems during www.selleckchem.com/products/NVP-AUY922.html the past decades. On the other hand, there is a few study about bonding to caries-affected dentin, in which the bond strengths to caries-affected dentin are lower than those of normal dentin [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12] and [13] (Table 1). The inferior bonding efficacy of caries-affected dentin would affect the clinical performance of adhesive composite restoration. This article discusses bonding potential to caries-affected dentin and also reviews the characteristics of caries-affected dentin. The mineral phase of dentin is mainly composed of carbonate-rich hydroxyapatite. The dentinal caries process consists of dynamic, cyclical episodes of demineralization and remineralization. A Fourier-transform infrared imaging (FTIR) study has shown that the mineral phase of caries-affected dentin is less crystalline and has a lower mineral content than normal dentin [14]. Micro-Raman spectroscopy investigation

has suggested that the relative intensity of the mineral carbonate peak at 1070 cm−1 decreased dramatically selleck inhibitor in caries-affected dentin [15]. Electron probe microanalysis Doxorubicin (EPMA) revealed that caries-affected dentin, as well as caries-infected dentin showed much lower magnesium (Mg) content compared with intact dentin, although the densities of calcium (Ca) and phosphorus (P) in caries-affected dentin were relatively similar to intact dentin [8] (Fig. 1). The reduction in Mg content in dentin starts before the commencement of a decrease in Ca and P content in dentinal caries [16] and [17]. Changes in Mg content

could be the first sign of carious demineralization and may indicate a loss of peritubular dentin matrix [18]. Moreover, larger apatite crystals are present in remineralized dentin after carious demineralization, compared to the apatite crystals in intact dentin [17] and [19]. These indicate that caries-affected dentin causes re-precipitation of CO3- and Mg-poor apatite after the dissolution of CO3- and Mg-rich apatite [20] and [21]. Mineral crystals in caries-affected dentin are scattered and randomly distributed, with larger apatite crystallites and wider intercrystalline spaces compared with intact dentin [19]. The dentin organic matrix contains different extracellular proteins, such as type I collagen, proteoglycans, dentin phosphoproteins and sialoprotein. Changes in dentin organic matrix associated with caries have been reported [15], [22], [23] and [24].