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Purpose: The purpose of this study was to evaluate fluorescence changes of remineralized and nonremineralized enamel margins adjacent to glass ionomer restorations during a pH cycling sequence. Methods: One hundred permanent molar and premolar teeth were placed in a demineralizing solution for 3 days and restored with a glass ionomer restoration (simulating Atraumatic Restorative Treatment [ART]). Half were placed in a remin solution for 7 days to create a remineralization (remin) group. Specimens were randomly divided into 4 groups (N=25): (a) 2 remin groups; and (b) 2 nonremin groups. One half of the remin and nonremin group specimens were treated with a 5,000-ppm sodium fluoride solution during pH cycling with remin fluid and an acidic beverage over 20 days. Fluorescence changes were recorded with quantitative light fluorescence (QLF). Higher fl uorescence values indicated less lesion porosity. Statistical comparisons between the groups over the 5 measurement sessions of cycling were performed using repeated measures of analysis of variance with a post-hoc test, paired-sample t test and 2-sample t tests (a=0.05). Results: The remin groups experienced significantly less lesion porosity than the nonremin groups. Fluoride groups experienced less lesion porosity than the nonfluoride groups. Conclusions: A brief period of remineralization and use of a prescription strength fluoridated rinse improved the enamel substrate surrounding glass ionomer restorations, resulting in less lesion porosity. [ABSTRACT FROM AUTHOR]

To evaluate the correlation between microtensile dentin bond strength (microTBS) and silver ion penetration, two total-etch 3-step and one self-etch 2-step system were investigated. OptiBond FL adhesive was applied to flat occlusal dentin on six non-carious human molars, and a resin composite "crown" was formed in 2 mm increments. After 24-hour water storage, the teeth were sectioned with a low-speed diamond saw to obtain four-square sticks (approximately 2 mm X 2 mm) per tooth. Cylindrical tensile test specimens were formed with an 0.5 mm2 cross-sectional area. Nail varnish was applied to the dentin within 0.5-1.0 mm of the interface before immersing in 50% silver nitrate for 15 minutes. Following silver fixation, tensile testing was performed in a Zwick UTM at 1 mm/minute using a passive gripping fixture to obtain 72-hour microTBS [23.9 MPa]. The percentage area of silver penetration was measured on debonded specimens using light microscopy and Image-Pro Plus Software [89%]. The procedures were repeated using Scotchbond Multi-Purpose Plus [microTBS = 27.8 MPa; nanoleakage = 67%] and Clearfil SE bond [microTBS = 36 MPa; nanoleakage = 55%]. No significant correlation between microtensile bond strength and nanoleakage was found for all systems. A weak-to-moderate negative relationship was found between microTBS and nanoleakage for OptiBond FL (Spearman r = -0.3844). No correlation was found for the remaining adhesive systems. The correlation between these two common laboratory measurements appears to be adhesive-system dependent.