IADR Abstract Archives
Spatially-resolved pH Evolution in Novel, Hybrid Self-Adhesive Composite and Glass Ionomer Materials Using Fluorescence Lifetime Imaging.
Objectives: The purpose of this study was to develop an effective method to monitor the pH of novel composite/ glass polyalkenoate (ionomer) materials at the micron scale for the initial period after mixing.
Methods: A fluorescent probe designed to alter its fluorescence properties in response to its environmental pH (LysoSensor™Yellow/Blue DND-160, ThermoFisher Scientific) was used to dose a series of buffer solutions pH 2- pH 7.7 at a concentration of 1 μM. A multi-channel series of fluorescence lifetime (τ)/pH standard curves were generated by analysis of the solutions using 2-photon fluorescence lifetime imaging microscopy.
The fluorescence properties of probe-dosed Material X, a recently developed dual-cure system, were microscopically monitored continuously for 5 hours following the combination of the liquid and powder components (n=5). The data were processed and analysed using TRI2 software and compared to that obtained from identical experiments observing Fugi II LC.
The standard curves were used to read pH measurements from the τ image series. Conventional glass ionomer cement EQUIA® Forte (GC) was used to validate the experimental model.
These data were compared to that obtained using traditional pH probe analysis techniques.
Results: The average pH profiles obtained using τ were similar to those obtained using the pH probes in all groups.
This type of analysis allowed the observation of an evolutionary pH gradient occurring within individual glass particulates of Material X and GC Fugi II over time. We were also able to digitally separate the pH evolution of glass particulates from the continuous phase. These data allowed the deduction of the mechanisms by which chemical homeostasis of these systems were achieved.
Conclusions: We have developed an adaptable experimental model which allows high-resolution micron-scale spatial analysis of pH over time in dental material systems.
Methods: A fluorescent probe designed to alter its fluorescence properties in response to its environmental pH (LysoSensor™Yellow/Blue DND-160, ThermoFisher Scientific) was used to dose a series of buffer solutions pH 2- pH 7.7 at a concentration of 1 μM. A multi-channel series of fluorescence lifetime (τ)/pH standard curves were generated by analysis of the solutions using 2-photon fluorescence lifetime imaging microscopy.
The fluorescence properties of probe-dosed Material X, a recently developed dual-cure system, were microscopically monitored continuously for 5 hours following the combination of the liquid and powder components (n=5). The data were processed and analysed using TRI2 software and compared to that obtained from identical experiments observing Fugi II LC.
The standard curves were used to read pH measurements from the τ image series. Conventional glass ionomer cement EQUIA® Forte (GC) was used to validate the experimental model.
These data were compared to that obtained using traditional pH probe analysis techniques.
Results: The average pH profiles obtained using τ were similar to those obtained using the pH probes in all groups.
This type of analysis allowed the observation of an evolutionary pH gradient occurring within individual glass particulates of Material X and GC Fugi II over time. We were also able to digitally separate the pH evolution of glass particulates from the continuous phase. These data allowed the deduction of the mechanisms by which chemical homeostasis of these systems were achieved.
Conclusions: We have developed an adaptable experimental model which allows high-resolution micron-scale spatial analysis of pH over time in dental material systems.