IADR Abstract Archives
A quantitative assessment of enamel permeability using fluid flow model
Objectives: To determine the rate and time-course of change of fluid flow through intact human teeth after applying different forms of agent to the enamel surface.
Methods: The experiments were carried out on 30 premolars, recently extracted for orthodontic purposes. Each tooth was cut transversely below to the cemento-enamel junction with a diamond disc and water coolant. All teeth were randomly assigned to one of the following groups: distilled water (control group; n=6), 0.2% NaF solution (n=8), 1.23% APF gel (n=8), 35% phosphoric acid (n=8). The treating agents were applied to the enamel surface of the crown, according to the manufacturer’s instructions then rinsed with water for 2 min. The fluid flow through crown was measured before and 0, 30, 60, 180 min after applying the agents, during which the simulating pulpal pressure of 20 mmHg was maintained.
Results: The median fluid flow rate significantly decreased at 30, 60, 180 min after applying the APF gel (P<0.001; Friedman RM ANOVA on Ranks; Holm-Sidak test) and NaF solution (P<0.05; Tukey test), when compared with their corresponding baseline values. The mean rate of fluid flow after treating with phosphoric acid was significantly increased at 30, 60, 180 min (P<0.05; one-way RM ANOVA; Holm-Sidak test). In control group, these changes were not significant after treating the crown with distilled water (P>0.05).
Conclusions: The applications of either 1.23% APF gel or 0.2% NaF solution to enamel surfaces resulted in a decrease of fluid flow rate, partly due to the effect of remineralization. This method was demonstrated to be useful for quantitative assessment of anti-caries agents.
Methods: The experiments were carried out on 30 premolars, recently extracted for orthodontic purposes. Each tooth was cut transversely below to the cemento-enamel junction with a diamond disc and water coolant. All teeth were randomly assigned to one of the following groups: distilled water (control group; n=6), 0.2% NaF solution (n=8), 1.23% APF gel (n=8), 35% phosphoric acid (n=8). The treating agents were applied to the enamel surface of the crown, according to the manufacturer’s instructions then rinsed with water for 2 min. The fluid flow through crown was measured before and 0, 30, 60, 180 min after applying the agents, during which the simulating pulpal pressure of 20 mmHg was maintained.
Results: The median fluid flow rate significantly decreased at 30, 60, 180 min after applying the APF gel (P<0.001; Friedman RM ANOVA on Ranks; Holm-Sidak test) and NaF solution (P<0.05; Tukey test), when compared with their corresponding baseline values. The mean rate of fluid flow after treating with phosphoric acid was significantly increased at 30, 60, 180 min (P<0.05; one-way RM ANOVA; Holm-Sidak test). In control group, these changes were not significant after treating the crown with distilled water (P>0.05).
Conclusions: The applications of either 1.23% APF gel or 0.2% NaF solution to enamel surfaces resulted in a decrease of fluid flow rate, partly due to the effect of remineralization. This method was demonstrated to be useful for quantitative assessment of anti-caries agents.