A comparison between two ion selective electrode (ISE) potentiometric
methods is reported for determining the amount of fluoride in hard dental tissue after
placement of fluoride-releasing dental restorations. The two methods are: (1) the
direct method involving linear calibration (LC), and (2) a spiking method involving
multiple standard additions (MA). Results showed that measurements performed by
the LC method underestimate the amount of fluoride released by up to 30%.
Recovery tests demonstrated that the use of MA and blank correction procedures is
useful for an accurate and sensitive ISE determination of fluoride in hard dental
tissues