Comparison of TISAB II and III for salivary fluoride determination: addressing a bioanalytical challenge in fluoride analysis

Background Accurate determination of salivary fluoride (F) depends on appropriate analytical conditions, particularly the buffering system used before ion-selective electrode measurements.Research design and methods This laboratory-based analytical study addressed the practical challenge of selecting between two total ionic strength adjustment buffers (TISAB II and TISAB III) for salivary F-determination using samples obtained from previously conducted clinical trials. Unstimulated saliva from eight participants was collected at baseline and at 5 min, 30 min, 1 h, 4 h, and 12 h after exposure to three F-treatments: F-varnish, 1,450 ppm F-dentifrice, and 5,000 ppm F-dentifrice. F-concentrations were measured using an F-ion-selective electrode after buffering with either TISAB II or TISAB III. Data were analyzed using paired statistical tests and Pearson correlation analysis (α = 0.05).Results No significant differences were observed between the buffers across most conditions, although differences were detected at later time points following dentifrice use. A strong positive correlation was found between the two buffering systems (p < 0.001), and no differences were detected in the area under the concentration–time curve.Conclusions These findings indicate that both TISAB II and TISAB III provide comparable analytical performance for salivary fluoride determination under the tested conditions, although differences may occur at lower fluoride concentrations.