Commercially available fluoride toothpaste formulations produced different short-term changes in total salivary calcium following brushing, but these differences diminished over time and were no longer statistically significant at 60 minutes.
Researchers conducted a randomized, 3-treatment, 3-period crossover trial involving 48 healthy participants recruited from Witten/Herdecke University in Germany. Participants had a mean age of 22.55 years; 26 (54%) were women, and 22 (46%) were men. Each participant used 3 commercially available sodium fluoride toothpastes in randomized order: Dentalux, containing pyrophosphate and zinc; Parodontax, containing sodium bicarbonate; and Sensodyne, containing methyl vinyl ether/maleic acid copolymer. A 2-day washout separated each treatment period, and all participants completed all 3 treatment periods.
The primary outcome was the interaction between toothpaste formulation and measurement timeon total salivary calcium concentration following a single toothbrushing procedure. Secondary outcomes included the effects of toothpaste formulation, measurement time, and treatment sequence. Unstimulated saliva was collected prior to brushing, immediately following brushing, and at 30 and 60 minutes. Calcium concentrations were measured using a colorimetric assay and evaluated with linear mixed-effects models accounting for repeated measurements within participants.
Changes in salivary calcium over time differed by toothpaste formulation. Immediately following brushing, the estimated mean calcium concentration was 18.81 ppm with Parodontax compared with 36.57 ppm with Dentalux and 37.70 ppm with Sensodyne. Parodontax produced an estimated mean concentration 17.76 ppm lower than Dentalux and 18.89 ppm lower than Sensodyne. Dentalux and Sensodyne did not differ significantly at this time point.
The differences narrowed substantially during follow-up. At 30 minutes, the estimated mean calcium concentration with Parodontax was 35.82 ppm compared with 39.15 ppm with Dentalux and 39.74 ppm with Sensodyne, corresponding to differences of 3.33 ppm and 3.92 ppm, respectively. By 60 minutes, no statistically significant differences remained among the 3 formulations. Dentalux and Sensodyne did not differ significantly at any measurement point. Treatment sequence also had no statistically significant effect, suggesting that the order of toothpaste administration did not account for the observed differences.
The findings reflected effects of the complete commercial formulations rather than specific ingredients. The toothpastes differed in multiple active and inactive components, so the decrease observed with Parodontax could not be attributed specifically to sodium bicarbonate. Similarly, the study could not determine whether pyrophosphate, zinc, methyl vinyl ether/maleic acid copolymer, or another component accounted for the responses observed with the other formulations.
Several limitations may affect interpretation. The study measured total salivary calcium rather than biologically active ionized calcium and did not assess salivary flow rate, pH, phosphate, fluoride, or buffering capacity. The study therefore could not establish effects on calcium bioavailability or remineralization. Participants were healthy young adults recruited from a single university, limiting generalizability to other populations. In addition, researchers assessed only the 60-minute response following a single brushing episode, leaving long-term effects on salivary mineral homeostasis, enamel remineralization, dental calculus formation, and caries incidence unknown. The trial was also retrospectively registered.
Commercially available fluoride toothpaste formulations may produce different but short-lived patterns in total salivary calcium following brushing, although the clinical relevance of these biochemical changes remains uncertain. Researchers called for studies examining whether these changes translate into longer-term oral health effects. “The observed effects were transient rather than sustained,” wrote lead study author Lina Aminy, from the Chair of Operative and Preventive Dentistry at Witten/Herdecke University, and colleagues.
The authors declared no competing interests.
Source: PLOS One