Plaque-pH After Mouthrinse Pre-Treatment with Different Fluorides

The objectives: of this study were to compare acid production by dental plaque in adults after rinsing with different mouthrinses: amine fluoride/sodium fluoride (AmF 100+ NaF 150ppm F; Elmex®), its components sodium fluoride or amine fluoride 250 ppm F respectively, chlorhexidine (0.2% CHX) or amine fluoride/stannous fluoride (125 ppm F; AmF-/SnF2 respectively). Methods: A telemetric system used in adults (n=5) to evaluate cariogenic sucrose challenge [Stösser et al. Oralprophylaxe 2005] was adjusted to determine antibacterial properties of mouthrinses. The sensing membrane of the glass pH electrode was mounted in the interdental area. After insertion the prostheses were not removed during the test period, thus allowing undisturbed growth of plaque. Subjects were asked to refrain from mechanical oral hygiene for four days. The pH-response of 4-day-old plaque was measured after challenge with 10% sucrose which was maintained in the mouth for 2 min and following the mouthrinses were used for 30 sec immediately before a second sucrose challange. The area of the curve was calculated for 30 minutes in µmol/L[H+]. Results: The average pH drop caused by sucrose was pH 4.33 ± 0.18 after 19 min in 5 adults (10 measurements). The inhibition of acid production amounted to 50% by Elmex®, to 30 % by NaF, to 40-45% by AmF, to 55% by AmF/SnF2 and to 66% by CHX. In conclusion: The combination of AmF with NaF or SnF2 increased the antibacterial effect of inorganic fluorides which is, however, predominated by chlorhexidine; furthermore antimicrobial mouthrinses do not inhibit completely bacterial metabolism of dental plaque.