In vitro Evaluation of the Effect of Mouth Rinse with Trimetaphosphate on Enamel Demineralization

Abstract

Objective: The aim of this study was to investigate the effectiveness of sodium trimetaphosphate (TMP) addition to mouth rinses to inhibit enamel demineralization. Design: Bovine enamel blocks (n = 88) were selected by surface hardness and divided into eight treatment groups (n = 11 per group): placebo, 100 or 225 μg F/ml; the rinses with 100 μg F/ml had differing TMP concentrations (range 0-0.6%). The blocks were subjected to pH cycling for 5 days and treated twice a day with mouth rinses. After that, surface and cross-sectional hardness as well as fluoride in enamel were measured. Results: The groups containing both 100 μg F/ml and 0.4% TMP inhibited demineralization most effectively (p < 0.001). This formulation yielded lower values of lesion areas than the formulations containing 100 or 225 μg F/ml but no TMP. The addition of 0.4% TMP increased the fluoride in enamel. Conclusion: It is possible to improve the effectiveness of a mouth rinse with 100 µg F/ml by addition of TMP, this being superior in inhibiting enamel demineralization compared with mouth rinses containing 225 µg F/ml.

Effect of Sodium Trimetaphosphate on Hydroxyapatite Solubility: An In Vitro Study

“…Thus, the data obtained using this model (or any other in vitro protocol) should be considered carefully. This statement is supported by data from this study that observed reduction in F concentration in the hydroxyapatite with the addition of TMP, while in the study by Favretto et al (8) there was an increase of F in the enamel with 0.4% TMP. The adsorption of TMP on enamel surface can modify the selective permeability of the enamel by facilitating the diffusion of ions (12,14,20).…”

“…Several studies have suggested that TMP reduces the demineralization process, and that an ideal TMP/F ratio allows an enhancement of the effects of F-containing products (7,8,(10)(11)(12)(13). When TMP and F are co-administered, the adsorption of TMP on the enamel surface can change the selective permeability and facilitate the diffusion of ions such as Ca and F (12) into the enamel (20,21).…”

“…The solution containing 100 ppm F and 0.4% TMP presented a greater protective effect under erosive conditions than a solution containing 225 ppm F. In another study (8), the same mouthrinse (100 ppm F and 0.4% TMP) was superior in inhibiting dental caries in vitro because it prevents acid diffusion into the enamel. It has also been observed a higher F content in the enamel after use of this mouthrinse, although the type of F deposits on the enamel has not been identified: loosely bound F (calcium fluoride -CaF 2 ) or firmly bound F (fluorapatite -FA) (11).…”

“…However, the 0.02% NaF solution shows lower anticaries efficacy (1,5,6). Addition of inorganic phosphate can be performed to improve the effectiveness of mouthrinses containing 0.02% NaF (7,8).…”

“…Sodium trimetaphosphate (TMP), a cyclic condensed phosphate, has lower capacity to bind to HA than polyphosphates, but it remains bound to enamel for a longer period (10). Studies have demonstrated the reduction of enamel solubility, suggesting an affinity of TMP to enamel surface and/or HA (7,8,10).…”