Development of a cycling protocol for the in vitro assessment of enamel erosion and the effect of a fluoridated mouthrinse containing micrometric- and nano-sized trimetaphosphate on erosion prevention

Abstract

Objectives To develop a cycling protocol for the evaluation of enamel erosion and to evaluate the effect of fluoride mouthrinses containing micrometric (TMPm) or nano-sized (TMPn) trimetaphosphate on enamel erosion using an artificial mouth apparatus.Materials and methodsFifty-three volunteers with high frequency of acid drink consumption were evaluated for duration and interval between sips, as well as the total drinking time. After standardizing the protocol, bovine enamel blocks (n = 120) were subjected to erosive cycles three times a day and treated with mouthrinses twice a day (1 min): placebo, 100 ppm F, 225 ppm F, 100 ppm F + 0.2% micrometric TMP (100F+TMPm) and 100 ppm F + 0.2% nano-sized TMP (100F+TMPn). The blocks were analyzed by profilometry (µm), surface hardness (KHN) and cross-sectional hardness (ΔKHN) after 1 or 3 days. Data were submitted to two-way ANOVA, followed by Student-Newman-Keuls’ test, and Pearson correlation (p < 0.05). ResultsMost volunteers were women (74.4%) with a mean age of 21 years. Among all volunteers, 35.9% preferred to consume juices. Median sip time was 3.4 s, with a pause of 6.4 s and a total drinking time of 1 min and 10 s. Mouthrinses containing TMP maintained significantly higher SH (p < 0.001), with 100F+TMPn showing the lowest ΔKHN among all groups (p < 0.05). After 3 days, placebo produced the greatest enamel wear, SH loss, and ΔKHN, whereas 100F+TMPn achieved the lowest values (p < 0.05). Conclusions The protocol developed using an artificial mouth is informative and suitable for studying erosive tooth wear under in vitro conditions. Treatment with mouthrinses containing TMP significantly reduced enamel erosive wear and mineral loss. Clinical relevance TMP supplementation in mouthrinses significantly enhances their protective effect against erosive enamel wear.