Effect of fluoridated versus nonfluoridated charcoal toothpaste on the enamel surface microhardness

Abstract Aim: To evaluate the effect of fluoridated and nonfluoridated charcoal toothpaste on the enamel surface microhardness compared to the regular fluoridated toothpaste. Patients and methods: Thirty human intact upper incisors were used in this study that were de-coronated and fixed in acrylic blocks leaving the labial surface exposed. The samples were randomly divided into three equal groups based on the type of toothpaste used for brushing ( n = 10); group I: samples were brushed using fluoridated charcoal toothpaste, group II: samples were brushed using nonfluoridated charcoal toothpaste, group III: samples were brushed using regular fluoridated toothpaste. They were brushed using custom made tooth brushing simulating machine, simulating a period of 12 weeks brushing. Vickers Microhardness values were evaluated before and after the brushing. All the collected data were tabulated and statistically analyzed using Statistical Package for Social Science (IBM SPSS version 26). Results: At the baseline, the mean enamel microhardness values were 342.5, 347.7 and 341.5 for group I, II, and III, respectively, with no statistically significant difference between them ( P = 0.366). These values were significantly increased after the brushing in group I and III to 352.1 and 368.8 ( P = 0.003 and 0.001), respectively. However, group II showed slightly decrease to 340.7 with nonsignificant difference ( P = 0.239). There was no significant difference between group I versus both group II and III ( P = 0.347 and 0.117), respectively. While group II was statistically significantly different versus group III ( P = 0.005). Conclusion: Fluoridated toothpastes either charcoal or regular had the ability to enhance the enamel microhardness. However, nonfluoridated charcoal toothpaste did not provide any noticeable effect on the enamel microhardness. Recommendation: Long-term clinical studies are recommended to assess the claimed whitening potential of charcoal-based toothpastes without affecting either the microstructure or microhardness of the enamel surface.