Effect of Silica-Based Abrasive Ingredients on Fluoride Concentration in Toothpaste: An In Vitro and In Vivo Study

Background/Objectives: Toothpastes have recently been developed with purposes ranging from strengthening teeth and restoring periodontal tissue to removing stains and alleviating tooth sensitivity. Although the individual effects of each component are well understood, their interactions with each other remain unclear. Methods: The oral fluoride concentration following the use of dentifrices with different abrasive contents was evaluated in seven healthy adults. In addition, in in vitro apatite pellet experiments, fluoride concentration from the pellets was compared after the use of dentifrices with different abrasive contents. Results: A comparison of fluoride ion concentrations in the oral cavity after using five different types of toothpaste showed that toothpaste without abrasive ingredients retained the highest concentration at all time points from 5 min onward. When the concentration of abrasive ingredients was adjusted in the same toothpaste and compared, the toothpaste with no abrasive (0%) resulted in the highest fluoride concentration compared to all the other toothpastes (10%, 20%, 30%) at 10, 20 and 30 min. The concentration of fluoride released from apatite pellets was also highest in the toothpaste without abrasive ingredients. Conclusions: These results suggest that abrasive ingredients affect the concentration of fluoride in the oral cavity, and the effect may be particularly pronounced in hard tissues such as teeth.