METHODS: A total of 16 probiotic toothpastes and 6 probiotic mouthrinses, available on the European and American markets, were analysed for the number of culturable (CFU; agar plating), live (viability qPCR), and total bacteria (qPCR), and if they indeed contain the probiotic species proclaimed (16S rRNA sequencing). The products with viable probiotics were further evaluated for their impact on an in vitro oral biofilm model. Additionally, culturable probiotic isolates from these products were tested for potential inhibitory effects against individual oral pathogens.
RESULTS: Not all of the examined products contained viable bacteria; instead, they contained ferments or inactivated probiotics. Only 2 toothpastes were found to contain culturable bacteria consistent with the probiotic species declared on their labels. Additionally, traces of DNA from actual probiotics were detected in 68% of the toothpastes and 50% of the mouthrinses. Furthermore, the tested products did not show any beneficial effect on an in vitro oral biofilm model. Similarly, the culturable probiotic isolates recovered from the products showed no inhibitory activity against selected oral pathogens.
CONCLUSIONS: This study highlights that in contrast to probiotic lozenges, which are widely used for oral probiotic delivery, currently available probiotic toothpastes and mouthrinses may not consistently meet established probiotic criteria. These findings highlight the need to critically reassess their use in scientific research and the commercial use of the term probiotic, while recognizing that the present findings are specific to the product batches analysed and may not represent each brand as a whole.