Clickbait based on a 5-year old source which actually says, "Twelve trials were included in this review which reported data on two outcomes (dental plaque and gum disease). Trials were of poor quality and conclusions must be viewed as unreliable. The review showed that people who brush and floss regularly have less gum bleeding compared to toothbrushing alone. There was weak, very unreliable evidence of a possible small reduction in plaque. There was no information on other measurements such as tooth decay because the trials were not long enough and detecting early stage decay between teeth is difficult."

So studies showed flossing helps prevent gum bleeding. This is not what the article reports.

Are there studies of effectiveness of tooth brushing? Imagine the control group - people who don't brush their teeth at all!