The Sequence Of Mechanical Cleansing May Affect Oral Health

Does the Order of Brushing and Flossing Matter? New Research Says Yes

When it comes to protecting your teeth and gums, brushing and flossing are the gold standard for daily oral hygiene. But a growing body of research suggests that the sequence in which you clean your teeth may impact how effective your routine is, especially in terms of plaque removal and fluoride absorption.

So, the big question remains: Should you floss before or after brushing?

What Is Mechanical Oral Cleansing?

Mechanical cleansing is a dentist-endorsed practice that involves physically removing plaque using tools like toothbrushes and dental floss. It’s been a key part of oral care since the early 20th century, gaining traction after high rates of dental decay prevented many individuals from qualifying for military service during World War I, World War II, and the Korean War.

This public health concern led to an emphasis on daily oral hygiene and the introduction of fluoridated water—a major step forward in national dental health standards.

What Science Says About Brushing vs. Flossing First

Although most research tends to focus on toothbrush types, toothpaste formulations, or brushing techniques, few clinical studies have compared the effects of brushing and flossing order—until recently.

A 2018 study by the Dental Materials Research Center at Mashhad University of Medical Sciences in Iran set out to explore this exact question. The study involved dental students and followed a strict testing process:

• Participants were split into two groups

• All stopped their usual oral hygiene routine for 48 hours

• One group brushed first, then flossed

• The other group flossed before brushing

• Both used fluoride toothpaste

• Plaque levels were measured using the Rustogi Modified Navy Plaque Index

• Fluoride levels in interdental areas were tracked using ion-specific electrodes

• After two weeks, the groups swapped routines and repeated the process

The Results: Flossing Before Brushing Wins

The study concluded that flossing before brushing resulted in significantly lower plaque accumulation, particularly between the teeth. More importantly, participants who flossed first retained higher fluoride concentrations in the interdental spaces.

Dr. Richard T. Kao, president-elect of the American Academy of Periodontology, praised the study for its practical relevance. “It’s a very straightforward study that provides useful insights into daily oral hygiene,” he noted.

Dr. Kao also addressed initial concerns over participant safety, clarifying that the students followed a structured brushing protocol and were not exposed to significant risk during the 48-hour no-cleaning phases.

Controversies and Considerations

Though some questioned the ethics of asking participants to suspend their oral care routine, the researchers took steps to ensure safety, including providing preventive dental treatments and clear instructions. Despite the fact that the subjects were students at the same institution conducting the research, the process was rigorously monitored.

Final Thoughts: What Dentists Recommend

While more research is always welcome, the current findings support the idea that flossing before brushing may enhance the benefits of your oral hygiene routine.

Dr. Stephen R. Daniel, president of the American Academy of Periodontology, summed it up best:

“Whether you floss before or after brushing, what truly matters is that you do both—consistently, and thoroughly.”

So, while flossing before brushing may give your mouth an extra edge in plaque removal and fluoride retention, don’t overthink the order. Just make sure you’re brushing twice daily for two minutes, flossing once a day, and keeping up with your regular dental checkups.