Is it Better to BRUSH or FLOSS First?

Lower Your Risk of Periodontal Disease According to the Findings of a New Study

I am often asked by patients, Should I floss or brush first? There are many different theories on this, but the best explanation is to critically evaluate our scientific literature to find the answer.

A recent randomized controlled clinical trial evaluated this question in detail1. Researchers evaluated two groups to see which sequence was the best to reduce plaque (bacteria). The first group was asked to brush teeth first, and then use dental floss to clean the spaces between the teeth (brush-floss). The second group was asked to use floss first, than brush their teeth (floss-brush).  Both groups used toothpaste that contained fluoride.

Researchers found that the amount of plaque between the teeth and in the mouth overall was significantly reduced when participants used the floss first, brush second method.  Their explanation contends that flossing loosens bacteria and debris from between the teeth and brushing afterwards (when the mouth is rinsed with water) further clears the mouth of these particles. Plaque (bacteria) is the primary culprit behind the development of periodontal disease, an inflammatory condition that occurs when bacteria accumulate below the gum line. Periodontal disease can lead to pain, swelling, bleeding gums, gum recession, and tooth loss if left untreated. Additionally, peridontal disease is associated with  many systemic dieases like cardiovacular diease, diabetes and alzheimers, just to name a few.

Both the doctors and hygienists at PDG recommend flossing regularly first, followed up by brushing twice a day with fluoridated toothpaste and undergoing yearly comprehensive periodontal evaluations for the prevention of periodontal disease, which is treatable and often reversible with proper and timely care from a periodontist.

Information about the Author: Dr. Tassos Sfondouris is a board certified periodontist and a former clinical assistant professor at the University of Maryland, Dental School.  I am passionate about periodontal and restorative therapies that promote the health, comfort and function of our mouths.   I welcome your comments and suggestions and encourage you to like me on Facebook or follow me on Twitter to get the latest unbiased information on dental health topics.


1.Mazhari F, Boskabady M, Moeintaghavi A. The effect of toothbrushing and flossing sequence on interdental plaque reduction and fluoride retention: A randomized controlled clinical trial. J PERIODONTOL 2018; 7: 824-832.