Floss Then Brush or the Other Way Around?

Prescription toothpaste has become increasingly popular in recent years to prevent and/or treat a variety of oral maladies such as caries, hypersensitivity, and periodontal diseases. While numerous prescription dentifrices are on the market, this response will consider fluoride as the active ingredient. While exploring this question, the “patient/problem, intervention, comparison, outcome,” or PICO method was used to search PubMed. A variety of comparisons, including no water rinsing, brush-floss sequence, and fluoride, were used. Fluoride retention, salivary fluoride, caries prevention, and interdental plaque were the outcomes explored.

A systematic review by Silva et al¹ investigated whether brush-floss or floss-brush is more effective. It assessed randomized control trials to determine which sequence (brush- floss or floss -brush) resulted in a reduction in dental plaque. The authors found no difference between the two approaches, however, the systematic review included two articles with a small sample size of 60 participants.

A randomized control trial by Mazahari et al² that was included in the Silva systematic review examined the effect of brushing and flossing sequence on interdental plaque. Researchers noted the presence or absence of interdental plaque in 25 adults. Reduction in interdental plaque in the floss-brush group was statistically significantly higher than in the brush-floss group. The authors also found higher interdental fluoride concentrations in the floss-brush group than in the brush- floss group.

Another study with 35 adult participants found that flossing and brushing had the greatest reduction in periodontal indicators, but only in men.³ Using a crossover design, the authors assessed bleeding on probing and dental plaque to assess the efficacy of the brushing and flossing sequence.

While this research indicates that the floss-brush sequence may be superior, the sample size in all of these studies was small. More research is needed to confirm these findings.

To address the question of rinsing or not rinsing with water after brushing with a fluoride product, Nazzal et al⁴ conducted a randomized control trial with 17 caries-free and caries-prone children: a total of 32 participants. When examining the residual salivary fluoride concentration, the authors found an increased fluoride concentration when no water rinsing was performed after brushing. In contrast, Opydo-Szumaczek et al⁵ examined salivary fluoride concentration in 14 volunteers finding that the concentration of the fluoride product had a greater influence on residual salivary fluoride concentrations than did post-water rinsing or no rinsing. In another randomized control trial, the authors found no post water rinsing had a greater anticaries effect and increased fluoride retention.⁶ This 8- to 9-week study was conducted on 20 adolescents with orthodontic bands. Again, the research is inconclusive due to the limited number of studies, the small sample size, and the short length of the studies.

Using an evidence-based approach, advising patients to floss and then brush and avoid rinsing with water appears to be reasonable. However, this recommendation is based on limited scientific evidence.

References

1. Silva C, Albuquerque P, de Assis, et al. Does flossing before or after brushing influence the reduction in the plaque index? A systematic review and meta-analysis. Int J Dent Hyg. 2022;20:18-25.
2. Mazhari F, Boskabady M, Moeintaghavi A, Habibi A. The effect of toothbrushing and flossing sequence on interdental plaque reduction and fluoride retention: A randomized controlled clinical trial. J Periodontol. 2018;89:824–832.
3. Torkzaban P, Arabi SR, Sabounchi SS, Roshanaei G. The efficacy of brushing and flossing sequence on control of plaque and gingival inflammation. Oral Health Prev Dent. 2015;13:267-273.
4. Nazzal H, Duggal MS, Kowash MB, Kang J, Toumba KJ. (2016). Comparison of residual salivary fluoride retention using amine fluoride toothpastes in caries-free and caries-prone children. Eur Arch Paediatr Dent. 2016;17:165-169.
5. Opydo-Szymaczek J, Pawlaczyk-Kamieńska T, Borysewicz-Lewicka M. Fluoride intake and salivary fluoride retention after using high-fluoride toothpaste followed by post-brushing water rinsing and conventional (1400-1450 ppm) fluoride toothpastes used without rinsing. Int J Environ Res Public Health. 2022;19:13235.
6. Al-Mulla A, Karlsson L, Kharsa S, Kjellberg H, Birkhed D. Combination of high-fluoride toothpaste and no post-brushing water rinsing on enamel demineralization using an in-situ caries model with orthodontic bands. Acta Odontol Scand. 2010;68:323-328.

From Dimensions of Dental Hygiene. March/April 2026;24(2):46