Reports & Studies

Are all interdental brushes equal ...?

PD Dr. Kristina Bertl, PhD MSc MBA

Interdental brushes are viewed as the tool of choice for patients with periodontitis. This is because for interdental attachment loss in particular, they are regarded as more effective than dental floss, for example. Most interdental brushes on the market are cylindrical in shape. However, a research group from Austria (Innsbruck Medical University) asked the valid question of whether this cylindrical shape truly is the ‘best’ for optimum cleaning efficacy (Schnabl 2019).

Are all interdental brushes equal …?

In a randomized controlled clinical cross-over study involving 17 participants, the authors compared the efficacy of cylindrical interdental brushes with that of waist-shaped interdental brushes. All included patients were classified as having stage 3 periodontitis, but were already in the maintenance phase following successful periodontal treatment. In accordance with the study design (‘cross-over’), all patients tested both the cylindrical and waist-shaped interdental brushes (both brushes were manufactured by the company Topcaredent® and were tested for 35 days each). Plaque and bleeding indices were both recorded.

Although no significant differences were observed with regard to the bleeding index, the plaque index was found to be statistically significantly different between the two groups. If the interdental brushes were used from the buccal side only, the waist-shaped brush was able to remove significantly more plaque than the cylindrical one. The lingual surfaces in particular were cleaned more effectively with the waist-shaped interdental brushes (39% plaque-free sites with the waist-shaped brushes compared with 24% with the cylindrical ones). It was also interesting to see that the waist-shaped interdental brushes were similarly effective in anterior, posterior, buccal and lingual sites (38–42% plaque-free sites).

Further studies will of course be required in future, but the shape of interdental brushes will probably be another thing for us to consider in the future.


  1. Schnabl D, Goebel G, Kadletz A, Gaenzer H, Steiner R, Laimer J, Kapferer-Seebacher I. Cleansing efficacy of waist‐shaped inter‐dental brushes. A randomized‐controlled crossover study. J Clin Periodontol. 2020;47:30–35.