Real improvements in oral health are more likely to result from daily habits than expensive devices, according to new research by dentist-periodontist Tim Thomassen. In his dissertation, which he will defend at the University of Amsterdam on December 12, Thomassen examines how different toothbrush types and brushing durations affect oral health.
Globally, about 3.5 billion people are affected by oral diseases such as cavities and gum disease. Dental plaque is a significant contributor to these issues, making effective brushing essential. However, questions remain about what constitutes “good” brushing.
Thomassen analyzed multiple aspects of tooth and gum disease prevention, including the effectiveness of various toothbrushes, the duration of brushing, and the clarity of oral hygiene advice provided to the public. His research included systematic reviews of international clinical studies as well as original experiments.
"For removing dental plaque, a powered toothbrush performs better than a manual one," said Thomassen. "But the difference between the two main powered types is negligible in everyday use." He added that manufacturers should focus on user education and developing affordable, sustainable products instead of releasing increasingly costly models.
The standard recommendation is to brush twice daily for two minutes each time. Thomassen’s findings confirm that two minutes of brushing removes more plaque than one minute; however, extending this period to three minutes yields only minimal additional benefit.
Manual toothbrush users—still the majority worldwide—tend to brush for less time: just under 1.5 minutes on average. "We know brushing works, and fortunately the average brushing time has been increasing in recent years, but many people still don't brush long enough," said Thomassen.
In contrast, users of powered toothbrushes are more likely to meet or exceed the recommended two-minute mark, averaging nearly 2.5 minutes per session. "Built-in timers may help people brush longer," he noted.
Thomassen also evaluated online advice from dental organizations globally and found that only about one-third provide clear instructions. "That needs to improve," he said. "Good oral care starts with accessible, understandable, and practical information that people can apply immediately."
He advocates for practical guidelines tailored to diverse lifestyles and budgets so that good oral care becomes achievable for everyone. "There is a clear need for a national oral-care guideline that is evidence-based and adapted to different needs and preferences. Such a guideline would help bridge the gap between research and everyday practice, supporting both patients and oral-health professionals."
Preparations for such guidelines are underway—a challenge Thomassen plans to pursue further.
