Biodegradable vs. conventional toothbrushes for biofilm control: a systematic review and meta-analysis of randomized trials

Background – Due to the immense environmental impact of plastic waste, there has been a significant increase in interest for both biodegradable and natural toothbrushes (BT) as sustainable forms of daily oral care. This includes bamboo toothbrushes, as well as plant-based products (i.e., miswak). As such, these two types of products can be considered similar because they are both renewable and biodegradable in nature. However, their effectiveness when compared to traditional plastic toothbrushes at controlling dental biofilm has not been fully established. Objective – To evaluate the effectiveness of biodegradable and natural oral hygiene tools compared with conventional plastic toothbrushes for controlling dental plaque in children and adults. Methods – This systematic review/meta-analysis was reported according to PRISMA guidelines, and its protocol was registered in PROSPERO. All databases were searched using electronic methods from their inception to December 2025: PubMed, Scopus, Web of Science, and Embase. All randomized controlled trials (RCTs) that examined biodegradable/natural oral hygiene products compared to conventional plastic toothbrushes and that had plaque index (PI) as outcome were included. The analyses used random effects model, and certainty of evidence was evaluated using GRADE methodology. Results – Five RCTs (n = 408) met the criteria for inclusion. There was no clear difference in plaque index between biodegradable/natural oral hygiene tools and conventional plastic toothbrushes [mean difference (MD): −0.09, 95% CI: −0.47 to 0.29]. However, the pooled estimate was characterized by very high statistical heterogeneity (I² = 89%) and the certainty of the evidence was rated as very low, which substantially limits confidence in this result. The results of subgroup analyses according to type of oral hygiene tool and population did not show any meaningful differences from those of the pooled analysis. The overall certainty of evidence was rated as very low and had a high risk of bias. Conclusions – Biodegradable and natural oral hygiene products may result in little to no difference in plaque control compared with conventional plastic toothbrushes; however, confidence in this estimate was very low. Well-designed, adequately powered RCTs are required to reduce uncertainty and inform evidence-based clinical and sustainability-related recommendations. Systematic Review Registration – https://www.crd.york.ac.uk/PROSPERO/view/CRD420251273997, PROSPERO CRD420251273997.