Are bristle stiffness and bristle end-shape related to adverse effects on soft tissues during toothbrushing? A systematic review

Background: Toothbrushing might be associated with the development of soft tissue lesions. This systemic review aimed to examine soft tissue lesions caused by different bristle stiffnesses and bristle end-shapes in manual toothbrushes in adult individuals.

Materials and methods: Scopus, EMBASE and PubMed databases were searched to find controlled trials that evaluated manual toothbrush bristle stiffness and/or end-shape in regard to soft tissue safety. The grey literature was also included in the search strategy. Two reviewers independently performed the screening, final selection and data extraction. To be included, studies had to have been performed using at least two manual toothbrushes differing in bristle stiffness and/or end-shape, and had to report any adverse effects on oral soft tissues after at least 7 days of follow-up. A meta-ethnography strategy was used for qualitative data synthesis. The Cochrane Collaboration tool was assessed to evaluate the risk of bias.

Results: Thirteen studies were included from the 1,945 initially retrieved. Toothbrush bristle end-shape was investigated in six studies, bristle stiffness in two, and both features were investigated in five studies. Hard-bristle toothbrushes produced more gingival lesions than medium- and soft-bristle brushes. A slight gingival recession width increase was identified in the end-rounded group, compared with the tapered group. Only four studies presented adverse effects as the primary outcome.

Conclusion: Soft and extra-soft toothbrushes tend to be safer. Oral soft tissue injuries are similar for both tapered and end-rounded bristles. Further studies investigating adverse effects as a primary outcome are recommended.