The purpose of this study was to investigate how plaque removal and gingival inflammation are affected by the utilisation time of manual toothbrushes. 96 subjects were included in the study. The subjects were divided into two groups, one group changed their toothbrush every four weeks during the 6 month trial period (renewal group) while the other group used the same toothbrush throughout the whole period (non-renewal group).

 

In each group four subgroups were formed: normal brush head size/soft filaments, normal brush head size/medium filaments, small brush head size/soft filaments and small brush head size/medium filaments. Plaque accumulation and gingival inflammation were assessed at baseline and after 2, 8, 12, 16 and 24 weeks. A final examination was performed after an additional 10 day period.

 

The results showed a significant difference between the two main groups in respect to plaque accumulation and gingival inflammation in favour of the renewal group. The initial worsening in plaque reduction occurred when the toothbrush had been used for four months, and up to this time gingival health also remained stable. After four months a reduced efficiency in plaque removal was found.

 

The authors conclude that the effectiveness of manual toothbrushes with respect to plaque removal and the development of gingival inflammation will be reduced after four months of utilisation. The effect of filament type and brush size was not clearly established. Therefore it is recommended to change toothbrush after no more than four months, independent of filament stiffness and brush head size.