Effects of Brushing Modalities: Electric vs Manual on Eroded Ename

Objectives: To compare the effects of manual and electric toothbrushes on enamel wear following acid erosion, focusing on surface and subsurface impacts.
Methods: Human enamel specimens (n=24) were allocated to two groups: manual brushing and electric brushing. Samples underwent four cycles of acid erosion (citric acid, pH 2.7) followed by brushing (30 strokes per cycle) under a standardised force of 290–295 grams. Step height changes were measured using non-contact laser profilometry, while enamel subsurface changes were assessed using scanning electron microscopy (SEM). Statistical analyses employed two-way ANOVA with Bonferroni’s multiple comparisons test (p < 0.05).
Results: Electric toothbrushing resulted in significantly greater enamel wear than manual brushing at all stages (p < 0.0001). After 20 minutes of cumulative exposure, mean step heights were 3.65 ± 0.39 μm for manual brushing and 5.13 ± 0.28 μm for electric brushing, reflecting ~40% greater wear with electric toothbrushes. SEM imaging revealed more pronounced subsurface alterations in the electric brushing group, including separation at the enamel-resin interface, compared to linear wear scars seen in manual brushing.
Conclusions: Electric toothbrushes caused significantly more enamel loss on acid-eroded surfaces than manual toothbrushes. Subsurface changes suggest heightened vulnerability to mechanical forces from electric brushing, emphasising the importance of careful brushing technique and toothbrush selection. These findings highlight the need for further investigation into brushing modalities under clinically relevant conditions to provide tailored recommendations for patients at risk of dental erosion.