Sample size estimation
CROSS
The sample size was determined based on findings in a similar crossover study, [Three different bristle designs of commercially available Oral B manual toothbrushes (CA, OT and FT) were used. The OT brush used was the Oral-B Pro-Expert Clinic Line Orthodontic Manual Toothbrush. The CA design brush used was an Oral-B Pro-Expert Cross action All In One Manual Toothbrush, and the third brush was the FT conventional Oral-B Pro Gum Care Manual Brush. All the brushes were adult brushes with soft brush heads (Fig. Three different bristle designs of commercially available Oral B manual toothbrushes. 