Brushing and flossing ability increased dramatically 3 weeks following 2 sessions of oral hygiene instructions. At the same time, the plaque index for these patients decreased significantly. 1 year after the oral hygiene instruction, the plaque index for these patients returned to the pre-intervention levels. However, these patients were able to maintain their 3-week post-intervention brushing and flossing scores. We conclude that increased levels of plaque 1 year later, was not due to loss of brushing and flossing skills.