The effect of tensile strength on the clinical effectiveness and patient acceptance of dental floss.

This study compared the clinical effectiveness and subjective approval of 2 waxed dental flosses that differed significantly in tensile strength and wax content. At the initial appointment, subjects (20 1st-year dental students) were instructed to stop interproximal cleaning on 2 contralateral quadrants in order to allow plaque to accumulate on these surfaces for 1 week. 1 week later, subjects were instructed to begin flossing these 2 contralateral quadrants with 1 of the 2 types of floss for the next 1-week period, while withdrawing interproximal cleaning on the opposite 2 contralateral quadrants. After flossing these 2 quadrants for 1 week, the subjects began flossing the opposite 2 contralateral quadrants with the same floss. After 2 weeks of flossing contralateral quadrants, the 1st floss was withdrawn and replaced with the alternative floss for another similar 2-week trial period. At the end of each 2-week trial period, subjects completed subjective questionnaires concerning the floss they had used during the previous 2-week period. Pre- and post-flossing plaque indices were calculated for each week for both flosses, and compared statistically by a repeated measures analysis of variance. The results showed that both flosses significantly reduced interproximal plaque deposits, and had equal subjective approval. However, neither the greater-strength nor the lower-wax content of the experimental floss was associated with an increase in clinical effectiveness or with a change in subjective approval.