The aim of this study was to assess whether a reference manual toothbrush alone and in conjunction with variable width of floss would have different efficacy in plaque removal or result in different amounts of reduction of gingival inflammation. The randomized, controlled, double blind examiner, two-period crossover study examined floss efficacy in 34 healthy subjects following use of a standardized manual toothbrush alone and in combination with four floss products (Oral B^® Essential floss, Oral B^®  Satin floss, Sparkle^®  expanded floss, Paldent^®  expanded floss). The gingival index score (Löe and Silness) and Rustogi Modified Navy plaque index score were examined. The results presented that mean gingival index score reductions (baseline minus endpoint) were as follows: 0.4628, 0.5005, 0.3818, and 0.3923 for the toothbrush in combination with Oral B^®  Essential floss, Oral B^®  Satin floss, Sparkle expanded floss, and Paldent^®  expanded floss, respectively. Mean plaque reductions in floss contact areas were as follows: 0.3475, 0.3096, 0.3159, and 0.198 for toothbrush in combination with Oral B^®  Essential floss, Oral B^®  Satin floss, Sparkle^®  expanded floss, and Paldent^®  expanded floss, respectively. No statistically significant differences were found between any pairs of floss. All four floss treatments showed greater (p<0.05) plaque removal and reduction in gingival inflammation than toothbrush alone. In conclusion, all four floss products in combination with a manual toothbrush removed plaque significantly better than the toothbrush alone. Among floss types, there were no significant treatment differences.