The choice of controls in toothpaste studies - The effect of a number of commercially available toothpastes compared to water on 4-day plaque regrowth

Toothpastes have been shown to have an antimicrobial activity both in vitro and in vivo; this activity variably translates into a plaque inhibitory effect in vivo Commercially available toothpastes have a complex chemical make-up and some contain additional chemicals for which improved effects against plaque have been claimed. The aim of this study was to assess the plaque inhibitory properties of 5 commercially available toothpastes compared to a rinse of water over 4 days. The study was a randomised, single-blind, cross-over design balanced for residual effects. Volunteers were rendered plaque-free at each baseline and rinsed for 1 min, under the supervision of an assistant, 2X a day with the allocated mouthrinse or toothpaste slurry. At the end of the 4-day test period, the plaque was disclosed and measured by plaque index and plaque area. The plaque measurements indicated a significant difference between the toothpastes. The order of efficacy was Colgate Total, Crest regular, Crest Tartar, Colgate regular, Colgate 0-6 gel and water. This confirms previously reported data confirming the plaque inhibitory properties of certain toothpastes compared to water. These data indicate that the choice of control toothpaste with which to compare toothpastes formulated for plaque control is important and could influence conclusions drawn from clinical trials of such products.