Comparison of two clinical methods for evaluating the anti-plaque efficacy of a dentifrice

The objective of this research was to assess two different published methods of plaque level evaluation on human subjects, and to determine whether both methods can produce similar findings to the point that the methods can be used interchangeably.

Healthy human volunteers entered into a number of double-blind, cross-over clinical trials. Two plaque scoring methods were used: The Modified Gingival Margin Plaque Index (MGMPI) and the Turesky Modified Quigley-Hein (TMQH). With the MGMPI, plaque was evaluated 24 hours after a single product use. With the TMQH, plaque was scored after four days of product use. Three dentifrices were studied: Colgate Total, Colgate Total plus Whitening, and Colgate Regular Dental Cream. Additionally, two mouthrinses were evaluated: PerioGard and Fluorigard. In all studies conducted, there was a one-week wash-out period between each product use.

There were no side effects observed or reported in any study. In all studies, both the plaque indices used found that the active products Colgate Total, Colgate Total plus Whitening and PerioGard produced significantly lower mean plaque scores compared to Colgate Regular Dental Cream and Fluorigard (p < 0.05).

The results of this investigation indicate that the two plaque evaluation methods continue to demonstrate that an active product is significantly more efficacious than a control product. Therefore, either method can be used to investigate the anti-plaque efficacy of a product. Additionally, the MGMPI method can be used 24 hours after product use, which is a clear advantage over a four-day product use and will yield the same results.