Objectives: To measure the anti-plaque and anti-gingivitis efficacy of toothpaste containing 2% zinc citrate trihydrate (ZCT).
Methods: Two studies were carried out. Study 1 was a randomised, double-blind, cross-over study measuring 18h plaque growth after brushing with the test (2%ZCT) or control (no ZCT) toothpaste; both pastes contained fluoride (1450ppm). Plaque was recorded with Gingival Margin Plaque Index (GMPI) and Modified Quigley and Hein Index (MQHI). 21 adult subjects completed the study. Study 2 was a randomised, double-blind, 2-group parallel study. Group 1 (n=87) used the 2% ZCT paste, group 2 (n=88) used a marketed gum-health toothpaste (0.3% triclosan) twice daily for 3 months; both pastes contained fluoride. Plaque (MQHI) and gingivitis (Gingival Index, GI) were assessed at the start and end of the study. Data were analysed by ANCOVA.
Results: The mean (sd) GMPI after 18h was 25.2 (11.5) for the 2%ZCT paste and 33.2 (11.1) for the control. Mean (sd) MQHI values after 18h were 0.70 (0.41) for the 2% ZCT paste and 0.91 (0.47) for the control. The difference between the groups was statistically significant (p<0.01) for both indices. Plaque growth was 59% (GMPI) and 55% (MQHI) lower in the 2% ZCT group than in the control group. The mean (sd) 3-month MQHI was 2.23 (0.53) for the 2%ZCT paste and 2.35 (0.50) for the 0.3%TCN paste. Both means were significantly lower than baseline means (p<0.001). The mean (sd) 3-month GI was 1.17 (0.41) for the 2%ZCT paste and 1.30 (0.40) for the 0.3%TCN paste. Both means were significantly lower than baseline means (p<0.001); the difference in 3-months GI between the groups was significant (p<0.001).
Conclusion: The 2% ZCT toothpaste was superior to a negative control in reducing plaque growth and as effective as a toothpaste with 0.3% triclosan over 3 months.