The effect of oxidising mouthrinses compared with chlorhexidine on salivary bacterial counts and plaque regrowth

For various clinical indications, oxidising agents have been used in dentistry for many years. Little is known, however, of their antibacterial activity and their ability to inhibit plaque formation. In this study, 2 mouthrinses containing peroxyborate (Bocasan) and peroxycarbonate (Kavosan) were compared alongside a negative control saline rinse and a positive control chlorhexidine rinse (Corsodyl) for their ability to inhibit plaque reformation. Employing a randomised four replicate 4 x 4 latin square cross over design and, whilst omitting all other oral hygiene, plaque was measured by area and index after rinsing for 4 days. In a second study, in vivo antibacterial effects of the rinses were assessed by measuring salivary bacterial counts following single rinses with the preparations at various time intervals over 7 h. Plaque inhibition by chlorhexidine was significantly greater than the other rinses. All rinses were significantly better than the saline rinse at inhibiting plaque. For plaque area, the peroxycarbonate rinse was significantly better than the peroxyborate rinse at inhibiting plaque. Salivary bacterial count reductions were significantly greater compared to saline with chlorhexidine at all time intervals up to 7 h. Whilst both peroxyborate and peroxycarbonate rinses produced greater reductions in bacterial counts than saline up to 3 h, at no time interval were the differences significant. The findings of these studies would suggest oxidising mouthrinses may inhibit plaque formation not by a direct antibacterial effect, but by some other mechanism. The magnitude of plaque reductions obtained with the peroxyborate and more so peroxycarbonate rinses would suggest a need for further study of these preparations when used as adjuncts to normal toothbrushing.