Microbiological and clinical effects of chlorhexidine digluconate and hydrogen peroxide mouthrinses on developing plaque and gingivitis

Abstract

While the ability of chlorhexidine (CHX) to prevent plaque formation and inhibit the development of gingivitis has been well documented in the literature, the therapeutic value of hydrogen peroxide (H₂O₂) in preventing gingivitis is in dispute. The purpose of this study was to compare the clinical and microbiological effects of an established therapeutic agent, such as chlorhexidine with that of H₂O₂in the experimental gingivitis model. Following a period of stringent oral hygiene, 32 subjects were allocated to 1 of 3 treatment groups which were balanced on the basis of their pre‐experimental gingivitis scores. The subjects then refrained from any oral hygiene for 21 days. During this period, they rinsed twice a day with either a placebo, 0.12% CHX. or a 1% H₂O₂ mouthrinse. After 21 days, supragingival and marginal plaque was collected from each subject and assayed for total cultivable microbiota, total facultative anaerobes, facultative Streptococci, Actinomyces, Fusobacterium, Veillonella and Capnocytophaga. At the end of the experimental period, the group rinsing with 0.12% CHX showed 95% reduction in gingivitis incidence, 100% reduction in bleeding sites, and 80% reduction in plaque scores compared to the group rinsing with placebo. Conversely, the group using 1% H₂O₂ showed a marginal reduction In gingivitis incidence of 15% and a 28% reduction in bleeding sites compared to the placebo group, but no significant reduction in plaque scores. The microbiological results showed that 0.12% CHX was an excellent broad‐spectrum antimicrobial agent which significantly reduced the number of both facultative and obligate anaerobes in plaque. This was particularly true for facultative anaerobes, the numbers of which were reduced by 1.5–2.5 logs. Compared with 0.12% CHX, 1% H₂O₂ had no effect on the total cultivable microbiota or on the facultative bacterial species such as Streptococci and Actinomyces. Treatment with 1% H₂O₂ was also significantly less effective (0.6 log₁₀. reduction) than 0.12% CHX (1.5 log₁₀ reduction) in reducing the number of obligate anaerobes such as Fusobacterium and Veillonella. The clinical data obtained in this study are thus consistent with previous data documenting the superior anti‐plaque and anti‐gingivitis efficacy of CHX. They also clearly demonstrate that treatment with 1% H₂O₂ does not provide meaningful anti‐plaque or anti‐gingivitis benefits. The bacteriological data indicate that the superior clinical efficacy of CHX is consistent with its superior antimicrobial activity in vivo, whereas the marginal clinical efficacy of H₂O₂ may be due to its relatively poor antimicrobial activity in vivo towards a broad range of plaque bacteria.