Influence of a chlorhexidine and a zinc mouthrinse on gingivitis

Chlorhexidine mouthrinse as an adjunctive treatment for gingival health

BACKGROUND

Dental plaque associated gingivitis is a reversible inflammatory condition caused by accumulation and persistence of microbial biofilms (dental plaque) on the teeth. It is characterised by redness and swelling of the gingivae (gums) and a tendency for the gingivae to bleed easily. In susceptible individuals, gingivitis may lead to periodontitis and loss of the soft tissue and bony support for the tooth. It is thought that chlorhexidine mouthrinse may reduce the build-up of plaque thereby reducing gingivitis.

OBJECTIVES

To assess the effectiveness of chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for the control of gingivitis and plaque compared to mechanical oral hygiene procedures alone or mechanical oral hygiene procedures plus placebo/control mouthrinse. Mechanical oral hygiene procedures were toothbrushing with/without the use of dental floss or interdental cleaning aids and could include professional tooth cleaning/periodontal treatment.To determine whether the effect of chlorhexidine mouthrinse is influenced by chlorhexidine concentration, or frequency of rinsing (once/day versus twice/day).To report and describe any adverse effects associated with chlorhexidine mouthrinse use from included trials.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 28 September 2016); the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8) in the Cochrane Library (searched 28 September 2016); MEDLINE Ovid (1946 to 28 September 2016); Embase Ovid (1980 to 28 September 2016); and CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 28 September 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for at least 4 weeks on gingivitis in children and adults. Mechanical oral hygiene procedures were toothbrushing with/without use of dental floss or interdental cleaning aids and could include professional tooth cleaning/periodontal treatment. We included trials where participants had gingivitis or periodontitis, where participants were healthy and where some or all participants had medical conditions or special care needs.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where feasible. For continuous outcomes, we used means and standard deviations to obtain the mean difference (MD) and 95% confidence interval (CI). We combined MDs where studies used the same scale and standardised mean differences (SMDs) where studies used different scales. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs. Due to anticipated heterogeneity we used random-effects models for all meta-analyses.

MAIN RESULTS

We included 51 studies that analysed a total of 5345 participants. One study was assessed as being at unclear risk of bias, with the remaining 50 being at high risk of bias, however, this did not affect the quality assessments for gingivitis and plaque as we believe that further research is very unlikely to change our confidence in the estimate of effect. Gingivitis After 4 to 6 weeks of use, chlorhexidine mouthrinse reduced gingivitis (Gingival Index (GI) 0 to 3 scale) by 0.21 (95% CI 0.11 to 0.31) compared to placebo, control or no mouthrinse (10 trials, 805 participants with mild gingival inflammation (mean score 1 on the GI scale) analysed, high-quality evidence). A similar effect size was found for reducing gingivitis at 6 months. There were insufficient data to determine the reduction in gingivitis associated with chlorhexidine mouthrinse use in individuals with mean GI scores of 1.1 to 3 (moderate or severe levels of gingival inflammation). Plaque Plaque was measured by different indices and the SMD at 4 to 6 weeks was 1.45 (95% CI 1.00 to 1.90) standard deviations lower in the chlorhexidine group (12 trials, 950 participants analysed, high-quality evidence), indicating a large reduction in plaque. A similar large reduction was found for chlorhexidine mouthrinse use at 6 months. Extrinsic tooth staining There was a large increase in extrinsic tooth staining in participants using chlorhexidine mouthrinse at 4 to 6 weeks. The SMD was 1.07 (95% CI 0.80 to 1.34) standard deviations higher (eight trials, 415 participants analysed, moderate-quality evidence) in the chlorhexidine mouthrinse group. There was also a large increase in extrinsic tooth staining in participants using chlorhexidine mouthrinse at 7 to 12 weeks and 6 months. Calculus Results for the effect of chlorhexidine mouthrinse on calculus formation were inconclusive. Effect of concentration and frequency of rinsing There were insufficient data to determine whether there was a difference in effect for either chlorhexidine concentration or frequency of rinsing. Other adverse effects The adverse effects most commonly reported in the included studies were taste disturbance/alteration (reported in 11 studies), effects on the oral mucosa including soreness, irritation, mild desquamation and mucosal ulceration/erosions (reported in 13 studies) and a general burning sensation or a burning tongue or both (reported in nine studies).

AUTHORS' CONCLUSIONS

There is high-quality evidence from studies that reported the Löe and Silness Gingival Index of a reduction in gingivitis in individuals with mild gingival inflammation on average (mean score of 1 on the 0 to 3 GI scale) that was not considered to be clinically relevant. There is high-quality evidence of a large reduction in dental plaque with chlorhexidine mouthrinse used as an adjunct to mechanical oral hygiene procedures for 4 to 6 weeks and 6 months. There is no evidence that one concentration of chlorhexidine rinse is more effective than another. There is insufficient evidence to determine the reduction in gingivitis associated with chlorhexidine mouthrinse use in individuals with mean GI scores of 1.1 to 3 indicating moderate or severe levels of gingival inflammation. Rinsing with chlorhexidine mouthrinse for 4 weeks or longer causes extrinsic tooth staining. In addition, other adverse effects such as calculus build up, transient taste disturbance and effects on the oral mucosa were reported in the included studies.

An evaluation of 6 dentifrice formulations for supragingival anticalculus and antiplaque activity

A 4 week, double blind clinical trial was conducted to assess the antiplaque/anticalculus activity of test dentifrices containing varying levels of zinc citrate. Subjects were divided into 6 groups, 4 experimental, 1 positive control and a placebo group. All subjects only brushed at home using the placebo control during study weeks 1 and 3. Plaque and calculus were collected at the end of study weeks 2 and 4 on mylar strips worn on lower incisor teeth. Dentifrice efficacy was assessed by comparing group dry and ash weight decrements. While there were no significant differences between the test and control groups, there was a demonstrable trend toward greater inhibition with higher zinc citrate levels, especially among subjects with high levels of plaque and calculus at baseline.

Lacking anti-plaque efficacy of 2 sanguinarine mouth rinses

The aim of the study was to compare the anti-plaque effect of sanguinaria extract to that of a known effective agent, chlorhexidine gluconate, and to that of a known ineffective agent, tap water. The study was conducted as a 3 times crossed-over and blindly evaluated 3 week clinical trial. 12 dental students rinsed in an individually randomized sequence twice daily for 4 days (Monday to Friday) with Viadent containing 0.03% sanguinaria extract (0.01% sanguinarine chloride) and a 1000 ppm concentration of zinc ions (ZnCl2), 2 X 30 s X 10 ml; with Hibitane Dental containing 0.2% chlorhexidine gluconate, 1 min X 10 ml; and with tap water, 1 min X 10 ml. Mechanical oral hygiene was allowed only during the 3 days between test periods. When measured according to the plaque index or in terms of plaque wet weight, only the chlorhexidine rinse further reduced the low Monday scores. No significant difference was observed between Friday scores after rinses with Viadent and water. The variation in effect of the 3 rinses was less marked when assessed by means of area of plaque on the tooth surfaces. Subjectively, both the taste and effect of Viadent was reported to be poor. In a second controlled clinical trial using the same design, no significant difference in anti-plaque effect was found between the commercially available Viadent rinse and an experimental rinse with a tripled concentration of sanguinarine chloride but the same content of zinc.

The influence of gingival stimulation on recovery from human experimental gingivitis

The present study concerns an investigation carried out to determine the effects of gingival stimulation on the resolution of a human experimental gingivitis. 10 young male dental students participated in the experiment. Following the baseline examination (day 0), the participants were instructed to abstain from all oral hygiene procedures during a 21-day period. Heavy plaque accumulation and gingivitis developed during the 21-day induction period. On the evening of the 21st day, active oral hygiene measures were reinstitued, for an 8-day period, using 2 different methods. For the left side of the maxillary arch, a hygiene procedure including gingival stimulation was prescribed. On the other hand, for the right side, a hygiene method without gingival stimulation was instituted. On both sides of the upper arch, the gingival condition was assessed by means of the gingival index, and soft deposits were assessed by the plaque index (selected teeth: 13, 14, 15, 23, 24, 25). Measurements were performed on days 0, 21, 22, 23, 24, 25, 26, 27, 28, 29. On day 29, ideal oral hygiene conditions and gingival health were re-established on both sides. However, a statistical analysis of the data collected during the recovery period revealed that gingival index scores were temporarily, but significantly, higher on the side where mechanical stimulation was performed, although plaque deposits there decreased more rapidly. Thus the present work supports the idea that gingival stimulation does not in any way improve recovery from experimental gingivitis.

Effects of a zinc citrate mouthwash on dental plaque and salivary bacteria

A double-blind crossover trial was carried out to assess the effect of zinc citrate on plaque accumulation in vivo and to measure total salivary aerobes and anaerobes both during the trial and throughout the day following a single rinse. When compared to the placebo, zinc citrate significantly reduced the plaque accumulation in the subjects. However, the mean reduction was small and of questionable clinical importance. A progressive increase in plaque was observed throughout both active and placebo 7-day rinsing periods. There was no significant reduction in salivary bacterial counts either during the crossover study or during the day following a single rinse with zinc citrate.

Design of studies to evaluate plaque control agents

The importance of plaque in the etiology of periodontal diseases is reviewed. A survey is also presented of the various indices for scoring plaque in clinical trials. Variations in the clinical design, type of population studied, and difficulty in scoring gingival plaque are reviewed. A survey is presented of some recent published studies of plaque-inhibiting agents.

The effect of a 1% chlorhexidine gel in the initial therapy of chronic periodontal disease

Thirty patients took part in a 4 week 'double-blind' clinical trial. Following initial oral hygiene instruction and scaling, half the patients were instructed to brush with a 1% Chlorhexidine gel in the evenings, the other half to use placebo. A standard dentifrice was used in the morning. In both groups there was a marked improvement in all parameters recorded, and although final plaque scores showed a statistically significant difference in favor of the test group, there was virtually no difference in rate or degree of resolution of gingivitis. The use of standard dentifrice was only partially successful in preventing staining.

Antimicrobial agents and dental caries in the rat

Two rat plaque-caries studies indicated that a 0.2% chlorhexidine solution topically applied to rat teeth was effective in reducing dental plaque. This reduction in plaque was accompanied by marked reductions in smooth surface caries, but not in sulcal lesions.