The effect of chlorhexidine mouthrinses on the human oral flora

Effect of two antibacterial mouth sprays and dentifrices on dental plaque and gingivitis in beagle dogs

Plaque inhibition by dilute mouth sprays and dentrifrices containing benzethonium chloride and chlorhexidine gluconate was compared in beagle dogs. Agents with chlorhexidine gluconate produced less plaque than their benzethonium chloride or placebo counterparts, but the differences were not significant when compared to mean control scores registered during interexperimental recovery periods.

Use of chlorhexidine gluconate and povidone iodine mouthwashes in the treatment of acute ulcerative gingivitis

A trial was conducted to compare the effectiveness of povidone iodine and chlorhexidine gluconate with buffered peroxyborate in the treatment of acute ulcerative gingivitis. After 20 patients had entered the trial and 11 had required additional therapy with metronidazole to control their symptoms, the study was terminated. Those patients receiving peroxyborate all showed a satisfactory improvement in clinical signs and symptoms. One patient each receiving povidone iodine or chlorhexidine reported a symptomatic improvement, although gingival ulceration was still apparent at 1 week. The remaining patients all required metronidazole therapy to control their symptoms. Povidone iodine and chlorhexidine gluconate therefore cannot be recommended for the treatment of acute ulcerative gingivitis.

Adsorption of Streptococcus mutans on chemically treated hydroxyapatite

Adsorption of Streptococcus mutans on hydroxyapatite and chemically treated hydroxyapatite was studied. Zeta potentials of the surfaces were measured. Chemically treated hydroxyapatite gave higher zeta potentials and lower S mutans adsorption.

Comparison of the in vivo and in vitro antibacterial properties of providone iodine and chlorhexidine gluconate mouthrinses

Clinical and laboratory studies were carried out to compare the antibacterial properties of two antiseptic mouthwashes, namely 1% povidone iodine and 0.2% chlorhexidine gluconate. In a group of 10 subjects after a single rinse with povidone iodine, an immediate mean fall in total salivary aerobes and anaerobes occurred, followed by a return to normal levels by 1-hour postrinsing. With chlorhexidine gluconate a similar but greater reduction in salivary bacterial counts was observed, which was still present up to the 7-h postrinsing period. Saliva samples obtained from the subjects 2 min after rinsing with providone iodine produced little or no inhibition to the growth of a test organism in vitro, whereas following chlorhexidine gluconate, antibacterial activity was present in the saliva specimens up to the 3-h sampling time. Using culture media containing comparable levels of soluble protein to saliva, the minimum inhibitory concentrations of povidone iodine against several standard test organisms were much higher than those of chlorhexidine gluconate. The results suggest that povidone iodine, as a mouthwash, exerts only an immediate antibacterial effect and unlike chlorhexidine, is not retained at antibacterial levels within the oral cavity after expectoration. This lack of prolonged action of povidone iodine in the oral cavity would appear to be relevant to its reported lack of antiplaque activity.

Compounds which affect the adherence of Streptococcus sanguis and Streptococcus mutans to hydroxyapatite

Several compounds were evaluated in an in vitro assay system for their ability to block the adherence of Streptococcus sanguis to saliva-coated hydroxyapatite and Streptococcus mutans to dextran-coated hydroxyapatitite. Fatty acids, ranging from C-12 to C-20, the enzyme amylase, chlorhexidine, human sera, and several serum proteins blocked S sanguis adherence to saliva-coated hydroxyapatite. Chlorhexidine blocked S mutans adherence to dextran-coated hydroxyapatite, but human sera and serum proteins did not. The effects of these compounds on the adherence of these organisms to hydroxyapatite may help in the development of specific plaque control methods for use in human populations.

Effect of toothbrushing with different concentrations of chlorhexidine on the development of dental plaque and gingivitis

This study showed that 0.15, 0.10, and 0.05% chlorhexidine gluconate solutions used on the toothbrush subsequent to scaling were for at least 45 days able to maintain plaque and gingivitis scores lower than those obtained 14 days after scaling and oral hygiene instruction. Discoloration of teeth and fillings were the only side effects observed.

Hibitane in the treatment of aphthous ulceration

In the absence of a known aetiology the management of recurrent aphthous ulceration is symptomatic with the removal of predisposing factors where possible. Since the severity and duration of ulcers may be increased by bacterial contamination, the effect of chlorhexidine gluconate in mouthwash and gel forms on the natural history of the condition has been studied. The mouthwash study employed a 0.2% chlorhexidine gluconate solution, a 0.5% astringent solution and a control mouthwash. Each mouthwash was used by all of the patients, with 5 ml of each preparation being diluted with 5 ml of water for use three times a day. The gel study employed a 1% chlorhexidine gluconate and a placebo gel with approximately a 1 inch of the gel from the tubes being placed in the mouth three times a day. Both studies were carried out in the double-blind crossover manner with each preparation used for 5 weeks with a 2-week interval between preparations. In the mouthwash trial chlorhexidine gluconate significantly reduced the incidence, duration and severity of ulcers, whereas in the gel trial chlorhexidine significantly reduced the severity and duration but not the incidence of ulceration. Since the dosage regimes for chlorhexidine in the two studies were comparable, the mode of delivery would appear to be important in the therapeutic effectiveness.

The effect of povidone iodine on plaque and salivary bacteria. A double-blind crossover trial

A double blind crossover trial was carried out to assess the effect of povidone iodine on plaque accumulation in vivo and to measure the total salivary aerobes and anaerobes throughout the study. When compared to the placebo preparation, povidone iodine was without effect on plaque accumulation in all the subjects and there was a progressive increase in plaque throughout the 10-day periods. A 30 to 40 % overall reduction in aerobes and anaerobes occurred with the active preparation which was significant. There appears to be no indication for the use of povidone iodine as an adjunct to oral hygiene or in the treatment of chronic gingivitis.

Furfurals in chlorhexidine-discolored pellicle

The purpose of the present study was to investigate the possible presence of furfurals in chlorhexidine-discolored pellicle. Pellicle material was scraped off teeth and hydrolyzed in sulfuric acid and the hydrolysate then extracted with ether and examined by thin layer chromatography and gas chromatography-mass spectrometry. The presence of furaldehyde in discolored pellicle was demonstrated by these methods. There were also indications of hydroxymethyl furfuraldehyde in the thin layer chromatograms.

Effect of SnF2 mouthrinse on initial bacterial colonization of tooth enamel

Microbiologic quantitative methods and scanning electron microscopy were used to observe the effect of stannous fluoride (100 ppm F-) mouthrinse on early plaque formation. An in vivo plaque model system was used on two individuals to test this experimental agent. Following SnF2 mouthrinsing, the total bacterial counts of two-day-old plaque on enamel cylinders were reduced up to 50.8 times or 98% and the streptococcal counts were decreased up to 48.4 times or 97.9%. Scanning electron microscopy confirmed a marked decrease of bacteria on enamel with use of SnF2 mouthrinse. It appears that, in addition to reducing enamel solubility and other properties, SnF2 may also alter bacterial accumulations on teeth.

Comparison of antiplaque agents using an in vitro assay reflecting oral conditions

An in vitro assay is described using saliva-treated bovine enamel slabs for determining the potential of chemotherapeutic agents to adsorb to tooth surfaces and act against plaque-forming bacteria. Chlorhexidine was found to inhibit the formation of in vitro plaque by Actinomyces viscosus, A naeslundii, Streptococcus mutans and S sanguis. Actinobolin was found to have marked antibacterial properties but limited adsorptive qualities.

An in vivo comparison of chlorhexidine and picloxydine mouthrinses: a possible association between chemical structure and antiplaque activity

A double blind clinical trial was conducted in which both the plaque-inhibiting ability and the in vivo effects on the oral flora of chlorhexidine and picloxydine mouthwashes was compared. While picloxydine in higher concentration suppressed the oral flora more effectively than chlorhexidine, the latter agent inhibited plaque development to a much greater extent. This lack of correlation between antibacterial and antiplaque activity can be related to structural differences between these two bis-biguanides.

The effect of chlorhexidine and some other detergents on the activity of dextransucrase from Streptococcus mutans

The inhibitory effect of chlorhexidine and other bis-biguanides on the formation of dental plaque is not fully understood. The present paper describes the effect of chlorhexidine and some selected detergents on the activity of dextransucrase (EC 2.4.1.5.), an enzyme involved in the formation of important components of dental plaque. All detergents examined exerted an inhibitory effect on dextransucrase activity, to some degree dependent on the presence of charged groups and their characters. The high concentrations of chlorhexidine necessary to inhibit dextransucrase activity seem to exclude the possibility that chlorhexidine exerts its plaque inhibiting effect by means of an effect on dextransucrase.

Effect of two antimicrobial rinses and oral prophylaxis on preoperative degerming of saliva

Two degerming mouthrinses, a 1% povidone-iodine and a 0.2% aqueous solution of chlorhexidine gluconate, were tested with regard to their degerming effect on the saliva. The study comprised two parts. In the first part 19 dental students with good oral hygiene rinsed their mouths at weekly intervals with 10 ml of the povidone-iodine and 10 ml of the chlorhexidine solution. A control group of 12 students and nurses with healthy teeth and gums rinsed their mouths with 10 ml of plain water. In the second part 11 adult patients with periodontal disease used the two test rinses at weekly intervals both before and after periodontal prophylaxis including scaling of the teeth. Non-stimulated saliva was simpled immediately before and 5, 30, 60, and 120 min after each rinse. Part of the saliva was cultured on blood agar plates to show the growth of aerobic microbes. The remainder of the saliva was poured over a Dentocult dip-slide for determination of the number of acidophilic bacteria. The results showed that in the water control group the bacterial count increased in spite of the rinse. When compared with the prerinse values, both test rinses clearly reduced the amounts of bacteria. Chlorhexidine reduced the bacterial count 5 min after the rinse about one logarithm more than povidone-iodine, did, and the degerming effect of chlorhexidine was also of longer duration than that of the povidone-iodine solution. The periodontal prophylaxis in the adult group did not seem to lower the pre-rinse bacterial counts but did slightly improve the duration of the effect of both test solutions. The dip-slide tests showed that 28% of the subjects had no growth of acidophilic bacteria. This absence was not dependent on the other bacterial flora of the saliva. In the cases with a positive dip-slide test, the number of acidophilic bacteria decreased with both test solutions according to the pattern revealed by the blood agar plate cultures.

The effect of two commercial antibacterial mouthrinses on plaque growth in vivo

An experimental study was designed to compare the claimed antibacterial effect of Betadine and Blend-a-med Fluid with the known plaque growth inhibiting effect of a 0.2% aqueous solution of chlorhexidine digluconate (Hibitane). Before the test perios for 5 days. During the following week they cleaned their teeth mechanically with toothbrush and toothpicks. For the third week the students were divided into three experimental groups. Following closely the manufacturers' recommendations, one group rinsed their mouths four times daily with 10 ml of Betadine, one group every 2 hours with a glassful of water containing 5-8 drops of Blend-a-med Fluid, and the control group twice daily with 10 ml of the 0.2% chlorhexidine solution. Mechanical cleaning of the teeth was not allowed during the experimental week. The Plaque Index scorings decreased significantly from the end of the no-hygiene to the end of the mechanical cleaning period. During the experimental period a further decrease of the mean P1I scores returned to the level recorded after the no-hygiene period. As neither Betadine nor Blend-a-med Fluid proved able to prevent plaque growth in vivo, there seems to be no indication for their use in treatment of gingivitis.

The use of chlorhexidine mouthwash compared with a periodontal dressing following the gingivectomy procedure

The clinical results achieved were compared when a group of 21 patients requiring gingivectomies in comparable bilateral segments received a dressing or a chlorhexidine mouthwash during the first post-operative week. Initial pre-operative conditions were comparable. In each of the two treatments highly significant reductions in pocket depths were achieved; the sizes of the reductions were of clinical significance (greater than 1.5 mm). The observed difference (0.16 mm) between the two treatments in favour of the mouthwash, although significant at the conventional 5% level, was clinically unimportant. More patients preferred the dressing as a post-operative treatment, and the clinical implications of the patients' preferences are discussed.

Turku sugar studies. VIII. Principal microbiological findings

The possible qualitative and/or quantitative alterations in the proportions of cultivable groups of oral microorganisms were analysed during a clinical trial involving the consumption of fructose (F) or xylitol (X) in comparison to sucrose (S). Supragingival plaque samples and paraffin-stimulated saliva were collected from 115 subjects. The samples were dispersed by sonication, diluted stepwise, plated on blood sugar, Mac Leod agar, Mac Concey agar, Rogosa S.L. agar, and Sabouraud agar plates and incubated anerobically and/or aerobically. The number of the total colony forming units (CFU) on blood agar plates in anaerobic incubation was about 1-3 X 10(9)/ml saliva and 1-4 X 10(8)/mg plaque and in aerobic respectively 5-18 X 10(8)/ml saliva and 10(8)/mg plaque. The total CFU on Mac Leod agar was of a similar order of magnitude. The variation between subjects and consecutive determinations was of a similar order of magnitude. The variation between subjects and consecutive determinations was relatively large. The arithmetic mean of the total CFU on Mac Concey agar was about 1-5 X 10(5)/ml saliva, on Rogosa S.L. agar 6-130 X 10(3)/ml saliva and on Sabouraud about 1-2 X 10(3)ml saliva, all in aerobic incubations. Replacement of dietary sucrose with xylitol did not affect the proportion of major microbial categories in saliva or dental plaque. The percentage of typical streptococcal colonies on blood agar was of a similar order of magnitude (about 60-70%) during the diets. The arithmetic and geometric means of the total CFU values on Rogosa and Sabouraud agar plates were significantly lower in the X-group than in the S- or F-groups after a diet period of some months. It was thought that the reason for the reduction of acidogenic and aciduric oral flora in the X-group was partly due to the fact that xylitol is generally not metabolized by these microorganisms.

Effect of chlorhexidine on dental plaque and gingivitis in mentally retarded children

The purpose of the investigation was to determine the effect of chlorhexidine mouthrinses as a supplement to toothbrushing in the plaque control of mentally retarded children. Fifty-four mentally subnormal children 7-14 years of age took part in the investigation. During the first period, half of the children rinsed their mouths with 0.2% chlorhexidine gluconate solution twice a day. The rest of the children used a placebo mouthrinse. After a n 8-week interval a "cross-over" experiment was carried out during which a 0.1% chlorhexidine solution was used. Plaque and gingival indices were scored at the beginning of each period, after 3 weeks, and at the termination after 6 weeks. The results revealed that mouthrinses with 0.1% as well as 0.2% chlorhexidine gluconate reduced plaque and gingivitis in mentally retarded children. The results were statistically significant (P is less than 0.05) for both concentrations. Furthermore, the investigation confirmed the occurrence of certain side effects such as discoloration of teeth and tongues.

A chlorhexidine-containing methacrylic gel as a periodontal dressing

The modification of a methacrylic gel for use as a periodontal dressing was attempted. The increased adhesion and rigidity of the resultant material appeared consistent with the clinical findings. Satisfactory retention of the dressing was found in 85% of those placed on a group of patients attending for periodontal surgery. The potential value of the methacrylic gel for carrying and releasing pharmacological agents useful in the management of lesions of the oral mucosa was assessed by incorporating chlorhexidine acetate into the dressing. In vitro and in vivo studies demonstrated effective release of the chlorhexidine from the dressing throughout the period of time a periodontal dressing is normally in situ. In conclusion the results suggested that the modified methacrylic gel fulfills the requirements of a periodontal dressing. Study to assess further the potential for this material to carry other pharmacological agents used in the topical treatment of lesions of the oral mucosa is indicated.

Inhibitory effect of benzethonium and zinc chloride mouthrinses on human dental plaque and gingivitis

In a double-blind study the plaque- and gingivitis-inhibiting capacities of three aqueous mouthrinse solutions of benzethonium chloride, zinc chloride, and benzethonium chloride combined with zinc chloride were compared to those of a placebo mouthrinse. Forth-three adults with clean teeth and healthy gingiva were randomly assigned to the treatment and control groups. All participants received an initial prophylaxis. Assessments of plaque and gingivitis were made before and after a 10-day test period. During this time the subjects suspended oral hygiene procedures and rinsed daily with 20 ml of their respective rinse solutions. According to the measurements made before and after the test period, the mouthrinse containing benzethonium chloride produced 42 to 42.9% less plaque than any of the other three formulations. The differences were statistically significant ( P smaller than 0.05). Gingivitis scores of the four groups did not differ significantly. These findings indicate that benzethonium chloride is a moderately effective antiplaque agent.

Method for preclinical evaluation of antiplaque agents

A preclinical method for the evaluation of antibacterial agents for use against dental plaques associated with caries and periodontal disease is proposed. The method is applicable to screening agents and to defining, in vitro, the minimal conditions required for maximal antiplaque effect. As a model of antiplaque agents, chlorhexidine was assessed in vitro against preformed plaques of microorganisms conducive to dental caries and periodontal disease. The agent was bactericidal to plaques of nine strains of Streptococcus mutans and one strain of Actinomyces viscosus when used in a single treatment for 20 min at 2 x 10(-1)%, in two 2-min treatments on the same day, or in daily 2-min treatments at this same concentration. Using the last of these experimental conditions, we then tested chlorhexidine in vivo by topical application to the maxillary teeth of infected hamsters and found it to be effective in controlling plaques of S. mutans and A. viscosus.

Dental caries: prospects for prevention

Combined utilization of measures now available or imminent could reduce caries of the crowns of the teeth to the point of negligibility as a public health problem, if public desire were great enough to motivate changes in some of our habits (64). Universal optimum application of fluoride and substitution of starchy foods for sugary ones (or even simply judicious consumption of sugar) would alone do most of the job. Sealing of susceptible occlusal areas with adhesive polymers promises to protect the sites where fluoride evidently cannot be maximally effective. It seems unlikely that any single measure will be found sufficient to control this multifactorial disease. Consequently, we must continue the search for new means to increase the caries resistance of teeth, to reduce the cariogenicity of foodstuffs, and to check the deleterious activities of cariogenic bacteria. Anticaries food additives and antibacterial agents for intraoral use seem to be approaching practicability. Past performance warrants expectation that ongoing fundamental investigations will produce leads for future development and application.