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PubMed1980

In vitro development of chlorhexidine resistance in Streptococcus sanguis and its transmissibility by genetic transformation.

Three chlorhexidine-sensitive strains of Streptococcus sanguis developed resistance to chlorhexidine when grown as continuous cultures in a fermenter containing medium with increasing concentrations of the drug. The MIC of the test strains increased by between two and three dilution steps and these high values were maintained after daily transfer in drug-free medium for at least 15 d. In addition, the resistance of one of the strains persisted for more than 1 month of continuous growth in drug-competent sensitive S. sanguis to increased chlorhexidine resistance, thus proving that resistance to this drug is an inheritable trait. Immunoelectrophoretic experiments showed that certain changes in the antigenic pattern of the Chxr variants had occurred as compared with their sensitive wild-type strains. Antigenic extracts of the Chxr variants and all Chxr recombinants tested contained consistently less protein than those of the sensitive wild-types.

Antigens, Bacterial↗
PubMed1981

Effect of chlorhexidine gel treatment on Streptococcus mutans population in human saliva and dental plaque.

The effect of topical application of a 1% chlorhexidine gel on the population of S. mutans in dental plaque and saliva was studied in five subjects highly infected with the organism. After treatment for 5 min daily for 14 d, S. mutans was not detected in three of the subjects and counts of 700 colony-forming units or less per ml of saliva were found in the other subjects. Reappearance of S. mutans was slow and did not reach pretreatment level until 14 weeks or more after therapy. The proportion of S. sanguis in plaque increased temporarily after chlorhexidine treatment, whereas the population of lactobacilli was unaffected. These observations indicate that short-term use of chlorhexidine is of value in controlling oral infection of humans by S. mutans.

Administration, Topical↗
PubMed1981

Effect of intensive treatment with chlorhexidine on number of Streptococcus mutans in saliva.

The effect of intensive treatment with chlorhexidine on the number of S. mutans in saliva was studied in 24 schoolchildren highly infected with this organism. Chlorhexidine gel in individual dental trays was applied under supervision on two consecutive days, four times the first day and three times the second day. The number of S. mutans in saliva was monitored for 6 months. Immediately after treatment, the number was greatly reduced in all of the children. Thirty days after treatment only three children had more than 2 X 10(5) S. mutans/ml saliva, and after 4 months, 11 children still had less than 2 X 10(5) S. mutans/ml saliva. After 6 months the effect of the treatment was obvious in 20% of the children. The results indicate that intensive treatment with chlorhexidine can be used to reduce the S. mutans infection. The antimicrobial treatment, however, should be individually controlled because of variations in the response of the subjects.

Adolescent↗
PubMed1983

Effect of chlorhexidine and lanthanum on plaque formation.

The present study included rinses with aqueous solutions of lanthanum prior to and after traditional chlorhexidine mouthrinses. Lanthanum has an extremely high affinity for phosphate, and the experiments were designed to examine the role of this anion as a receptor site for chlorhexidine in the oral cavity. The results indicate that from 1/3 to 1/2 of the chlorhexidine retained in the oral cavity may be bound to phosphate groups.

Chlorhexidine↗
PubMed1987

Prolonged oral reduction of Streptococcus mutans in humans after chlorhexidine disinfection followed by fluoride treatment.

The effect of oral chlorhexidine gel treatment supplemented with fluoride applications was studied in subjects with high salivary levels of S. mutans. In two experiments short-term treatment with a 1% chlorhexidine gel was followed by applications of either a 1% NaF gel daily for 2 weeks or a 1% NaF gel daily for 6 weeks supplemented twice with topical application of an 8% SnF2 solution. The salivary numbers of S. mutans were lower in the test group than in the placebo group after 6 and 12 weeks in experiments 1 and 2, respectively, and considerably lower than the pretreatment values. The findings show that fluoride applications can be a valuable adjunct to chlorhexidine treatment for combatting S. mutans.

Adolescent↗
PubMed1988

Gingival and mucosal reactions after intensive chlorhexidine gel treatment with or without oral hygiene measures.

The aim of this study was to elucidate whether soft tissue reactions during chlorhexidine (CHX) treatment might be associated with meticulous oral hygiene measures. A commercially available 1% chlorhexidine digluconate gel (Hibitane Dental Gel) was applied in a custom tray for the mandibular arch, 10 min daily, for 14 days. A split mouth approach was used to allow evaluation of the effect of oral hygiene measures with toothbrush, toothpaste, and dental floss on one side of the arch. During the treatment period, 8 out of 12 subjects developed gingival and/or mucosal reactions appearing as white patches or ulcerations. Both the gingival reactions on the buccal marginal gingiva and the mucosal reactions near the margin of the custom tray occurred only when the gel treatment was combined with meticulous oral hygiene measures. The white patches, which could easily be detached, leaving ulcerated areas, consisted entirely of stratified squamous epithelium. The findings suggest that intensive treatment with chlorhexidine gel, in individually fitted custom trays, combined with meticulous oral hygiene measures may induce toxic effects on the surface layers of the gingiva and mucosa.

Chlorhexidine↗
PubMed1989

Reduction of dental plaque formation by chlorhexidine dihydrochloride lozenges.

The effect of chlorhexidine dihydrochloride (chlorhex HCl) in lozenges on plaque growth was assessed on 21 subjects with fresh plaque of 7 days duration. The lozenges, which contained 5 mg chlorhex HCl, were sucked three times daily after meals, for 2 weeks. The study was a single-blind crossover. Placebo lozenges had all the ingredients except chlorhex HCl. These were used as a control. Results indicated that lozenges containing chlorhex HCl were a potent plaque inhibitor. The mean plaque score was reduced by 62.8% from an initial mean plaque score (DO) of 2.38 +/- 0.48 to (D7) 0.89 +/- 0.26 (p less than 0.0001), after 1 wk of usage. A further reduction to plaque score (D14) of 0.56 +/- 0.27 (p less than 0.0001) was recorded by the end of the 2nd wk. Usage of the placebo during the same time period did not show significant differences in the plaque score (DO = 2.38; D7 = 2.33; D14 = 2.42). Inhibition of plaque formation to the 1104 test surfaces revealed a total elimination of the higher levels of plaque (scores 4 and 5), a considerable reduction of the middle levels (scores 2 and 3) and a significant increase (44.7%) of low level plaque (score 1). Total elimination of plaque (score 0) was observed in 50.3% of the test group surfaces. Lozenges containing 5 mg chlorhexidine dihydrochloride, taken three times daily, were an efficient, comfortable and potent agent for reducing and inhibiting plaque formation. These lozenges are a more convenient alternative to chlorhexidine mouthrinses and may prove to be superior to these.

Adolescent↗
PubMed1989

Bactericidal concentrations of chlorhexidine-digluconate, amine fluoride gel and stannous fluoride gel for subgingival bacteria tested in serum at short contact times.

In vitro inhibitory and bactericidal concentrations in serum of chlorhexidine-digluconate, amine fluoride gel, stannous fluoride gel, stannous fluoride, metronidazole and amoxicillin were determined against Bacteroides gingivalis, Bacteroides intermedius, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans and Capnocytophaga sputigena. The minimal inhibitory concentration was assessed by the agar dilution technique. The killing curves and minimal bactericidal concentration of the antimicrobial agents in inactivated bovine serum were determined after 5, 10, 20 and 60 minutes contact time. The minimal inhibitory concentration varied amongst the tested bacteria. A concentration of 128 micrograms/ml chlorhexidine digluconate, 20 mg/ml amine fluoride gel, 1 mg/ml stannous fluoride, 128 micrograms/ml metronidazole and 4 micrograms/ml amoxicillin inhibited the growth of the tested species. The minimal bactericidal concentration in serum for B. gingivalis, B. intermedius, F. nucleatum, A. actinomycetemcomitans and C. sputigena after 10 min contact time was 5 mg/ml for chlorhexidine digluconate and 100 mg/ml for amine fluoride gel. A concentration of 200 mg/ml stannous fluoride gel in serum was bactericidal for the tested species after 10 min contact time, with exception of F. nucleatum.

Actinobacillus↗
PubMed1991

Inhibition of intergeneric coaggregation among oral bacteria by cetylpyridinium chloride, chlorhexidine digluconate and octenidine dihydrochloride.

The potential inhibitory effect of chlorhexidine digluconate on the intergeneric coaggregation of 11 pairs of Gram-positive organisms was compared to its ability to inhibit coaggregations of 14 pairs comprised of both a Gram-positive and a Gram-negative cell type. Dramatic differences in the inhibitory effectiveness of the antimicrobial compound on the two kinds of coaggregation pairs were found. Gram-positive pairs were not inhibited at a concentration of 0.25%, whereas the coaggregations involving a Gram-negative partner were usually completely blocked at concentrations as low as 0.01%. Similar effects to chlorhexidine digluconate were found with octenidine dihydrochloride and cetylpyridinium chloride, while sodium dodecylsulfate was inhibitory only at 10- to 50-fold higher concentrations. These results suggest that chlorhexidine digluconate, octenidine dihydrochloride, and cetylpyridinium chloride may be effective inhibitors of later microbial colonizers of dental plaque but may not disturb a normal healthy indigenous flora.

Actinomyces↗
PubMed1995

Residual effect of chlorhexidine gluconate in 4-day plaque regrowth crossover trials, and its implications for study design.

The efficacy of oral hygiene agents in preventing the accumulation of plaque from a zero baseline is conveniently evaluated in the 4-day plaque regrowth model. In many studies a panel of volunteers has been used to compare several agents according to a highly efficient Latin square based crossover design. Often chlorhexidine gluconate is included as a positive control; there is concern that the effect of this potent agent might persist for longer than the 3-day washout period often employed. To test this hypothesis of residual effect, we put together the evidence relating to possible carryover from 12 studies. The residual effect of chlorhexidine differs from that of an inert rinse such as saline or water. Consequently, a longer washout period, such as 10 days, is preferable. Studies omitting chlorhexidine are worth considering. Designs should be balanced for residual effects, at least from the preceding treatment period; several useful designs with this property are presented.

Chlorhexidine↗
PubMed1994

Effects of chlorhexidine on the isolated rat phrenic nerve-diaphragm preparation.

Dose-dependent inhibitory effect of chlorhexidine (2.5 x 10(-5)-5.0 x 10(-4) g/ml on neuromuscular transmission were localized by tension and electromyogram recording during indirect stimulation. Subsequent direct stimulation showed an additional inhibition which might be located to the sarcolemma. In addition, contracture was observed at the highest concentrations. Microelectrode experiments showed a miniature endplate potential frequency increase (at 1.0 x 10(-6) g/ml), suggesting a presynaptic action. Increasing the dose to 5.0 x 10(-6) g/ml disclosed a decrease of the miniature endplate potential amplitude, indicating a reduction of the postsynaptic receptor sensitivity, which might cause neuromuscular inhibition. This was confirmed by endplate potential recording in cut preparations. The endplate potential showed a moderate degree of use-dependent inhibition which did not usually cause a tetanic fade. Experiments with curare, decamethonium and neostigmine indicated that chlorhexidine probably caused a decamethonium-like inhibition. A small depolarization of the sarcolemma was probably not the cause of the directly elicited inhibition or contracture. The contracture was potentiated in preparations made myotonic by pretreatment with para-hydroxy-mercuribenzoate. It could not be inhibited by the excitation-contraction uncoupler dantrolene, but it was dependent on extracellular Ca2+. Chlorhexidine-induced influx of Ca2+ might thus cause the contracture.

Animals↗
PubMed1997

Therapeutic effects of supervised chlorhexidine mouthrinses on untreated gingivitis.

AIM: The aim of the present study was to test the presumptive therapeutic effect of chlorhexidine digluconate in a population with untreated gingivitis and presence of abundant calculus. SETTING AND STUDY DESIGN: Sixty subjects (approximately mean age of 23.4) were recruited from a knitting factory in the Province of Guangdong, People's Republic of China. By applying a double-blind clinical trial design the participants were divided into two groups (Test and Control) and matched according to their mean GI scores. The Test group (n = 20) was assigned to two daily mouthrinses for 6 days per week using 0.12% chlorhexidine digluconate (Peridex). The Control group (n = 40) rinsed twice daily with a placebo solution. All the rinsings were supervised and timed for 45 s. No attempt was made to influence the oral hygiene habits of the participants. Prior to and after 3 months of the supervised rinsing, plaque was scored using the Plaque Index system (PII), and gingivitis was assessed using the criteria of the Gingival Index system (GI). Calculus was scored according to the Calculus Surface Severity Index system (CSSI), and stain was also graded by the Discoloration Index system (DI). RESULTS: After 3 months, the Test group (n = 13) showed significant reduction in mean PII, GI and percentage of gingival bleeding (GB%), while significant increases in mean DI were observed. The improvement in gingival health was observed at all regions with marked reduction in mean GI (from GI = 1.40 to 1.08) and GB% reduction by 24-52%. The proportion of GI = 2 was also reduced significantly from 50-36%. The Control group (n = 23) also showed a decrease in mean PII but significant increases in the mean GI and GB%. Intergroup comparison showed statistically significant differences between mean GI, percentage of gingival bleeding (GB%) and mean DI for the test and control groups after 3 months of supervised rinsing. However, there were no significant intergroup differences for mean PII. CONCLUSION: In conclusion, there was a significant effect of chlorhexidine on gingivitis, although the effect may be too limited to assure prognostic benefits in the prevention of future disease progression.

Adolescent↗
PubMedDate not supplied

Effects of a 1% chlorhexidine gel on the cariogenic bacteria in high-risk elders: a pilot study.

Root caries in dentate elderly patients is a problem which may be controlled with chlorhexidine. The purpose of this pilot study was to establish the extent and duration of the antimicrobial effects from an intensive regimen of a 1% chlorhexidine gel in institutionalized elders who had experienced high caries activity in the previous year. Stimulated saliva samples from all subjects before treatment produced more than 105 colony forming units/milliliters of Streptococcus mutans (mean: 2.0 x 10(7); s.d.: 2.0 x 10(7)) when diluted and cultured on Mitus Salivarius-bacitracin agar for 48 hours. Findings suggest that daily treatments for 1 week with a 1% chlorhexidine gel can reduce the number of cariogenic bacteria in elderly people for approximately 3 weeks after treatment.

Aged↗
PubMedDate not supplied

Administration of chlorhexidine to persons with mental retardation residing in an institution: patient acceptance and staff compliance.

Chlorhexidine is beneficial in maintaining the oral health of persons diagnosed with mental retardation. Proper daily oral administration, however, depends upon the compliance of caregivers as well as patient acceptance. If caregivers are noncompliant or if patients are overly resistant to daily applications of chlorhexidine, its proven benefits will not be realized. This study evaluated two methods of chlorhexidine administration for patient acceptance and direct-care staff compliance among 44 institutionalized individuals diagnosed with mental retardation.

Adult↗
PubMed1980

The influence of various counter ions on the interaction of chlorhexidine with the hydrophilic contact lens polymer, poly(2-hydroxyethyl methacrylate).

The commercially available salts of chlorhexidine were found to interact with the hydrogel poly (2-hydroxyethyl methacrylate) to different extents, the affinity for the polymer decreasing in the order acetate, gluconate, chloride. The uptakes of the acetate and gluconate salts were almost entirely irreversible over the concentration range studied. The influence of some alternative counter ions, namely amino acids and dicarboxylic acid salts, was examined and found to generate a three-fold variation in the extent of the chlorhexidine interaction. Uptakes were greatest for counter ions that were either hydrophobic in character or bore a net negative charge. Only two compounds, glycine and monosodium oxalate, were successful in reducing the extent of sorption below that observed for chlorhexidine hydrochloride.

Acetates↗
PubMed1980

On the anomalous sorption behaviour of chlorhexidine with poly(2-hydroxyethyl methacrylate).

General observations of solute: plastic interactions would suggest that the sorption of the cationic preservative, chlorhexidine, with poly (2-hydroxyethyl methacrylate) (PHEMA) is not only unexpected but also atypical in its properties. The polymer and preservative were investigated independently and the sorption of PHEMA with simple solutes, namely benzoic acid, benzocaine and aniline found to exhibit conventional properties. The single exception was the uptake of small amounts of benzocaine and aniline cations at acidic pH's. In order to elucidate the sorption characteristics of chlorhexidine a series of N1-(p-chlorophenyl)-N5-alkylbiguanide acetates were synthesized. The anomalous sorption behaviour observed between PHEMA and the bis biguanide, chlorhexidine, was also found to be characteristic of these monofunctional biguanide derivatives. The extent of the interactions increased with increasing alkyl chain length (R = methyl to n-octyl), this being interpreted in terms of an interaction binding mechanism via the biguanide functional group stabilized by van der Waal's forces between the alkyl chain and the polymer backbone. Atypical sorption behaviour was observed for simple organic cations, biguanide and N2-phenylbiguanide acetate with PHEMA, a possible inference being that this is a general characteristic of all cationic sorption with PHEMA.

Adsorption↗
PubMed1993

In vitro susceptibility of Streptococcus mutans to chlorhexidine and six other antimicrobial agents.

The susceptibility of Streptococcus mutans to chlorhexidine and to six commonly used, systemic antibacterial agents (amoxicillin, cefuroxime, penicillin, sulfamethoxazole-trimethoprim, tetracycline, and erythromycin) was studied for 424 clinical isolates from 116 children and students. The MIC of chlorhexidine for all isolates was < or = 1 micrograms/ml. No resistance to the other antimicrobial agents was detected. Although widely exposed to various antimicrobial agents, S. mutans has remained susceptible to common antimicrobial agents, most importantly to chlorhexidine.

Adult↗
PubMed1996

Gamma radiation-sterilized, triple-lumen catheters coated with a low concentration of chlorhexidine were not efficacious at preventing catheter infections in intensive care unit patients.

In a randomized, double-blind trial, gamma radiation-sterilized, chlorhexidine-coated triple-lumen catheters were compared with uncoated control catheters for their ability to prevent catheter infection in 254 intensive care unit patients. The chlorhexidine coating was not efficacious, and a rabbit model demonstrated that reduction of chlorhexidine activity by gamma radiation sterilization was the likely explanation for the failure.

Bacteremia↗