Clinical studies of plaque control agents: an overview

The effect of antiseptic oral sprays on dental plaque and gingival inflammation: A systematic review and meta-analysis

OBJECTIVES

To review the effectiveness of antiseptic oral sprays on oral health.

METHODS AND MATERIALS

Three electronic databases (PubMed, Cochrane Library and Web of Science) were systematically searched to identify relevant studies. Only randomized controlled trials (RCTs) comparing the effect of oral sprays to placebo/control spray or mouthrinse on dental plaque and gingival inflammation were included.

RESULTS

Among a total of 996 papers, 20 effective studies fulfilled the selection criteria, and 8 studies were suitable for inclusion in meta-analyses. A meta-analysis of three studies using a 0.2% chlorhexidine (CHX) spray intervention, without prophylaxis at baseline, showed reductions in Plaque Index (PI) (Silness and Löe) and Gingival Index (GI) (Silness and Löe) scores of 0.74 (95% CI: -1.03 to -0.45) and 0.22 (95% CI: -0.38 to -0.06), respectively. Five studies provided a prophylaxis for subjects before study initiation. Three of these five studies used 0.2% CHX spray. A meta-analysis demonstrated an increase of 0.18 (95% CI: -0.01 to 0.37) in PI (Silness and Löe) scores. Two RCTs compared 0.12% and 0.2% CHX spray, and a meta-analysis showed increases of 1.71 (95% CI: 1.27 to 2.14) and 1.58 (95% CI: 1.23 to 1.93), respectively, in PI (Quigley and Hein) scores. Of the RCTs not amenable to meta-analysis, eight studies reported significant improvements in PI and GI scores.

CONCLUSIONS

Available evidence suggests that oral sprays are an acceptable delivery method for antiseptic agents. Further high-quality studies are warranted to determine the effectiveness of alternative chemotherapeutic agents delivered via oral sprays on oral health.

Short term clinical effectiveness of a 0.07% cetylpyridinium chloride mouth rinse in patients undergoing fixed orthodontic appliance treatment

OBJECTIVES

To test the short term clinical effectiveness of commercially available 0.07%.cetylpyridinium chloride mouth rinse in patients undergoing fixed orthodontic treatment as compared to a placebo mouth rinse and patients using toothbrush and toothpaste.

METHOD

Forty-five subjects for this double blind study were assigned randomly into three groups of 15 each. Gingival inflammation, plaque accumulation, and bleeding on probing, were recorded at baseline (10 days after prophylaxis), and at the end of one month in all the three groups and compared.

RESULTS

Paired t test showed significant differences in bleeding index for pre and post treatment recordings for cetylpyridinium group. Modified gingival index showed no significant difference in the cetylpyridinium group. For plaque index significant difference was found for cetylpyridinium and control groups.

CONCLUSION

Cetylpyridinium mouth rinse 0.7% was found to be effective in reducing the bleeding and plaque index scores. It was not effective in reducing the modified gingival index scores. Cetylpyridinium mouth rinse 0.07% improves the oral hygiene of orthodontic patients when used as an adjunct to normal oral hygiene measures.

Oral-derived bacterial flora defends its domain by recognizing and killing intruders--a molecular analysis using Escherichia coli as a model intestinal bacterium

Within the same human gastrointestinal tract, substantial differences in the bacterial species that inhabit oral cavity and intestinal tract have been noted. Previous research primarily attributed the differences to the influences of host environments and nutritional availabilities ("host habitat" effect). Our recent study indicated that, other than the host habitat effect, an existing microbial community could impose a selective pressure on incoming foreign bacterial species independent of host-mediated selection ("community selection" effect). In this study, we employed in vitro microbial floras representing microorganisms that inhabit the oral cavities and intestinal tract of mice in combination with Escherichia coli as a model intestinal bacterium and demonstrated that E. coli displays a striking community preference. It thrived when introduced into the intestinal microbial community and survived poorly in the microbial flora of foreign origin (oral community). A more detailed examination of this phenomenon showed that the oral community produced oxygen-free radicals in the presence of wild-type E. coli while mutants deficient in lipopolysaccharides (LPS) did not trigger significant production of these cell-damaging agents. Furthermore, mutants of E. coli defective in the oxidative stress response experienced a more drastic reduction in viability when cocultivated with the oral flora, while the exogenous addition of the antioxidant vitamin C was able to rescue it. We concluded that the oral-derived microbial community senses the E. coli LPS and kills the bacterium with oxygen-free radicals. This study reveals a new mechanism of community invasion resistance employed by established microflora to defend their domains.

Antimicrobial properties of an orthodontic adhesive combined with cetylpyridinium chloride

INTRODUCTION

Patients undergoing fixed appliance treatment are at greater risk for increases in salivary and plaque levels of Streptococcus mutans and an elevated risk of dental caries. Cetylpyridinium chloride (CPC) is known to be an effective antiplaque agent. The purpose of this study was to investigate whether incorporating CPC into a commercially available orthodontic adhesive would impart antimicrobial properties without altering the diametral tensile strength of the material.

METHODS

CPC was added to a commercially available, filled, photo-activated bracket adhesive (Transbond XT, Unitek 3M, Monrovia, Calif) in varying amounts, to obtain specimens with CPC concentrations of 0% (control), 2.5%, 5.0%, and 10.0% by weight. Adhesive discs 2 mm thick and 4 mm in diameter were incubated with Streptococcus mutans for 48 hours. The diameters of the zones of bacterial inhibition were measured in an agar disc diffusion assay; specimens of each concentration were tested every other week for 196 days. Other discs were soaked in distilled water for 180 days. The amount of CPC released into the water from the modified discs was measured and recorded on days 7, 15, 30, 60, and 180 by using a spectrophotometer at 254 nm. Diametral tensile strength of the modified adhesive discs was measured with a universal testing machine, and the effect of water aging was also evaluated.

RESULTS

The measured zone of bacterial inhibition increased as CPC content increased. All CPC-adhesive specimens maintained antimicrobial activity up to 196 days. No zone of bacterial inhibition was measured around the control specimens. CPC release was observed through the end of 180-day period, but the greatest release was recorded in the first week. There was no significant difference (P < .05) in diametral tensile strength between the 2.5% CPC-adhesive group and the control; there were significant differences among the 5.0% and 10.0% CPC-adhesive groups and the control. Water aging had no significant effect on diametral tensile strength other than decreasing it for the test group containing 10.0% CPC.

CONCLUSIONS

The incorporation of 2.5% CPC in adhesive material imparted antimicrobial activity without altering diametral tensile strength.

The effectiveness of a disposable tooth cleansing device on plaque

A disposable polyester foam sponge on a stick, impregnated with a non-foaming dentifrice, has been widely dispensed to hospitalized and nursing home patients for intraoral cleansing and refreshing. Since no information was found relative to tooth cleansing capabilities, we have evaluated its effectiveness in the removal of accumulated plaque and also in prevention of plaque accumulation. Removal of 72 hours of accumulated plaque was assessed in a cross-over design study comparing the device with a commercially-available toothbrush by two different groups of 13 and 29 adult, healthy subjects who used each instrument for 1 and 3 minutes respectively. No significant differences were found between mean scores assessed by Turesky's modification of the Quigley-Hein plaque index by either group using either instrument at either time period (P > 0.05). Prevention of plaque accumulation was assessed in a third group of 25 subjects who used each instrument an average of 3 times a day for 1 week in a cross-over study. While the toothbrush was found significantly more effective in retarding the accumulation of plaque from a plaque-free baseline on both facial and lingual surfaces (P < 0.02), the tooth cleansing device still retained plaque-preventive capabilities by maintaining plaque formation below 2 mm at the cervical margin of the tooth. Results of this study indicate the tooth cleansing device may be a viable alternative to conventional toothbrushes.

Agents for the management of plaque and gingivitis

Numerous chemical agents have been evaluated for the supplementation of patient-dependent mechanical plaque control and thus the reduction or prevention of oral diseases. Agents discussed in this paper are those most frequently evaluated in recent studies and include chlorhexidine, essential oils, triclosan, sanguinarine, fluorides, oxygenating agents, quaternary ammonium agents, prebrushing rinses, enzymes, and antibiotics. Of the agents discussed, the greatest effect on the reduction of plaque and gingivitis can be expected from chlorhexidine, essential oils, and triclosan-containing products. These chemical agents vary in dosage form and include mouthrinses, gels, and dentifrices. Some may also be of value as irrigants. Adverse effects vary according to the chemical agent and include poor taste, burning sensation of oral tissue, staining of teeth and soft tissues, excess supragingival calculus, oral lesions in young patients, and allergic reactions. When a product is selected for a patient, consideration should be given to necessity, efficacy, adverse effects, and cost-effectiveness.

Chemotherapeutic inhibition of supragingival dental plaque and gingivitis development

A 6-month double-blind, controlled clinical study was conducted on 107 healthy adult subjects to determine the efficacy of a mouthrinse used as a supplement to regular oral hygiene measures on supragingival dental plaque and gingivitis. 115 healthy adult patients were recruited for the study. Following screening examinations for minimal entry levels of existing gingivitis and plaque in patients with a minimum of 20 sound natural teeth, extrinsic tooth stain, gingivitis and plaque index scores were recorded. Soft tissues were evaluated. All subjects then received a complete dental prophylaxis, removing plaque, calculus and extrinsic stain. Utilizing their normal oral hygiene, subjects began a regimen of rinsing with 20 ml of the randomly assigned rinse, twice daily for 30 s for 6 months. 7 days after prophylaxis, gingivitis was again scored (baseline 2). Soft tissue, gingivitis, plaque area and extrinsic stain were evaluated again at 3 and 6 months. Results demonstrated that after 6 months, listerine produced a 34% inhibition of both plaque and of gingivitis compared to a hydroalcohol control (p less than 0.001).

An incisor plaque model in rats

An in vivo model for studying plaque accumulation in rats has been described. This model investigates plaque formation on the mandibular incisors in animals which have been found to be rapid plaque-formers during a pre-test period. The accessibility of these tooth surfaces permits the removal of plaque prior to initiation of tests, the use of test groups balanced on the basis of plaque-forming potential, and interim assessments of plaque formation throughout the test period. In addition, baseline plaque scores of near zero can be attained, thereby permitting investigations of the impact of experimental measures on plaque formation. Moreover, the model permits intermittent plaque assessments throughout the test period. This model was found to have adequate sensitivity to distinguish effects between antimicrobial agents known to differ in their clinical activity and to detect differences between varying concentrations of the same agent.

Binding of 18F by cell membranes and cell walls of Streptococcus mutans

The binding of 18F to isolated cell membranes and cell walls of Streptococcus mutans GS-5 or other bacteria was assayed. The attachment of 18F to these cell envelopes proceeded slowly and reached equilibrium within 60 min. 18F binding was stimulated by Ca2+ (1 mM). The binding of 18F to cellular components was dependent upon the pH, as well as the amount of 18F and dose of the binder employed. The binding of 18F by cell walls prepared from fluoride-sensitive and fluoride-resistant cells of S. salivarius and S. mutans did not differ significantly. The pretreatment of cell walls or cell membranes for 60 min at 30 degrees C with 1 mg of RNase, DNase, or trypsin per ml did not influence the binding of 18F by the walls and membranes of S. mutans GS-5. However, prior exposure of cell membranes to sodium dodecyl sulfate caused a significant reduction in the number of 18F atoms bound by the membranes. In saturated assay systems, cell membranes of S. mutans GS-5 bound 10(15) to 10(16) atoms of 18F per mg (dry weight), whereas cell walls from S. mutans GS-5, FA-1, and HS-6 or Actinomyces viscosus T14V and T14AV bound 10(12) to 10(13) atoms of 18F per mg (dry weight). 18F in this quantity (10(12) to 10(13) atoms) cannot be detected with the fluoride electrode. The data provide, for the first time, a demonstration of 18F binding by cell membranes and walls of oral flora.