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Notizen: Background: Recent research has indicated that bacteria within a biofilm may undergo changes in susceptibility to antimicrobial agents when compared to planktonic forms. This study was conducted to determine the bactericidal effect of an essential oil-containing mouthrinse (Listerine® Antiseptic) on dental plaque bacteria in situ.Methods: 1-day-old plaque in 17 subjects was sampled at baseline from the buccal surfaces of diagonally contralateral maxillary and mandibular bicuspids and 1st molars. Subjects were then randomly assigned either an essential oil mouthrinse or a sterile saline negative control and rinsed under supervision with 20 ml for 30 s. 30 min later, plaque was sampled from the remaining contralateral posterior teeth. Subjects repeated these procedures with their respective alternate rinse after 1 week. Pooled plaque samples from each subject at each sampling period were stained with a commercially-available fluorescent stain which fluoresces live and dead bacteria green and red, respectively. The stained plaque specimens were analyzed using computerized image analysis. A separate in vitro study was conducted to determine the relationship between the % red stain per sample and bacterial viability.Results: Analysis of vital stained plaque specimens indicated that following rinsing with the essential oil mouthrinse, 78.7% of bacteria were dead compared to 27.9% following rinsing with the negative control (p〈0.001). The in vitro findings demonstrated that the % red stain per sample is reflective of actual bacterial kill.Conclusions: This study confirms the findings of previous in vitro and in vivo studies which demonstrated the essential oil mouthrinse to have significant biocidal activity against oral micro-organisms. These studies all support the primacy of a bactericidal mechanism in producing the plaque and gingivitis reductions observed in numerous clinical trials conducted on the essential oil mouthrinse.

Notizen: Background: Bacteria contained in biofilms have been shown to have a decreased susceptibility to antimicrobial agents compared to those in planktonic form. Thus, in vitro biofilm models have been developed for screening oral antimicrobial formulations in an effort to produce findings more predictive of clinical activity. This study compared the antimicrobial activity of three mouthrinse formulations when tested against isogenic strains of Actinobacillus actinomycetemcomitans (Aa), one of which was a clinical isolate which forms tenacious biofilms in vitro and the other of which was a spontaneous variant which always grows planktonically.Method: Biofilm-forming Aa strains CU1000 and NJ4300, obtained as clinical isolates, and their respective spontaneous planktonic variants, CU1060 and NJ4350, were grown under standard laboratory conditions and exposed for 15 s to either a negative control (phosphate buffered saline [PBS]), an essential-oil containing mouthrinse (Listerine® Antiseptic [LA]), an amine fluoride/stannous fluoride-containing mouthrinse (Meridol®[M]), or a triclosan and PVM/MA copolymer-containing mouthrinse (Plax®[P]). The cells were then washed, serially diluted, plated, and incubated for enumeration of viable bacteria. Colony-forming units (CFU)/ml were log10 transformed and the mouthrinse groups were compared to the PBS group using analysis of variance.Results: All 3 mouthrinses produced statisically significant 99.99% reductions (p〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:03036979:JCPE280714:les" location="les.gif"/〉0.0001) in both planktonic strains compared to the PBS control. Effects on the biofilm forms of the organisms were more variable. Exposure to LA produced statistically significant (p〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:03036979:JCPE280714:les" location="les.gif"/〉0.0001) reductions in strains CU1000 and NJ4300 of 98.20% and 96.47%, respectively, compared to PBS. M and P produced much smaller reductions which were not statistically significant.Conclusions: The results of this study, in which antimicrobial mouthrinses were tested against biofilm-forming and planktonic strains of the same organism, provide a clear demonstration of the resistance to antimicrobial agents conferred by biofilm formation and provide additional support for employing tests using biofilms to more accurately assess the relative activities of antiplaque agents in vitro.

Notizen: Background: With an increasing body of data suggesting an association between periodontitis and cardiovascular disease, studies have been conducted to elucidate potential mechanisms by which oral bacteria might exert systemic effects.2 oral bacteria, Streptococcus sanguis and Porphyromonas gingivalis, have been shown to induce platelet aggregation in vitro. This study was conducted to determine the effect of treatment with an essential oil mouthrinse (Listerine® Antiseptic) on the platelet-aggregating activity of these organisms.Method: Bacteria were grown under standard culture conditions. S. sanguis ATCC strain 10556 was exposed for 3 min to the essential oil mouthrinse at either full strength or a 1:1 dilution, while P. gingivalis FDC strain 381 was exposed to the essential oil mouthrinse at a 1:10 dilution. Positive control cells were treated with Hanks balanced salt solution (HBSS). Aggregation was measured using a recording platelet aggregometer. The assay of each organism in its respective mouthrinse dilution(s) or HBSS was repeated 5 times.Results: In all cases, the HBSS-treated organisms induced platelet aggregation, with mean(±S.E.) lag times of 12.30 (±1.36) min and 11.36 (±0.58) min for P. gingivalis and S. sanguis, respectively. In contrast, treatment with the essential oil mouthrinse completely inhibited the platelet aggregating activity of P. gingivalis and of S. sanguis exposed to the 1:1 mouthrinse dilution in all assays; the aggregating activity of S. sanguis treated with full-strength mouthrinse was completely inhibited in 4 of 5 assays, and inhibited by 75% in the 5th, for a mean inhibition of 95±1.5%.Conclusion: This study provides additional evidence that the essential oil mouthrinse can interfere with bacterial cell surface-associated activities which may have clinical relevance.

Notizen: Background: Clinical studies in which antimicrobial mouthrinses were shown to have significant antiplaque activity most frequently have used gingivitis as the clinically relevant endpoint. However, there is evidence to suggest that mouthrinses containing active agents effective against Streptococcus mutans, such as chlorhexidine, may also have a rôle in inhibiting dental caries. This clinical study was conducted to determine the effect of 2×-daily rinsing with an essential oilcontaining antiseptic mouthrinse (Listerine® Antiseptic) on levels of recoverable S. mutans and total streptococci in supragingival interproximal plaque and in saliva. Additionally, a follow-up in vitro study is reported which determined whether a differential susceptibility to the antiseptic mouthrinse exists among different strains of streptococci.Method: Following baseline saliva and plaque sampling for quantification of recoverable S. mutans and total streptococci, 29 qualifying subjects were randomly assigned either the essential oil mouthrinse or a sterile water control. They rinsed with 20 ml for 30 s 2×daily for 11 days and once on the 12th day, in addition to their usual oral hygiene procedures. On day 12, saliva and plaque samples were again collected and microbiological quantification performed. The procedures were repeated with the alternate rinse after a 1-week washout period.Results: The essential oil mouthrinse produced respective reductions of 69.9% and 75.4% in total recoverable streptococci and in S. mutans in plaque, and corresponding reductions of 50.8% and 39.2% in saliva. The in vitro study revealed that streptococci from the mutans group were more susceptible to the bactericidal activity of the essential oil mouthrinse than streptococci from the mitis group.Conclusions: As antimicrobial mouthrinses are most frequently recommended to patients whose mechanical oral hygiene procedures are not adequate for the control of supragingival plaque and gingivitis, this study provides an additional rationale for the inclusion of the essential-oil mouthrinse as an adjunct to daily oral hygiene procedures.

Notizen: Abstract. Although laboratory studies are not necessarily predictive of clinical activity, they can help to elucidate mechanisms underlying clinical activity when the latter has been established. In a recent clinical study, an essential oil mouthrinse (Listerine® Antiseptic) was shown to be significantly more effective than an amine fluoride/stannous fluoride mouthrinse (Meridol®) in inhibiting supragingival plaque formation. This paper reports the results of laboratory studies comparing the antimicrobial effectiveness of these 2 mouthrinses using a kill kinetics assay and a plaque biofilm kill assay. In both assays, the essential oil mouthrinse was considerably more effective than the amine fluoride/stannous fluoride mouthrinse. These findings are consistent with the results of the clinical trial and may help to explain the observed differences in clinical activity.

Notizen: Abstract. The adjunctive use of antimicrobial mouthrinses to help control supragingival plaque and gingivitis has been shown to contribute significantly to patients' daily oral hygiene regimens. This controlled clinical study used an observer- blind, randomized, cross-over design in a 4-day plaque regrowth model to determine the relative efficacies of an essential oil-containing mouthrinse (Listerine® Antiseptic) and an amine fluoride/stannous fluoride-containing mouthrinse (Meridol®) in inhibiting the development of supragingival plaque. A 0.1% chlorhexidine mouthrinse (Chlorhexamed®-Fluid) was used as a positive control, and a 5% hydroalcohol solution was used as a negative control. Dosing for each of the test mouthrinses was based on the manufacturers' label directions. Because the volume and rinse time for each of the test mouthrinses were different, each test mouthrinse had its own negative control group. On day 1 of each test period, subjects received an oral soft and hard tissue examination and a dental prophylaxis to remove all plaque, calculus, and extrinsic stain. Starting the same day, subjects refrained from all mechanical oral hygiene procedures for the next 4 days and rinsed 2× daily under supervision with their randomly-assigned mouthrinse. On day 5, each subject received a plaque assessment as well as an oral examination to assess side effects. Each test period was separated by a 2-week washout period. 23 volunteers with a median age of 26 years completed the study. Compared to the respective placebos, the median percent plaque reductions at 5 days were 23.0%, 12.2%, and 38.2% for the essential oil, amine/stannous fluoride, and chlorhexidine rinses, respectively. The plaque reductions seen in the essential oil and chlorhexidine rinse groups were statistically significant (p〈0.001), while the plaque reduction in the amine/stannous fluoride rinse group was not statistically significant (p〉0.05). Additionally, the essential oil rinse was significantly more effective (p〈0.001) than the amine/stannous fluoride rinse in inhibiting plaque accumulation in this clinical model.

Notizen: Abstract Although the mechanism responsible for the clinical antiplaque efficacy of oral antiseptics is generally considered to be primarily one of bactericidal activity, it has been suggested that oral antiseptics may have additional effects on bacteria exposed to sublethal levels. Studies reported herein, investigated the effects of sublethal levels of an essential oil-containing antiseptic mouthrinse (Listerine Antiseptic, Warner-Lambert Co., Morris Plains. NJ) on selected activities of representative plaque microorganisms using in vitro models. These studies demonstrated that sublethal exposure to the tested oral antiseptic can have significant effects in reducing intergeneric coaggregation, increasing bacterial generation time, and extracting endotoxin from Gram-negative bacteria. These in vitro activities can be correlated with features of plaque formation and pathogenicity seen in vivo: however, additional studies will be necessary to confirm that these mechanisms are, in fact, operative clinically.

Notizen: Abstract This 6-month, double-blind, controlled clinical trial determined the efficacy of the non-steroidal anti-inflammatory drug, meclofenamate sodium (Meclomen®), as an adjunct to scaling and root planing in the treatment of rapidly progressive periodontitis (RPP). 22 subjects (7 male. 15 female) aged 36.5±7.88 years with RPP and disease-active sites as determined by pretreatment bone scan had standardized radiographs at baseline and 6 months, and clinical measurements at baseline, 3 and 6 months. Following full-mouth scaling and root planing, subjects were randomly assigned to either a placebo, 50 or 100 mg meclofenamate sodium bid group. Bone change over the 6-month period as assessed by subtraction radiography was the primary efficacy determinant. Specialized software was used to isolate the lesion from the subtraction image and to measure bone change along the root surface. ANOVA using the subject as the unit of analysis revealed a significant dose response (P〈0.001) with the placebo group having a mean bone loss of 0.42±0.06 mm and the low and high dose groups having mean bone gains of 0.07±0.05 and 0.20±0.07 mm, respectively. These findings indicate that meclofenamate sodium may be a useful adjunct in the treatment of rapidly progressive periodontitis.

Notizen: Gap junctions were found in all layers of human gingival keratinizing epithelium, except the stratum corneum. En bloc staining revealed the seven-layered structure of these junctions, with a gap of approximately 20Å between the outer leaflets of adjacent unit membranes. Treatment of specimens with lanthanum strikingly demonstrated the gap junctions, since the lanthanum completely fills the central gap. Oblique and tangential sections of gap junctions in lanthanum-treated specimens produced characteristic striated and honey-comb appearances, respectively. It appears as though many junctions in gingival epithelium formerly thought to be variants of tight junctions (and thus regions of membrane fusion) are, in reality, gap junctions. In view of findings regarding the function of gap junctions in other tissues, it is suggested that gap junctions have a significant role in the synchronous differentiation of normal human gingival keratinizing epithelium.

Notizen: Electron microscopic examination of the walls of periodontal pockets revealed that connective tissue mast cells were distributed throughout the tissue. These cells had a variety of shapes, and were often in close association with remaining collagen fibers, as well as with smaller fibrils and other collagen fragments. Totally distrupted, necrotic mast cells were also observed which had morphologically intact granules in continuity with the extracellular space.