Triclosan and sodium lauryl sulphate mouthrinses. (II). Effects of 4-day plaque regrowth

Effects of sodium lauryl sulfate and postbiotic toothpaste on oral microecology

The diversity and delicate balance of the oral microbiome contribute to oral health, with its disruption leading to oral and systemic diseases. Toothpaste includes elements like traditional additives such as sodium lauryl sulfate (SLS) as well as novel postbiotics derived from probiotics, which are commonly employed for maintaining oral hygiene and a healthy oral cavity. However, the response of the oral microbiota to these treatments remains poorly understood. In this study, we systematically investigated the impact of SLS, and toothpaste containing postbiotics (hereafter, postbiotic toothpaste) across three systems: biofilms, animal models, and clinical populations. SLS was found to kill bacteria in both preformed biofilms (mature biofilms) and developing biofilms (immature biofilms), and disturbed the microbial community structure by increasing the number of pathogenic bacteria. SLS also destroyed periodontal tissue, promoted alveolar bone resorption, and enhanced the extent of inflammatory response level. The postbiotic toothpaste favored bacterial homeostasis and the normal development of the two types of biofilms in vitro, and attenuated periodontitis and gingivitis in vivo via modulation of oral microecology. Importantly, the postbiotic toothpaste mitigated the adverse effects of SLS when used in combination, both in vitro and in vivo. Overall, the findings of this study describe the impact of toothpaste components on oral microflora and stress the necessity for obtaining a comprehensive understanding of oral microbial ecology by considering multiple aspects.

Antibacterial effects of children's and adults' toothpastes containing different amounts of fluoride: An in vitro study

Background

In recent years, fluoride concentrations in toothpaste for children and adults have increased. However, the effects of different concentrations on bacterial activity have rarely been compared. We aimed to investigate and compare the antibacterial activity of children's and adults' toothpaste containing 500, 1000‒1100, and 1450‒1500 ppm fluoride.

Methods

Three strains of bacteria (Streptococcus mutans, Streptococcus salivarius, and Lactobacillus casei) were cultured in brain heart infusion agar. Thirty commercially available toothpaste products for children and adults containing 500, 1000‒1100, and 1450‒1500 ppm fluoride were selected and tested. Toothpaste's ability to inhibit bacterial growth was evaluated by agar diffusion assay, in which plates were incubated for 24 hours, and then the diameter of the microbial inhibition zone was measured. Comparisons between children's and adults' fluoride toothpastes were made using the Mann-Whitney U test. The association between bacterial growth inhibition and sodium lauryl sulfate (SLS) was analyzed by the chi-square test. A P value of <0.05 was considered statistically significant.

Results

No difference in the inhibition zone was observed for different fluoride concentrations. However, there were significant differences between toothpastes for children and adults, with higher inhibition zones for adults' toothpastes. Most toothpastes for adults contained SLS, which was associated with antibacterial activity.

Conclusion

Fluoride concentrations ranging from 500 to 1500 ppm did not affect bacterial growth. The antibacterial activity of toothpastes for adults was significantly higher than that of toothpastes for children, which was mainly attributed to the SLS usually added to adult formulations.

Effect of a gel containing green tea extract and hyaluronic acid on palate pain scores and wound healing after free gingival graft: a quasi-randomized controlled clinical trial

OBJECTIVES

The aim of this study was to evaluate the effect of a gel containing green tea extract and hyaluronic acid (HA) on pain scores and wound healing in donor sites after free gingival graft (FGG).

MATERIALS AND METHODS

Forty-two patients requiring FGG were included in three groups: (1) control group (n = 14), no material was placed in the donor area; only the clot was kept in position by sutures; (2) placebo group (n = 14), vehicle gel applied 3 times a day for 7 days; and (3) test group (n = 14), gel containing green tea extract and HA applied 3 times a day for 7 days. The wound size by clinical measurement (WS-CM) and photographic image (WS-PI), complete wound epithelialization (CWE), and palatal mucosa color were evaluated after 3 days and 1, 2, and 4 weeks postoperatively. The visual analog scale (VAS) for pain and analgesic consumption were used to assess participant's perception in the same postoperative periods.

RESULTS

A similar progressive reduction in the wound size, associated with an improvement in the color pattern, was observed in all groups (p > 0.05). No significant differences were found for CWE and pain assessment between the examined groups (p > 0.05).

CONCLUSION

The gel containing green tea extract and HA application in palatal wounds after FGG removal does not provide clinical healing benefits using this investigated protocol.

CLINICAL RELEVANCE

This is the first clinical study evaluating the effect of gel containing green tea extract and HA on the palate postoperative pain control and wound healing after FGG.

TRIAL REGISTRATION

http://clinicaltrials.gov : NCT05270161.

Hormesis: Wound healing and keratinocytes

Hormetic dose responses (i.e., a biphasic dose/concentration response characterized by a low dose stimulation and a high dose inhibition) are shown herein to be commonly reported in the dermal wound healing process, with the particular focus on cell viability, proliferation, and migration of human keratinocytes in in vitro studies. Hormetic responses are induced by a wide range of substances, including endogenous agents, numerous drug and nanoparticle preparations and especially plant derived extracts, including many well-known dietary supplements as well as physical stressor agents, such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings suggest that the concept of hormesis plays a fundamental role in wound healing, with important potential implications for agent screening and evaluation, as well as clinical strategies.

In Situ Antibacterial Activity of Essential Oils with and without Alcohol on Oral Biofilm: A Randomized Clinical Trial

Currently, there is little evidence on the in situ antibacterial activity of essential oils (EO) without alcohol. This study aimed to evaluate in situ the substantivity and antiplaque effect on the plaque-like biofilm (PL-biofilm) of two solutions, a traditional formulation that contains EO with alcohol (T-EO) and an alcohol-free formulation of EO (Af-EO). Eighteen healthy adults performed a single mouthwash of: T-EO, Af-EO, and sterile water (WATER) after wearing an individualized disk-holding splint for 2 days. The bacterial viability (BV) and thickness of the PL-biofilm were quantified at baseline, 30 s, and 1, 3, 5, and 7 h post-rinsing (Test 1). Subsequently, each volunteer wore the splint for 4 days, applying two daily mouthwashes of: T-EO, Af-EO, and WATER. The BV, thickness, and covering grade (CG) of the PL-biofilm were quantified (Test 2). Samples were analyzed by confocal laser scanning microscopy after staining with the LIVE/DEAD® BacLight™ solution. To conduct the computations of the BV automatically, a Matlab toolbox called Dentius Biofilm was developed. In test 1, both EO antiseptics had a similar antibacterial effect, reducing BV after a single rinse compared to the WATER, and keeping it below baseline levels up to 7 h post-rinse (P < 0.001). The mean thickness of the PL-biofilm after rinsing was not affected by any of the EO formulations and ranged from 18.58 to 20.19 μm. After 4 days, the T-EO and Af-EO solutions were significantly more effective than the WATER, reducing the BV, thickness, and CG of the PL-biofilm (P < 0.001). Although, both EO antiseptics presented a similar bactericidal activity, the Af-EO rinses led to more significant reductions in the thickness and CG of the PL-biofilm than the T-EO rinses (thickness = 7.90 vs. 9.92 μm, P = 0.012; CG = 33.36 vs. 46.61%, P = 0.001). In conclusion, both essential oils antiseptics had very high immediate antibacterial activity and substantivity in situ on the 2-day PL-biofilm after a single mouthwash. In the 4-day PL-biofilm, both essential oils formulations demonstrated a very good antiplaque effect in situ, although the alcohol-free formula performed better at reducing the biofilm thickness and covering grade.

The effectiveness of a dentifrice without sodium lauryl sulphate on dental plaque and gingivitis - a randomized controlled clinical trial

OBJECTIVES

The purpose of the study was to evaluate the effect on dental plaque and gingivitis of a dentifrice without sodium lauryl sulphate (SLS) compared to two SLS-containing dentifrices.

MATERIAL AND METHODS

For this double-blind, parallel study, 90 volunteers having moderate gingival inflammation (≥40%) were randomly divided among three groups: one group using non-SLS dentifrice containing enzymes, colostrum and low concentrations of zinc and two control groups each using different SLS-containing dentifrices. Dental plaque scores (Turesky modification of Quigley & Hein) and gingivitis scores (Bleeding On Marginal Probing) were assessed at baseline, after 2 and 4 weeks.

RESULTS

Eighty-nine participants provided evaluable data. A slight decrease in gingivitis scores was observed for all groups over 4 weeks, which was statistically significant for the non-SLS group. Mean values for dental plaque scores did not show major differences over 4 weeks. For both parameters, no significant differences between groups could be observed at any time point. Patient appreciation was in favour of the SLS groups especially regarding the foaming effect.

CONCLUSION

No significant differences could be observed with respect to the effect on plaque and gingivitis between SLS-containing and SLS-free dentifrice containing enzymes, colostrum and low concentration zinc. Patients enjoyed the duration of taste and the 'foaming effect' of SLS-containing dentifrices better.

Effectiveness of mechanical brushing with different denture cleansing agents in reducing in vitro Candida albicans biofilm viability

The adhesion of Candida albicans to surfaces is the prerequisite for occurrence of denture stomatitis, a common disease diagnosed among denture wearers. A routine of denture cleansing is essential to prevent biofilm formation and the onset of this infection. The aim of this study was to investigate the effectiveness of combining brushing and cleansing agents in killing C. albicans biofilm. Disks of acrylic resin were made, sterilized, and inoculated with C. albicans (10(7) cfu/mL). After incubation (37°C/48 h), specimens were randomly assigned to 10 experimental groups (n=9): 5 subjected to brushing with distilled water or cleansing agents - dentifrice slurry, 2% chlorhexidine gluconate (CHX), 1% sodium hypochlorite (NaOCl), and Polident fresh cleanse(®) (combined method) - and 4 exposed to the cleansing agents without brushing (immersion). Non-cleansed specimens were used as positive controls. The viability of cells was evaluated by XTT reduction method. Results were analyzed by Mann-Whitney and Kruskal-Wallis tests (α=0.05). The combined method was significantly more effective (p<0.0001) in reducing biofilm viability than the immersion. Brushing with CHX and NaOCl resulted in 100% removal of the biofilm. Immersion in the agents reduced significantly (p<0.0001) the biofilm viability, with CHX being the most effective (p<0.0001). The use of the combined method of brushing with cleansing agents is an effective method to reduce C. albicans biofilm, being CHX and NaOCl the most effective solutions.

Automutanolysin disrupts clinical isolates of cariogenic streptococci in biofilms and planktonic cells

INTRODUCTION

Dental caries remains one of the most common chronic infectious diseases throughout the world. The formation of dental plaque is one of the caries risk factors. As a consequence, the removal of plaque may reduce the incidence of caries development. We identified an autolysin produced by Streptococcus mutans named auto-mutanolysin (Aml). Aml selectively lyses S. mutans and Streptococcus sobrinus. The specificity towards these cariogenic bacteria suggests that Aml may be used to prevent dental caries. Here, with the aim towards therapeutic application, we investigated the lytic activity of Aml against clinical isolates of S. mutans and S. sobrinus using planktonic cells and biofilms.

METHODS

Planktonic cell suspensions and biofilms of clinically isolated streptococci were treated with Aml in the absence or the presence of Triton X-100. The lytic activity of Aml was monitored as the change in turbidity. The disruption of biofilms was evaluated by detecting the released DNA by polymerase chain reaction and observing the alteration of optical density of treated biofilms.

RESULTS

Triton X-100 enhances the lytic ability of Aml. Using planktonic cells, Aml had various lysis levels against clinical strains. Repeated Aml treatment showed disruption of the biofilm using the representative clinical strains.

CONCLUSION

Our study demonstrates that Aml has an ability to lyse planktonic and biofilm cells of clinically isolated mutans streptococci in the presence of Triton X-100. These results suggest the possibility of using Aml as an alternative or additional approach for caries prevention.

Dual effects of sodium lauryl sulphate on human oral epithelial structure

Sodium lauryl sulphate (SLS) is a common detergent known to cause irritation and inflammatory reactions in skin. SLS is also the most commonly used toothpaste detergent and has been related to intraoral adverse effects. However, its specific biological effects on the oral mucosa (OM) have not yet been identified. The objective of this study was to investigate the putative effects of SLS on human oral epithelium using a novel in vitro reconstructed three-dimensional cell culture model. Reconstructed human OM, generated from primary normal human oral keratinocytes and fibroblasts, was exposed to clinically relevant concentrations of SLS (range 0.015-1.5%). The cultured tissues were evaluated by histomorphometry, immunohistochemistry (Ki-67, epithelial (E)-cadherin, alpha6-, beta1-integrins, cleaved caspase-3) and the TUNEL method. Increased epithelial thickness, enhanced proliferation (Ki-67), a more pronounced expression of E-cadherin throughout all epithelial cell layers and single TUNEL-positive cells in the middle spinous cell layers were observed in cultures exposed to low concentrations (0.015%) of SLS. At exposure to higher SLS concentrations (>or=0.15%), epithelial thickness, cell proliferation and E-cadherin expression gradually decreased and in the central areas of exposed regions, cells detached from each other and underwent cell death. In conclusion, clinically relevant concentrations of SLS have dual effects on reconstituted human OM; although occasional cell death within the epithelium was also observed, the increased epithelial thickness, proliferation and E-cadherin expression induced at lower concentrations might be associated with a protective mucosal response, whereas at higher concentrations a more destructive type of reaction predominated.

Triclosan and Antimicrobial Resistance in Bacteria: An Overview

Triclosan is a widely used biocide that is considered as an effective antimicrobial agent against different microorganisms. It is included in many contemporary consumer and personal health-care products, like oral and dermal products, but also in household items, including plastics and textiles. At bactericidal concentrations, triclosan appears to act upon multiple nonspecific targets, causing disruption of bacterial cell wall functions, while at sublethal concentrations, triclosan affects specific targets. During the 1990s, bacterial isolates with reduced susceptibility to triclosan were produced in laboratory experiments by repeated exposure to sublethal concentrations of the agent. Since 2000, a number of studies have verified the occurrence of triclosan resistance amongst dermal, intestinal, and environmental microorganisms, including some of clinical relevance. Of major concern is the possibility that triclosan resistance may contribute to reduced susceptibility to clinically important antimicrobials, due to either cross-resistance or co-resistance mechanisms. Although the number of studies elucidating the association between triclosan resistance and resistance to other antimicrobials in clinical isolates has been limited, recent laboratory studies have confirmed the potential for such a link in Escherichia coli and Salmonella enterica. Thus, widespread use of triclosan may represent a potential public health risk in regard to development of concomitant resistance to clinically important antimicrobials.

Wear of dentine in vitro by toothpaste abrasives and detergents alone and combined

AIM

To measure in vitro the abrasion of dentine by toothpaste detergents and abrasives alone and combined.

MATERIALS AND METHODS

Detergents used were tego betain, sodium lauryl sulphate (SLS), adinol and pluronic diluted to 1% w/v. Abrasives were three artificial silicas, tixosil 73 and 123 and Zeodent 113, and calcium carbonate used at 2.5% w/v. Flat human dentine specimens were brushed with aqueous detergent solutions or abrasive slurries, detergent abrasive slurries and water for 20,000 brush strokes. Dentine loss was measured by non-contacting profilometry at 10,000 and 20,000 strokes. Silica particle size distribution was measured by laser deflection.

RESULTS

Loss of dentine occurred with all detergents, abrasives and detergent abrasion combinations, but was not linear with number of brush strokes. Water appeared to remove the smear layer only, but all detergents exceeded the predicted smear layer thickness. The silica abrasives differed in abrasion properties despite similar particle size distribution. Different detergents modulated the abrasives actions in mainly positive or mainly negative directions.

CONCLUSIONS

Detergents appear able to attack the dentine surface to produce wear. Abrasives vary considerably in wear produced under similar conditions. Detergents modulate the effect of abrasives in a way that may reflect the rheological properties of the mixture.

A study into the plaque-inhibitory activity of experimental toothpaste formulations containing antimicrobial agents

BACKGROUND/AIMS

The use of specific antimicrobial agents in toothpastes may help reduce plaque and gingivitis. There would also appear to be some value in formulating products that contain combinations of such agents that may potentiate any activity present. The aims of this exploratory and pragmatic study were twofold: (1) Exploratory: to compare the effects on plaque re-growth of two zinc citrate/triclosan formulations, one of which contained bromochlorophene and hence demonstrate any additional beneficial effects produced by the addition of the phenol. (2) Pragmatic: to assess whether both pastes were significantly better than a benchmark control, proprietary fluoride toothpaste at inhibiting plaque formation.

METHODS

Following an initial prophylaxis to remove all plaque and calculus, toothpaste slurry rinses were used over a 96 h period by 24 volunteers, while omitting all other oral hygiene procedures. After 24, 48 and 96 h, plaque was measured by plaque area and by plaque index. For comparative purposes, a conventional commercial fluoride toothpaste rinse was also used as a benchmark control in this triple cross-over double-blind study.

RESULTS

With one exception, comparisons between the three pastes failed to show any significant differences in plaque accumulation at 96 h whether assessed by plaque index or area. At this time period, significantly more plaque was seen with the zinc citrate paste without bromochlorophene, compared with that of the control paste.

CONCLUSIONS

The findings from this study failed to demonstrate a plaque-inhibitory action from the two novel formulations beyond that of a conventional benchmark toothpaste, although overall levels of plaque formed by the volunteers, especially on the control paste were generally lower than in previous studies. Nevertheless, it remains to be determined whether the test formulations could exert a direct anti-inflammatory action against gingivitis by way of the triclosan delivery system. Neither test formulation was subsequently marketed.

The anti-plaque efficacy of a chlorhexidine mouthrinse used in combination with toothbrushing with dentifrice

BACKGROUND

Although the efficacy of chlorhexidine (CHX) chemically can be affected by the presence of a sodium lauryl sulphate (SLS)-containing dentifrice in the oral cavity, previous data, collected without supervision, showed that the level of plaque inhibition offered by a 0.2% CHX post-brushing rinse in one jaw is not reduced under the influence of toothbrushing with a 1.5% SLS-containing dentifrice in the opposite jaw.

OBJECTIVES

The aim of the present study was to investigate, during a 4-day supervised study period, the anti-plaque efficacy of a 0.2% CHX pre-brushing rinse in one jaw, under the influence of toothbrushing in the opposite jaw, either with a SLS-containing dentifrice or with a SLS-free dentifrice. Three different dentifrices were tested. Two of them contained SLS (Colgate Total & Aquafresh Natural Whitening), the other (Zendium) did not.

METHODS

The study was an examiner blind, randomised 4-cell, crossover design. It used a 4-day plaque accumulation model to compare under supervision 4 different oral hygiene regimens with a washout period of at least one week. Thirty-five healthy volunteers were enrolled in the study and were randomly assigned to a sequence according to a 4 x 4 Latin square design. At the beginning of each 4-day test period, they received a thorough dental prophylaxis. Plaque was scored in one randomly assigned (upper or lower) jaw, called the study jaw. At the end of the 4-day period the study jaw was used to study the effect of the four regimens on the level of plaque accumulation. The opposite jaw was assigned as the dentifrice jaw and served only to introduce the effect of brushing with a dentifrice in the study model. Four oral hygiene regimens were designed. During the randomly assigned test periods, rinsing with 0.2% CHX and then brushing the dentifrice jaw was performed twice daily. In regimen 1, 2, and 3 the subjects used a dentifrice in the assigned dentifrice jaw being either a dentifrice with SLS (Colgate Total and Aquafresh Natural Whitening) or a SLS-free dentifrice (Zendium). Regimen 4 served as a control during witch subjects only rinsed with 0.2% CHX. No other oral hygiene methods were allowed. After 4 days of undisturbed plaque accumulation, the amount of plaque was evaluated (Lobene et al. 1982, Quigley & Hein 1962, Turesky et al. 1970 modifications).

RESULTS

The overall plaque index for regimen 1, 2 and 3 was, respectively, 1.8, 1.8 and 1.9. For regimen 4, the overall plaque index was 1.9. There was no significant difference in plaque accumulation between the four regimens.

CONCLUSIONS

Within the present study design, it can be concluded that the anti-plaque efficacy of a pre-brushing 0.2% CHX mouthrinse does not seem to be reduced under the influence of a normal toothbrushing exercise with a dentifrice after rinsing, whether the dentifrice contains SLS or not.

Impact of mouthrinses on morning bad breath in healthy subjects

BACKGROUND

During sleep, a proliferation of oral bacteria is responsible for the release of offending gases in morning breath even in healthy people. Thus, the aim of this study was to evaluate the bad breath-inhibiting effect of four commercially available mouthrinses (0.03% triclosan, 0.12% chlorhexidine gluconate, 0.05% cetylpyridinium chloride and essential oils) on morning breath when compared with a positive and a negative control.

METHOD

A six-step double-blind, crossover, randomised study was conducted in 12 dental students with healthy periodontium, who refrained from mechanical plaque control during a 4-day period. The subjects were instructed to rinse twice daily with the assigned product during each period. Fifteen-day washout intervals were used. Before professional plaque and tongue coating removal (baseline), the morning breath was scored through volatile sulphur compounds (VSCs) level measured by a sulphide monitor. After 4 days, VSCs and plaque index (PI) were recorded.

RESULTS

Even in the absence of mechanical plaque control, there was a decrease in VSC level with the use of all mouthrinses, with the exception of an increase with the use of the negative control. The VSC formation was inhibited in descending order, by positive control (0.2% chlorhexidine), 0.12% chlorhexidine, triclosan and essential oils and cetylpyridinium chloride. Plaque formation was inhibited by chlorhexidine mouthrinses and essential oils.

CONCLUSIONS

These findings suggest that mouthrinses can reduce morning bad breath, and that such a reduction is not attributable only to the reduction of supragingival plaque formation.

The role of therapeutic antimicrobial mouthrinses in clinical practice: control of supragingival plaque and gingivitis

BACKGROUND

Although mechanical plaque control methods have the potential to maintain adequate levels of oral hygiene, clinical experience and population-based studies demonstrate that such methods are not being employed sufficiently by large numbers of the population. The need for additional help in controlling bacterial plaque provides the rationale for patients' using antimicrobial mouthrinses as adjuncts to their mechanical oral hygiene regimens.

TYPES OF STUDIES REVIEWED

The author presents an overview of the types of studies used to support the effectiveness of antiplaque and antigingivitis mouthrinses, ranging from laboratory studies to six-month clinical trials. He discusses plaque as an example of a biofilm and the implications of recent research on the nature of biofilms with respect to the nature of the evidence that can be used to demonstrate clinical effectiveness.

CONCLUSIONS

The safety and clinical effectiveness of antiplaque and antigingivitis antimicrobial mouthrinses are best determined using prospective, randomized clinical trials conducted in accordance with ADA guidelines.

CLINICAL IMPLICATIONS

The adjunctive use of antimicrobial mouthrinses can provide significant benefits to patients who cannot maintain adequate levels of plaque and gingivitis control through mechanical methods alone. Dentists should recommend products that have proven clinical activity as demonstrated using generally accepted safety and effectiveness criteria.

A method to compare four mouthrinses: time to gingivitis level as the primary outcome variable

BACKGROUND AND AIM

The experimental gingivitis model is a well-established method in comparing the chemical antiplaque activity of agents and products. The aim of the present study was to use time in order to achieve an exit level of bleeding on probing (BOP) as the primary outcome variable.

METHODS

The study was a single blind, randomised four treatment parallel group design employing 76 healthy volunteers. The cohort was accepted into the study proper if they achieved a level of </= 25% BOP after a 5-week pre-study oral hygiene phase. At baseline, 1, 2, 3, 4, 5 weeks BOP, modified gingival index (MGI) and plaque index scores were obtained from each subject. After baseline, oral hygiene was suspended and subjects rinsed twice daily with one of the test rinses, namely: 1 0.05% cetylpyridinium chloride 2 Control fluoride 3 0.2% chlorhexidine 4 0.3% triclosan Subjects were removed from the study when they achieved >/= 50% BOP. Using the baseline and exit BOP, MGI and plaque, a deterioration rate for each parameter was derived and used as the unit of analysis.

RESULTS

There were highly significant treatment differences for all three parameters. Paired analyses revealed chlorhexidine was highly significantly more effective than the other rinses for all three parameters. CPC and triclosan were not different from the control for BOP, but CPC was significantly different from the control for MGI and plaque, and triclosan was different from the control for plaque. There were no differences between the CPC and triclosan rinses.

CONCLUSIONS

The method achieved the expected result of differentiating between the chlorhexidine and the other rinses. Some modification of the method, primarily to group sizes, should improve specificity. The method has the considerable volunteer appeal of early exit, particularly when allocated to control or low activity treatments for plaque.

Substantivity of toothpaste slurries and their effect on reestablishment of the dental biofilm

OBJECTIVES

Toothpastes are good vehicles for antibacterial substances to exert a prolonged effect. This effect depends on the substantivity and ability to interfere with plaque metabolism and/or vitality. It was the purpose of this clinical, randomized 2 x 4 cell crossover study to evaluate and to compare the antibacterial effects of two toothpastes (Colgate Total(R), COL and Parodontax(R), PAR) applied as slurries on established plaque over 24 h (Part I) and their effect on 4-day plaque regrowth (Part II). Chlorhexamed(R) (0.1%; CHX) and water served as positive and negative controls.

MATERIAL AND METHODS

After professional toothcleaning eight students were asked to refrain from all mechanical hygiene measures for the next 72 h. After 48 h plaque was sampled and vitality of the plaque flora examined (baseline, VF0%). The subjects then rinsed for 1 min with 15 mL of one of the test or control solutions. Every second hour up to 14 h and 24 h after rinsing, plaque sampling and staining was performed to assess plaque vitality (VF2-24, Part I). In Part II, the classical 4-day plaque regrowth design was used with two rinses (1 min) a day as the only oral hygiene measure. Vitality values were assessed on day 1 and day 4 (VF1, VF2). At day 4, teeth were stained to assess the whole mouth plaque index (PlI) and to evaluate the percentage of plaque area (PA) of the anterior teeth.

RESULTS

Compared to placebo, all active rinses reduced plaque vitality significantly over a period of 24 h (Part I). PAR, COL and CHX revealed reductions of 18-31%, 28-50% and 19-50%, respectively. In Part II, similar reductions of all parameters were found for all active rinses (PAR 12-30%, COL 34-51%, CHX 40-64%).

CONCLUSIONS

Colgate Total has shown a significant action on plaque regrowth and a high substantivity during 24 h, while Parodontax revealed a more moderate but still significant effect.

Plaque removal with the uninstructed use of electric toothbrushes: comparison with a manual brush and toothpaste slurry

BACKGROUND

Individuals purchasing electric toothbrushes for the 1st time will mostly only have the manufacturer's instructional leaflet for information of usage.

AIMS

This study was designed to simulate the 1st-time purchase and early use of an electric toothbrush with the aim of comparing plaque removal with a manual toothbrush. Secondary aims were to assess chemical plaque removal effects of a toothpaste slurry and to compare between 2 electric brushes which differed only in head speed.

METHODS

A group of 16 dentate subjects participated in this single-examiner blind, randomised, crossover design balanced for residual effects. Subjects had "average" oral hygiene and had never used an electric toothbrush previously. 7 days prior to the study, all subjects received the slower oscillating rotating toothbrush under test to use at home as they wished. The test treatments were brushing with 2 oscillating rotating electric toothbrushes, a manual toothbrush and a rinse with a toothpaste slurry (3 g/10 ml water). On day 1 of each study period, subjects were rendered plaque-free, suspended oral hygiene and returned on day 5. Plaque was scored at baseline by index and area and after 30 s, 30 s (total 60 s) and 60 s (total 120 s) of the cleaning treatments. Washout periods were at least 2 1/2 days.

RESULTS

Highly significant treatment differences were found between the 4 treatments because the toothpaste slurry was totally without effect. Analyses between the 3 brush treatments overall revealed no consistent significant differences. The data suggest that in the early days of electric toothbrush use, subjects perform no better than using a manual brush.

CONCLUSIONS

The present study, taken with results from others showing greater benefits from the use of electric brushes, supports the idea that dental professionals should, where possible, provide advice and instruction in the use of such devices.

A study to assess the plaque inhibitory action of a new zinc citrate toothpaste formulation

BACKGROUND, AIMS

Zinc-citrate-containing toothpastes have previously been suggested to be of value at inhibiting plaque and gingival inflammation. Present formulations have included triclosan which is thought to contribute major antibacterial/antiplaque effects. Alternative antimicrobial agents and other ingredients such as oils could help to produce equally effective formulations. The aim of this study was to determine whether zinc citrate toothpastes containing bromochlorophene and a triglyceride oil (1% and 8%) could inhibit de novo plaque formation.

METHODS

Toothpaste slurry rinses were used over a 96-h period by 24 volunteers, whilst omitting all other oral hygiene procedures. For comparative purposes, a conventional commercial fluoride control toothpaste was also used in this triple cross-over double blind study.

RESULTS

After 24 and 48 h, there were no statistically significant differences in plaque between the 2 test pastes and the control paste, whether assessed using a plaque index or plaque area. After 96 h, however, a significant reduction in plaque score of 10.6% and 24.2%) in plaque area (both p < 0.001) was found for the zinc citrate/1% oil toothpaste compared to the control paste. In addition, at 96 h, the 8% oil toothpaste significantly reduced plaque score compared to the control paste by 4.3% (p = 0.029).

CONCLUSIONS

These findings would appear to warrant further investigation into the potential value of the zinc citrate/bromochlorophene/triglyceride formulation at inhibiting both plaque and gingival inflammation.

Alcohol-free mouthrinse solutions to reduce supragingival plaque regrowth and vitality. A controlled clinical study

BACKGROUND

The aim of this study was to evaluate the clinical and antibacterial properties of alcohol-free mouthrinses, an amine fluoride/stannous fluoride mouthrinse (ASF) and two triclosan solutions in comparison with a chlorhexidine and a placebo rinse.

MATERIAL AND METHODS

In a double-blind, randomised 5-cell cross-over 4-day plaque regrowth study, 19 volunteers rinsed 2 x a day with 15 ml of each of the distributed solutions. Each test cycle was followed by a 10 days wash-out period. On day 0 of each test week, volunteers received a dental prophylaxis. Thereafter they refrained from all mechanical oral hygiene procedures for the next four days. Plaque regrowth was assessed daily by the plaque index and on day 4 by calculating the plaque area with a computer program after disclosure and photography of the front teeth. The vitality of the plaque was examined on days 1 to 4 by the vital fluorescence technique.

RESULTS

19 participants completed the study. Compared to the placebo the ASF solution showed 15.7% (p>0.5), 30.6% (p<0.001), 40.5% (p<0.001) and 44.7% (p<0.001) reductions on the consecutive days 14 in plaque index and a reduction of 61.9% in plaque area. The decrease of vitality of supragingival plaque was highly significant compared to placebo on every test day ranging between 30.9% and 36.6%. A reduction in plaque index from 19.4% (p<0.01) on day 2, 34.9% (p<0.001) on day 3 and 40.4% (p<0.001) on day 4 concommitant with a reduction in plaque area of 48.9% (p<0.001) was noted for alcohol-free chlorhexidine. Concerning the vitality chlorhexidine reduced the percentage of vital bacteria significantly on every day (16.0% to 24.9%). The reductions in mean plaque index for the 0.15% triclosan solution during the test period were 6.3%, 22.4%, 24.6% and 36% and in plaque area 41.8%. Vitality was significantly reduced at every day compared to placebo. Plaque Index reduction with the 0.02% triclosan increased from 15.3% (day 2) to 31.0% (day 4) and a reduction of 23.6% was seen in plaque area. A significant effect concerning the vitality of the plaque was only found at the first and the last day of the test cycle.

CONCLUSION

Alcohol-free mouthrinse solutions were shown to be effective in reducing both plaque accumulation and plaque biofilm vitality compared to a placebo solution.

The effect of toothpaste on the propensity of chlorhexidine and cetyl pyridinium chloride to produce staining in vitro: a possible predictor of inactivation

BACKGROUND/AIMS

Cationic antiseptics such as chlorhexidine (CHX) and cetyl pyridinium chloride (CPC) interact with dietary chromogens to produce extrinsic stain, and this can be used as a measure of activity of products. The aim of these studies in vitro was to determine if toothpaste influenced the tea staining effects of CHX and CPC as a predictor of action in vivo.

METHOD

Clear acrylic specimens were soaked in pooled human saliva followed by sequential 2-min soaks in pairs of agents, namely 0.05% CHX, 0.05% CPC, 0.2% CHX, water (W) and toothpaste slurry (TP). The combinations were; TP/CHX, CHX/TP, TP/CPC, CPC/TP, W/CHX, CHX/W, W/CPC, CPC/W, TP/W, W/TP, W/W. These treatments were followed by a 60 min soak in tea. Optical density readings were taken at baseline and after each of 8 cycles.

RESULTS

In the separate CHX and CPC studies by comparison with W/CHX, TP/0.05% CHX had little effect on staining, but TP/0.2% CHX showed a reduction in staining of 18%. 0.05% CHX/TP reduced staining by >40%, and 0.2% CHX by >78%. TP/CPC reduced staining by >26% and CPC/TP by 80%. Water after 0.2% CHX, 0.05% CHX and CPC reduced staining by 18%, 13% and 17% respectively. Little staining was seen with TP and W combinations. The data for CHX are in agreement with a study in vivo except TP followed by CHX reduced the activity of CHX.

CONCLUSION

Toothpaste appears to adversely affect the activity of CHX and CPC particularly if used immediately after the antiseptics. The data further supports the concept of separating the use of antiseptics until sometime after the use of toothpaste, and the idea of developing mouthwash friendly toothpastes.

A study to assess the plaque inhibitory action of a newly formulated triclosan toothpaste

BACKGROUND/AIMS

Triclosan containing toothpastes have been noted for their potential to inhibit plaque and gingival inflammation. The aim of this study was to determine whether a toothpaste containing triclosan and an enhanced fluoride system would inhibit de novo plaque formation beyond that of a non-triclosan, conventional fluoride toothpaste.

METHODS

This study used a 4-day plaque regrowth model in which 24 volunteers used toothpaste rinses as the only form of oral hygiene. Following a prophylaxis and a single brushing with the toothpastes, 2x daily rinsing with toothpaste slurries was used over the following 96 h.

RESULTS

After 24 h, there was no difference in plaque area between the triclosan paste and its control paste. After 96 h, a reduction in plaque score of 5% was noted for the test toothpaste compared to the control paste which was statistically significant (p=0.028). For plaque area this reduction was increased to 16%, which was also significant (p=0.006).

CONCLUSIONS

These findings would appear to warrant further investigation into the potential value of the paste in inhibiting both plaque and gingivitis.

Validation of an in vitro biofilm model of supragingival plaque

The study of biofilm structure and function mandates the use of model systems for which a host of environmental variables can be rigorously controlled. We describe a model of supragingival plaque containing Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis wherein cells are cultivated anaerobically in a saliva-based medium on hydroxyapatite discs coated with a salivary pellicle, with material and pieces of apparatus common to all microbiology laboratories. After 0.5 hr, 16.5 hrs, 40.5 hrs, and 64.5 hrs, the composition of adherent biofilms was analyzed by culture techniques, live/dead fluorescence staining, and confocal laser scanning microscopy. Repeated independent trials demonstrated the repeatability of biofilm formation after 40.5 hrs and 64.5 hrs. Brief exposures of biofilms to chlorhexidine or Triclosan produced losses in viability similar to those observed in vivo. This biofilm model should prove very useful for pre-clinical testing of prospective anti-plaque agents at clinically relevant concentrations.

Antibacterial agents in the control of supragingival plaque--a review

This review considers the main agents which have been used as antibacterial agents in mouthwashes and other vehicles to inhibit the growth of supragingival plaque. The agents discussed are bisguanide antiseptics, quaternary ammonium compounds, phenolic antiseptics, hexetidine, povidone iodine, triclosan, delmopinol, salifluor, metal ions, sanguinarine, propolis and oxygenating agents. The plaque inhibitory, anti-plaque and anti-gingivitis properties of these agents are considered along with their substantivity, safety and possible clinical usefulness. Clinical trials of these agents that have been published are also reported. The possible clinical uses of antiseptic mouthwashes are finally considered along with some advice about assessing manufacturers claims. Throughout this review the terms plaque inhibitory, anti-plaque and anti-gingivitis have been used according to the clarification of terminology suggested by the European Federation of Periodontology at its second workshop. This defines a plaque inhibitory effect as one reducing plaque to levels insufficient to prevent the development of gingivitis; an anti-plaque effect as one which produces a prolonged and profound reduction in plaque sufficient to prevent the development of gingivitis; and anti-gingivitis as an anti-inflammatory effect on the gingival health not necessarily mediated through an effect on plaque.

Evaluation of oral hygiene products: science is true; don't be misled by the facts

Most people in industrialized countries use oral hygiene products. When an oral health benefit is expected, it is important that sufficient scientific evidence exist to support such claims. Ideally, data should be cumulative derived from studies in vitro and in vivo. The data should be available to the profession for evaluation by publication in refereed scientific journals. Terms and phrases require clarification, and claims made by implication or derived by inference must be avoided. Similarity in products is not necessarily proof per se of efficacy. Studies in vitro and in vivo should follow the basic principles of scientific research. Studies must be ethical, avoid bias and be suitably controlled. A choice of controls will vary depending on whether an agent or a whole product is evaluated and the development stage of a formulation. Where appropriate, new products should be compared with products already available and used by the general public. Conformity with the guidelines for good clinical practice appears to be a useful way of validating studies and a valuable guide to the profession. Studies should be designed with sufficient power to detect statistically significant differences if these exist. However, consideration must be given to the clinical significance of statistically significant differences between formulations since these are not necessarily the same. Studies in vitro provide supportive data but extrapolation to clinical effect is difficult and even misleading, and such data should not stand alone as proof of efficacy of a product. Short-term studies in vivo provide useful information, particularly at the development stage. Ideally, however, products should be proved effective when used in the circumstances for which they are developed. Nevertheless, a variety of variable influence the outcome of home-use studies, and the influence of the variable cannot usually be calculated. Although rarely considered, the cost-benefit ratio of some oral hygiene products needs to be considered.

A short-term clinical study design to investigate the chemical plaque inhibitory properties of mouthrinses when used as adjuncts to toothpastes: applied to chlorhexidine

The removal of plaque by toothbrushing with toothpaste is the most common form of plaque control in the developed world. However, the use of chemical adjuncts such as mouthrinses is increasing. In practice mouthrinses and toothpaste are used together, however, in many clinical trials, employed to assess mouthrinse activity, toothpaste use is suspended. This fails to measure the effect of chemical interactions which are known to occur between toothpaste ingredients and mouthrinses. The objective of this trial was to develop a methodology which would assess the adjunctive chemical plaque inhibitory action of mouthrinses, when used with toothpaste but without the indeterminate variable of toothbrushing. The study was a single blind, randomised, 7-way crossover design, based on a variation of a 4 day plaque regrowth model. The 2 x daily rinsing regimens produced increasing plaque scores in the following order: (1) water/chlorhexidine, (2) chlorhexidine/water, (3) chlorhexidine/toothpaste slurry, (4) toothpaste slurry/chlorhexidine, (5) water/toothpaste slurry, (6) toothpaste slurry/water, (7) water/water. Chlorhexidine and water or chlorhexidine and toothpaste slurry combinations produced significantly lower plaque scores than water alone. Slurry and water combinations resulted in less plaque than water alone, but differences were not significant. Toothpaste slurry and chlorhexidine produced significantly increased plaque scores compared to chlorhexidine and water. The study suggests that, outside the Hawthorne effect, chlorhexidine rinses would be less effective in reducing plaque when used with toothpaste than when used alone. The methodology could be employed as a screening tool for the evaluation of mouthrinses expected to be used as adjuncts to normal oral hygiene methods. The same could be used to optimise oral hygiene regimens which include the use of mouthrinses.

Clearance of sodium lauryl sulphate from the oral cavity

Sodium lauryl sulphate (SLS) is used in toothpaste and mouth rinses as an emulsifying and surface cleaning agent. SLS has been implicated in an increased incidence of oral irritation in subjects predisposed to recurrent aphthous stomatitis (RAU). Hence, the purpose of this study was to determine the levels of SLS found in the oral cavity following rinsing with an SLS containing mouth rinse and brushing with a SLS containing dentifrice. An analytical method to separate SLS from saliva and other complex systems was developed. The method used high performance liquid chromatography (HPLC) and detection performed using conductivity measurements. Standard curves with known concentrations showed a detection limit of less than 0.4 ug SLS/ml of fluid. 2 clinical studies were conducted to determine the amount of SLS retained in the mouth by a healthy population after rinsing or brushing with commercially available products. The results showed, after rinsing, that 96% of the available SLS from the rinse was recovered in the collected samples within 2 min. Similarly, after brushing, 86% of the SLS contained within the toothpaste was recovered from the collected samples within the first 10 min. These results showed that the amount of SLS retained in the oral cavity was minimal and the contact time between SLS and the oral cavity was very short. A 2nd study was conducted to measure the amount of SLS retained in the mouth by a population susceptible to RAU. After rinsing, 97% of the available SLS was recovered within the first 2 min. Following brushing, 89% of the SLS in the dentifrice was recovered within the first 10 min. These results were comparable to those determined by the study involving the healthy population.

Studies on stannous fluoride toothpaste and gel (2). Effects on salivary bacterial counts and plaque regrowth in vivo

There has been a resurgence of interest in stannous fluoride (SF) products in particular to provide oral hygiene and gingival health benefits. The aim of this study was to assess the persistence of antimicrobial action of a number of SF formulations in the mouth and relate these to plaque inhibitory activity. The formulations were 2 SF toothpastes (SF1, SF2), 2 SF plus stannous pyrophosphate toothpastes (SFSP1, SFSP2), a SF gel (G), a NaF toothpaste (C) and saline (S) as control. Both studies involve 2 different groups of 21 healthy dentate volunteers. The studies were single, blind, randomised, crossover designs balanced for residual effects, with a minimum 2 1/2 day washout period. Salivary bacterial counts were determined before and to 7 h after a single rinse with the formulations. Plaque regrowth from a zero baseline (day 1) was measured by index and area on day 5, after 2x daily rinsing with slurries of the formulations or saline. For bacterial counts, highly significant treatment differences were found. Bacterial counts were variably reduced by all treatments to 30 min then showed a variable rate of return towards baseline. All test agents were significantly better than S at some timepoints. The order for greatest persistence of action downwards was; (1) SFSP2; (2) SFSP1, G, and SF1; (3) SF2; (4) C; (5) S. Highly significant differences in plaque regrowth between treatments were found with similar mean ordering of efficacy as for salivary bacterial counts from most effective downwards namely; (1) SFSP1 and SFSP2; (2) SF1; (3) SF2; G and C; (4) S. The results were consistent with a parallel study measuring tea staining in vitro, whereby formulations causing the most staining produced the greatest persistence of action and plaque inhibitory activity. This suggests the availability of stannous ions was important for the clinical effects. It is concluded that stannous ions can enhance the plaque inhibitory action of toothpaste via a persistent antimicrobial action.

The effects of antimicrobial mouthrinses on de novo plaque formation at sites with healthy and inflamed gingivae

The objective of the present investigation was to evaluate to what extent mouthrinses containing triclosan and chlorhexidine may modify the amount of de novo plaque that forms on tooth surfaces adjacent to healthy and inflamed gingival units. 10 volunteers were recruited. On day 0, gingival crevicular fluid (GCF) was obtained at predetermined sites and gingivitis (GI) was assessed. A careful oral prophylaxis was given to each of the volunteers who subsequently abstained from all mechanical plaque control measures for the following 18 days. During the first 4 days (rinse phase I), they rinsed with either 0.12% chlorhexidine, 0.06% triclosan or placebo solution. Clinical examinations (GCF, GI) were repeated and the amount of plaque formed determined on days 4, 7 and 14. On day 14, the participants received a new professional tooth cleaning after which rinse phase II was initiated. During this 2nd phase, the participants rinsed for 4 days with the same mouthwash preparation and in the same manner as during rinse phase I. The examinations were repeated on day 18. Each participant received a comprehensive oral prophylaxisis and was instructed to perform meticulous mechanical plaque control during the following 4 weeks. A 2nd experimental period was then initiated. A total of 3 experimental periods were repeated until all subjects had rinsed with the 3 different mouthwash preparations. The results demonstrated (i) that significantly more plaque formed at sites with gingivitis than at surfaces adjacent to healthy gingival units and (ii) pre-existing gingivitis significantly increased the amount of de novo plaque that formed in subjects who rinsed with mouthwash preparations containing chlorhexidine and triclosan.

The comparative effects on plaque regrowth of phenolic chlorhexidine and anti-adhesive mouthrinses

The inhibition of bacterial attachment to the tooth surface is one possible approach to plaque control. This study evaluated in vivo the plaque inhibitory action of a novel copolymer reported to have considerable antiadhesive properties in vitro. The study was a single blind, 5-treatment, randomised Latin square crossover design, incorporating balance for carry-over effects. The rinses were the antiadhesive (1%), the antiadhesive with 0.02% chlorhexidine, a 0.2% chlorhexidine rinse product, an essential oil/phenolic rinse product and water. 15 volunteers participated and on day 1 of each study period were rendered plaque-free, ceased toothcleaning and rinsed 2 x daily, under supervision, with the allocated formulation. On day 5, plaque was scored by index and area. Washout periods were 2 1/2 days. Alone or combined with chlorhexidine, the antiadhesive agent showed no effects greater than water. The chlorhexidine rinse was significantly more effective than the essential oil/phenolic rinse which in turn was significantly more effective than the other rinses.

The effect of a commercially available triclosan-containing toothpaste compared to a sodium-fluoride-containing toothpaste and a chlorhexidine rinse on 4-day plaque regrowth

Many compounds could be added to toothpaste to assist plaque inhibition, but ionic interactions can cause formulation difficulties. Moreover, the actual chemical action of a plaque inhibitory agent added to a toothpaste is difficult to assess when the product is used in the conventional manner, i.e., in addition to toothbrushing. The non-ionic antimicrobial triclosan has been incorporated in toothpastes and shown to have variable plaque inhibitory activity both alone and in conjunction with certain polymers or metal ions. Little is known of the efficacy of triclosan toothpastes compared to conventional fluoride toothpastes. The aim of this study was to compare a commercially available toothpaste containing 0.3% triclosan/co-polymer with a sodium fluoride toothpaste for chemical plaque inhibitory effects over a 4-day period. The study was designed to stratify the relative efficacy plaque inhibitory action of the products, comparisons were made with a positive control, chlorhexidine rinse and a negative control, saline. The study design was a randomised single blind crossover design balanced for first-order carryover. A total of 18 healthy, dentate volunteers participated in the study. On day 1 of each period the volunteers suspended toothcleaning and rinsed 2 x daily with the allocated mouthrinse or toothpaste slurry. On day 5, the plaque on the teeth was disclosed and scored by index and area. Increasing plaque scores were in the order chlorhexidine, triclosan toothpaste, fluoride toothpaste, and saline. Chlorhexidine was significantly more effective than all the other agents tested, and both toothpaste preparations were significantly better than the saline rinse. There was no significant difference between the two toothpaste rinses. Consistent with other studies the triclosan toothpaste offers only moderate plaque inhibitory properties when compared to a conventional toothpaste.

Efficacy of mouthrinses in inhibiting the development of supragingival plaque over a 4-day period of no oral hygiene

This study was a first stage evaluation of the plaque inhibitory properties of an experimental cetylpyridinium chloride (CPC)/essential oil mouthrinse. The study was a formulation, not ingredient, evaluation and comparisons were made with established mouthrinse products. The 5 rinses tested were: the experimental formulation; a triclosan/copolymer prebrushing mouthrinse; two negative control rinses, which differed only in color; and as a positive control, a 0.2% chlorhexidine mouthrinse. The study used a 5 cell, 4-day plaque regrowth, double-blind crossover design in which 15 subjects participated. Allocation of mouthrinse sequences was accomplished using 3 replicates of a 5 x 5 Latin square, incorporating balance for carryover. On Day 1, subjects received a scaling and polishing to reduce plaque, ceased toothcleaning, and commenced rinsing twice daily, under supervision, with the randomly assigned rinse. Rinsing time for the experimental and one negative control rinse was 30 seconds and for the other rinses was 60 seconds. On Day 5, plaque was scored by both index and area. Differences in plaque regrowth between the rinse groups were highly significant. The order of efficacy from the most effective was: chlorhexidine rinse (positive control); experimental CPC/essential oil rinse; triclosan/copolymer rinse; and the negative control rinses. From the calculated confidence intervals each rinse differed significantly from each other rinse, except for the two negative control rinses which were comparable to each other. Proportionately, the CPC/essential oil rinse was positioned 30 to 50% between the triclosan/copolymer rinse and the chlorhexidine (positive control). These findings suggest that the CPC/phenolic rinse would seem worthy of further evaluation for adjunctive benefits to oral hygiene.

Organic solvents and oils as vehicles for triclosan in mouthrinses: a clinical study

Previous experiments have shown that the nature of the detergents used in aqueous triclosan-containing mouthrinses affects the plaque-inhibiting effect of these mouthrinses, probably because of the properties of the micelles formed. It has also been shown that triclosan has a marked plaque-inhibiting effect when dissolved in pure propylene glycol. The aim of the present study was to compare the clinical effect of triclosan dissolved in oils and in the pure solvents glycerol (GLY) and polyethylene glycol (PEG). A test panel of 12 volunteers rinsed with the allocated mouthrinses for 4 days in a double-blind, crossover study. Three different oils were tested: olive oil, soy oil, and sunflower seed oil, as well as PEG and GLY. Triclosan was used in a 0.3% concentration to facilitate comparison with previous studies. However, only 0.15% triclosan was added to the GLY-containing rinse (maximum soluble concentration). In addition, soy oil without triclosan was tried. The mean plaque score for water was 1.42 +/- 0.19; for olive oil, 1.08 +/- 0.34; for soy oil with triclosan, 0.95 +/- 0.35; for pure soy oil, 0.94 +/- 0.09; for sunflower seed oil, 1.19 +/- 0.19; for PEG, 1.04 +/- 0.22; and for GLY, 1.12 +/- 0.28. The results indicate that triclosan dissolved in oils loses its clinical effect. However, oils in themselves exhibit significant plaque inhibition. In vitro tests showed no antibacterial activity of triclosan dissolved in oils. Toothpastes and mouthrinses contain flavoring oils and occasionally also GLY and PEG. Such substances may well interfere with the clinical effect of triclosan in these products.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of choice of solvents for the clinical effect of triclosan-containing mouthrinses

The aim of this study was to investigate the plaque-inhibiting effect of triclosan. It is known that triclosan and sodium lauryl sulfate (SLS) have a marked inhibitory effect. However, since SLS has a plaque-reducing effect in itself, the relative importance of triclosan and the surfactant is undecided. Twelve dental students participated in the trial, during which oral hygiene was suspended for 4-day periods when the different mouthrinses were used twice daily. The following mouthrinses were used: A, water (negative control); B, 0.2% chlorhexidine acetate (CHX) (positive control); C, 0.3% triclosan in water-free propylene glycol (PG); D, 0.3% triclosan with 1.5% SLS in PG; E, 0.15% triclosan in PG; F, 0.075% triclosan in PG; G, 0.3% triclosan in diluted PG (1:8 in water) with 1.5% SLS; and H, 0.3% triclosan in 0.5% sodium carbonate. The results showed that triclosan dissolved in the organic solvent PG had a significant plaque-inhibiting effect, whereas, dissolved in alkali, it had a negligible effect. The addition of SLS to PG somewhat reduced the antiplaque activity, and the aqueous solution of triclosan had markedly less effect. Lower concentrations of triclosan exhibited less clinical effect than higher concentrations. It can be concluded that triclosan alone, dissolved in a suitable solvent, has an antiplaque effect. The study confirmed the hypothesis that the nature of the detergent or organic solvent used to dissolve triclosan affects its clinical effect markedly.

A comparison of cetylpyridinium chloride, triclosan and chlorhexidine mouthrinse formulations for effects on plaque regrowth

A relatively small number of agents are used in mouthrinse products, although the possible variability in the final formulations is enormous. The aim of this study was to compare equal concentrations of 3 antimicrobial agents, in simple formulations, for plaque inhibition. This 4-day plaque regrowth study was a 5-cell, randomised, double blind cross-over design, involving 20 healthy human volunteers. The mouthrinse formulations were aqueous 0.05% solutions of cetylpyridinium chloride (CPC), chlorhexidine and triclosan, together with a 0.1% CPC and a minus active control rinse. On Day 1, from a zero plaque baseline, volunteers ceased normal oral hygiene and rinsed 2x daily for 1 min. with 10-ml volumes of the allocated rinses. On Day 5, plaque was scored by index and area. All rinses produced lower mean plaque values compared to control, but unlike the CPC and chlorhexidine rinses, the differences with triclosan did not always reach significance. The CPC and chlorhexidine rinses were always significantly more effective than the triclosan rinse. The greatest plaque inhibition was with 0.1% CPC although rarely significantly greater than the 0.05% CPC and chlorhexidine rinses which were similar in efficacy. The results indicate that further studies on lower concentration chlorhexidine solutions are warranted.

The magnitude and duration of the effects of some mouthrinse products on salivary bacterial counts

The persistence of action or substantivity of an antimicrobial agent in the mouth relates to the plaque inhibitory action of that compound. Substantivity can be assessed by measuring the magnitude and duration of the fall in salivary bacteria following single rinses with antimicrobials. This was a randomised single-blind, cross-over study measuring the effects of single 60-s rinses of 5 mouthwash products on salivary bacterial counts in 14 healthy human volunteers. Effects over a 7-h period were compared with a chlorhexidine rinse product (positive control) and saline (negative control). All but one rinse, containing cetylpyridinium chloride (CPC), significantly reduced bacterial counts compared to saline up to 5-7 h. No rinse produced the magnitude or duration of effect noted for chlorhexidine and decrements from baseline, with one exception, were highly significantly lower than with the chlorhexidine product. Comparing the 2 CPC rinses, the findings suggest that the activity of one product was vitiated by some other ingredient. The triclosan/copolymer, the essential oil/phenolic and one CPC products exhibited similar persistence. In those cases where information is available, these data are consistent with comparative plaque inhibitory findings for the products or their active ingredients. Again, it is concluded that the method is a useful screening and comparison test for the potential plaque inhibitory activity of antimicrobial oral hygiene products.

Mouthrinses

Mouthrinses have been used for centuries for medicinal and cosmetic purposes, but it is only in recent years that the rationale behind the use of the ingredients has been subject to scientific research and clinical trials. Although Listerine held its position for many years in the vanguard of the anti-plaque agents, the advent of mouthrinses containing chlorhexidine was a major breakthrough in the research for a chemical means to prevent disease. Since that time, and especially in the past ten years, the number of formulations that claim to have anti-plaque, anti-calculus, and anti-caries activity has increased, and much emphasis has been placed on such substances as an adjunct to, or indeed to replace, conventional toothbrushing techniques. This review covers the literature on mouthrinses over the past five years, concentrating more on the anti-plaque, anti-gingivitis, and anti-calculus formulations. In the first section, the methods of conducting clinical trials of mouthrinses are discussed, and a plea is made for a greater degree of standardization of methodology with agreed acceptable levels of clinical benefit. Trials of established mouthrinses are considered, and the advantages and disadvantages of several newer formulations discussed. From the review, it appears that chlorhexidine has no equal in its effects on reduction of plaque and gingivitis, but major drawbacks lie in the taste and stain-producing problems. The pre-brushing rinse, Plax, does not have unqualified success in all trials, though the more recent European formulation may have promise. Newer rinses which inhibit bacterial adhesion to tooth surfaces also appear promising, and it is suggested that more work on combinations of active ingredients is necessary.

The effect of prebrushing mouthrinse solutions on the desorption of albumin from apatite

This study evaluated the desorption of radiolabelled albumin from synthetic hydroxypatite by 4 commercial prebrushing solutions: Lysoplac (containing chlorhexidine), Plax (sodium benzoate), Acti-Brush (triclosan), and Sanogyl (sodium fluoride). In 3 min, Lysoplac and Plax were found to desorb about 90% of albumin while Acti-Brush and Sanogyl failed to desorb hardly any albumin in 15 min. The desorbing effectiveness of the test solutions was not due to their pH, because when buffer solution was being tested in different ionic strengths at pH range 6-8, it appeared to desorb less than 3% of adsorbed albumin, irrespective of the pH used. The results obtained cannot, however, be directly applied to the clinical situation where much more complex interactions occur than what were tested under the present in vitro conditions.

The effect of mouthrinses containing zinc and triclosan on plaque accumulation and development of gingivitis in a 3-week clinical test

Experimental mouthrinses containing 0.4% zinc sulphate and 0.15% triclosan were compared with a chlorhexidine and a negative control mouthrinse in a 3-week clinical trial. The zinc/triclosan mouthrinses 1 and 2 differed in their ethanol and humectant contents used to deliver the triclosan. The experimental protocol employed the partial mouth gingivitis design, whereby participants wear a toothshield during toothbrushing. Gingival health at baseline was established by professional cleaning, oral hygiene instruction and effective toothbrushing 3 x per day during a pre-experimental period of 2 weeks. The mouthrinses were subsequently used 2x daily following normal toothbrushing during 3 weeks. The pre-experimental oral hygiene phase very effectively reduced plaque levels and gingival bleeding. During the rinsing period, in the absence of mechanical removal of plaque from the protected teeth, gingival bleeding rose to above the prestudy level in the negative control group. The increments (change from baseline to 21 days) of plaque and bleeding scores for the zinc/triclosan mouthrinse 1 were significantly lower than those in the negative control group. As expected, plaque and gingivitis scores were lowest in the group that rinsed with chlorhexidine. The results extend previous observations on the efficacy of the zinc/triclosan system to maintain gingival health.

Dose response of chlorhexidine against plaque and comparison with triclosan

The optimum dose of chlorhexidine delivered by mouthrinse, which balances efficacy against local side-effects, is generally considered to be in the region of 20 mg 2 x daily. Unfortunately, there have been few dose-response studies for chlorhexidine mouthrinses and for these, only limited details are published. The aims of this study were to determine the dose response of chlorhexidine to plaque inhibition and position a 0.1% triclosan rinse within this model. 28 subjects took part in this 7-treatment, double-blind, randomised cross-over 4-day plaque regrowth study. The rinses were 0.01%, 0.05%, 0.1% and 0.2% chlorhexidine, 0.1% triclosan and minus active controls for chlorhexidine and triclosan. On day 1 from a zero plaque baseline, volunteers suspended tooth-cleaning and commenced supervised 2 x daily rinsing with 10 ml volumes of the allocated rinses. On Day 5, plaque was scored by index and area. Treatment differences between the 7 rinses were highly significant. A clear dose-response pattern was seen for chlorhexidine with mean plaque scores decreasing with increasing dose. Even at 0.01%, chlorhexidine showed considerable and significant plaque inhibition compared to control. Triclosan at 0.1% showed limited plaque inhibition and less than 0.01% chlorhexidine. The findings of this study suggest that consideration could be given to low concentration chlorhexidine rinses as adjuncts to oral hygiene.

Triclosan-containing mouthwashes--does the nature of the solvent influence their clinical effect?

The effect of triclosan on plaque inhibition was studied with various solvents. Eight subjects used the solutions as mouthwashes twice daily for 4 days while refraining from any other form of oral hygiene. Bacteriologic tests were also done with the same solutions. The study showed that the nature of the substance used to dissolve triclosan may be of clinical significance. Solutions of triclosan in polyethylene glycol, glycerol, or 3% sodium lauryl sulfate (SLS) alone showed marked antiplaque effect. (The first two solutions both contained 1.5% SLS). However, triclosan dissolved in Tween 80 had only a negligible clinical effect. In vitro experiment showed that antibacterial tests did not correlate well with clinical data. It is proposed that the nature of the micelles of the detergents which are used to dissolve triclosan is of significant importance. Strongly charged micelles such as SLS show clinical effect, whereas less charged micelles of SLS/Tween 80 or uncharged micelles of Tween 80 alone appear not to have this effect.

A dose-response study of triclosan mouthrinses on plaque regrowth

Triclosan is used in toothpastes and mouthrinses as a plaque inhibitory agent. The concentrations used and therefore the dose of triclosan varies between products and there is, as with most plaque inhibitory agents, little information on the dose response of this agent. The purpose of this investigation was to measure the plaque inhibitory properties of triclosan in a simple mouthrinse formulation over a range of concentrations and therefore doses. The study was a 5 treatment, double-blind, Latin-square randomised, minus-active controlled design balanced for residual effects. The formulations were 0.01%, 0.05%, 0.1% and 0.2% triclosan in 0.5% sodium carbonate and 5% alcohol aqueous solutions, used as 10 ml, 1-min rinses 2 x daily, without tooth-brushing. 2 groups each of 15 healthy volunteers rinsed during alternate 4-day treatment, 1-week washout periods with the allocated rinses. From a zero-plaque baseline on Day 1, plaque was scored by index and area on Day 5. A dose response pattern of decreasing plaque indices and particularly areas, with increasing triclosan dose was observed. However, by far the largest sequential drop in plaque scores occurred between 0.1% and 0.2% triclosan treatments. Extending the dose-response study to higher concentrations is considered impractical if not unjustifiable, because of potential harmful local side-effects and compliance difficulties. Dose-response studies to assess the agents thought to potentiate triclosan would seem warranted.

Effects of oral rinsing with triclosan and sodium lauryl sulfate on dental plaque formation: a pilot study

Mouthwashes containing 0.3% or 0.15% triclosan in combination with 1.5% sodium lauryl sulfate (SLS) produced a significant reduction in plaque formation in a test panel of 11 students who refrained from oral hygiene during the test periods, during which they rinsed twice daily with different mouthwashes. Pl.I. was evaluated after each test period. A mouthwash containing only 1.5% SLS inhibited plaque to almost the same degree. In both cases, the major effect was on the buccal/lingual surfaces, where score 2 was changed to score 0. Addition of triclosan appeared to reduce the untoward side-effects of mouth-washes containing SLS alone (i.e. desquamation and a burning sensation in the mouth).