Oral mucosal desquamation caused by two toothpaste detergents in an experimental model

Comparative evaluation of six commercial adult toothpaste formulations reveals cytotoxicity and altered functions in a human oral melanocyte model: an in vitro study

This study aims to compare six commercial adult toothpaste (labeled as A, B, C, D, E, and F) for cytotoxicity and melanocyte function alterations in vitro using primary human epidermal melanocytes from a Caucasian donor (HEMn-LP cells) as a model of oral melanocytes. Cells were incubated with toothpaste extracts (50% w/v) in culture media at dilutions (1:25, 1:50, 1:100, 1:200, 1:500, 1:800, and 1:1000) for 24 h. MTS and LDH assays were used to assess cytotoxicity. The effects of noncytotoxic toothpaste concentrations on melanocyte functional endpoints were then examined using spectrophotometric methods. All toothpaste showed concentration-dependent cytotoxicity that was heterogeneous across toothpaste containing SLS detergent. IC50 values of cytotoxicity followed the order: A = E > C > B > D > F. To compare toothpaste, they were tested at 1:800 and 1:1000 dilutions that were noncytotoxic after 24 h. None of the toothpaste affected cellular melanin production. However, toothpaste A, C, and D suppressed tyrosinase activity at both dilutions, while toothpaste B suppressed tyrosinase activity only at 1:800 dilution. Toothpaste A, C, E, and F elevated ROS production at 1:800 dilution, with no change at 1:1000 dilution. Toothpaste has a heterogeneous effect on melanocytes. Toothpaste B, E, and F at 1:1000 dilution were the safest as they did not alter melanocyte functions at this dilution, although toothpaste F is the least cytotoxic of these. Future studies are necessary to expand these results in a physiological environment of oral tissue. The findings of this study provide novel insight into the biocompatibility studies of toothpaste on oral melanocytes. They can aid dental practitioners and consumers in selecting noncytotoxic toothpaste that do not contribute to ROS generation by melanocytes in the oral cavity or lead to cytotoxicity and impaired cellular function.

Toothpastes for children and their detergent contents affect molecular mechanisms of odontogenesis in zebrafish embryos

We aimed to evaluate how different types of toothpaste (TP) for children affected molecular mechanisms of odontogenesis in zebrafish embryos. Commercially available TPs were selected according to their detergent contents as the cocamidopropyl betaine (CAPB) containing TP (TP1) and sodium lauryl sulfate (SLS) containing TP (TP2). TP3 contained no detergent. Effects of SLS, and CAPB alone were also examined. TP and detergent concentrations affecting development were determined as 750 mg/L and 4 mg/L, respectively. Embryos were exposed to TP1, TP2, TP3, SLS, CAPB, and embryo medium (control) for 72 h post fertilization. Acetylcholinesterase (AChE) activity and oxidant-antioxidant parameters were analyzed spectrophotometrically. Expressions of tooth development genes were evaluated by reverse transcription PCR (RT-PCR). Intraocular distance, lower jaw, and ceratohyal cartilage length were displayed using Alcian Blue staining. axin2 and wnt10a expressions increased in SLS and TP2 groups. igf2a and eve1 expressions decreased in all groups except TP3. nrOb1 expression decreased in TP1, SLS, and CAPB groups. Oxidant-antioxidant balance was disturbed in all groups except TP3, evidenced by increased lipid peroxidation, nitric oxide. SLS, and CAPB groups were more affected in terms of AChE, glutathione-S-transferase, and superoxide dismutase; perturbations were observed in cartilage structures. Altered expression of tooth development gene axin2 correlated with wnt10a, and with changes in cartilage structures in SLS and TP2 groups. TP3 group presented no disruptions in oxidant-antioxidant balance. Our study shows the availability of externally developing zebrafish embryos in examining the effects of TP' contents on embryogenesis.

Microphysiological Modeling of Gingival Tissues and Host-Material Interactions Using Gingiva-on-Chip

Gingiva plays a crucial barrier role at the interface of teeth, tooth-supporting structures, microbiome, and external agents. To mimic this complex microenvironment, an in vitro microphysiological platform and biofabricated full-thickness gingival equivalents (gingiva-on-chip) within a vertically stacked microfluidic device is developed. This design allowed long-term and air-liquid interface culture, and host-material interactions under flow conditions. Compared to static cultures, dynamic cultures on-chip enabled the biofabrication of gingival equivalents with stable mucosal matrix, improved epithelial morphogenesis, and barrier features. Additionally, a diseased state with disrupted barrier function representative of gingival/oral mucosal ulcers is modeled. The apical flow feature is utilized to emulate the mechanical action of mouth rinse and integrate the assessment of host-material interactions and transmucosal permeation of oral-care formulations in both healthy and diseased states. Although the gingiva-on-chip cultures have thicker and more mature epithelium, the flow of oral-care formulations induced increased tissue disruption and cytotoxic features compared to static conditions. The realistic emulation of mouth rinsing action facilitated a more physiological assessment of mucosal irritation potential. Overall, this microphysiological system enables biofabrication of human gingiva equivalents in intact and ulcerated states, providing a miniaturized and integrated platform for downstream host-material and host-microbiome applications in gingival and oral mucosa research.

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.

Clinical assessment of various imaging systems for dental plaque scoring after the use of 3 different toothpastes

Purpose

This study was conducted to compare dental plaque scores obtained through clinical examinations and various imaging techniques, as well as to assess the effectiveness of herbal and conventional toothpastes for plaque removal.

Material and Methods

Thirty volunteers were divided into 3 groups. Each group was given a different toothpaste (from 2 herbal toothpastes and a conventional toothpaste) with which to brush their teeth for 21 days. Both initially and after brushing, dental plaque samples were collected, and plaque on the buccal surfaces of anterior teeth was scored using several imaging systems after staining with a disclosing agent. Specifically, digital dental photography, intraoral digital scanning, and FluoreCam imaging were employed to capture intraoral images. The Turesky Modified Quigley-Hein Plaque Index was used for clinical examination and image analysis. Quantitative polymerase chain reaction analyses and correlational assessments between clinical examination and imaging scores were conducted before and after toothpaste use. The Shapiro-Wilk test and Pearson correlations were utilized.

Results

The lowest mean value was observed in the clinical examination without staining, while the highest was obtained using the FluoreCam method. No significant change was found in the level of any microorganism assessed following toothpaste use (P<0.05), with the exception of a decrease in S. mutans levels after using conventional toothpaste (P<0.05).

Conclusion

Herbal toothpaste demonstrated plaque-removal effectiveness comparable to that of conventional toothpaste. The use of imaging methods for measuring plaque index has been suggested as a means to educate patients about plaque control and promote ongoing oral care.

Allergies Come Clean: The Role of Detergents in Epithelial Barrier Dysfunction

PURPOSE OF REVIEW

The prevalence and incidence of allergic disease have been rising in Westernized countries since the twentieth century. Increasingly, evidence suggests that damage to the epithelium initiates and shapes innate and adaptive immune responses to external antigens. The objective of this review is to examine the role of detergents as a potential risk factor for developing allergic disease.

RECENT FINDINGS

Herein, we identify key sources of human detergent exposure. We summarize the evidence suggesting a possible role for detergents and related chemicals in initiating epithelial barrier dysfunction and allergic inflammation. We primarily focus on experimental models of atopic dermatitis, asthma, and eosinophilic esophagitis, which show compelling associations between allergic disease and detergent exposure. Mechanistic studies suggest that detergents disrupt epithelial barrier integrity through their effects on tight junction or adhesion molecules and promote inflammation through epithelial alarmin release. Environmental exposures that disrupt or damage the epithelium may account for the increasing rates of allergic disease in genetically susceptible individuals. Detergents and related chemical compounds represent possible modifiable risk factors for the development or exacerbation of atopy.

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.

Cytotoxic effects of different detergent containing children's toothpastes on human gingival epithelial cells

Background

This study aimed to evaluate possible cytotoxic effects to gingival epithelial cells exposed to children toothpastes containing different detergent.

Methods

Tissues required for the isolation of human gingival epithelial cells were obtained by biopsy during the extraction of the impacted third molar tooth. Toothpaste solutions of different concentrations were prepared from five different children’s toothpastes with different detergent contents. Isolated gingival epithelial cells were stimulated with experimental groups consisting of toothpaste solutions (Colgate, Sensodyne, Splat, Nenedent, Perlodent) at different concentrations and a control group consisting of complete Dulbecco’s modified eagle medium. After the experiments, cell viability was evaluated using flow cytometry. 2 Way ANOVA was used to see the interaction effect of the main effects of toothpaste solution and concentration factors. Pairwise comparisons were made by Tukey post hoc tests. In the study, the significance level was taken as 0.05.

Results

As a result of the analysis, it was seen that the toothpaste solution and concentration factors and the interactions of these 2 factors were effective on the viable, early apoptotic, late apoptotic and necrotic cell rates. The statistically highest live cell ratios were detected in Splat’s toothpaste solutions (90.14% at 0.4% concentration) after the control group (90.82%) and the group with the lowest viability values was determined in Colgate group (75.74% at 0.4% concentration) (p < 0.05).

Conclusions

According to the results of the study, it was observed that toothpastes containing SLS affected the viability of cells more negatively than toothpastes with other detergent contents.

Effects of different detergent-containing children's toothpastes on the viability, osteogenic and chondrogenic differentiation of human dental periodontal ligament stem cells and gingival stem cells in vitro

BACKGROUND

Detergents are the most commonly used compounds in toothpastes due to their foaming and cleaning peoperties. This study aimed to investigate the effects of children's toothpastes with different detergent content on the viability, the osteogenic and chondrogenic differentiation potentials of human mesenchymal stem cells.

METHODS

The necessary tissues for human periodontal ligament mesenchymal stem cells (hPDLMSCs) and human gingival mesenchymal stem cells (hGMSCs) isolation were obtained during extraction of 10 impacted third molar teeth. The viability of the cells stimulated with different concentratiaons of Colgate, Sensodyne, Splat, Nenedent, Perlodent toothpaste solutions and complete Dulbocco's modified eagle medium (control group) were evaluated by using the flow cytometer. In addition, the osteogenic and chondrogenic differentiation potential of human gingival and periodontal ligament mesenchymal stem cells exposed to toothpaste solutions were examined morphologically. Datas were analyzed with IBM SPSS V23. One way ANOVA test was used to determine the differences between the groups for multiple comparisons, while the Tukey post-hoc test was used for pair wise comparisons in determining which groups differed.

RESULTS

A higher percentage of cell viability was detected in Control group at 20 %, 50 % and 80 % (p = 0.000) on hGMSCs. After the Control group, the highest cell viability ratios were observed in the detergent-free Splat group (p = 0.000) followed by the Sensodyne experimental group containing CABP (p = 0.000). While the cell viability rates in Nenedent group was found significantly higher than the Perlodent group at other concentrations except for 20 % concentration (p = 0.000). Colgate group had the lowest percentage of cell viability among the experimental groups at all concentrations on hPDMSCs (p = 0.000). The highest live cell ratios was detected in Control group (p = 0.000), followed by Splat and Sensodyne groups (p = 0.000). The cell viability ratios at 50 % concentration were higher in Perlodent group than Nenedent group (p = 0.000). The highest osteogenic and chondrogenic differentiation potential of mesenchymal stem cells stimulated with different toothpaste was determined in Control and Splat group.

CONCLUSIONS

As a result of the findings, it was observed that toothpaste containing SLS had a more negative effect on the viability of the cells and the differentiation potentials than the other groups.

Recent advances in the aetiology of recurrent aphthous stomatitis (RAS)

Recurrent aphthous stomatitis (RAS) is the most common disease of oral mucosa, which almost attacks each individual once in their lifespan. Although plenty of factors have been suggested to play a role in the pathogenesis of RAS, the aetiology of RAS is still controversial, which might lead to limited clinical therapies in accordance with each RAS patient. This review mainly illustrates recent advances in potential causes associated with RAS in detail. Deeper comprehension of the aetiology of RAS will support doctors and researchers to make a better management of RAS patients and to discover new treatments. The aetiology of RAS is complicated, hence we should take a comprehensive view into its aetiology, with multiple potential factors being considered. Sample collection of RAS patients have greatly limited the progress in the aetiology of RAS. A research model of multiagency cooperation can help achieve perfect sample collection of year-round and multiposition.

Stannous Fluoride Effects on Enamel: A Systematic Review

In recent years there has been a lot of talk about toothpastes with a particular chemical compound: stannous fluoride (SnF2). Its presence is currently still highly controversial, as the latter could have negative health effects. The different companies that produce toothpastes express its dosage in ppm. The purpose of this systematic literature review is to analyze all randomized clinical trials in the literature over the last 10 years and to draw clear results on the function of stannous fluoride, for this purpose the authors performed a Mann-Whitney U Test.

MATERIALS

The first analysis of the literature produced a number greater than 800 results, subsequently applying the inclusion and exclusion criteria, and following a manual analysis of the results, 26 manuscripts have been obtained.

RESULTS

From the results analyzed in this review, it could be shown that stannous fluoride does not present important contraindications, if not those commonly reported for fluorine. A meta-analysis on enamel loss has been conducted, it shows that SnF2 products provide better results with a p < 0.05 value.

CONCLUSION

This compound could have significant effects in favor of erosion and recalcification of the enamel, on the biofilm formation, gingival inflammation, and in addition, it could be an important aid in the removal of tooth stains and halitosis.

A randomised clinical study comparing the effect of Steareth 30 and SLS containing toothpastes on oral epithelial integrity (desquamation)

OBJECTIVE

To compare the clinical effect of toothpastes containing Steareth 30 and SLS (sodium lauryl sulphate) surfactants on oral epithelial integrity (desquamation) using a new Oral Mucosal Sloughing Index (OMSI).

METHODS

30 volunteers participated in a single centre, double-blind, randomised, crossover clinical study. After a lead-in, subjects were allocated to the first test toothpaste, which was applied to the maxilla via a cap splint, followed by whole mouth brushing with the respective toothpaste and rinsing with the toothpaste slurry. Soft desquamation (lesion status) was assessed using a novel Oral Mucosal Sloughing Index (OMSI). Soft tissue status was measured at baseline (prior to test product use), 30 min following test product application and 4 days later following "at home" use of test toothpaste. After a wash out period, soft tissue assessment and product use were repeated for the remaining toothpaste.

RESULTS

Using the OMSI, 30 min post-application, significantly fewer lesion counts (all sites) were observed for the Steareth 30 toothpaste compared to SLS toothpaste (p < 0.0001). Additionally, 30 min after toothpaste use, the average lesion severity score was significantly lower for the Steareth 30 toothpaste compared to SLS toothpaste (p < 0.0001). There were no significant differences in lesion status at baseline or following 4 days of "at home" use of the toothpastes. No product related adverse events were reported.

CONCLUSION

Using an Oral Mucosal Sloughing Index for assessment, application of a toothpaste containing Steareth 30 generated significantly less transient soft tissue desquamation (fewer lesion counts and lower severity) than a toothpaste containing SLS.

CLINICAL SIGNIFICANCE

Treatment with a toothpaste containing Steareth 30 surfactant generated fewer transient soft tissue lesions (lower desquamation) compared to a toothpaste containing SLS surfactant.

Limited Evidence Suggests That Patients With Recurrent Aphthous Stomatitis May Benefit From Using Sodium Lauryl Sulfate-free Dentifrices

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Effect of sodium lauryl sulfate on recurrent aphthous stomatitis: A systematic review. Alli BY, Erinoso OA, Olawuyi AB. J Oral Pathol Med. 2019;48(5):358-64.

SOURCE OF FUNDING

None. The authors declared no conflict of interest.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data from double-blind randomized controlled trials.

Oral mucosal peeling related to dentifrices and mouthwashes: A systematic review

Background

The aim of this systematic review was to summarise the clinical information available about oral mucosal peeling (OMP) and to explore its aetiopathogenic association with dentifrices and mouthwashes.

Material and Methods

PICOS outline: Population: subjects diagnosed clinically and/or pathologically. Intervention: exposition to oral hygiene products. Comparisons: patients using products at different concentrations. Outcomes: clinicopathological outcomes (primary) and oral epithelial desquamation (secondary) after use. Study design: any. Exclusion criteria: reports on secondary or unpublished data, in vitro studies. Data were independently extracted by two reviewers.

Results

Fifteen reports were selected from 410 identified. Descriptive studies mainly showed low bias risk, experimental studies mostly an “unclear risk”. Dentifrices or mouthwashes were linked to OMP, with an unknown origin in 5 subjects. Sodium lauryl-sulphate (SLS) was behind this disorder in 21 subjects, tartar-control dentifrices in 2, and flavouring agents in 1 case. Desquamation extension was linked to SLS concentration. Most cases were painless, leaving normal mucosa after desquamation. Tartar-control dentifrices caused ulcerations more frequently.

Conclusions

OMP management should consider differential diagnosis with oral desquamative lesions, particularly desquamative gingivitis, with a guided clinical interview together with pathological confirmation while discouraging the use of the product responsible for OMP.

Key words:Systematic review, oral mucosal peeling, dentifrices, sodium lauryl-sulphate, oral hygiene products.

Assessment of the impact of aerosol from a potential modified risk tobacco product compared with cigarette smoke on human organotypic oral epithelial cultures under different exposure regimens

Cigarette smoke (CS) is affecting considerably the oral mucosa. Heating, instead of burning, tobacco reduces consistently the amount of toxic compounds and may exert a lower impact on oral health than combusted cigarettes. The carbon-heated tobacco product 1.2 (CHTP1.2) is a potential modified risk tobacco product (MRTP) based on heat-not-burn technology. Using a systems toxicology assessment framework, we compared the effects of exposure to CHTP1.2 aerosol with those of CS from a reference cigarette (3R4F). Human organotypic cultures derived from buccal and gingival epithelia were exposed acutely (28-min) or repeatedly (28 min/day for 3 days), respectively, to two matching concentrations of CHTP1.2 aerosol or 3R4F CS, and a non-diluted (100%) CHTP1.2 aerosol. The results showed an absence of cytotoxicity, reduction in pathophysiological alterations, toxicological marker proteins, and inflammatory mediators following exposure to CHTP1.2 aerosol compared with 3R4F CS. Changes in mRNA and miRNA expression were linked by an integrative analysis approach, suggesting a regulatory role of miRNAs in several smoke/disease-relevant biological processes induced by 3R4F CS. The identification of mechanisms by which potential MRTPs can reduce the impact of tobacco use on biological systems is of great importance in understanding the molecular basis of the smoking harm reduction paradigm.

Systems Toxicology Assessment of the Biological Impact of a Candidate Modified Risk Tobacco Product on Human Organotypic Oral Epithelial Cultures

Cigarette smoke (CS) has been reported to increase predisposition to oral cancer and is also recognized as a risk factor for many conditions including periodontal diseases, gingivitis, and other benign mucosal disorders. Smoking cessation remains the most effective approach for minimizing the risk of smoking-related diseases. However, reduction of harmful constituents by heating rather than combusting tobacco, without modifying the amount of nicotine, is a promising new paradigm in harm reduction. In this study, we compared effects of exposure to aerosol derived from a candidate modified risk tobacco product, the tobacco heating system (THS) 2.2, with those of CS generated from the 3R4F reference cigarette. Human organotypic oral epithelial tissue cultures (EpiOral, MatTek Corporation) were exposed for 28 min to 3R4F CS or THS2.2 aerosol, both diluted with air to comparable nicotine concentrations (0.32 or 0.51 mg nicotine/L aerosol/CS for 3R4F and 0.31 or 0.46 mg/L for THS2.2). We also tested one higher concentration (1.09 mg/L) of THS2.2. A systems toxicology approach was employed combining cellular assays (i.e., cytotoxicity and cytochrome P450 activity assays), comprehensive molecular investigations of the buccal epithelial transcriptome (mRNA and miRNA) by means of computational network biology, measurements of secreted proinflammatory markers, and histopathological analysis. We observed that the impact of 3R4F CS was greater than THS2.2 aerosol in terms of cytotoxicity, morphological tissue alterations, and secretion of inflammatory mediators. Analysis of the transcriptomic changes in the exposed oral cultures revealed significant perturbations in various network models such as apoptosis, necroptosis, senescence, xenobiotic metabolism, oxidative stress, and nuclear factor (erythroid-derived 2)-like 2 (NFE2L2) signaling. The stress responses following THS2.2 aerosol exposure were markedly decreased, and the exposed cultures recovered more completely compared with those exposed to 3R4F CS.

In vitro Effect of Mouthrinse Containing Essential Oils on Proliferation and Migration of Gingival Epithelial Cells

We aimed to investigate in vitro the effects of mouthrinses containing essential oils (EOs) on proliferation and migration of gingival epithelial cells. Human gingival epithelial cells were treated with predetermined dilutions of commercially available EO mouthrinses with or without ethanol and a mouthrinse containing cetyl pyridinium chloride (CPC) for 60 s. Cell proliferation was evaluated using WST-1 assay. Cell migration was assessed using a wound closure model. Within 10 s of exposure to EO mouthrinse without ethanol, the epithelial cells became aberrant and shrank. No statistically significant difference in cell migration or proliferation was observed among cells pretreated by the EO mouthrinse with ethanol, CPC mouthrinse and control (phosphate buffered saline). In contrast, the EO mouthrinse without ethanol significantly reduced cell proliferation (p < 0.001) to approximately 20% relative to control. As for the EO mouthrinse without ethanol, it was not possible to assess its effect on cell migration using this model, because treated cells could be easily detached from the culture plate upon scratch, possibly because of the surfactant ingredient in the formulation. Within the limitations of the study, the EO mouthrinse with ethanol exerted no inhibitory effect on proliferation and migration of the gingival epithelial cells. Copyright © 2016 John Wiley & Sons, Ltd.

Dentifrices for children differentially affect cell viability in vitro

Objectives

Child dentifrices vary in their composition, with possible differential impacts on cells in the oral soft tissue. While cytotoxicity studies have been performed on adult dentifrices, no respective studies have thus far been reported on child dentifrices.

Material and methods

Seventeen commercial dentifrices for children up to 12 years of age were evaluated with respect to their in vitro cytotoxicity on gingival fibroblasts, oral squamous cell carcinoma HSC-2 cells, and L929 mouse fibroblasts. Proliferation was analyzed and live-dead staining was performed.

Results

Ten child dentifrices greatly reduced cell viability with LC50 values below 5 %. Four dentifrices showed a moderate cytotoxicity with LC50 values between 5 and 20 %. Three child dentifrices showed almost no cytotoxicity with LC50 values above 95 %. The results of the assays for proliferation and live-dead staining supported these findings.

Conclusions

The different composition of the child dentifrices translated into a broad spectrum of in vitro cytotoxicity on cells of the oral cavity.

Clinical relevance

The in vitro data provide the scientific foundation for further in vivo research testing the clinical relevance of the present findings.

The effectiveness of dentifrices without and with sodium lauryl sulfate on plaque, gingivitis and gingival abrasion--a randomized clinical trial

OBJECTIVES

The aim of this study was to compare the efficacy of a dentifrice without sodium lauryl sulfate (SLS) to a dentifrice with SLS in young adults aged 18-34 years on gingivitis.

MATERIAL AND METHODS

One hundred twenty participants (non-dental students) with a moderate gingival inflammation (bleeding on probing at 40-70 % of test sites) were included in this randomized controlled double blind clinical trial. According to randomization, participants had to brush their teeth either with dentifrice without SLS or with SLS for 8 weeks. The primary outcome was bleeding on marginal probing (BOMP). The secondary outcomes were plaque scores and gingival abrasion scores (GA) as well as a visual analogue scale (VAS) score at exit survey. Baseline and end differences were analysed by univariate analysis of covariance (ANCOVA) test, between group differences by independent t test and within groups by paired sample t test.

RESULTS

BOMP improved within groups from on average 0.80 at baseline to 0.60 in the group without SLS and to 0.56 in the group with SLS. No statistical difference for BOMP, plaque and gingival abrasion was found between both groups. VAS scores for taste, freshness and foaming effect were significantly in favour of the SLS-containing dentifrice.

CONCLUSION

The test dentifrice without SLS was as effective as a regular SLS dentifrice on gingival bleeding scores and plaque scores. There was no significant difference in the incidence of gingival abrasion.

CLINICAL RELEVANCE

In patients diagnosed with gingivitis, a dentifrice without SLS seems to be equally effective compared to a dentifrice with SLS and did not demonstrate any significant difference in gingival abrasion. In patient with recurrent aphthous ulcers, the absence of SLS may even be beneficial. However, participants indicate that they appreciate the foaming effect of a dentifrice with SLS more.

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.

Relationship between toothpastes properties and patient-reported discomfort: crossover study

OBJECTIVES

This study aims to correlate patient-reported reactions with in vitro analyses of the pH, abrasive quality, and cytotoxicity of four toothpastes.

MATERIALS AND METHODS

One hundred twenty-one patients received non-identified samples of toothpaste to be used for 6 days and answered a questionnaire about their sensations. In vitro analysis: the pH of toothpastes was measured with a pH meter. The abrasivity of toothpastes was evaluated against composite resin specimens (n = 10). A toothbrushing machine was used to simulate wear, which was indirectly measured by mass loss using a scale. Cell culture media conditioned with toothpaste were used to assess the cytotoxicity. Confluent cells were kept in contact with the conditioned media or control for 24 h. The cell viability was measured using the 3-(bromide, 4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium (MTT)-reduction assay. The obtained data on the pH, weight loss, and cell viability were compared by ANOVA/Tukey's tests (p < 0.05).

RESULTS

With the exception of the bleaching effect paste, the Oral B® paste produced the highest frequencies of irritation reports, tooth sensitivity, taste discomfort, and texture discomfort in the clinical study; patients also reported rougher teeth, soft tissue peeling, dry mouth, thrush, tingling, and taste changes in response to this paste. The in vitro analysis demonstrated that Oral B® had the lowest pH, the highest abrasivity, and produced the lowest cell viability (p < 0.01).

CONCLUSION

Results suggest that low pH toothpastes that are highly abrasive and cytotoxic may cause undesirable reactions in patients.

CLINICAL RELEVANCE

Toothpaste's properties should be well known for indication to patient therefore minimizing discomfort reports.

The Bedside Oral Exam and the Barrow Oral Care Protocol: translating evidence-based oral care into practice

AIM

To introduce the Bedside Oral Exam (BOE) and the Barrow Oral Care Protocol (BOCP) to guide oral care for intensive care unit patients. Secondary aim: To explore quality improvement data for incidence of ventilator associated pneumonia (VAP), cost effectiveness of oral hygiene supplies and staff response to change in practice.

METHODS

Descriptive case design for implementation and evaluation of oral assessments and oral hygiene. Incidence of VAP and the cost of oral care supplies before and after implementation was compared. Staff responses were elicited both pre- and post-implementation.

RESULTS

Incidence of VAP fell significantly from 4.21 to 2.1 per 1000 ventilator days (p =.04). A cost savings of 65% was noted on a monthly basis for oral hygiene supplies. Staff reported increased satisfaction in providing oral hygiene with a combination of oral care products.

CONCLUSIONS

A significant reduction in VAP was noted using the BOCP. The BOE guided individualised oral care with contemporary supplies, including a tongue scraper, electric toothbrush, non-foaming toothpaste and oral moisturisers. Cost-effective, comprehensive oral care appears to be effective in reducing VAP. Further studies are needed to assess impact of oral hygiene on oral health and patient comfort.

Effects of a standard versus comprehensive oral care protocol among intubated neuroscience ICU patients: results of a randomized controlled trial

The purpose of the study was to compare changes in oral health during intubation until 48 hours after extubation in neuroscience intensive care unit (ICU) patients enrolled in a standard or a comprehensive oral care protocol. The effects of manual toothbrushing (standard group, n = 31) were compared with those of tongue scraping, electric toothbrushing, and moisturizing (comprehensive group, n = 25) in intubated patients in a neuroscience ICU in a 2-year randomized clinical trial. Oral health was evaluated based on the Oral Assessment Guide (OAG) on enrollment, the day of extubation, and 48 hours after extubation. There were no significant differences in the frequency of the oral care protocol. Protocol compliance exceeded 91% in both groups. The total OAG score and all eight categories significantly deteriorated (Friedman test, p < .001, Bonferroni corrected) in the standard oral care group and did not return to baseline after extubation. Large effect sizes were present at all three points in this group. The total OAG score deteriorated during intubation within the comprehensive protocol group (Friedman test, p < .004) but returned to baseline status after extubation. In four categories, the ratings on tongue, mucous membranes, gingiva, and teeth did not deteriorate significantly over time. Published oral care protocols are substandard in promoting and maintaining oral health in intubated patients. A comprehensive oral care protocol, using a tongue scraper, an electrical toothbrush, and pharmacological moisturizers, was more effective for oral hygiene throughout intubation and after extubation than manual toothbrushing alone.

Recurrent aphthous ulcers--a Toll-like receptor-mediated disease?

BACKGROUND

Recurrent aphthous ulcer (RAU) is characterized by acute and painful inflammatory ulcerations, which heal spontaneously but tend to recur. Many pathogens have been proposed as causative agents, but none has been consistently proven. According to our hypothesis, RAU is an autoinflammatory disorder triggered by pathogen-associated molecular patterns (PAMPs) shared by different pathogenic and commensal microbes.

METHODS

PAMP-reactive Toll-like receptors (TLRs) were mapped in oral epithelium in healthy controls compared to RAU.

RESULTS

In controls, the superficial epithelium formed a TLR(-), a PAMP non-reactive physical barrier zone, but all TLRs were found deeper in the epithelium, usually restricted to suprabasal and basal cell layers. In RAU, the epithelial TLR polarity was lost: TLRs 1, 2, 5, 7, and 8 were found throughout the epithelium, but also TLRs 4, 6, and 10 extended higher up than normally, whereas TLR-3 was almost lost in RAU. In RAU lesions, connective tissue stroma was heavily infiltrated by TLR(+) inflammatory cells.

CONCLUSIONS

Normal TLR architecture prevents inflammatory responses against normal microbes but still contains a deep TLR(+) , PAMP-reactive dormant defense zone. In RAU, the TLR(+), PAMP-reactive zone extends to surface or subsurface exposed to microbial PAMPs. TLR reactivity is further enhanced by recruitment of inflammatory leukocytes forming a new deep line of defense. The organization of the TLR system in healthy mucosa and its changes in RAU are compatible with active pathogenic involvement of TLRs, which together with the typical clinical picture and course suggest that RAU is a TLR-mediated disease.

Possible Association between Th1 Immune Polarization and Epithelial Permeability with Toll-Like Receptors 2 Dysfunction in the Pathogenesis of the Recurrent Aphthous Ulceration

Recurrent Aphthous Ulceration (RAU) is a chronic oral inflammatory disease that affects approximately 25% of the general population. The etiology of the disease is unknown; however, factors that favor the onset of RAU have been correlated with a Th1 immune polarization, while factors that reduce RAU episodes have been associated with down regulation of immune reaction or stimulation of the peripheral tolerance. In this context, the integrity of the epithelial barrier is also fundamental for the prevention of the disease and conditions that augment its permeability or produce disruption are considered potential triggers. The key factor responsible for increased susceptibility is unclear, though a deficiency of Toll-like receptor (TLR) activity seems to be a good candidate. TLRs are a group of membrane proteins that recognize conserved molecules derived from bacterial, virus, fungal, or host tissues. Particularly, the TLR2 is involved in both immune regulation and control of epithelial barrier integrity. Thus, based on literature review, we showed evidences that correlate the TLR2 dysfunction and the diverse predisposing factors with the elements considered critical for disease pathogenesis: the Th1 immune reaction and the increased epithelial permeability.

Toothpaste detergents: a potential source of oral soft tissue damage?

OBJECTIVES

Toothpastes are thought to be of benefit to cleaning teeth but may also have the potential for soft tissue damage at least on the cellular level by inclusion of detergents in their formulation. The aim of this study was to observe the in vitro response of oral mucosa like cells to toothpaste detergents.

METHODS

TERT-1 keratinocytes were exposed to varying concentrations of the detergents Adinol, Sodium Lauryl Sulphate, Tego Betain and Pluronic as well as PBS and culture medium. After 2-min exposure, cells were washed and incubated in fresh medium for 24 h. Cell death was then spectrophotometrically measured using an MTT assay.

RESULTS

Except for Pluronic, cell viability was markedly reduced for all detergents at all increasing concentrations when compared to the positive medium control. Cells treated with Pluronic were stimulated compared to medium alone.

CONCLUSIONS

These in vitro data suggest that some detergents may have the potential to cause soft tissue damage in the mouth. Although in vivo, saliva may neutralize such effects. The results for Pluronic suggest a possible oxidative stress response that bears further study.

Safety and effectiveness of topical dry mouth products containing olive oil, betaine, and xylitol in reducing xerostomia for polypharmacy-induced dry mouth

Polypharmacy is a common cause of salivary hypofunction, producing symptoms of dry mouth or xerostomia, especially among older populations. As the number of older people continues to increase, polypharmacy-induced salivary hypofunction is becoming an increasing problem. Many over-the-counter products are available for relieving symptoms of dry mouth, but few have been tested in controlled clinical investigations. The purpose of this investigation was to evaluate the safety and efficacy of a group of topical dry mouth products (toothpaste, mouth rinse, mouth spray and gel) containing olive oil, betaine and xylitol. Forty adults were entered into this single-blinded, open-label, cross-over clinical study and 39 completed all the visits. Subjects were randomly assigned at baseline to using the novel topical dry mouth products daily for 1 week, or to maintain their normal dry mouth routine care. After 1 week, they were crossed over to the other dry mouth regimen. The results demonstrated that the use of the novel topical dry mouth products increased significantly unstimulated whole salivary flow rates, reduced complaints of xerostomia and improved xerostomia-associated quality of life. No clinically significant adverse events were observed. These data suggest that the daily use of topical dry mouth products containing olive oil, betaine and xylitol is safe and effective in relieving symptoms of dry mouth in a population with polypharmacy-induced xerostomia.

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.

Organotypic human oral tissue models for toxicological studies

Three-dimensional models of the human oral epithelia have been developed to test the irritation of oral-care products and to provide systems to study the pathology of the oral cavity. The in vitro tissue models, cultured using normal oral epithelial cells and serum free medium, adopt a buccal or gingival phenotype. The buccal tissue (designated ORL-200) is 8-12 cell layers thick and non-cornified; the gingival tissue (designated GIN-100) is 9-13 layers thick and cornified at the apical surface. The tissues express cytokeratins 13 and 14 similar to their corresponding native oral tissues. The MTT viability assay was used to assess inter-lot and intra-lot reproducibility. The MTT average intra-lot coefficient of variation (CV) was less than 10% for both tissues and the time required to reduce tissue viability by 50% (ET-50) following application of 1% Triton-X 100 averaged 1.02+/-0.33 h (n=26) and 7.97+/-0.80 h (n=14) for the buccal and gingival tissues, respectively. The utility of the buccal tissue for irritation studies was examined by testing prototype dentifrice formulations and commercially available products including mouthwashes, toothpastes, and oral cleansers. Use of the MTT ET-50 assay and cytokine release clearly differentiated between the formulations and the oral care products. In conclusion, the oral tissue models represent highly reproducible, non-animal means to screen the irritation potential of newly developed oral care products and should be useful to study the innate immunity, biology, and pathology of the oral mucosa.

Efficacy of the BioXtra dry mouth care system in the treatment of radiotherapy-induced xerostomia

INTRODUCTION

Xerostomia is a common complication of radiotherapy for head and neck cancer. Symptomatic treatment consists of stringent oral hygiene to prevent oral infections and saliva substitutes to increase comfort. The aim of the study was to evaluate the clinical effectiveness of the BioXtra (BX) dry mouth care system.

MATERIALS AND METHODS

A xerostomia questionnaire consisting of 3 parts (xerostomia symptom score, quality of life (QoL) survey and visual analogue scale (VAS)) was completed by 34 patients suffering from radiation-induced xerostomia, before and after 4 weeks of treatment with the BioXtra moisturizing gel, toothpaste and mouthwash.

RESULTS

The BioXtra products significantly diminished the most common symptoms of xerostomia. Mean VAS score at the start of treatment was 59.8. After treatment, this decreased to 36.4 (p < 0.001). Twenty-six patients (77%) responded to treatment, 11 of these patients (32%) reported a major improvement. Quality of life significantly improved under treatment: mean QoL score at the start was 59.4; this increased to 70.5 (p < 0.001). None of the 34 patients reported any adverse effects and all but 1 patient found the BX dry mouth care system easy to use.

CONCLUSIONS

The results of this study suggest that the BioXtra dry mouth care system is effective in reducing the symptoms of radiation-induced xerostomia and improving the quality of life of xerostomia patients, even if a proportion of the benefit is due to a placebo effect. However, further research is necessary to evaluate the efficacy of BioXtra on oral health.

The ability of betaine to reduce the irritating effects of detergents assessed visually, histologically and by bioengineering methods

BACKGROUND/AIMS

A novel approach for reducing the undesired irritating properties of detergents on skin might be offered by betaine, which is a natural product derived from the sugar beet. The aim of the study was to explore the ability of betaine to reduce the irritating effects of two surfactants, sodium lauryl sulphate (SLS) and cocoamidopropylbetaine (CAPB). For evaluation of changes in skin reactions visual scoring, electrical impedance, transepidermal water loss and histology were used.

METHODS

Twenty-one healthy subjects were patch tested for 24 h with SLS and CAPB alone and together with betaine, betaine alone, and the two controls distilled water and an unoccluded test site on both volar forearms. Responses were evaluated by measuring electrical impedance and transepidermal water loss before exposure and 24 h after the removal of the test substances, and also by visual inspection and histology. The electrical impedance device enables measurements at 31 frequencies and relevant information was extracted from the spectra using four indices.

RESULTS

CAPB was found to be less irritating than SLS. The used detergents gave rise to distinctive impedance patterns also reflected by different types of histopathological skin responses. After the adding of betaine, the irritant reaction decreased for both detergents.

CONCLUSIONS

Betaine is a promising ingredient to reduce the side effects of detergents and electrical impedance is a suitable tool both to quantify the degree of irritation as well as to differentiate between various types of reactions.

Betaine reduces the irritating effect of sodium lauryl sulfate on human oral mucosa in vivo

Our aim was to evaluate whether betaine has a protective effect during exposure of the human oral mucosa in vivo to sodium lauryl sulfate (SLS) or cocoamidopropylbetaine (CAPB) as measured with a multifrequency electrical impedance spectrometer (EI). Both detergents were used at the concentration of 2.0% w/v with and without 4.0% w/v betaine in distilled water in 20 volunteers, and 0.5% and 1.0% w/v SLS combined with 4.0% w/v betaine in 5 volunteers. EI measurements were taken before application of the test solutions, after their removal, and every 15 min up to 45 min. Both 0.5% and 1% SLS solutions showed a significant reduction in 3 of the 4 indices, indicating mucosal irritation after the 15-min exposure (P < 0.05), whereas 2% SLS did so in all 4 indices (P < 0.001). Betaine had no effect on the detergent-induced decline with either the 2% or the 0.5% SLS solutions. However, when combined with the 1% SLS solution, betaine significantly (P < 0.05) reduced mucosal irritation by abolishing decreases in indices MIX (magnitude index) and IMIX (imaginary part index) and lowering it for PIX (phase index). The 2% CAPB solution showed a significant (P < 0.05) reduction in all 4 indices after the 15-min exposure, but the effect was significantly weaker than that of 2% SLS (P < 0.05). Betaine did not reduce the irritating effect of 2% CAPB. These findings can be used in the development of less irritating products for oral health care.

The effect of sodium lauryl sulphate, triclosan and zinc on the permeability of normal oral mucosa

OBJECTIVE

Sodium lauryl sulphate (SLS), an important component in many oral health products, is well established as a contact irritant in skin. Recent studies have suggested that it may also affect the structural integrity of oral mucosa. SLS is rarely used alone in dentifrices or mouthwashes and the aim of this study was to establish the effect of SLS both alone and in combination with Triclosan (TCN) and zinc (Zn) on the permeability barrier properties of normal human oral mucosa.

METHOD

Ventral tongue mucosa was obtained from nine males and seven females within 60 h of death and stored frozen at -70 degrees C until use. The permeability of the tissue to tritiated water was measured after pretreatment for 15 min with SLS alone, SLS/TCN, SLS/Zn and a SLS/TCN/Zn mixture. Treatment with distilled water (DW) served as control. The histological appearance of the tissue before and after treatment was also examined by light microscopy.

RESULTS

SLS treatment caused a significant increase in water permeability compared to control tissue (Kp = 11.7 +/- 1.00; 4.96 +/- 0.50 respectively; P < 0.005). Treatment with a SLS/TCN/Zn mixture, however, had no effect on the permeability to water (Kp = 5.5 +/- 0.56). Histological examination revealed that tissue exposed to SLS had a marked disruption of the epithelial surface whilst tissue treated with a SLS/TCN/Zn mixture was indistinguishable from controls.

CONCLUSION

Although mucosa exposed to SLS alone showed an increase in permeability to water, the addition of TCN and Zn to SLS appeared to prevent this effect. As SLS is included in some dental products to solubilise compounds such as TCN, its presence may have no effect on the permeability barrier property of oral mucosa.

Betaine-containing toothpaste relieves subjective symptoms of dry mouth

Subjects with dry mouth often experience irritation of the oral mucosa when using sodium lauryl sulfate containing products for oral hygiene. Betaine, or trimethylglycine, reduces skin-irritating effects of ingredients of cosmetics such as sodium lauryl sulfate. The aim of the present study was to compare the effects of a betaine-containing toothpaste with a regular toothpaste on the oral microbial flora, the condition of the oral mucosa, and subjective symptoms of dry mouth in subjects with chronic dry mouth symptoms. Thirteen subjects with chronic dry mouth symptoms and with a paraffin-stimulated salivary flow rate < or = 1 mL/min participated in the double-blind crossover study. Ten subjects had a very low salivary flow rate (< or = 0.6 mL/min). The subjects used both experimental toothpastes (with or without 4% betaine) twice a day for 2 weeks. Oral examinations and microbiologic sample collections were made at the base lines preceding the two experimental periods and at the end. Standardized questions on subjective symptoms of dry mouth were used when the subjects were interviewed at the end of the two experimental periods. No study-induced significant changes were observed in the microbiologic variables (plaque index, mutans streptococci, lactobacilli, Candida species) or in the appearance of the oral mucosa. The use of the betaine-containing toothpaste was, however, associated with a significant relief of several subjective symptoms of dry mouth. Betaine appears thus to be a promising ingredient of toothpastes in general and especially of toothpastes designed for patients with dry mouth.

Electrical impedance. A method to evaluate subtle changes of the human oral mucosa

In a previous study, we mapped the differences in electrical impedance between various anatomical locations in the oral mucosa. We now explore the ability of the impedance technique to detect mild reactions in the buccal mucosa induced by the irritant sodium lauryl sulphate. This substance was applied for 15 min at a concentration of 2% to the mucosa of 26 healthy subjects. A contralateral site was used as a control. Responses were evaluated by measuring electrical impedance before exposure and after removal of the irritant, and also by visual inspection and histology. Magnitude and phase of impedance were determined in the frequency range 1 kHz to 1 MHz at 5 depth settings, and 4 physically distinct indices were calculated from the impedance data. The results showed the response to be at its maximum 5 min after removal of the test chamber, for all indices. These changes were statistically significant, whereas visual and histological alterations were slight or negligible. We conclude that the electrical impedance technique is capable of detecting mucosal changes in the invisible or barely visible range, and that the mucosal response to sodium lauryl sulphate is well characterised by the 4 indices.

Detachment of linking film bacteria from enamel surfaces by oral rinses and penetration of sodium lauryl sulphate through an artificial oral biofilm

The biofilm mode of growth protects plaque micro-organisms against environmental attacks, such as from antimicrobials or detergents. Dental plaque is linked to enamel through the adhesion of initial colonizers. Once this link is disrupted, the entire plaque mass adhering to it detaches. Experiments in a parallel-plate flow chamber demonstrated that bacteria adhering to saliva-coated enamel could not be stimulated to detach by perfusion of the flow chamber with two traditional mouthrinses (Corsodyl and Scope), whereas perfusion with a prebrushing rinse (Plax) or its detergent components stimulated detachment from saliva-coated enamel of a wide variety of bacterial strains. Following perfusion of the flow chamber with the mouthrinses, little additional detachment of adhering bacteria by the passage of a liquid-air interface occurred. After perfusion with the prebrushing rinse, however, significant numbers of still-adhering bacteria could be stimulated to detach by passage of a liquid-air interface, indicating that Plax had weakened their adhesive bond. The ability of Plax or its detergent components to detach plaque bacteria is not always obvious from in vivo experiments, and reports on its clinical efficacy are inconsistent. Likely, antimicrobials or detergents are unable to penetrate the plaque and reach the linking film bacteria, as demonstrated here by Fourier transform infrared spectroscopy.

The influence of triclosan, zinc or propylene glycol on oral mucosa exposed to sodium lauryl sulphate

Previous studies on triclosan treatment of skin exposed to sodium lauryl sulphate (SLS) indicated a protective rôle of zinc and an irritant effect of propylene glycol (PG). The aim was hence to examine whether zinc or PG also may affect SLS-induced oral mucosal reactions, and also to test the influence of zinc in combination with triclosan. 15 healthy dental students participated in this double-blind crossover study performed in 2 experimental series. They were rinsing 2x daily with solutions containing (A) 1.5% SLS, (B) 1.5% SLS/0.5% zinc citrate and (C) 1.5% SLS/PG (1:8) in experiment 1, and (D) 1.5% SLS/0.15% triclosan/0.3% zinc citrate and (E) 1.5% SLS/0.15% triclosan in experiment 2. Clinical evaluation by 2 examiners of degree of erythema and oral mucosal desquamations was then performed. The critical micellar concentration was also determined. SLS and SLS/PG, which were not different in effect, evoked significantly more erythematous reactions than SLS/Tri/Zn. This solution was numerically but not statistically better than SLS/Tri, and the latter also did lead to significantly less erythema than SLS/PG. In conclusion, the present study revealed no irritation of the oral mucosa due to PG, whereas a protective effect of zinc as well as the anti-inflammatory effect of triclosan were confirmed.

Skin reactions and irritation potential of four commercial toothpastes

Skin reactions to 4 toothpastes were tested in 19 healthy dental students in a double-blind study. The hypothesis was that common toothpaste brands with and without sodium lauryl sulfate (SLS) and triclosan and with different additives/emulgators differ in irritation potential. An occlusion test system on human skin was used. The toothpastes tested were A) Zendium (non-ionic detergent), B) Solidox F (SLS/polyethylene glycol), C) Colgate Total (triclosan/copolymer/SLS/propylene glycol), and D) Solidox G (triclosan/zinc citrate/SLS/polyethylene glycol). Toothpaste C was the greatest irritant, causing skin erythema in 16 of the 19 subjects, whereas toothpaste D gave no reactions. Toothpaste B provoked three reactions (two severe), whereas toothpaste A caused only one mild reaction. Although this study was carried out on skin and hence not directly applicable to the oral cavity, these and previous results may indicate that a toothpaste without propylene glycol and SLS may be preferred by susceptible persons.

The effect of toothpaste containing triclosan on oral mucosal desquamation. A model study

SLS-containing toothpaste has previously been shown to cause oral mucosal desquamations when used in an experimental cap splint model. The aim of the present study was to examine the effect of toothpastes containing SLS in combination with triclosan on oral mucosal desquamation in a similar cap splint model system. It has previously been shown that the antibacterial agent triclosan also may have anti-inflammatory properties. The concentration of triclosan in the experimental toothpastes was 0.3%, while SLS varied from 1.5% to 3%. No oral mucosal desquamations were observed after use of a 1.5% SLS 0.3% triclosan containing toothpaste, contrary to the positive control toothpaste that contained 1.5% SLS without triclosan. Furthermore, a statistically significant reduction in severe desquamations was observed after use of a toothpaste containing 3% SLS-0.3% triclosan compared with the positive control. It may thus be suggested that triclosan exerts a moderating effect on desquamative reactions caused by SLS and that the effect is dependent on the relative amount of triclosan and SLS in the toothpastes.

The effect of two toothpaste detergents on the frequency of recurrent aphthous ulcers

The aim of the present clinical double-blind crossover study was to investigate the effect of two different toothpaste detergents, sodium lauryl sulfate (SLS) and cocoamidopropyl betaine (CAPB), as compared with a detergent-free paste, on 30 patients with frequent occurrences of recurrent aphthous ulcers. The study consisted of three 6-week periods during which the patients brushed twice daily with the different test toothpastes. The localization and number of new ulcers were assessed. A significantly higher frequency of aphthous ulcers was demonstrated when the patients brushed with an SLS- than with a CAPB-containing or a detergent-free placebo paste. An SLS-free toothpaste may thus be recommended for patients with recurrent aphthous ulcers.