Dual protective effect of the association of plant extracts and fluoride against dentine erosion: In the presence and absence of salivary pellicle.

OBJECTIVES: To verify the protective effect of plant extracts associated with fluoride against dental erosion of dentine, in the presence and absence of a salivary pellicle. METHODS: Dentine specimens (n = 270) were randomly distributed into 9 experimental groups (n = 30/group): GT (green tea extract); BE (blueberry extract); GSE (grape seed extract); NaF (sodium fluoride); GT+NaF (green tea extract and NaF); BE+NaF (blueberry extract and NaF); GSE+NaF (grape seed extract and NaF); negative control (deionized water); and a positive control (commercialized mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the presence (P) or absence (NP) of salivary pellicle. The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (NP), 2 min immersion in experimental solutions, 60 min of incubation in saliva (P) or not (NP), and 1 min erosive challenge. Dentine surface loss (dSL-10 and dSL-total), amount of degraded collagen (dColl) and total calcium release (CaR) were evaluated. Data were analyzed with Kruskal-Wallis, Dunn's and Mann-Whitney U tests (p>0.05). RESULTS: Overall, the negative control presented the highest values of dSL, dColl and CaR, and the plant extracts showed different degrees of dentine protection. For the subgroup NP, GSE showed the best protection of the extracts, and the presence of fluoride generally further improved the protection for all extracts. For the subgroup P, only BE provided protection, while the presence of fluoride had no impact on dSL and dColl, but lowered CaR. The protection of the positive control was more evident on CaR than on dColl. CONCLUSION: We can conclude that the plant extracts showed a protective effect against dentine erosion, regardless of the presence of salivary pellicle, and that the fluoride seems to improve their protection.

Plant extracts have dual mechanism on the protection against dentine erosion: action on the dentine substrate and modification of the salivary pellicle.

To investigate the effect of some polyphenol-rich plant extracts on the protection of dentine against demineralization, both acting on the dentine and on the salivary pellicle. Dentine specimens (n = 180) were randomly distributed into 6 experimental groups (n = 30/group): Control (deionized water), Açaí extract, Blueberry extract, Green tea extract, Grape seed extract, and Sn2+/F- (mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the site of action of the substance: on the dentine surface (D) or on the salivary pellicle (P). The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (D), 2 min immersion in experimental substances, 60 min of incubation in saliva (P) or not (D), and 1 min erosive challenge. Dentine surface loss (DSL), amount of degraded collagen (dColl) and total calcium release were analyzed. Green tea, Grape seed and Sn2+/F- showed significant protection, with least DSL and dColl. The Sn2+/F- showed better protection on D than on P, whereas Green tea and Grape seed showed a dual mode of action, with good results on D, and even better on P. Sn2+/F- showed the lowest values of calcium release, not differing only from Grape seed. Sn2+/F- is more effective when acting directly on the dentine surface, while Green tea and Grape seed have a dual mode of action: with a positive effect on the dentine surface itself, but an improved efficacy in the presence of the salivary pellicle. We further elucidate the mechanism of action of different active ingredients on dentine erosion, where Sn2+/F- acts better on the dentine surface, but plant extracts have a dual mode of action, acting on the dentine itself as well as on the salivary pellicle, improving the protection against acid demineralization.

Pellicle modification with natural bioproducts: Influence on tooth color under erosive conditions.

Salivary pellicle was modified with bioproducts and we assessed the change in tooth color and the protection of enamel to erosion. Human enamel specimens were assigned to one of three solutions: grape seed extract or black tea (bioproducts), or deionized water (negative control); after which one half the specimens underwent erosive challenges. The specimens underwent 15 cycles involving salivary pellicle formation (10 min, 37°C), incubation in solution (2 min, 25°C), subsequent pellicle formation (90 min, 37°C). Half of the specimens was kept in a humid chamber and the other half was submitted to erosion (2 min, 1% citric acid). After 15 such cycles, the pellicle was removed. Tooth color and the surface reflection intensity were assessed after every five cycles and after pellicle removal. For non-eroded specimens, the exposure to bioproducts promoted significantly greater color change than the deionized water, with increases in yellow appearance. After pellicle removal, the color was similar in all non-eroded specimens. The bioproducts increased the surface reflection intensity over cycles. For the erosion-exposed specimens, erosion itself resulted in color change. Black tea and deionized water resulted in increased yellow appearance. Exposure to the bioproducts resulted in higher relative surface reflection intensity values over time, but only grape seed extract resulted in higher relative surface reflection intensity value at the time of pellicle removal. The bioproducts caused transient staining effect, which was reduced after pellicle removal. For enamel submitted to erosion, grape seed extract resulted in less color change and better protection of enamel against erosion than black tea or water.

Influence of periodic polyphenol treatment on the anti-erosive potential of the acquired enamel pellicle-A qualitative exploratory study.

OBJECTIVE: The aim of the present study was to investigate the impact of periodic polyphenol treatment on the ultrastructure and anti-erosive potential of an in-situ formed pellicle. METHODS: Subjects wore intraoral appliances with buccally and palatally fixed bovine enamel specimens. During 6 h of intraoral pellicle formation, 100 ml black tea or tannic acid was applied ex-vivo every 25 min for 5 min. Untreated pellicles served as control. After the trial, specimens were immersed in 0.1% or 1% citric acid for 60 s and analysed for calcium release with atomic adsorption spectrometry and ultrastructure with transmission electron microscopy. RESULTS: Specimens covered by pellicles treated with black tea or tannic acid released less calcium than untreated pellicles. Ultrastructural analyses reveal an increase in pellicle's thickness and density after treatment with polyphenols. CONCLUSIONS: Periodic polyphenol treatment of the pellicle modify its ultrastructure and increase its anti-erosive potential. CLINICAL SIGNIFICANCE: Consumption of polyphenolic beverages can enhance the anti-erosive potential of the enamel pellicle.

Preventive Applications of Polyphenols in Dentistry-A Review.

Polyphenols are natural substances that have been shown to provide various health benefits. Antioxidant, anti-inflammatory, and anti-carcinogenic effects have been described. At the same time, they inhibit the actions of bacteria, viruses, and fungi. Thus, studies have also examined their effects within the oral cavity. This review provides an overview on the different polyphenols, and their structure and interactions with the tooth surface and the pellicle. In particular, the effects of various tea polyphenols on bioadhesion and erosion have been reviewed. The current research confirms that polyphenols can reduce the growth of cariogenic bacteria. Furthermore, they can decrease the adherence of bacteria to the tooth surface and improve the erosion-protective properties of the acquired enamel pellicle. Tea polyphenols, especially, have the potential to contribute to an oral health-related diet. However, in vitro studies have mainly been conducted. In situ studies and clinical studies need to be extended and supplemented in order to significantly contribute to additive prevention measures in caries prophylaxis.

Salivary Pellicle Modification with Grape-seed Extract: In Vitro Study on the Effect on Bacterial Adhesion and Biofilm Formation.

PURPOSE: Grape-seed extract (GSE) contains polyphenols that readily adhere to proteins and modify the acquired enamel pellicle (AEP). The first step in biofilm formation is bacterial adhesion to the AEP-covered enamel. The aim of this in vitro study was to test whether AEP modification with GSE, fluoride (F-), or their combination (GSE+F-) modulates bacterial adhesion, biofilm metabolism and composition, or cariogenic demineralisation of the enamel. MATERIALS AND METHODS: The study comprised 3 parts: 1) single-strain Streptococcus gordonii species, 2) a five-species biofilm model, or 3) biofilm (re-)formation using the five-species biofilm model after removal of initial biofilm with toothbrushing. Human whole-mouth stimulated saliva was used to form an AEP on human enamel specimens. The AEP was incubated in water (control), or modified with GSE, F-, or GSE+F-. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and cariogenic demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 4 h or 22 h. Differences between groups were analysed with one-way ANOVA and post-hoc Bonferroni tests. RESULTS: GSE and GSE+F- statistically significantly decreased single-strain S. gordonii adhesion, but had no relevant influence when the five-species biofilm model was used. In the biofilm (re-)formation model, GSE reduced bacterial adhesion compared to GSE+F-, while F- caused less cariogenic demineralisation than was found in the control group. CONCLUSION: AEP modified with GSE retards S. gordonii adhesion, but it does not influence the formation, metabolism and composition of a cariogenic multi-species biofilm.

Salivary pellicle modification with polyphenol-rich teas and natural extracts to improve protection against dental erosion.

OBJECTIVE: To investigate the modification of the salivary pellicle with different polyphenol-rich teas and natural extracts for the protection against dental erosion. METHODS: We performed two experiments: one with teas (Green tea, Black tea, Peppermint tea, Rosehip tea, negative control [NC]) and other with natural extracts (Grape seed, Grapefruit seed, Cranberry, Propolis, NC), where NC was deionized water. A total of 150 enamel specimens were used (n = 15/group). Both experiments followed the same design, consisting of 5 cycles of: salivary pellicle formation (30 min, 37 °C), modification with the solutions (30 min, 25 °C), further salivary pellicle formation (60 min, 37 °C) and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), relative surface reflection intensity (rSRI) and amount of calcium release (CaR) were evaluated. Data were analysed with Kruskal-Wallis and Wilcoxon rank sum tests with Bonferroni correction (α = 0.05). RESULTS: Regarding teas, Black and Green teas showed the best protection against dental erosion, presenting higher rSMH and lower CaR than NC. Peppermint tea was not different to NC and Rosehip tea caused erosion, showing the highest CaR and greatest loss of SMH and SRI. Regarding natural extracts, Grape seed and Grapefruit seed extracts presented the best protective effect, with significantly higher rSMH and lower CaR. Cranberry caused significantly more demineralization; and Propolis did not differ from NC. CONCLUSION: Green tea, Black tea, Grape seed extract and Grapefruit seed extract were able to modify the salivary pellicle and improve its protective effect against enamel erosion, but Rosehip tea and Cranberry extract caused erosion. CLINICAL RELEVANCE: Some some bio-products, such as teas and natural extracts, improve the protective effect of the salivary pellicle against enamel erosion. More studies should be performed in order to test the viability of their use as active ingredients for oral care products.

Influence of salivary conditioning and sucrose concentration on biofilm-mediated enamel demineralization.

INTRODUCTION: The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. OBJECTIVE: To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. METHODOLOGY: Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. RESULTS: The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). CONCLUSION: Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.

Influence of salivary conditioning and sucrose concentration on biofilm-mediated enamel demineralization

Abstract The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. Objective To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. Methodology Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. Results The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). Conclusion Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.

Remineralisation of enamel white spot lesions pre-treated with chitosan in the presence of salivary pellicle.

OBJECTIVE: To investigate the remineralisation of chitosan pre-treated enamel white spot lesions (WSLs) by bioglass in the presence of the pellicle layer. METHODS: 50 artificial enamel white spot lesions were created by acidic gel. Two lesions were used to investigate the formation of the pellicle layer by treating with human whole saliva for 3 min. 48 lesions were assigned to 6 experimental groups (n = 8): (1) bioactive glass slurry, (2) bioactive glass containing polyacrylic acid (BG + PAA) slurry, (3) chitosan pre-treated WSLs with BG slurry (CS-BG), (4) chitosan pre-treated WSLs with BG + PAA slurry (CS-BG + PAA), (5) "standard" remineralisation solution (RS) and (6) de-ionised water (negative control, NC). Remineralisation was carried out using a pH-cycling model for 7 days. Before each treatment using remineralising agents, 3-min pellicle was formed on lesions' surfaces. Mineral content changes, surface and subsurface microhardness and ultrastructure were evaluated by Raman intensity mapping, Knoop microhardness and scanning electron microscopy, respectively. Data were statistically analysed using one-way ANOVA with Tukey's test (p < 0.05 is considered as significant). RESULTS: Despite the heterogeneously formed pellicle layer, all groups showed an increase in surface mineral content after pH-cycling. Chitosan pre-treatment enhanced the subsurface remineralisation of WSLs using bioglass as both pre-treated groups showed greater surface and subsurface microhardness compared to NC. CS-BG exhibited denser subsurface structure than BG, while in CS-BG + PAA the crystals were bigger in size but resemble more enamel-like compared to BG + PAA as shown in SEM observations. Remineralisation of RS was limited to the surface as no significant subsurface changes of mechanical properties and structure were found. CONCLUSIONS: Chitosan pre-treatment can enhance WSL remineralisation with bioglass biomaterials when a short-term salivary pellicle is present. A further investigation using a long-term pH-cycling model with mature pellicle is suggested with regards to clinical application. CLINICAL SIGNIFICANCE: Chitosan pre-treatment has the potential in clinical application to remineralise subsurface lesions to achieve lesion consolidation.

Effect of vegetable oils applied over acquired enamel pellicle on initial erosion.

OBJECTIVE: The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. MATERIAL AND METHODS: Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group): GP5 and GP100 - 5% and pure palm oil, respectively; GC5 and GC100 - 5% and pure coconut oil; GSa5 and GSa100 - 5% and pure safflower oil; GSu5 and GSu100 - 5% and pure sunflower oil; GO5 and GO100 - 5% and pure olive oil; CON- - Deionized Water (negative control) and CON+ - Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control). Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf) / SHf )×100]. Data were analyzed by one-way ANOVA and Tukey's test (p<0.05). RESULTS: Enamel blocks of GP100 presented similar hardness loss to GSu100 (p>0.05) and less than the other groups (p<0.05). There was no difference between GP5, GC5, GC100, GSa5, GSu100, GSa100, GSu5, GO5, GO100, CON- and CON+. CONCLUSION: Palm oil seems to be a promising alternative for preventing enamel erosion. However, further studies are necessary to evaluate a long-term erosive cycling.

Effect of vegetable oils applied over acquired enamel pellicle on initial erosion

Abstract Objective The prevalence of dental erosion has been recently increasing, requiring new preventive and therapeutic approaches. Vegetable oils have been studied in preventive dentistry because they come from a natural, edible, low-cost, and worldwide accessible source. This study aimed to evaluate the protective effect of different vegetable oils, applied in two concentrations, on initial enamel erosion. Material and Methods Initially, the acquired pellicle was formed in situ for 2 hours. Subsequently, the enamel blocks were treated in vitro according to the study group (n=12/per group): GP5 and GP100 - 5% and pure palm oil, respectively; GC5 and GC100 - 5% and pure coconut oil; GSa5 and GSa100 - 5% and pure safflower oil; GSu5 and GSu100 - 5% and pure sunflower oil; GO5 and GO100 - 5% and pure olive oil; CON− - Deionized Water (negative control) and CON+ - Commercial Mouthwash (Elmex® Erosion Protection Dental Rinse, GABA/positive control). Then, the enamel blocks were immersed in artificial saliva for 2 minutes and subjected to short-term acid exposure in 0.5% citric acid, pH 2.4, for 30 seconds, to promote enamel surface softening. The response variable was the percentage of surface hardness loss [((SHi - SHf) / SHf )×100]. Data were analyzed by one-way ANOVA and Tukey's test (p<0.05). Results Enamel blocks of GP100 presented similar hardness loss to GSu100 (p>0.05) and less than the other groups (p<0.05). There was no difference between GP5, GC5, GC100, GSa5, GSu100, GSa100, GSu5, GO5, GO100, CON− and CON+. Conclusion Palm oil seems to be a promising alternative for preventing enamel erosion. However, further studies are necessary to evaluate a long-term erosive cycling.

Efficacy of a mouthrinse based on hydroxyapatite to reduce initial bacterial colonisation in situ.

OBJECTIVE: The present in situ - investigation aimed to specify the impact of pure hydroxyapatite microclusters on initial bioadhesion and bacterial colonization at the tooth surface. DESIGN: Pellicle formation was carried out in situ on bovine enamel slabs (9 subjects). After 1min of pellicle formation rinses with 8ml of hydroxyapatite (HA) microclusters (5%) in bidestilled water or chlorhexidine 0.2% were performed. As negative control no rinse was adopted. In situ biofilm formation was promoted by the intraoral slab exposure for 8h overnight. Afterwards initial bacterial adhesion was quantified by DAPI staining and bacterial viability was determined in vivo/in vitro by live/dead-staining (BacLight). SEM analysis evaluated the efficacy of the mouthrinse to accumulate hydroxyapatite microclusters at the specimens' surface and spit-out samples of the testsolution were investigated by TEM. RESULTS: Compared to the control (2.36×106±2.01×106bacteria/cm2), significantly reduced amounts of adherent bacteria were detected on specimens rinsed with chlorhexidine 0.2% (8.73×104±1.37×105bacteria/cm2) and likewise after rinses with the hydroxyapatite testsolution (2.08×105±2.85×105bacteria/cm2, p<0.001). No demonstrable effect of HA-particles on Streptococcus mutans viability could be shown. SEM analysis confirmed the temporary adsorption of hydroxyapatite microclusters at the tooth surface. Adhesive interactions of HA-particles with oral bacteria were shown by TEM. CONCLUSION: Hydroxyapatite microclusters reduced initial bacterial adhesion to enamel in situ considerably and could therefore sensibly supplement current approaches in dental prophylaxis.

Anti-plaque effect of a synergistic combination of green tea and Salvadora persica L. against primary colonizers of dental plaque.

OBJECTIVE: Green tea (Gt), leafs of Camellia sinensis var. assamica, is widely consumed as healthy beverage since thousands of years in Asian countries. Chewing sticks (miswak) of Salvadora persica L. (Sp) are traditionally used as natural brush to ensure oral health in developing countries. Both Gt and Sp extracts were reported to have anti-bacterial activity against many dental plaque bacteria. However, their combination has never been tested to have anti-bacterial and anti-adherence effect against primary dental plaque colonizers, playing an initial role in the dental plaque development, which was investigated in this study. METHODS: Two-fold serial micro-dilution method was used to measure minimal inhibitory concentration (MIC) of aqueous extracts of Gt, Sp and their combinations. Adsorption to hexadecane was used to determine the cell surface hydrophobicity (CSH) of bacterial cells. Glass beads were used to mimic the hard tissue surfaces, and were coated with saliva to develop experimental pellicles for the adhesion of the primary colonizing bacteria. RESULTS: Gt aqueous extracts exhibited better anti-plaque effect than Sp aqueous extracts. Their combination, equivalent to 1/4 and 1/2 of MIC values of Gt and Sp extracts respectively, showed synergistic anti-plaque properties with fractional inhibitory concentration (FIC) equal to 0.75. This combination was found to significantly reduce CSH (p<0.05) and lower the adherence ability (p<0.003) towards experimental pellicles. CONCLUSION: Combination between Gt and Sp aqueous extracts exhibited synergistic anti-plaque activity, and could be used as a useful active agent to produce oral health care products.

Efficacy of citronella and cinnamon essential oils on Candida albicans biofilms.

INTRODUCTION: The discovery of new antimicrobials derived from plants could aid in the management of biofilm-associated infections, including denture-induced stomatitis (DS). DS is an oral infection caused by Candida biofilms on the surfaces of poorly cleansed dentures. Effective treatment of DS requires the use of an appropriate denture cleanser and preferably one that exhibits antimicrobial properties. OBJECTIVE: This study aimed to evaluate the anti-Candida and anti-biofilm efficacy of two essential plant oils from Cymbopogon winterianus (citronella) and Cinnamon cassia (cinnamon). MATERIALS AND METHODS: Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) were determined by broth microdilution, whilst anti-biofilm activity was measured against mature (cultured for 72 h) biofilms on acrylic surfaces. Candida cell viability was assessed immediately (0 h) after treatment (T0) and 48 h after biofilm re-growth (T48). Biofilm structure was determined using Scanning Electron Microscopy (SEM) at T0 and T48. RESULTS: The respective MICs of cinnamon and citronella oils were 65 and 250 µg/ml and these were also the MFC values. For anti-biofilm efficacy, both oils significantly (p < 0.05) reduced the number of viable micro-organisms and accumulation of biofilms at T0. However, at T48, there was no difference between treated and untreated biofilms. CONCLUSIONS: It is concluded that citronella and cinnamon essential oils have potential for daily anti-candidal denture cleansing.

Application of Plant Extracts for the Prevention of Dental Erosion: An in situ/in vitro Study.

OBJECTIVES: Antiadherent and antibacterial effects of certain plant extracts have been proven to be beneficial in preventive dentistry. In the present in situ/in vitro crossover study, the impact of plant extracts rich in polyphenols on the erosion-protective properties of the in situ pellicle was evaluated. METHODS: Individual splints were prepared for 12 subjects for intraoral exposure of bovine enamel specimens. Following formation of a 1-min pellicle, watery plant extracts (leaves of the wild form of Ribes nigrum, the wild form of Origanum as well as a combination of both) were administered for 10 min in situ. Alternatively, a mouth rinse with fluorides (Elmex Kariesschutz) was performed for 1 min. After further oral exposure for 19/28 min, respectively, slabs were removed and incubated with HCl in vitro over 120 s (pH 2, 2.3, 3). The resulting calcium and phosphate release was quantified photometrically. Slabs with and without a 30-min in situ pellicle served as controls. The modification of pellicle ultrastructure was evaluated by transmission electron microscopy (TEM). RESULTS: Plant extracts modulated the erosion-protective properties of the native in situ pellicle in all test groups in a pH-dependent manner. The combination of R. nigrum leaves and Origanum enhanced the protective properties of the pellicle at all pH values; the administration of this preparation was comparable, yet superior, to the effect of the fluoridated mouth rinse. TEM images indicated that rinsing with R. nigrum leaves/Origanum yielded a distinctly thicker and more electron-dense pellicle. CONCLUSION: The combination of certain plant extracts offers a novel approach to the complementary prevention of dental erosion.

Antibacterial Efficacy of a Propolis Toothpaste and Mouthrinse Against a Supragingival Multispecies Biofilm.

PURPOSE: To determine in vitro the antibacterial properties of propolis toothpaste and mouthrinse against an in vitro multispecies biofilm model. MATERIALS AND METHODS: Six-species biofilms grown anaerobically on pellicle-coated hydroxyapatite disks were fed with glucose/sucrose-supplemented medium 3 times daily for 45 min and incubated in 37°C saliva between feedings for up to 64.5 h. At each interval, biofilms were exposed to six different slurries and solutions, including: 1) toothpaste without propolis, 2) toothpaste with propolis, 3) toothpaste with chlorhexidine, 4) mouthrinse with propolis, 5) mouthrinse with chlorhexidine, 6) saline solution (control). Afterwards, biofilms were harvested and the number of colony forming units were determined (CFU). The results were analysed using ANOVA, followed by the Bonferroni test at a 5% significance level. RESULTS: The strongest CFU reduction was shown after treatment with 0.12% chlorhexidine (p<0.0004). When comparing the different toothpastes, there was no statistically significant difference (p<0.05) in CFU reduction. However, they all showed a significant reduction in CFU of more than one log-step vs the saline control group. Nevertheless, the propolis-containing mouthrinse showed no significant reduction in CFU. CONCLUSION: All toothpastes under investigation displayed some growth inhibition in this supragingival biofilm model, which accounted for an approximately 80%-88% linear reduction. However, the propolis mouthwash had no effect.

Composition of enamel pellicle from dental erosion patients.

Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p < 0.05). In particular, statherin, a calcium-binding protein, was 35% less abundant (p < 0.05). Calcium concentration within the acquired pellicle was also reduced by 50% in erosion patients (p < 0.001). In contrast, the natural pellicle on the incisor had similar amounts of total protein in erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth.

Fatty acid profile of the initial oral biofilm (pellicle): an in-situ study.

The first step of bioadhesion on dental surfaces is the formation of the acquired pellicle. This mainly acellular layer is formed instantaneously on all solid surfaces exposed to oral fluids. It is composed of proteins, glycoproteins and lipids. However, information on the lipid composition is sparse. The aim of the present study was to evaluate the fatty acid (FA) profile of the in-situ pellicle for the first time. Furthermore, the impact of rinses with safflower oil on the pellicle's FA composition was investigated. Pellicles were formed in situ on bovine enamel slabs mounted on individual upper jaw splints. The splints were carried by ten subjects over durations of 3-240 min. After comprehensive sample preparation, gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS) was used in order to characterize qualitatively and quantitatively a wide range of FA (C12-C24). The relative FA profiles of the pellicle samples gained from different subjects were remarkably similar, whereas the amount of FA showed significant interindividual variability. An increase in FA in the pellicle was observed over time. The application of rinses with safflower oil resulted in an accumulation of its specific FA in the pellicle. Pellicle formation is a highly selective process that does not correlate directly with salivary composition, as shown for FA.

An in vitro study on the anti-adherence effect of Brucea javanica and Piper betle extracts towards oral Candida.

OBJECTIVE: The adherence of Candida to mucosal surfaces is the initial step for successful invasive process of the oral cavity. The study aimed to investigate the effect of two plant extracts on the non-specific and specific bindings of oral candida. METHODS: In the former, adsorption to hexadecane was used to measure the hydrophobic interaction of the candida cells. In the later, glass beads coated with saliva represented the experimental pellicles in specific adhesion of oral candida to hard tissue surface. RESULTS: Candida krusei, Candida dubliniensis and Candida tropicalis showed the highest adsorption to hexadecane at 30.23%, 26.19% and 19.70%, respectively, while the others within the range of 7-10%. All candidal species were significantly affected by the extracts (P<0.05) with Brucea javanica exhibited more than 60% reduction of CSH than Piper betle. Candida parapsilosis showed the highest affinity in specific-bindings to pellicle with 18.72±0.71×10(5)CFU/ml. Exposing to P. betle-treated pellicle has drastically reduced the adherence of C. tropicalis, Candida albicans and C. krusei by 86.01%, 61.41% and 56.34%, respectively. B. javanica exhibited similar effect on C. tropicalis (89.86%), Candida lusitaniae (88.95%), C. albicans (79.74%), Candida glabrata (76.85%) and C. krusei (67.61%). CONCLUSION: The extracts demonstrated anti-adherence activities by modifying the CSH and the characteristics of the experimental pellicle.