Voriconazole inhibits cross-kingdom interactions between Candida albicans and Actinomyces viscosus through the ergosterol pathway.

Candida albicans and Actinomyces viscosus are prominent microbes associated with dental root caries. The aim of this study was to investigate the effect of C. albicans on A. viscosus biofilms and to identify the mechanisms associated with this interaction. A. viscosus and C. albicans strains (wide-type and mutants) were used to form biofilms in vitro and in vivo, which were subsequently analysed by crystal violet assay and scanning electron microscopy (SEM) to investigate the effect of C. albicans on A. viscosus growth. A viable plate count and survival curve for C. albicans mutants and A. viscosus combinations were used to identify which C. albicans pathway was crucial for cross-kingdom interactions. Voriconazole was used to block their interactions both in vitro and in vivo. SEM, fluorescence in situ hybridisation (FISH), quantitative PCR and survival curve analyses were performed to evaluate the activity of voriconazole on C. albicans and A. viscosus interactions. The biomass and virulence of mixed-species biofilms were significantly enhanced compared with the A. viscosus biofilm alone. However, this was not observed in the mixed-species biofilms with the C. albicans mutant erg11Δ/Δ in vitro and in vivo, indicating that azoles may work on the mixed-species biofilms. As expected, voriconazole can effectively reduce the biomass of mixed-species biofilms. A high concentration of voriconazole (1 µg/mL) reduced the abundance of C. albicans, whilst a low voriconazole concentration (0.25 µg/mL) blocked their interactions similar to the effect of the erg11Δ/Δ mutant. Voriconazole may be a candidate strategy to combat root caries pathogens.

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.

Tantalum Nitride-Decorated Titanium with Enhanced Resistance to Microbiologically Induced Corrosion and Mechanical Property for Dental Application.

Microbiologically induced corrosion (MIC) of metallic devices/implants in the oral region is one major cause of implant failure and metal allergy in patients. Therefore, it is crucial to develop practical approaches which can effectively prevent MIC for broad clinical applications of these materials. In the present work, tantalum nitride (TaN)-decorated titanium with promoted bio-corrosion and mechanical property was firstly developed via depositing TaN layer onto pure Ti using magnetron sputtering. The microstructure and chemical constituent of TaN coatings were characterized, and were found to consist of a hard fcc-TaN outer layer. Besides, the addition of TaN coatings greatly increased the hardness and modulus of pristine Ti from 2.54 ± 0.20 to 29.88 ± 2.59 GPa, and from 107.19 ± 6.98 to 295.46 ± 19.36 GPa, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy studies indicated that TaN coating exhibited higher MIC resistance in comparison to bare Ti and TiN-coated coating in two bacteria-containing artificial saliva solutions. Moreover, the biofilm experiment showed that the TaN-decorated Ti sample possessed good antibacterial performance. The SEM and XPS results after biofilm removal demonstrated that TaN film remained its integrity and stability, while TiN layer detached from Ti surface in the bio-corrosion tests, demonstrating the anti-MIC behavior and the strong binding property of TaN coating to Ti substrate. Considering all these results, TaN-decorated Ti material exhibits the optimal comprehensive performance and holds great potential as implant material for dental applications.

Antibiotic resistance and capacity for biofilm formation of different bacteria isolated from endodontic infections associated with root-filled teeth.

INTRODUCTION: To date, a variety of microbial species have been isolated from endodontic infections. However, endodontic clinical bacterial isolates have not been sufficiently characterized with regard to their capacity for antibiotic resistance and biofilm formation. In this study, antibiotic resistance and biofilm formation of 47 different aerobic and anaerobic bacterial isolates, belonging to 32 different species previously isolated from infected filled root canals, were studied. METHODS: Antibiotic sensitivity to 11 antibiotics including penicillin G, amoxicillin, clindamycin, gentamicin, vancomycin, tetracycline, doxycycline, fosfomycin, rifampicin, ciprofloxacin, and moxifloxacin was tested using the standardized Etest method (Bio Merieux, Marcy-1'Etoile, France). The antibiotic sensitivity of 4 control strains was also estimated in parallel. Additionally, the capacity to form biofilms was quantified using the microtiter plate test. RESULTS: Different aerobic and anaerobic bacterial species were either resistant against a number of antibiotics or showed high minimal inhibitory concentrations against clinically relevant antibiotics. Five aerobic and 2 anaerobic isolates, including Enterococcus faecalis, Streptococcus mutans, Lactobacillus fermentum, Actinomyces naeslundii, Actinomyces viscosus, Prevotella buccae, and Propionibacterium acidifaciens, were characterized as being high biofilm producers, whereas 8 aerobic and 3 anaerobic isolates were found to be moderate biofilm producers. Most isolates with resistance or markedly high minimal inhibitory concentration values were also either moderate biofilm producers or high biofilm producers. CONCLUSIONS: These results suggest that the clinical significance of endodontic infections could include that they serve as a reservoir for antibiotic resistance. Furthermore, endodontic treatment should consider the adhesion and biofilm formation by a variety of bacteria.

Novel thermostable lipase from Bacillus circulans IIIB153: comparison with the mesostable homologue at sequence and structure level.

Thermophilic Bacillus circulans IIIB153 isolated from hot springs of North West Himalayas, India, produced an extracellular lipase, which exhibited significant biofilm disruption property on the static biofilm disruption model with a single species of Actinomyces viscosous. The gene encoding the lipase was cloned and overexpressed in Escherichia coli. Recombinant Bacillus circulans lipase (BCL), a monomer with molecular mass of 43 kDa also exhibited significant biofilm disruption activity. The enzyme was optimally active at 60°C, pH 8.5 and retained >70% of its original activity after 1 h incubation at 60°C. 3D structure of BCL developed by homology modeling showed a typical α/ß hydrolase fold, a characteristic feature of lipolytic enzymes. Comparison of thermostable BCL with mesostable lipase from Chromobacterium viscosum at the sequence and structure level showed distinct variations in the structural features, with the presence of a high content of proline residues, aromatic amino acids and salt bridges. These features along with the presence of zinc-binding site observed in BCL structure could have a potential role in thermal stability of the enzyme.

Oral bacteria induce a differential activation of human immunodeficiency virus-1 promoter in T cells, macrophages and dendritic cells.

INTRODUCTION: The human immunodeficiency virus (HIV) can integrate into T cells, macrophages and dendritic cells resulting in a latent infection. Reports have also demonstrated that various microbial and host cell factors can trigger HIV reactivation leading to HIV recrudescence, potentially undermining highly active antiretroviral therapies. METHODS: This study evaluated the capacity of oral bacteria associated with chronic periodontal infections to stimulate HIV promoter activation in various cell models of HIV latency. RESULTS: T cells (1G5) challenged with oral bacteria demonstrated a dose-response of HIV promoter activation with a subset of the bacteria, as well as kinetics that were generally similar irrespective of the stimuli. Direct bacterial challenge of the T cells resulted in increased activation of approximately 1.5- to 7-fold over controls. Challenge of macrophages (BF24) indicated different kinetics for individual bacteria and resulted in consistent increases in promoter activation of five fold to six fold over basal levels for all bacteria except Streptococcus mutans. Dendritic cells showed increases in HIV reactivation of 7- to 34-fold specific for individual species of bacteria. CONCLUSION: These results suggested that oral bacteria have the capability to reactivate HIV from latently infected cells, showing a relationship of mature dendritic cells > immature dendritic cells > macrophages > or = T cells. Expression of various pattern recognition receptors on these various cell types may provide insight into the primary receptors/signaling pathways used for reactivation by the bacteria.

Activity of panduratin A isolated from Kaempferia pandurata Roxb. against multi-species oral biofilms in vitro.

The formation of dental biofilm caused by oral bacteria on tooth surfaces is the primary step leading to oral diseases. This study was performed to investigate the preventive and reducing effects of panduratin A, isolated from Kaempferia pandurata Roxb., against multi-species oral biofilms consisting of Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus. Minimum inhibitory concentration (MIC) of panduratin A was determined by the Clinical and Laboratory Standards Institute (CLSI) broth microdilution assay. Prevention of biofilm formation was performed on 96-well microtiter plates by coating panduratin A in mucin at 0.5-40 microg/ml, followed by biofilm formation at 37 degrees C for 24 h. The reducing effect on the preformed biofilm was tested by forming the biofilm at 37 degrees C for 24 h, followed by treatment with panduratin A at 0.2-10 microg/ml for up to 60 min. Panduratin A showed a MIC of 1 microg/ml for multi-species strains. Panduratin A at 2 x MIC for 8 h exhibited bactericidal activity against multi-species planktonic cells for 8 h. At 8 x MIC, panduratin A was able to prevent biofilm formation by > 50%. Biofilm mass was reduced by > 50% after exposure to panduratin A at 10 microg/ml for 15 min. Panduratin A showed a dose-dependent effect in preventing and reducing the biofilm. These results suggest that panduratin A is applicable as a natural anti-biofilm agent to eliminate oral bacterial colonization during early dental plaque formation.

Effect of xylitol on an in vitro model of oral biofilm.

PURPOSE: The aim of the present study was to examine whether xylitol, at different concentrations, inhibits the formation of an experimental model of oral biofilm. MATERIALS AND METHODS: Biofilms of six bacterial species (Streptococcus mutans, Streptococcus sobrinus, Lactobacillus rhamnosus, Actinomyces viscosus, Porphyromonas gingivalis and Fusobacterium nucleatum) were prepared on hydroxyapatite (HA) discs according to the Zürich Biofilm Model. Xylitol was tested at two concentrations, 1% and 3%. At the end of their designated incubation times, some HA discs were destined for confocal laser scanning microscopy (CLSM) and the others were harvested using a sterile surgical instrument. Aliquots of harvested biofilms were diluted and plated onto specific media. After a 48-h anaerobic incubation at 37 degrees C, the colony-forming units (CFUs) were counted. RESULTS: CLSM images showed that only a small amount of isolated bacteria was observed on the surface of HA discs. Culture of harvested biofilms showed an inhibition in the growth of different species included in the biofilms. CONCLUSIONS: Xylitol has a clear inhibitory effect on the formation of the experimental biofilms. This study shows that xylitol is not only efficient in inhibiting the acid production of cariogenic bacteria, but also in preventing the formation of a multispecies biofilm; it confirms the relevance of the use of this polyol for the prevention of oral diseases caused by dental plaque.

Tyrosine sulfation of statherin.

Tyrosylprotein sulfotransferase (TPST), responsible for the sulfation of a variety of secretory and membrane proteins, has been identified and characterized in submandibular salivary glands (William et al. Arch Biochem Biophys 1997; 338: 90-96). In the present study we demonstrate the sulfation of a salivary secretory protein, statherin, by the tyrosylprotein sulfotransferase present in human saliva. Optimum statherin sulfation was observed at pH 6.5 and at 20 mm MnCl(2). Increase in the level of total sulfation was observed with increasing statherin concentration. The K(m)value of tyrosylprotein sulfotransferase for statherin was 40 microM. Analysis of the sulfated statherin product on SDS-polyacrylamide gel electrophoresis followed by autoradiography revealed (35)S-labelling of a 5 kDa statherin. Further analysis of the sulfated statherin revealed the sulfation on tyrosyl residue. This study is the first report demonstrating tyrosine sulfation of a salivary secretory protein. The implications of this sulfation of statherin in hydroxyapatite binding and Actinomyces viscosus interactions are discussed.

[Effects of traditional Chinese medicine on oral bacteria biofilm].

OBJECTIVE: To investigate the effects of compounds of Galla chinensis extract (GCE) and Nidus vespae extract-1 (WVE1) on oral bacteria biofilm structure and activity and to determine the possibility of caries prevention by the compounds. METHODS: The morphology and activity of treated-oral bacterial biofilm and untreated-oral bacterial biofilm were observed by using fluorescence microscope in combination of idio-fluorochrome to label the died and living bacteria. The visible light semiquantitative method was used to measure biomass glucosyltransferase (GTF, A620) values and to determine the effects of active compounds of GCE and NVE1 on GTF of oral bacteria biofilm. RESULTS: The living bacteria in the untreated 24 h bacterial biofilm was dominant, and only a small number of died bacteria were found, the biofilm structure was regular and clear. GCE, GCE-B and NVE1 could inhibit the bacteria in the dental biofilm, which showed significant difference with the negative control. GCE and NVE1 could also inhibit GTF activity of 24 h bacterial biofilm in comparison with the negative control. CONCLUSIONS: The traditional Chinese medicine Galla chinensis and Nidus vespae could not only inhibit bacteria growth on oral bacterial biofilm, but also function by adjusting biofilm structure, composition and GTF activity of 24 h bacterial biofilm.

[On the relationship between exopolysaccharides and Actinomyces viscosus in biofilms].

OBJECTIVE: To elucidate the biofilm structure of Actinomyces viscosus and the spatial distribution of exopolysaccharides in it. METHODS: The Actinomyces viscosus biofilm was made by allowing bacteria to attach to the cover glass surface. The biofilm structure and exopolysaccharides distribution at 24 hours were stained with Fluorescein, BODIPY and Calcofluor respectively and were visualized by confocal laser scanning microscopy (CLSM). RESULTS: Actinomyces viscosus could attach to glass surface and form a structural biofilm where bacteria were embedded in the EPS glycocalyx polymers, and characteristic microcolonies and channels were taking shape. Bacteria were sparse in the substratum area but crowd in the center. In the biofilm, the distribution of bacteria was consistent with the distribution of exopolysaccharides. CONCLUSION: The findings demonstrate an important role of exopolysaccharides in the process of Actinomyces viscosus biofilm formation.

In vitro binding interactions of oral bacteria with immobilized fructosyltransferase.

AIMS: The objective of the present study was to explore the role of immobilized fructosyltransferase (FTF) in adhesion process. METHODS AND RESULTS: We investigated real-time biospecific interactions between several types of oral bacteria and recombinant FTF immobilized on a biosensor chip, using surface plasmon resonance technology. Streptococcus mutans, Streptococcus sobrinus and Actinomyces viscosus demonstrated significant binding to FTF. Actinomyces viscosus had a greater binding to FTF, with 373 Resonance Units (RU), than the other tested bacteria. The binding level to FTF of Strep. sobrinus was 320 RU, whereas Strep. mutans and Streptococcus salivarious show binding of 296 and 245 RU, respectively. The binding sensograms displayed different profiles for the tested bacteria at various cell density, suggesting a different affinity to immobilized FTF. CONCLUSIONS: The results from this study suggest that FTF may influence bacterial adherence and colonization of the dental biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY: The biomolecular interaction analysis enables real-time monitoring of the interaction between adhesions of intact bacteria and their ligands, which might be crucial in the initial phase of biofilm development in vivo.

Anticaries efficacy of a new dentifrice for hypersensitivity.

PURPOSE: To evaluate the expected anticaries efficacy of a new dentifrice containing stannous fluoride as the anticaries agent and potassium nitrate as the antihypersensitivity agent using a series of laboratory and animal studies. METHODS: Four surrogate studies were performed in this assessment including fluoride uptake in sound enamel, enamel solubility reduction, fluoride bioavailability and animal caries. RESULTS: Each of these studies indicated the new dentifrice for hypersensitivity (Colgate Sensitive Maximum Strength) was effective in inhibiting the caries process. The data demonstrate that this new dentifrice is predicted to be highly effective against caries and equivalent to a positive control dentifrice.

[Effect of para-aminobenzonic acid on cell-surface hydrophobicity of Actinomyces viscosus].

OBJECTIVE: To study the effect of Para-aminobenzonic acid (PABA) on cell-surface hydrophobicity of Actinomyces viscosus. METHODS: Microbial adhesion to hydrocarbons (MATH) was used to measure the cell-surface hydrophobicity of Actinomyces viscosus which grew in modified Carlsson medium with different dilution of PABA. RESULTS: Following the increase of concentration of PABA, the value of cell-surface hydrophobicity of Actinomyces viscosus decreased, which were 0.38900 +/- 0.00026, 0.25462 +/- 0.00168, 0.16360 +/- 0.00026 respectively(P < 0.05). CONCLUSION: PABA could inhibit the adherence of Actinomyces viscosus by way of changing its cell-surface hydrophobicity.

The role of fructans on dental biofilm formation by Streptococcus sobrinus, Streptococcus mutans, Streptococcus gordonii and Actinomyces viscosus.

Dental plaque biofilm plays a pivotal role in the progression of dental diseases. Polysaccharides are of great importance in the ecology of the dental biofilm. We studied the effect of fructans, glucans and a mixture of both fructans and glucans, synthesized in situ by immobilized fructosyltransferase or glucosyltransferase, on the adhesion of Streptococcus sobrinus, Streptococcus mutans, Streptococcus gordonii and Actinomyces viscosus to hydroxyapatite beads coated with human saliva (sHA). The adhesion of A. viscosus to sHA was found to be fructan-dependent. Adhesion of both S. sobrinus and S. mutans was found to be mediated mainly by glucans, while the adhesion of S. gordonii was found to be both glucan- and fructan-dependent. Treatment with fructanase prior to A. viscosus adhesion resulted in a significant reduction in adhesion to sHA, while adhesion of S. sobrinus, S. mutans and S. gordonii was slightly influenced by fructanase treatment. Treatment with fructanase after adhesion of S. gordonii to sHA resulted in a significant reduction in their adhesion to sHA. Our results show that fructans may play a role in the adhesion and colonization of several cariogenic bacteria to sHA, thus contributing to the formation of dental plaque biofilm.

Reduced fimbria-associated activities of Porphyromonas gingivalis induced by recombinant fimbrial expression.

The adhesion properties of the recombinant fimbriae (r-fimbriae) recovered from a YH522 transformant of Porphyromonas gingivalis which harbors a chimeric plasmid, pYHF2, containing the fimA gene of strain 381 were compared with those of the endogenous fimA fimbriae of strain 33277. The adhesion level of the r-fimbriae to Actinomyces viscosus was clearly lower than that of the endogenous fimbriae. In addition, the r-fimbriae were shown to lack some minor components detectable in the endogenous fimbriae. The plasmid pYHF2 prepared from the YH522 transformant was then transformed into six different P. gingivalis strains and the resultant pYHF2-containing strains were examined for their fimbrial expression. In spite of the presence of a considerable diversity in the expression level of the r-fimbriae among these transformants, it was evident that the strains expressing higher levels of the r-fimbriae exhibited a greater decrease in adhesion activity to other bacteria and to oral epithelial cells, as well as in self-aggregation.

In vitro colonisation of acrylic resin denture base materials by Streptococcus oralis and Actinomyces viscosus.

AIM: The aim of the study was to compare the attachment of two typical strains of oral bacteria to four denture base materials. DESIGN: In vitro study. METHOD: Discs of acrylic resin denture base materials (Paladon 65, polished and unpolished; Palapress; Microbase, polished and unpolished, and Triad VLC) were placed into Petri dishes with Schaedler's medium, inoculated with Streptococcus oralis 34 or Actinomyces viscosus T14V. MAIN OUTCOME MEASURES: After 24 h or 48 h the numbers of adhering bacteria were measured. RESULTS: The bacteria adhered to all discs in similar numbers: 3-9 x 10(6)/ml (viable cell count) and 9-22 x 10(8)/ml (total cell count) for T14V, and 2-6 x 10(6)/ml (viable cell count) and 1.5-3 x 10(8)/ml (total cell count) for 34. CONCLUSIONS: Polishing had little effect on adherence. Denture base materials are not resistant against adherence and possible surface damage by oral bacteria. Therefore, thorough oral hygiene is important for denture wearers.

Studies concerning the glucosyltransferase of Streptococcus sanguis.

We have shown in previous studies that the glucosyltransferase (Gtf) enzymes of Streptococcus mutans have distinct properties when adsorbed to a surface. In the present study, we compared the activity of Gtf from Streptococcus sanguis, designated GtfSs, in solution and on the surface of saliva-coated hydroxyapatite (sHA) beads, and determined the ability of its product glucan to support the adherence of oral microorganisms. Gtf from S. sanguis 804 NCTC 10904 was purified from culture supernatant fluids by means of hydroxyapatite chromatography. Enzyme and the substrate were prepared in buffers at pH values from 3.5 to 7.5. Maximum activity of GtfSs occurred between pH 5.5 and pH 6.5, whether in solution or adsorbed onto a surface. The solubilized and insolubilized enzymes showed highest activity at 40 degrees C; activity was reduced by 50(+/-2)% at 20 and 30 degrees C. The enzyme did not form glucans in either phase at 10 or 60 degrees C. The K(m), determined from Lineweaver-Burk plots, for the enzyme in solution was 4.3(+/-0.4) mmol/l sucrose, and the K(m) for the enzyme on sHA beads was 5.0(+/-1.0) mmol/l sucrose. The ability of the GtfSs glucan synthesized on the surface of sHA beads to support the adherence of oral bacteria was investigated. (3)H-thymidine-labeled bacteria (S. mutans GS-5, S. sobrinus 6715, S. sobrinus 6716, S. sanguis 10904, Actinomyces viscosus OMZ105E, A. viscosus 2085, and A. viscosus 2086) were incubated with sHA beads coated with GtfSs glucan. S. mutans GS-5 displayed the highest level of binding numerically. These results show that the GtfSs of S. sanguis is active on sHA beads, that the pH optimum for activity on a surface differs slightly from that in solution, and that its product glucan can support the adherence of oral microorganisms.

Automatic enumeration of adherent streptococci or actinomyces on dental alloy by fluorescence image analysis.

The aim of the present study was to develop an automated image analysis method to quantify adherence of Streptococcus sanguinis or Actinomyces viscosus on surfaces of a currently used dental alloy. Counting such bacterial strains was difficult because of their arrangement, thus S. sanguinis being a coccus arranged in chains or pairs, and A. viscosus a long complexly arranged polymorph rod. Direct counting of fluorescently stained adherent bacteria was done visually and with image analysis methods. To differentiate these two morphotypes, two programs were developed: (i) for streptococci, thresholding and selection of the object maxima, and (ii) for actinomyces, two step thresholding and processing of the characteristic points of the object skeletons. The triplicate enumerations for each bacterial strain were not significantly different (p > 0.005) and correlations between visual counting and automated counting were significant (r = 0.91 for S. sanguinis and r = 0.99 for A. viscosus, p <00.0001). These rapid and reproducible methods, allowed us to count either cocci or rods, adherent on an inert substratum, in high density conditions.

Effect of salivary biofilm on the adherence of oral bacteria to bleached and non-bleached restorative material.

OBJECTIVE: The objective of this work was to examine the effect of in vitro salivary biofilm on the adherence of oral bacteria to bleached and non-bleached restorative material (Charisma). METHODS: Charisma samples, prepared in silicon models, were treated with either 10% carbamide peroxide (CP) or 10% hydrogen peroxide (HP). After incubation with the bleaching agent for a period of one, two or three days, the samples were coated with freshly collected human saliva. The adsorption pattern of the saliva to the restorative material was determined using gel electrophoresis coupled with computerized densitometry techniques. The amount of salivary proteins adsorbed onto the treated surfaces was measured using the Bradford method. Sucrose-dependent bacterial adhesion to the salivary-coated Charisma was tested using radio-labeled Streptococcus mutans, Streptococcus sobrinus and Actinomyces viscosus. Adhesion of each bacterium to surfaces pretreated with the bleaching agents was compared with saliva coated bleached surfaces. RESULTS: The profile of salivary proteins adsorption followed a similar pattern in Charisma samples pretreated with either CP or HP or untreated samples. However, the total amount of salivary proteins adsorbed onto the samples decreased after bleaching with CP or HP. Salivary biofilm, coating the surface of the restorative material, significantly decreased sucrose-dependent adhesion of Streptococcus sobrinus and Streptococcus mutans to the bleached and non-bleached surfaces, compared to non-coated specimens (p < 0.05). Saliva had a minor effect on adhesion of Actinomyces viscosus. SIGNIFICANCE: Our study demonstrates the importance of salivary biofilm in controlling adhesion of oral bacteria to restorative material pretreated with bleaching agents or untreated.