PURPOSE:To assess the impact of anodization and instrumentation on titanium abutment surface characteristics (surface roughness and wettability) and biofilm formation (viability and mass). MATERIALS AND METHODS:Titanium discs were obtained from pre-milled abutment blanks made of titanium-6aluminum-7niobium alloy. Polished samples were divided into three groups: un-anodized, gold-anodized, and pink-anodized. Instrumentation methods included no-instrumentation, air polishing, and titanium scaling treatment. Surface roughness was measured using an optical profilometer, and wettability was determined by measuring the contact angles using the sessile drop method with an optical tensiometer. Biofilm formation by Streptococcus sanguinis was evaluated based on the biofilm viability and mass. The biofilm viability was evaluated through colony-forming unit counting (CFU/mL), and biofilm mass was assessed with crystal violet staining (mean absorbance measured at 490 nm, in optical density values). Sample surfaces before and after biofilm formation were also examined by scanning electron microscope (SEM). Two-way ANOVA was performed to determine the group differences, and Spearman's correlation (ρ) was used to analyze the correlation among surface roughness, wettability, and CFU/mL (α = 0.05). RESULTS:Pink anodization significantly increased surface roughness (0.38 ± 0.07 µm, p < 0.001) compared to un-anodized samples (0.25 ± 0.01 µm), while gold anodization did not (0.24 ± 0.03 µm, p = 0.301). Among pink-anodized groups, air polishing resulted in significantly lower surface roughness (0.33 ± 0.08 µm) compared to titanium scaling (0.51 ± 0.11 µm, p < 0.001) and no instrument treatment (0.38 ± 0.07 µm, p = 0.050). Anodization significantly increased wettability (p < 0.001), while instrumentation with a titanium scaling decreased it (p < 0.001). The combination of un-anodized samples and titanium scaling treatment showed the lowest wettability with the highest contact angle (70.72 ± 2.63°). The biofilm viability, measured by CFU/mL, was significantly inhibited by anodization (p < 0.001) and air polishing (p < 0.001) while promoted by titanium scaling (p < 0.001). Gold-anodized titanium discs subjected to air polishing exhibited the lowest CFU/mL (279,420 ± 16,300), while un-anodized samples instrumented with a titanium scaler had the highest CFU/mL (945,580 ± 13,580). Biofilm mass, quantified by optical density values, was significantly inhibited by anodization (p < 0.001) as well as air polishing (p = 0.001). A moderate negative correlation was observed between CFU and wettability (ρ = -0.55, p < 0.001). CONCLUSION:Gold- and pink-anodized titanium surfaces were more hydrophilic, leading to less biofilm formation than un-anodized ones. Biofilm formation was inhibited by air polishing while promoted by titanium scaling. Gold anodization combined with air polishing had the least biofilm formation and can be considered the preferred abutment anodization/instrumentation combination.

To evaluate the efficacy of commercially available, fluoride-free mouthwashes sold in Indianapolis, IN, on Streptococcus mutans biofilm. Eighty-one different mouthwashes were purchased. A 16-h culture of S. mutans UA159 was treated with the mouthwashes in three dilutions (1:3, 1:6, and 1:12), prepared in Tryptic Soy broth supplemented with 1

Background Silver diamine fluoride (SDF) reagent is used to prevent and arrest caries lesions. However, the mechanism of its action is not fully reported. The antimicrobial effect of SDF was determined on an established nicotine-induced Streptococcus mutans biofilm by measuring colony-forming units (CFUs), different application times, and extracellular polysaccharide (EPS) synthesis. Methods S mutans biofilm was established with and without 2 mg/mL of nicotine in tryptic soy broth supplemented with sucrose. Nicotine and nonnicotine-induced biofilm groups were treated with 38% SDF for 1 minute. Non-SDF-treated groups were used as a control. The biofilm was plated on blood agar plates, and CFUs were determined. In addition, different SDF application times (30 seconds and 1, 2, and 3 minutes) were tested. For EPS production, S mutans were incubated with and without nicotine in tryptic soy broth supplemented with sucrose. SDF groups were treated with SDF for 1 minute. A phenol-sulfuric acid assay was used to measure the total carbohydrate produced. Results There was a significant effect of SDF on reducing CFUs for both nicotine and nonnicotine groups. The different application times of SDF reduced CFUs for all tested groups. EPS production was significantly reduced with the SDF application. Conclusions The use of SDF with different application times disrupted established S mutans biofilms. In addition, EPS production was reduced by the application of SDF. This confirms the ability of a shorter SDF treatment time to be effective and suggests a possible mechanism of action for the inhibition of caries development.

During implant maintenance, preserving a smooth surface on the machined transmucosal abutment is critical to reduce biofilm attachment and colonization. The present study compared the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined grade 23 titanium discs were instrumented with a round polyether ether ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units per milliliter were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared with the other groups. This resulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness, and SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared with discs instrumented with plastic or PEEK tips despite the possibility of debris from tip dissolution. Our results suggest that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increased machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion.

Background: Enterococcus faecalis has been found to be related to periodontitis and secondary endodontic infections. In this study, we aimed to study samples of E. faecalis to determine their incidence and virulence in Jordanian patients. Methods: A total of 167 samples were collected from patients with periodontitis and secondary endodontic infections. The Kirby-Bauer method was used to determine the antimicrobial susceptibility. Biofilm formation was studied using the microtiter plate assay and congo red agar assay. Polymerase chain reaction (PCR) was used to detect the presence of E. faecalis virulence genes, namely; asa1, gelE, cylA, esp, hyl, efaA, and ace. Gelatinase and cytolysin activity were also tested using phenotypic methods. Results: Twenty-three (13.8%) samples were positive for E. faecalis. The highest resistance rates were observed against ampicillin (87%), followed by penicillin (82.6%), and erythromycin (60.9%). The highest susceptibility was for levofloxacin (100%), followed by gentamycin and chloramphenicol, each with 95.7%. Most isolates were able to produce biofilm (78.3%). Gelatinase and cytolysin activity were detected in 21.7% and 56.5% of isolates, respectively. efaA was significantly associated with asa1 and gelE (P < 0.05), and esp was significantly associated with cylA, gelE, ace, efaA and asa1 ( P < 0.05). In addition, the gelE. gene was significantly associated with gelatinase production (P < 0.01). Conclusion: In conclusion, we have shown that E. faecalis is involved with periodontal disease and secondary root canal infection with several virulence genes detected. Clinical Relevance: Around 13% of the periodontitis and secondary root canal infection patients were positive for E. faecalis and isolates were resistant to commonly used antibiotics.

Purpose: The purposes of this in vitro study were to evaluate the effect of three isolation methods to mitigate bioaerosols during stainless steel crown (SSC) preparations and assess the distribution of Streptococcus mutans by aerosolization in closed-room operatories. Methods: Melamine teeth coated in laboratory-grown S. mutans biofilm were prepared for SSCs using three different isolation methods. Agar plates were placed in five locations throughout the operatory and opened during each preparation as well as for 10 minutes immediately following to collect aerosolized S. mutans. Bacterial colonies were counted after incubating plates for 48 hours. Data were analyzed for differences between the isolation method and plate locations. Results: Bacterial colony counts for teeth prepared using high-volume evacuation suction (HVE) with dental dam (DD) isolation were statistically significantly higher than for those prepared using HVE with a DryShield (R) (DS) and HVE with no isolation at the assistant (A) (P<0.001), operator face shield (FS) (P<0.001), and patient (Pt) (P=0.002) locations. No significant differences were found among isolation methods for parent (Pa) or rear delivery (RD) locations. The location that produced the most bacterial colony counts using HVE with DD isolation was FS (P<0.001), followed by A (P=0.04), Pt (P<0.001), and RD and Pa (P<0.001). Counts produced from teeth prepared with DS isolation were significantly higher at the Pt location than the A (P<0.001), FS (P=0.002), RD (P<0.001), and Pa (P=0.008) locations. Conclusion: The use of dental dam with high-volume evacuation suction during stainless steel crown preparations increased bioaerosols near the procedure, while dental evacuation systems (DryShield (R)) may effectively limit their spread.

Abstract Aims This study evaluated the antimicrobial effect of coriander oil (CO) and isothiocyanates (ITC; Allyl, Benzyl and Phenyl-A-, B-, P-ITC) on clinical oral isolate Streptococcus mutans . We evaluated inhibition of biofilm, metabolic activity and exopolysaccharide formation. Methods The composition of CO was determined by gas chromatography- mass spectrometry (GC-MS). CO and ITC were dissolved in 0.1% Tween 80. Different concentrations (0.0039-1%) of CO, ITC and CO-ITC were made in Tryptic soy broth (TSB) and with sucrose (TSBS). Broth dilution method was used to determine the minimum inhibitory concentration (MIC). Minimum biofilm inhibitory concentrations (MBIC) were established by staining biofilm with crystal violet. Checkerboard assay was used to evaluate combination effects. An XTT assay was used to determine the metabolic activity and a sulphuric acid-phenol assay for inhibition of S. mutans exopolysaccharide production. Results CO was dominated by Linalool (65.5%) followed by 2-bornanone (6.16%) and Gamma-terpinene (4.31%). The least was Terpinen-4-ol (0.13%). The MIC of CO was 0.00195% and < 0.00195% for ITCs. MBIC for B-ITC was at < 0.0039%, while with CO-ITC at 0.00195% (p < 0.05). The MBC of CO was 0.125% and for CO-B-ITC MBIC was < 0.00195%. The B-ITC MBC was > 0.25%. Strong S. mutans exopolysaccharide inhibition was observed with ITC and CO at 0.0039%. CO reduced S. mutans metabolic activity at 0.125% and ITC at 0.0078%. Conclusion and clinical relevance: CO and ITC are promising agents in prevention of both periodontal disease and dental caries. Further data is required to warrant development of products to help mitigate dental caries and periodontal disease.

Background: Streptococcus mutans ( S. mutan s) participates in the dental caries process. Titanium dioxide (TiO 2 ) nanoparticles produce reactive oxygen species capable of disrupting bacterial DNA synthesis by creating pores in cell walls and membranes. Objective: The objective of this study was to determine the effect of TiO 2 on the disruption of S. mutans biofilm. Methods: This study was conducted in four phases involving a TiO 2 -containing toothbrush and TiO 2 nanoparticles. Each phase was completed using 24 h established S. mutans biofilm growth. Phase one data was collected through a bacterial plating study, assessing biofilm viability. Biofilm mass was evaluated in phase two of the study by measuring S. mutans biofilm grown on microtiter plates following crystal violet staining. The third phase of the study involved a generalized oxygen radical assay to determine the relative amount of oxygen radicals released intracellularly. Phase four of the study included the measurement of insoluble glucan/extracellular polysaccharide (EPS) synthesis using a phenol-sulfuric acid assay. Results: Both exposure time and time intervals had a significant effect on bacterial viability counts ( p = 0.0323 and p = 0.0014, respectively). Bacterial counts after 6 min of exposure were significantly lower than after 2 min ( p = 0.034), compared to the no treatment control ( p = 0.0056). As exposure time increased, the amount of remaining biofilm mass was statistically lower than the no treatment control. Exposure time had a significant effect on oxygen radical production. Both the 30 and 100 nm TiO 2 nanoparticles had a significant effect on bacterial mass. The silver nanoparticles and the 30 and 100 nm TiO 2 nanoparticles significantly inhibited EPS production. Conclusion: The TiO 2 -containing toothbrush kills, disrupts, and produces oxygen radicals that disrupt established S. mutans biofilm. TiO 2 and silver nanoparticles inhibit EPS production and reduce biofilm mass. The addition of TiO 2 to dental products may be effective in reducing cariogenic dental biofilm. Keywords Oral bacteria , dental plaque , toothbrush , viability , oxygen radicals , nanoparticles

Background:Peri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants. Methods:Biofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants. Results:Three-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm. Conclusion:While early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.

Background: Streptococcus mutans (S. mutans) participates in the dental caries process. Titanium dioxide (TiO2) nanoparticles produce reactive oxygen species capable of disrupting bacterial DNA synthesis by creating pores in cell walls and membranes.Objective: The objective of this study was to determine the effect of TiO2 on the disruption of S. mutans biofilm.Methods: This study was conducted in four phases involving a TiO2-containing toothbrush and TiO2 nanoparticles. Each phase was completed using 24 h established S. mutans biofilm growth. Phase one data was collected through a bacterial plating study, assessing biofilm viability. Biofilm mass was evaluated in phase two of the study by measuring S. mutans biofilm grown on microtiter plates following crystal violet staining. The third phase of the study involved a generalized oxygen radical assay to determine the relative amount of oxygen radicals released intracellularly. Phase four of the study included the measurement of insoluble glucan/extracellular polysaccharide (EPS) synthesis using a phenol-sulfuric acid assay.Results: Both exposure time and time intervals had a significant effect on bacterial viability counts (p = 0.0323 and p = 0.0014, respectively). Bacterial counts after 6 min of exposure were significantly lower than after 2 min (p = 0.034), compared to the no treatment control (p = 0.0056). As exposure time increased, the amount of remaining biofilm mass was statistically lower than the no treatment control. Exposure time had a significant effect on oxygen radical production. Both the 30 and 100 nm TiO2 nanoparticles had a significant effect on bacterial mass. The silver nanoparticles and the 30 and 100 nm TiO2 nanoparticles significantly inhibited EPS production.Conclusion: The TiO2-containing toothbrush kills, disrupts, and produces oxygen radicals that disrupt established S. mutans biofilm. TiO2 and silver nanoparticles inhibit EPS production and reduce biofilm mass. The addition of TiO2 to dental products may be effective in reducing cariogenic dental biofilm.

Background:This study evaluated the antifungal and antibacterial effects of stabilized chlorine dioxide-containing oral care products against yeast and bacterial species associated with pneumonia. Methods:Six yeast species (Candida albicans, Candida glabrata, Cryptococcus neoformans, Candida dubliniensis, Candida krusei, Candida tropicalis) and 5 bacterial species (Streptococcus pneumoniae, Klebsiella pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Pseudomonas aeruginosa) were grown in Sabouraud dextrose broth and brain-heart infusion media, respectively, overnight. Each microorganism was treated with individual chlorine dioxide-containing ClōSYS (Rowpar Pharmaceuticals) products (Silver Multi-Benefit Fluoride Mouthwash, Sensitive Fresh Breath Mouthwash, Ultra Sensitive Mouthwash, Oral Spray, Silver Toothpaste, Sensitive Toothpaste, Fluoride-free Toothpaste) at serial dilutions. Chlorhexidine gluconate (0.12%) mouthrinse and water were positive and negative controls, respectively. Treated species were grown overnight. Minimum inhibitory concentration (MIC) was evaluated. Five microliters of each culture were transferred to blood agar plates incubated overnight, and minimum fungicidal concentration (MFC) and minimum bactericidal concentrations (MBC) were evaluated. Results:All undiluted products produced antifungal effects against tested yeast species. Similarly, antibacterial effects were observed for all products except for S pneumoniae and H influenzae, which were resistant to killing by some products. All tested products produced fungistatic or bacteriostatic effects against tested fungal or bacterial species. Different concentrations of each product are required to produce MIC, MFC, and MBC for each species tested. Some species required an equal or higher MIC than MFC and MBC. Conclusions:Stabilized chlorine dioxide-containing ClōSYS oral care products exhibit antifungal and antibacterial effects against common yeast and bacterial species associated with pneumonia.

AIMS:The purpose of this study was to compare the effect of hop extracts with diverse β-acid concentrations on Streptococcus mutans biofilm formation.METHODS AND RESULTS:Ten different hop extracts, with α-acid concentrations similar to those found in commercial beer products and β-acid concentrations ranging from 2.6 to 8.1%, were added to distilled water to make standardized concentrations. S. mutans isolates were treated with hop extract dilutions varying from 1:2 to 1:256. The minimum inhibitory, minimum bactericidal and minimum biofilm inhibitory concentrations were determined and the optical density was evaluated. Live/dead staining confirmed the bactericidal effects. Biofilm formation of several strains of S. mutans was significantly inhibited by hop extract dilutions of 1:2, 1:4, 1:8, 1:16 and 1:32. Strong negative correlations were observed between α- and β-acid concentrations of the hop extracts and S. mutans total growth and biofilm formation.CONCLUSIONS:The use of hop extracts prepared similarly to commercial beer decreased S. mutans biofilm formation.SIGNIFICANCE AND IMPACT OF THE STUDY:The inclusion of hops in the commercial beer products may provide beneficial health effects. Further studies are warranted to determine an effect in vivo on the development of dental caries.

The authors appreciate Dr Nair’s comments and interest in our article.1Alfaifi A.A. Lin W.S. Aldhaian B.A. Levon J.A. Gregory R.L. Impact of caffeine on metabolic activity and biofilm formation of Candida albicans on acrylic denture resin in the presence of nicotine.J Prosthet Dent. 2020; 123: 875-879Google Scholar The study aimed to examine the effect of caffeine on metabolic activity and biofilm formation of Candida albicans growing on acrylic denture resin while simultaneously exposed to nicotine. Upon consulting with our team, we appreciate these comments pointing out limitations of the study and proposing interesting ideas for future research. The scope of a single study is often controlled to answer well-defined research questions and to fulfill the aims of the study. We consider that Dr Nair’s comments are somewhat beyond the scope of the original publication, and the authors would encourage future studies to provide answers to these questions. We are unable to speculate on the influences or effects of salivary pH values, surface treatments, cleansing solutions, and other chemicals because they were not the intended variables in the original publication.

Abstract Background Streptococcus pyogenes is an important global human pathogen that causes pharyngitis, and antibacterial therapy has become an important part of the overall therapy for pharyngitis. As natural derivatives, honey and green tea are often recommended for patients with pharyngitis in traditional Chinese medicine without experimental theoretical basis on wether the combined effect of honey and green tea on pharyngitis is better than they alone. The aims of this study were to explore the effects of artificial honey (AH) and epigallocatechin-3-gallate (EGCG) on S. pyogenes and elucidate the possible mechanisms, which were investigated using MIC (the minimum inhibitory concentration), FIC (fractional inhibitory concentration) index, growth pattern, biofilm formation and RT-qPCR. Results The MIC of AH on S. pyogenes was 12.5% (v/v) and the MIC of EGCG was 1250 μg/ml. The FIC index of AH and EGCG was 0.5. The planktonic cell growth, growth pattern and biofilm formation assays showed that AH and EGCG mixture had stronger inhibitory effect on S. pyogenes than they alone. RT-qPCR confirmed that the expression of hasA and luxS gene were inhibited by AH and EGCG mixture. Conclusions AH and EGCG mixture can inhibit the planktonic cell growth, biofilm formation and some virulence genes expression of S. pyogenes, better than they alone. The combination of honey and green tea have the potential to treat pharyngitis as natural derivatives, avoiding drug resistance and double infection.

Background To compare anti-bacterial activity of 0.12% Chlorhexidine (CHX), 10% Povidone Iodine (PVD), Vega Oral Care Gel (VEGA), and Antioxidant Gel (AO) on Streptococcus mutans, Streptococcus sanguis, Fusobacterium nucleatum, and Porphyromonas gingivalis with and without nicotine and to evaluate their effects on human gingival fibroblasts (HGFs). Methods S. mutans, S. sanguis, P. gingivalis, and F. nucleatum were incubated with serial dilutions (1/4, 1/8, 1/16, 1/32, and 1/64) of anti-bacterial agents in media (with and without nicotine). Minimum inhibitory and minimum bactericidal concentrations (MIC/MBC) were measured, and confocal microscopy was performed. HGFs were exposed to serial dilutions (1/10, 1/100, 1/1000, and 1/10,000) of antibacterial agents with media. Water-soluble tetrazolium-1 (WST-1) assay and lactate dehydrogenase (LDH) assay were used to assess proliferation and cytotoxicity towards HGFs. Results CHX and PVD significantly inhibited growth of all bacterial species (P < 0.0001) at all dilutions. AO and VEGA inhibited growth of all bacterial species up to only the 1/4 dilution. CHX and PVD decreased HGF proliferation at 1/10 and 1/100 dilution, whereas AO at all dilutions (P < 0.05). CHX and AO were cytotoxic at all dilutions (P < 0.05). VEGA was not cytotoxic to HGFs and did not affect HGF proliferation at any dilution (P > 0.05). An increased bacterial growth was seen for all species except P. gingivalis with addition of nicotine. Conclusion CHX and PVD demonstrate superior antibacterial properties, but significantly reduce HGF proliferation. AO is bacteriostatic at lower dilutions but is highly toxic to HGFs. VEGA was bacteriostatic and demonstrated no detrimental effects on HGF's.

(1) To explore the influence of biofilm maturation and timing of exposure on fluoride anticaries efficacy and (2) to explore biofilm recovery post-treatment. Bovine enamel specimens were utilized in a pH cycling model (28 subgroups [n = 18]). Each subgroup received different treatments [exposure]: sodium fluoride [NaF]; stannous fluoride [SnF2]; amine fluoride [AmF]; and de-ionized water [DIW], at a specific period: early: days 1–4; middle: days 3–6; and late: days 7–10. During non-exposure periods, pH cycling included DIW instead of fluorides. Objective 1: part 1 (cycling for 4, 6, or 10 days). Part 2 (cycling for 10 days). Objective 2: early exposure: three sample collection time points (immediate, 3 days, and 6 days post-treatment); middle exposure: two sample collection time points (immediate, 4 days post-treatment). The enamel and biofilm were analyzed ([surface microhardness; mineral loss; lesion depth]; [lactate dehydrogenase enzyme activity; exopolysaccharide amount; viability]). Data were analyzed using ANOVA (p = 0.05). Objective 1: Early exposure to fluorides produced protective effects against lesion progression in surface microhardness and mineral loss, but not for lesion depth. Objective 2: Early exposure slowed the demineralization process. SnF2 and AmF were superior to NaF in reducing LDH and EPS values, regardless of exposure time. They also prevented biofilm recovery. Earlier exposure to SnF2 and AmF may result in less tolerant biofilm. Early fluoride treatment may produce a protective effect against demineralization. SnF2 and AmF may be the choice to treat older biofilm and prevent biofilm recovery. The study provides an understanding of biofilm-fluoride interaction with mature biofilm (e.g., hard-to-reach areas, orthodontic patients) and fluoride’s sustainable effect hours/days after brushing.

Streptococcus mutans serotype k strains comprise <3% of oral isolates of S. mutans but are prominent in diseased cardiovascular (CV) tissue. Collagen binding protein (CBP) genes, cbm and cnm, are prevalent in serotype k strains and are associated with endothelial cell invasion. Nicotine increases biofilm formation by serotype c strains of S. mutans, but its effects on serotype k strains and strains with CBP are unknown. Saliva contains arginine which alters certain properties of the extracellular polysaccharides (EPS) in S. mutans biofilm. We examined whether nicotine and arginine affect sucrose-induced biofilm of S. mutans serotypes k (n = 23) and c (n = 10) strains with and without CBP genes. Biofilm mass, metabolism, bacterial proliferation, and EPS production were assessed. Nicotine increased biomass and metabolic activity (p < 0.0001); arginine alone had no effect. The presence of a CBP gene (either cbm or cnm) had a significant effect on biofilm production, but serotype did not. Nicotine increased bacterial proliferation and the effect was greater in CBP + strains compared to strains lacking CBP genes. Addition of arginine with nicotine decreased both bacterial mass and EPS compared to biofilm grown in nicotine alone. EPS production was greater in cnm + than cbm + strains (p < 0.0001). Given the findings of S. mutans in diseased CV tissue, a nicotine induced increase in biofilm production by CBP + strains may be a key link between tobacco use and CV diseases.

Objective: The purpose of this study was to compare the effects of different levels of nicotine and tobacco extract exposure on Streptococcus mutans biofilm formation and the inhibitory effect of the polyphenol epigallocatechin-3 gallate (EGCG) found in green tea. This study addressed the results of biofilm assays with EGCG and varying relative concentrations of nicotine and tobacco extract consistent with primary, secondary and tertiary levels of smoking exposure. Primary smoking exposure to nicotine has been demonstrated to significantly increase biofilm formation, while EGCG has been demonstrated to reduce S. mutans biofilm formation.Methods: S. mutans was treated with varying levels of nicotine or cigarette smoke condensate (CSC) concentrations (0-32 mg/ml and 0-2 mg/ml, respectively) in Tryptic Soy broth supplemented with 1% sucrose for different lengths of time simulating primary, secondary and tertiary smoking exposure with and without 0.25 mg/ml EGCG. The amount of total growth and biofilm formed was determined using a spectrophotometric crystal violet dye staining assay.Results: For both nicotine and CSC, primary exposure displayed overall significantly less growth compared to secondary exposure. For nicotine, secondary exposure demonstrated significantly greater growth than tertiary exposure levels. Overall, significantly greater total bacterial growth and biofilm formation in the presence of nicotine and CSC was observed in the absence of EGCG than in the presence of EGCG. However, biofilm growth was not significantly different among different concentrations of CSC.Conclusion: The results of this study help illustrate that nicotine-induced S. mutans biofilm formation is reduced by the presence of EGCG. This provides further evidence of the potential beneficial properties of polyphenols.

Introduction: Xylitol can affect caries-inducing bacteria; however, different Streptococcus mutans strains might respond differently. Aim: To investigate the effect of xylitol on biofilm formation and metabolic activity of seven S. mutans strains. Methods: Seven S. mutans strains (UA159, A32-2, NG8, 10449, UA130, LM7, and OMZ175) were inoculated into 96-well microtiter plates and were tested with various xylitol concentrations (0.0, 0.0016, 0.0031, 0.0063, 0.0125, 0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 g/mL) for inhibition of biofilm formation and bacterial metabolic activity by recording absorbance values. Lactate dehydrogenase and extracellular polysaccharide assays were conducted at 0.0, 0.1, 0.2, 0.4, and 0.8 g xylitol/mL. Data were analyzed by one-way analysis of variance, Tukey's, paired t, and LSD tests at 0.05 significance level. Results: Xylitol produced a significant decrease in bacterial biofilm formation compared to controls at 0.4 g/mL, with almost complete lack of biofilm formation at 0.8 g/mL. This was consistent with metabolic activity which demonstrated a significant activity reduction occurring for all strains at 0.4 g/mL, and a complete lack of activity at 0.8 g/mL for all seven strains. There was a trend for lower LDH and EPS production with the increase in xylitol concentration especially with UA159, UA130, and NG8. Conclusion: Xylitol has a clear anticariogenic effect on S. mutans which was slightly different depending on the tested strain confirming that the benefit of xylitol might vary from one patient to another. The effect is more apparent at concentrations of 0.4 g/mL and higher.

The use of herbal products in oral hygiene care has a long history, and their use is popular today. A tree stick, named Salvadora persica (S. persica), is commonly used to remove dental plaque and clean teeth in many countries. In addition, extracts of S. persica can be used as a mouthwash, as they demonstrate antimicrobial properties. This study aimed to investigate the antibacterial effect of S. persica methanol and aqueous extracts against Streptococcus mutans (S. mutans) biofilm. A S. mutans biofilm formation assay was conducted using different concentrations of S. persica methanol or water extracts in tryptic soy broth (TSB) supplemented with 1% sucrose. The biofilm was stained with crystal violet dye, and the absorbance was assessed to examine biofilm formation. One-way analysis of variance (ANOVA) and Tukey tests were used to analyze the results. The S. persica methanol extract displayed a significant inhibition (p ≤ 0.001) against the S. mutans biofilm. The 10 mg/mL concentration of the S. persica methanol extract was determined as the minimum biofilm inhibitory concentration (MBIC). The used methanol concentration, mixed with TSB supplemented with 1% sucrose and without the S. persica extract, did not inhibit the S. mutans biofilm. The S. persica aqueous extract did not demonstrate any biofilm inhibition at any concentration (p ≥ 0.05). The findings of this study suggest the potential of using S. persica methanol extract as a mouthwash or adjunctive to oral hygiene tools.