Influence of different growth conditions on the composition and acidogenicity of saliva-derived microcosm biofilm and their effects on enamel demineralization.

This study compared the influence of growth conditions on the composition and acidogenicity of saliva-derived microcosm biofilms and enamel demineralization. Biofilms grown in sucrose-supplemented modified McBain medium, containing 25/50 mmol/L PIPES (buffer), under anaerobiosis/microaerophilia, for 3 and 7 days were evaluated for their acidogenicity, microbial composition, matrix, and enamel mineral content. The viability of total lactobacilli was higher in the group containing 25 mmol/L PIPES grown under anaerobiosis, which also showed lower pH values. The viability of total streptococci and total microorganisms was significantly higher at 7 days in the groups with 50 mmol/L PIPES than at 3 days, regardless of the incubation atmosphere. No significant differences were observed in lactic acid, calcium, superficial hardness loss, or lesion depth. In conclusion, the incubation atmosphere, buffer content in the growth media, and duration of biofilm formation displayed species-varied influence on microcosm biofilms, without causing significant changes in acid metabolism or enamel demineralization.

Interkingdom biofilm of Streptococcus pyogenes and Candida albicans: establishment of an in vitro model and dose-response validation of antimicrobials.

Although Streptococcus pyogenes and Candida albicans may colonize tonsillar tissues, the interaction between them in mixed biofilms has been poorly explored. This study established an interkingdom biofilm model of S. pyogenes and C. albicans and verified the dose-response validation of antimicrobials. Biofilms were formed on microplates, in the presence or absence of a conditioning layer of human saliva, using Brain Heart Infusion (BHI) broth or artificial saliva (AS) as a culture medium, and with variations in the microorganism inoculation sequence. Biofilms grown in AS showed higher mass than those grown in BHI broth, and an opposite trend was observed for metabolism. The number of S. pyogenes colonies was lower in AS. Amoxicillin and nystatin showed dose-dependent effects. The inoculation of the two species at the same time, without prior exposure to saliva, and using BHI broth would be the model of choice for future studies assessing the effects of antimicrobials on dual S. pyogenes/C. albicans biofilms.

Evaluation of Solutions Containing Fluoride, Sodium Trimetaphosphate, Xylitol, and Erythritol, Alone or in Different Associations, on Dual-Species Biofilms.

Although the association of polyols/polyphosphates/fluoride has been demonstrated to promote remarkable effects on dental enamel, little is known on their combined effects on biofilms. This study assessed the effects of solutions containing fluoride/sodium trimetaphosphate (TMP)/xylitol/erythritol on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were grown in the continuous presence of these actives alone or in different associations. Quantification of viable plate counts, metabolic activity, biofilm biomass, and extracellular matrix components were evaluated. Overall, fluoride and TMP were the main actives that significantly influenced most of the variables analyzed, with a synergistic effect between them for S. mutans CFUs, biofilm biomass, and protein content of the extracellular matrix (p < 0.05). A similar trend was observed for biofilm metabolic activity and carbohydrate concentrations of the extracellular matrix, although without statistical significance. Regarding the polyols, despite their modest effects on most of the parameters analyzed when administered alone, their co-administration with fluoride and TMP led to a greater reduction in S. mutans CFUs and biofilm biomass compared with fluoride alone at the same concentration. It can be concluded that fluoride and TMP act synergistically on important biofilm parameters, and their co-administration with xylitol/erythritol significantly impacts S. mutans CFUs and biomass reduction.

Are the counts of Streptococcus mutans and Staphylococcus aureus changed in complete denture wearers carrying denture stomatitis? A systematic review with meta-analyses.

STATEMENT OF PROBLEM: Despite the importance of Candida spp. on the etiology of denture stomatitis (DS), information on the role of the bacterial component is still scarce. PURPOSE: The purpose of this systematic review was to evaluate whether the counts of Staphylococcus aureus and Streptococcus mutans were changed in complete denture wearers diagnosed with Candida-associated DS. MATERIAL AND METHODS: The literature search was performed in 8 databases and by hand searching. The risk of bias was assessed according to the Newcastle-Ottawa qualifier. Meta-analyses were performed considering the microorganism evaluated (S. aureus or S. mutans) and the collection area (mucosa or dentures). The certainty of evidence was assessed according to the grading of recommendations assessment, development and evaluations (GRADE) criteria. RESULTS: Participants with DS presented higher counts of S. aureus in the mucosa compared with those from the control group (OR, 3.16 [1.62, 6.15]; P<.001). No significant difference between the groups was observed for samples collected from dentures (OR, 0.73 [0.50, 1.07]; P=.110). Conversely, participants without DS presented higher counts of S. mutans both in the mucosa (OR, 0.19 [0.06, 0.63]; P=.006) and dentures (OR, 0.64 [0.41, 1.0]; P=.050). CONCLUSIONS: Microbial counts in participants with DS changed as a function of the type of microorganism and collection site. The certainty of evidence ranged from very low to low. The findings reinforce the fact that bacteria also play a relevant role in DS and should be more extensively studied. Such information may be useful to guide further therapies to prevent or control DS.

Effects of nano-sized sodium hexametaphosphate on the viability, metabolism, matrix composition, and structure of dual-species biofilms of Streptococcus mutans and Candida albicans.

This study evaluated the effects of micrometric or nano-sized sodium hexametaphosphate (HMPnano), combined or not with fluoride (NaF, 1100 ppm), on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were treated with solutions containing the polyphosphates at 0.5% or 1.0%, with/without fluoride (F), in addition to positive and negative controls. Biofilms were analysed by colony-forming units (CFU) counting, metabolic activity, production of biomass, composition of extracellular matrix, and structure. 1% HMPnano + F led to the lowest S. mutans CFU, while C. albicans CFU counts were not affected by any solution. 1% HMPnano led to the lowest metabolic activity, except for 1% HMPnano + F. All solutions promoted reductions in biofilm biomass compared to controls. Also, 1% HMPnano + F promoted the lowest concentrations of carbohydrates in the biofilm matrix, besides substantially affecting biofilms' structure. In conclusion, HMPnano and F promoted higher antibiofilm effects compared with its micrometric counterpart for most of the parameters assessed.

Effects of sodium hexametaphosphate microparticles or nanoparticles on the growth of saliva-derived microcosm biofilms.

OBJECTIVES: This study evaluated the effects of sodium hexametaphosphate microparticles (HMPmicro) or nanoparticles (HMPnano) on the growth of saliva-derived microcosm biofilms MATERIALS AND METHODS: Saliva-derived biofilms were formed on glass coverslips for 24 h. Thereafter, Streptococcus mutans (C180-2) was incorporated or not into the biofilms. From that time point onwards, solutions containing 0.2% HMPmicro or HMPnano, combined or not with 220 ppm F, were constantly present in the culture medium. In addition, 220 ppm F alone (220F) and McBain medium without any compound were also tested as positive and negative controls (CTL), respectively. After 96 h, the biofilms were plated on anaerobic blood agar or sucrose agar bacitracin for total and S. mutans CFU-counting, respectively. Biofilms' lactic acid production was analysed spectrophotometrically. Data were submitted to ANOVA or Kruskal-Wallis' tests, followed by Student-Newman-Keuls' test (p<0.05; n=12). RESULTS: HMPmicro or HMPnano led to significantly lower lactic acid production, and significant reductions in total CFU-counting in microcosm biofilms, supplemented or not with S. mutans, in comparison to both controls, with significant differences between 220F and CTL. No significant differences were observed among the groups treated with HMPmicro or HMPnano (with or without F). The same trend was seen for S. mutans CFU-counting, in biofilms supplemented with S. mutans. CONCLUSIONS: HMP significantly reduced total and S. mutans CFU counts, as well as lactic acid production by saliva-derived microcosm biofilms. CLINICAL RELEVANCE: These findings in saliva-derived microcosm biofilms suggest that HMP stands as a promising alternative for the control of cariogenic biofilms.

Effect of sodium hexametaphosphate and fluoride on dual-species biofilms of Candida albicans and Streptococcus mutans.

This study evaluated the effect of sodium hexametaphosphate (HMP), administered alone or in combination with fluoride (F), on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were treated with HMP solutions at 0.25%, 0.5% and 1%, alone or combined with F (0.05%), and compared by evaluating their structure and quantifying the colony-forming units (CFUs), metabolic activity, production of biomass and extracellular matrix components. All HMP-containing solutions were capable of reducing metabolic activity, the biofilm biomass, and the extracellular matrix components. Furthermore, the treatment with 1% HMP/F significantly reduced the CFUs of S. mutans, although it showed no effect on the CFUs of C. albicans, in the dual-species biofilms. In general, the combination of HMP and F influenced all the parameters analyzed from dual-species biofilms, except the CFUs of C. albicans.

Assessment of the reliability of the IHI Global Trigger Tool: new perspectives from a Brazilian study.

OBJECTIVE: To assess the reliability of the Institute for Healthcare Improvement's Global Trigger Tool (IHI-GTT) between nurses and medical students as primary reviewers to measure adverse events (AEs). DESIGN: Interrater reliability study. SETTING: A 500-bed general public hospital in Belo Horizonte, Brazil. PARTICIPANTS: A randomly selected sample of 220 hospital admissions of adults (≥18 years) from Oct-Nov, 2016. INTERVENTION: Two 4th-5th year-medical students and two experienced nurses applied a Portuguese-translated version of the IHI-GTT to medical records. The role of medical reviewer was performed by two senior physicians specialists in Internal Medicine. MAIN OUTCOME MEASURES: Ability to identify AEs was compared between pairs and against medical reviewer through percentage inter-examiner agreement and Kappa coefficient (K). Two outcomes -- "AE identification" and "category of harm" -- were evaluated according to two different denominators -- "admissions" (the total number of admissions evaluated in the sample; reflects the presence or not of at least one AE in each admission) and "all possibilities of agreement" (obtained by adding each identified AE to the admissions without events; allows agreement assessment to be performed for each AE individually). RESULTS: Were identified 199 adverse events in 90 hospitalizations, with rates of 40.9% of admissions with AEs, 76.1 AEs/1,000 patient-days and 90.5 AEs/100 admissions. Comparing student-pair and nurse-pair, we found K = 0.76 (95% IC 0.62-0.88) and K = 0.17 (95% IC 0.06-0.27) for "AE identification" outcome and K = 0.28 (95% IC 0.01-0.55) and K = 0.46 (95% IC 0.28-0.64) for "category of harm" outcome to denominators "admission" and "all possibilities of agreement", respectively. There was no significant difference between the performances of the different primary reviewers composed in any analyses. CONCLUSION: IHI-GTT reliability varies considerably depending on the denominator used to calculate agreement. As the purpose of the tool is, in addition to measuring, promoting opportunities for quality of care improvement, the individual analysis of the AEs seems more appropriate. Further studies are needed to assess the implications of the slight agreement reached between primary reviewers on the test's overall accuracy. Moreover, advanced medical students may be considered for primary review in settings where unavailability of staff is a barrier to IHI-GTT adoption.

Amount of Dentifrice and Fluoride Concentration Influence Salivary Fluoride Concentrations and Fluoride Intake by Toddlers.

The present study evaluated fluoride (F) concentrations in saliva of toddlers after brushing with dentifrices containing different F concentrations, applied in different quantities, and estimated F intake from toothbrushing. The study comprised a double-blind, crossover protocol, in which toddlers (n = 18, 2-3 years old) were randomly assigned into six groups, according to possible combinations of dentifrices (0/550/1,100 ppm F, as NaF) and amounts (rice grain, pea size, and transverse technique). Volunteers used a F-free dentifrice during 1 week. On the 7th day, saliva samples were collected before (baseline), and at 5/15/30/60 min after toothbrushing. All dentifrice expectorated after brushing was collected. F concentrations (saliva and expectorate) were determined with an ion-specific electrode. Data were submitted to ANOVA or Kruskal-Wallis test, followed by Fisher's LSD or Student-Newman-Keuls' tests (p <0.05). Brushing with 550 ppm F dentifrice (pea size or transversal technique) increased the area under the curve (AUC) at similar levels compared to 1,100 ppm F (rice grain). The highest AUC and salivary F at 5 min after brushing were achieved by 1,100 ppm F (pea size), followed by 550 ppm F (transversal technique). Regarding F intake, the highest values were observed for 550 ppm F (transversal technique), followed by 1,100 ppm F (pea size). It is possible to conclude that the amount of dentifrice and F concentration in the product significantly affected both salivary F concentrations and F intake during toothbrushing.

Effects of Sodium Trimetaphosphate, Associated or Not with Fluoride, on the Composition and pH of Mixed Biofilms, before and after Exposure to Sucrose.

The aim of the present study was to evaluate the influence of sodium trimetaphosphate (TMP), associated or not with fluoride (F), on the concentrations of F, calcium (Ca), and phosphorus (P) and on the pH of mixed biofilms of Streptococcus mutans and Candida albicans, before and after exposure to sucrose. The biofilms received three treatments (72, 78, and 96 h after the beginning of their formation), at three TMP concentrations (0.25, 0.5, or 1%), with or without F at 500 ppm. Solutions containing 500 and 1,100 ppm F as well as artificial saliva were also tested as controls. Biofilm pH was measured and the concentrations of F, Ca, and P were determined (solid and fluid phases). In a parallel experiment, after the third treatment (96 h), the biofilms were exposed to a 20% sucrose solution to simulate a cariogenic challenge and the pH of the medium, F, Ca, P, and TMP were determined. The data were submitted by two-way ANOVA, followed by Fisher's least significant difference test (p < 0.05). Treatment with TMP and 500 ppm F led to higher F concentration in the biofilm fluid. Although TMP did not affect Ca concentrations, biofilms treated with TMP alone presented higher P concentrations. Treatment with 1% TMP and F led to the highest pH values of the biofilm, both before and after the cariogenic challenge. It was concluded that TMP increases F and P in the biofilm and that its presence promotes an increase in the pH of the medium, even after the cariogenic challenge.

Activity of sodium trimetaphosphate, associated or not with fluoride, on dual-species biofilms.

This study aimed to evaluate the effect of sodium trimetaphosphate (TMP), either with fluoride (F) or without fluoride, on dual-species biofilms of Streptococcus mutans and Candida albicans. The 72 h biofilms were treated with 0.25%, 0.5%, or 1% TMP solutions, combined or not with 500 ppm F, and analysed by quantification of viable plate counts, metabolic activity, biomass, and extracellular matrix components. Biofilm structure was evaluated by scanning electron microscopy (SEM). TMP significantly reduced the number of S. mutans cells and biomass only when associated to F. Furthermore, fluoride-free TMP promoted significant reductions in biofilm metabolism, while all the tested solutions decreased the contents of the biofilm matrix compared to untreated groups. Regarding biofilm structure, TMP associated with F led to the formation of a less compact biofilm. It was concluded that TMP alone had a reducing effect, mainly on the metabolism and the extracellular matrix components of the biofilms.

Arginine and sodium fluoride affect the microbial composition and reduce biofilm metabolism and enamel mineral loss in an oral microcosm model.

OBJECTIVE: To assess the effects of arginine, with or without sodium fluoride (NaF; 1,450 ppm), on saliva-derived microcosm biofilms and enamel demineralization. METHODS: Saliva-derived biofilms were grown on bovine enamel blocks in 0.2 % sucrose-containing modified McBain medium, according to six experimental groups: control (McBain 0.2 %); 2.5 % arginine; 8 % arginine; NaF; 2.5 % arginine with NaF; and 8 % arginine with NaF. After 5 days of growth, biofilm viability was assessed by colony-forming units counting, laser scanning confocal microscopy was used to determine biofilm vitality and extracellular polysaccharide (EPS) production, while biofilm metabolism was evaluated using the resazurin assay and lactic acid quantification. Demineralization was evaluated by measuring pH in the culture medium and calcium release. Data were analyzed by Kruskal-Wallis' and Dunn's tests (p < 0.05). RESULTS: 8 % arginine with NaF showed the strongest reduction in total streptococci and total microorganism counts, with no significant difference compared to arginine without NaF. Neither 2.5 % arginine alone nor NaF alone significantly reduced microbial counts compared to the control, although in combination, a reduction in all microbial groups was observed. Similar trends were found for biofilm vitality and EPS, and calcium released to the growth medium. CONCLUSIONS: 8 % Arginine, with or without NaF, exhibited the strongest antimicrobial activity and reduced enamel calcium loss. Also, NaF enhanced the effects of 2.5 % arginine, yielding similar results to 8 % arginine for most parameters analyzed. CLINICAL SIGNIFICANCE: The results provided further evidence on how arginine, with or without NaF, affects oral microcosm biofilms and enamel mineral loss.

In vitro effect of fluoride gels supplemented with nano-sized sodium trimetaphosphate on enamel erosive wear.

OBJECTIVE: To assess the protective effect of fluoride (F) gels supplemented with micrometric or nano-sized sodium trimetaphosphate (TMPmicro and TMPnano, respectively) against enamel erosion in vitro. METHODS: Bovine enamel blocks (n = 140) were selected according to their surface hardness, and randomly divided into seven groups (n = 20/group), according to the gels tested: Placebo (without F/TMP), 4,500 µg F/g (4500F), 9,000 µg F/g (9000F), 4500F plus 2.5 % TMPnano (2.5 % Nano), 4500F plus 5 % TMPnano (5 % Nano), 4500F plus 5 % TMPnano (Micro 5 %) and 12,300 µg F/g (Acid gel). Blocks were treated once during one minute with the gels, and submitted to erosive (ERO, n = 10/group) or erosive plus abrasive (ERO+ABR, n = 10/group) challenges 4 times/day, for 90 s for each challenge (under reciprocating agitation), during consecutive 5 days. Blocks were analyzed by profilometry, and by surface (SH) and cross-sectional hardness (∆KHN). Data were submitted to two-way ANOVA, and Fisher's LSD test (p < 0.05). RESULTS: For ERO, both TMPnano-containing gels promoted enamel wear significantly lower than Placebo and 4500F, reaching levels similar to both positive controls (9000F and acid gel); significantly lower softening was observed for enamel treated with 4500F+5 % Micro and 4500F+2.5 % Nano. Also, the lowest ∆KHN values were observed for 4500F+2.5 % TMPnano among the TMP-containing gels. For ERO+ABR, the lowest enamel wear was achieved by the use of 4500F+5 % Nano among all gels, including both positive controls; lower softening was observed for Placebo and 9000F groups. CONCLUSION: The addition of 5 % nano-sized TMP to a low-fluoride gel produced superior protective effects for enamel under both challenges conditions, when compared with micrometric TMP, reaching values similar to or superior than both positive controls, respectively for ERO and ERO+ABR. CLINICAL SIGNIFICANCE: The supplementation of low-F gels with TMP was shown to significantly improve their effects on enamel erosive wear, and the use of nano-sized TMP further enhances this protective action.

Dual-species biofilm of Streptococcus mutans and Candida albicans produces subsurface caries lesions on bovine enamel.

OBJECTIVES: To develop a protocol for forming subsurface caries lesions on bovine enamel by dual-species biofilms of Streptococcus mutans and Candida albicans in vitro. DESIGN: Biofilms were grown on bovine enamel specimens in artificial saliva (AS) for seven days. After 24 h of formation, the AS was supplemented or not with fluoride (F) using sodium fluoride (0.005 or 0.008 ppm F), and the biofilms were exposed or not to a 20 % sucrose solution (reproducing a cariogenic challenge) once/day. On the seventh day, the biofilms were harvested and had their extracellular polysaccharides (EPS) and inorganic components analyzed. The specimens were subjected to computed X-ray microtomography analysis to determine their mineral concentration. Data were compared using two-way analyses of variance, followed by Fisher's LSD or Student-Newman-Keuls tests (p < 0.05). RESULTS: Biofilms exposed to the cariogenic challenge had significantly higher EPS concentrations than those not exposed, regardless of the presence of F. For biofilms grown with 0.008 ppm F, those exposed to the cariogenic challenge had lower F levels than those not exposed. For biofilms exposed to the cariogenic challenge, those grown with 0.008 ppm F had lower lesion depths and integrated mineral loss, and higher outer layers than those grown without F. CONCLUSIONS: The dual biofilm model assessed was able to create subsurface caries lesions in bovine enamel in vitro, which was influenced by the presence of F in the culture medium and exposure to sucrose.

Amount of Dentifrice and Fluoride Concentration Affect the pH and Inorganic Composition of Dual-Species Biofilms of Streptococcus mutans and Candida albicans.

This work assessed the influence of the amount of dentifrice and fluoride (F) concentration in the product on the pH and inorganic components of Streptococcus mutans and Candida albicans dual-species biofilms. The biofilms were treated with suspensions of fluoride dentifrices containing 550 or 1100 ppm of F (550 F or 1100 F, respectively) administered at comparable intensities: (i-1) 550 F/0.08 g or 1100 F/0.04 g; (i-2) 550 F/0.16 g or 1100 F/0.08 g; and (i-3) 550 F/0.32 g or 1100 F/0.16 g. A placebo dentifrice (without NaF, 0.32 g) was used as a negative control. After the last treatment, the biofilm pH was measured and the F, calcium (Ca), and phosphorus (P) concentrations were determined. Data were subjected to an ANOVA/Kruskal-Wallis test, and a Student-Newman-Keuls test. The highest biofilm pH and F concentrations (biomass and fluid) were observed for 1100 F at i-3. Overall, 1100 F resulted in F levels similar to 550 F for i-1 and i-2. In addition, 550 F applied at i-2 and i-3 led to higher F in the biomass/fluid compared to 1100 F applied at i-1 and i-2, respectively. In biomass, the lowest Ca concentrations were observed for 1100 F at i-3. The conclusion drawn is that the treatment intensity holds greater significance as a parameter compared to the concentration of F or the amount of dentifrice when considered individually.

Dentin erosive wear is reduced by fluoride varnishes containing nanosized sodium trimetaphosphate in vitro.

This study evaluated the effect of fluoride varnishes containing micrometric or nanosized sodium trimetaphosphate (TMP) on dentin erosive wear in vitro. Bovine root dentin blocks were selected by surface hardness and randomly divided into five experimental groups/varnishes (n = 20/group): placebo, 5% sodium fluoride (NaF); 5% NaF+5% micrometric TMP; 5% NaF+2.5% nanosized TMP; and 5% NaF+5% nanosized TMP. Half of the surface of all blocks received a single application of the assigned varnish, with subsequent immersion in artificial saliva for 6 h. Varnishes were then removed and the blocks were immersed in citric acid (90 s, 4×/day, 5 days). After each erosive cycle, ten blocks of each group were immersed in a placebo dentifrice for 15 s (ERO), while the other ten blocks were subjected to abrasion by brushing (ERO+ABR). Dentin erosive wear was assessed by profilometry. Data were submitted to 2-way ANOVA and to the Holm-Sidak test (p<0.05). Dentin erosive wear was significantly higher for ERO+ABR than for ERO for all varnishes. TMP-containing varnishes promoted superior effects against dentin erosive wear compared with 5% NaF alone; and 5% nanosized TMP led to the lowest wear among all varnishes. In conclusion, the addition of TMP to conventional fluoride varnish (i.e., varnish containing only NaF) enhanced its protective effects against bovine root dentin erosion and erosion+abrasion. Additionally, the use of 5% nanosized TMP led to superior effects in comparison to 5% micrometric TMP, both for erosion and erosion+abrasion in vitro.

Fluoride varnishes supplemented with nano-sized sodium trimetaphosphate reduce enamel erosive wear in vitro.

OBJECTIVE: To evaluate the effect of fluoride (F) varnishes with sodium trimetaphosphate (TMP) on erosive tooth wear (ETW) in vitro. METHODS: Enamel blocks (n = 100) were divided into 5 experimental groups (n = 20/group): Placebo (Pla - without F/TMP); 5 % NaF (NaF); 5 % NaF + 5 % micrometric TMP (NaF+5 %MICRO); 5 % NaF + 2.5 % nano-sized TMP (NaF+2.5 %NANO), and 5 % NaF + 5 % nano-sized TMP (NaF+5 %NANO). Blocks received a single varnish application (6 h contact), and were submitted to 4 daily erosive challenges (ERO, 0.05 M citric acid, pH 3.2, 90 s, under agitation), for 5 days. After ERO, half of the blocks (n = 10/group) were subjected to brushing abrasion (ERO+ABR). Profilometry, surface hardness (SH), and cross-sectional hardness (ΔKHN) were determined. The data were submitted to 2-way ANOVA and Fisher's LSD test (p < 0.05). RESULTS: Enamel wear was significantly lower for ERO compared with ERO+ABR for all varnishes tested (p < 0.001), following the pattern NaF+5 %NANO < NaF+5 %MICRO < NaF < NaF+2.5 %NANO < Pla (both for ERO and ERO+ABR). The highest SH loss was observed for Pla and the lowest for NaF (ERO) and NaF+2.5 %NANO (ERO+ABR), without significant differences among NaF+2.5 %NANO, NaF, and NaF+5 %MICRO. The highest ΔKHN values were observed for NaF+5 %MICRO and NaF+5 %NANO at 5-30 µm, with less marked differences among the groups at 30-70 µm (ERO and ERO+ABR). CONCLUSIONS: The addition of TMP to F varnishes significantly improves protection against ETW in vitro. The use of 5 % nano-sized TMP further enhances such effects. CLINICAL SIGNIFICANCE: F varnishes containing TMP can reduce enamel loss caused by ERO or ERO+ABR.

The Activity of Calcium Glycerophosphate and Fluoride against Cariogenic Biofilms of Streptococcus mutans and Candida albicans Formed In Vitro.

This study evaluated the effects of calcium glycerophosphate (CaGP), with or without fluoride (F), on dual-species biofilms of Streptococcus mutans and Candida albicans. The biofilms were treated three times with 0.125, 0.25, and 0.5% CaGP solutions, with or without 500 ppm F (NaF). Additionally, 500 and 1100 ppm F-solutions and artificial saliva served as controls. After the final treatment, the microbial viability and biofilm structure, metabolic activity, total biomass production, and the composition of the extracellular matrix composition were analyzed. Regardless of the presence of F, 0.25 and 0.5% CaGP promoted a higher biomass production and metabolic activity increase than the controls (p < 0.05). F-free CaGP solutions reduced bacterial cell population significantly more than the 500 ppm F group or the negative control (p < 0.05). All the groups reduced the proteins, and 0.5% CaGP combined with F led to the highest reduction in the carbohydrate and nucleic acids content of the extracellular matrix (p < 0.05). It can be concluded that CaGP alone affected the number of bacterial cells and, when combined with F, reduced its production of biomass, metabolic activity, and the expression of the extracellular matrix components.

Antimicrobial Effect of Low-Fluoride Toothpastes Containing Polyphosphate and Polyols: An In Vitro Assessment of Inhibition Zones.

This study evaluated the antimicrobial effect of toothpastes containing 200 ppm fluoride (200F), xylitol (X, 16%), erythritol (E, 4%), and sodium trimetaphosphate (TMP, 0.25%), alone or in different associations, against Streptococcus mutans (SM), Lactobacillus casei (LC), Actinomyces israelii (AI), and Candida albicans (CA). Suspensions of the micro-organisms were added to a BHI Agar medium. Five wells were made on each plate to receive toothpaste suspensions at different dilutions. Toothpastes containing no actives (placebo) or 1100 ppm F (1100F) were used as negative and positive controls. Two-way ANOVA and Tukey's HDS test were used (p < 0.05). For SM, the largest halo was for 200F+TMP at all dilutions, followed by the 200F+X+E toothpaste (p < 0.001). For LC, the overall trend showed that the polyols effectively inhibited microbial growth, and the association with the other compounds enhanced such effects (p < 0.001). For AI, a less-defined trend was observed. For CA, the experimental toothpaste (200F+X+E+TMP) was consistently more effective than the other treatments, followed by 200F+X+E (p < 0.001). The association of polyols and TMP in a low-fluoride toothpaste effectively reduced the growth of cariogenic micro-organisms (SM, CA, and LC), suggesting that this formulation could be an interesting alternative for children due to its low fluoride content.

Effect of fluoride gels with nano-sized sodium trimetaphosphate on the in vitro remineralization of caries lesions.

OBJECTIVE: To evaluate the effects of fluoride (F) gels supplemented with micrometric or nano-sized sodium trimetaphosphate (TMPmicro and TMPnano, respectively) on the in vitro remineralization of caries-like lesions. METHODOLOGY: Bovine enamel subsurface lesions (n=168) were selected according to their surface hardness (SH) and randomly divided into seven groups (n=24/group): Placebo (without F/TMP), 4,500 ppm F (4500F), 4500F + 2.5% TMPnano (2.5% Nano), 4500F + 5% TMPnano (5% Nano), 4500F + 5% TMPmicro (5% Micro), 9,000 ppm F (9000F), and 12,300 ppm F (Acid gel). The gels were applied in a thin layer for one minute. Half of the blocks were subjected to pH cycling for six days, whereas the remaining specimens were used for loosely- (calcium fluoride; CaF2) and firmly-bound (fluorapatite; FA) fluoride analysis. The percentage of surface hardness recovery (%SHR), area of subsurface lesion (ΔKHN), CaF2, FA, calcium (Ca), and phosphorus (P) on/in enamel were determined. Data (log10-transformed) were subjected to ANOVA and the Student-Newman-Keuls' test (p<0.05). RESULTS: We observed a dose-response relation between F concentrations in the gels without TMP for %SHR and ΔKHN. The 2.5% Nano and 5% Micro reached similar %SHR when compared with 9000F and Acid gels. For ΔKHN, Placebo and 5% Nano gels had the highest values, and 5% Micro, 2.5% Nano, 9000F, and Acid gels, the lowest. All groups had similar retained CaF2 values, except for Placebo and Acid gel. We verified observed an increase in Ca concentrations in nano-sized TMP groups. Regarding P, TMP groups showed similar formation and retention to 9000F and Acid. CONCLUSION: Adding 2.5% nano-sized or 5% micrometric TMP to low-fluoride gels lead to enhanced in vitro remineralization of artificial caries lesions.