Are salivary NO2- / NO2- and NO3- levels biomarkers for dental caries in children? Systematic review and meta-analysis.

The literature is conflicting regarding salivary nitrite (NO2-)/nitrite and nitrate (NO2- and NO3-) levels in children affected by dental caries. For this reason, a systematic review to provide a consensus on the subject was propose, whose objective is to verify whether these molecules could be used as biomarkers in children with caries. A comprehensive search was performed on online database and eleven articles were included in the meta-analysis. The methodological quality of studies was assessed by Newcastle-Ottawa Scale recommended for case-control studies and by AXIS tool for cross-sectional studies. Grading of Recommendations Assessment, Development and Evaluation was used for the assessment of the certainty of the evidence for each outcome. The results showed lower NO2- levels in the group of children affected by dental caries (SMD = -2.18 [-3.24, -1.13], p < 0.01). Age, saliva collection and methods of evaluation can impact the results. When evaluating the severity of the condition, an important variation was detected in relation to the different evaluation methods NO2-/NO2- and NO3-. In conclusion, based on the evidence presented, the results suggest that NO2- levels in saliva are a possible biomarker of dental caries. Results should be evaluated with caution due to the very low evidence from primary studies. Longitudinal studies are necessary to strengthen this hypothesis.

Hemoglobin Protects Enamel against Intrinsic Enamel Erosive Demineralization.

INTRODUCTION: This study investigated the changes in the acquired enamel pellicle (AEP) proteome when this integument is formed in vivo after treatment with sugarcane-derived cystatin (CaneCPI-5), hemoglobin (HB), and a statherin-derived peptide (StN15), or their combination and then exposed to an intrinsic acid challenge. The effectiveness of these treatments in preventing intrinsic erosion was also evaluated. METHODS: Ten volunteers, after prophylaxis, in 5 crossover phases, rinsed with the following solutions (10 mL, 1 min): control (deionized water-H2O) - group 1, 0.1 mg/mL CaneCPI-5 - group 2, 1.0 mg/mL HB - group 3, 1.88 × 10-5M StN15 - group 4, or a blend of these - group 5. Following this, AEP formation occurred (2 h) and an enamel biopsy (10 µL, 0.01 m HCl, pH 2.0, 10 s) was conducted on one incisor. The biopsy acid was then analyzed for calcium (Arsenazo method). The vestibular surfaces of the other teeth were treated with the same acid. Acid-resistant proteins in the residual AEP were then collected and analyzed quantitatively via proteomics. RESULTS: Compared to control, treatment with the proteins/peptide, mixed or isolated, markedly enhanced acid-resistant proteins in the AEP. Notable increases occurred in pyruvate kinase PKM (11-fold, CaneCPI-5), immunoglobulins and submaxillary gland androgen-regulated protein 3B (4-fold, StN15), Hb, and lysozyme C (2-fold, StN15). Additionally, a range of proteins not commonly identified in the AEP but known to bind calcium or other proteins were identified in groups treated with the tested proteins/peptide either in isolation or as a mixture. The mean (SD, mM) calcium concentrations released from enamel were 3.67 ± 1.48a, 3.11 ± 0.72a, 1.94 ± 0.57b, 2.37 ± 0.90a, and 2.38 ± 0.45a for groups 1-5, respectively (RM-ANOVA/Tukey, p < 0.05). CONCLUSIONS: Our findings demonstrate that all treatments, whether using a combination of proteins/peptides or in isolation, enhanced acid-resistant proteins in the AEP. However, only HB showed effectiveness in protecting against intrinsic erosive demineralization. These results pave the way for innovative preventive methods against intrinsic erosion, using "acquired pellicle engineering" techniques.

Analysis of dentin wear and biological properties promoted by experimental inoffice desensitizing materials.

BACKGROUND: This study aimed to evaluate dentin wear and biological performance of desensitizing materials. METHODS: Seventy bovine root dentin blocks were sectioned. Half of the surface of each specimen was untreated (control) and the other half was immersed in EDTA and treated with the following desensitizing materials: placebo varnish (PLA), fluoride varnish (FLU), sodium fluoride (NaF) varnish + sodium trimetaphosphate (TMP), universal adhesive (SBU), S-PRG varnish (SPRG), biosilicate (BIOS), and amelotin solution (AMTN). After application, the specimens were submitted to an erosive-abrasive challenge and the wear analyzed by optical profilometer. Serial dilutions of extracts obtained from the culture medium containing discs impregnated with those desensitizers were applied on fibroblasts and odontoblasts-like cells cultures. Cytotoxicity and production of total protein (TP) by colorimetric assays were determined after 24 h. Data were statistically analyzed using Kruskal-Wallis, Dunn's, One-way ANOVA and Tukey tests (p ≤ 0.05). RESULTS: No dentin wear was observed only for SBU. The lowest dentin wear was observed for AMTN and TMP. Cell viability was significantly reduced after treatment with undiluted extracts of PLA, FLU, TMP and SBU in fibroblasts and TMP and SBU in odontoblast-like cells. SPRG, BIOS and AMTN were cytocompatible at all dilutions tested. Considering TP results, no statistical difference was observed among the groups and high levels for TP were observed after TMP and FLU treatments. CONCLUSIONS: Universal adhesive system may protect dentin with opened tubules from wear after challenge. Extracts of adhesive and fluoride varnishes presented cytotoxic mainly on fibroblasts. The enamel protein may be a future alternative to treat dentin with opened tubules because it may cause low wear under erosive-abrasive challenge with low cytotoxic effects.

Teeth with acute apical abscess vs. teeth with chronic apical periodontitis: a quantitative and qualitative proteomic analysis.

OBJECTIVE: To quantitatively and qualitatively analyze the proteomic profile of teeth with acute apical abscesses (AAA) compared with teeth with chronic apical periodontitis (CAP) and to correlate the expression of detected human proteins with their main biological functions. MATERIALS AND METHODS: Samples were obtained from root canals of 9 patients diagnosed with AAA and 9 with CAP. Samples were analyzed by reversed-phase liquid chromatography coupled to mass spectrometry. Label-free quantitative proteomic analysis was performed by Protein Lynx Global Service software. Differences in protein expression were calculated using the t-test (p < 0.05). RESULTS: In total, 246 human proteins were identified from all samples. Proteins exclusively found in the AAA group were mainly associated with the immunoinflammatory response and oxidative stress response. In the quantitative analysis, 17 proteins were upregulated (p < 0.05) in the AAA group, including alpha-1-acid glycoprotein, hemopexin, fibrinogen gamma chain, and immunoglobulin. Additionally, 61 proteins were downregulated (p < 0.05), comprising cathepsin G, moesin, gelsolin, and transketolase. Most of the proteins were from the extracellular matrix, cytoplasm, and nucleus. CONCLUSIONS: The common proteins between the groups were mainly associated with the immune response at both expression levels. Upregulated proteins mostly belonged to the acute-phase proteins, while the downregulated proteins were associated with DNA/RNA regulation and repair, and structural function. CLINICAL RELEVANCE: The host response is directly related to the development of apical abscesses. Thus, understanding the behavior of human proteins against the endodontic pathogens involved in this condition might contribute to the study of new approaches related to the treatment of this disease.

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.

Proteomic analysis of infected root canals with apical periodontitis in patients with type 2 diabetes mellitus: A cross-sectional study.

AIM: This study aimed to quantitatively and qualitatively determine the proteomic profile of apical periodontitis (AP) in type 2 diabetes mellitus (T2DM) patients in comparison with systemically noncompromised patients and to correlate the protein expression of both groups with their biological functions. METHODOLOGY: The sample consisted of 18 patients with asymptomatic AP divided into two groups according to the presence of T2DM: diabetic group-patients with T2DM (n = 9) and control group-systemically healthy patients (n = 9). After sample collection, the root canal samples were prepared for proteomic analysis using reverse-phase liquid chromatography-mass spectrometry. Label-free quantitative proteomic analysis was performed by Protein Lynx Global Service software. Differences in protein expression between groups were calculated using t-test (p < .05). Biological functions were analysed using the Homo sapiens UniProt database. RESULTS: A total of 727 human proteins were identified in all samples. Among them, 124 proteins common to both groups were quantified, out of which 65 proteins from the diabetic group showed significant differences compared with the control: 43 upregulated (p < .05) and 22 downregulated (p < .05) proteins. No significant differences in protein expression were seen for the remaining 59 proteins (p > .05). Most proteins with differences in expression were related to immune/inflammatory response. Neutrophil gelatinase-associated lipocalin, Plastin-2, Lactotransferrin and 13 isoforms of immunoglobulins were upregulated. In contrast, Protein S100-A8, Protein S100-A9, Histone H2B, Neutrophil defensin 1, Neutrophil defensin 3 and Prolactin-inducible protein were downregulated. CONCLUSIONS: Quantitative differences were demonstrated in the expression of proteins common to diabetic and control groups, mainly related to immune response, oxidative stress, apoptosis and proteolysis. These findings revealed biological pathways that provide the basis to support clinical findings on the relationship between AP and T2DM.

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.

Oral prosthetic microbiology: aspects related to the oral microbiome, surface properties, and strategies for controlling biofilms.

The oral cavity is an environment that allows for the development of complex ecosystems; the placement of prosthetic devices as a consequence of partial or total tooth loss may alter the diversity of microbial communities. Biofilms on the surface of materials used in dental prostheses can promote important changes in the mechanic and aesthetic properties of the material itself and may cause local and systemic diseases for the prosthetic wearer. This review presents the main features of the oral microbiome associated with complete or partial dentures and dental implants. The main diseases associated with microbial colonization of prosthetic surfaces, factors that may affect biofilm formation on prosthetic materials, as well as novel alternative therapies aiming to reduce biofilm formation and/or to eradicate biofilms formed on these materials are also explored.

Surface Free Energy, Interaction, and Adsorption of Calcium and Phosphate to Enamel Treated with Trimetaphosphate and Glycerophosphate.

This study aimed to evaluate the surface (γs) and interaction (ΔGiwi) free energy and calcium (Ca2+) and phosphate (PO43-) adsorption to dental enamel treated with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP) that had or had not been exposed to CaPO4-containing solutions. Bovine enamel blocks (n = 192; 24 blocks/group) were treated (2 mL/block; 2 min) with TMP (0%, 1%, 3%, and 9%) and CaGP (0, 0.25, 0.5, and 1%) or exposed to a CaPO4-containing solution. The adsorption of these compounds by enamel was assessed before and after treatment. γs and ΔGiwi and their apolar (γsLW and ΔGiwiLW) and polar (γsAB and ΔGiwiAB) components and acid-base interactions (γs+/γs-) were determined by the contact angles. The data were subjected to ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). The adsorption of TMP was dose dependent (p < 0.001), and it reduced γs and γsAB and increased ΔGiwiAB (ΔGiwi > 0) and γs- when compared with the group without TMP (p < 0.001). The immersion in CaPO4-containing solution increased γs and γsAB and reduced ΔGiwiAB (ΔGiwi > 0) and γs- (p < 0.001). There was a correlation between the adsorption of TMP and Ca2+ (r = 0.916; p < 0.001) and PO43- (r = 0.899; p < 0.001). The adsorption of CaGP on the enamel was dose dependent (p < 0.001), reducing γs, ΔGiwiAB (ΔGiwi < 0), γsLW, and γs- when compared to the group without CaGP (p < 0.001). When exposed to the CaPO4-containing solution, there was an increase in ΔGiwiAB (ΔGiwi > 0), γsLW, and γs- and a decrease in γsAB (p < 0.001) without adsorption of Ca2+ by enamel. It may be concluded that TMP and CaGP were adsorbed onto the enamel, producing hydrophilic and hydrophobic surfaces, respectively. TMP produces electron donor sites that induce Ca2+ adsorption, while CaGP releases Ca2+ into the medium.

Effect of daily use of fluoridated dentifrice and bleaching gels containing calcium, fluoride, or trimetaphosphate on enamel hardness: an in vitro study.

OBJECTIVE: This study evaluated the effects of calcium gluconate (CaGlu), sodium fluoride (NaF), sodium trimetaphosphate (TMP), and NaF/TMP added to a 35% hydrogen peroxide (HP) bleaching gel for the reduction in enamel demineralization in vitro, with and without the use of a fluoridated dentifrice. DESIGN: Enamel blocks (n = 100) were obtained from bovine incisors (n = 200) after flattening and subjected to initial surface hardness (SH) analysis. The blocks were divided according to the bleaching gel (35% HP; 35% HP + 0.05% NaF; 35% HP + 0.25% TMP; 35% HP + 0.05% NaF + 0.25% TMP; 35% HP + 2% CaGlu) and were treated with ether non-fluoridated or fluoridated (1100 ppm) dentifrice. The bleaching gels were applied thrice (40 min/session) at the intervals of 7 days between each application. After 21 days, the final SH for the calculation of the percentage of SH loss (%SH) and cross-sectional hardness for the evaluation of the integrated hardness area (IH) were determined. RESULTS: Bleaching containing HP + NaF + TMP presented lowest %SH (p < 0.001), regardless of the dentifrice used. HP + NaF + TMP bleaching gel led to lower subsurface enamel mineral loss (IH) compared to the other groups (p < 0.001), and these did not differ from each other (p > 0.05). Daily use of fluoride dentifrice led to higher IH values (p < 0.001), regardless of the bleaching gels. CONCLUSION: The addition of NaF/TMP to a 35% HP bleaching gel remarkably reduced the mineral loss compared to the cases of the other bleaching gels, regardless of dentifrice. CLINICAL RELEVANCE: The association of TMP/NaF can be used as a strategy for reducing mineral loss during the bleaching procedure, even without the daily use of fluoride dentifrice.

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.

Protective Effect of Fluoride Varnish Containing Trimetaphosphate against Dentin Erosion and Erosion/Abrasion: An in vitro Study.

This in vitro study evaluated the protective effect of fluoride varnishes containing sodium trimetaphosphate (TMP) against dentin erosion and abrasion. Specimens of coronal dentin were divided into: placebo, 2.5% NaF, 5% NaF, 2.5% NaF + 5% TMP, and 5% NaF + 5% TMP groups (n =24/group). After single application of the varnishes, the samples were immersed in citric acid (0.05 mol/L, pH = 3.2, 5 min) followed or not by brushing, and the dentin wear was assessed after 5 days. Varnishes containing fluoride + TMP led to the lowest wear. TMP varnishes showed a superior effect against dentin erosive wear.

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.

Anticaries effect of toothpaste with nano-sized sodium hexametaphosphate.

OBJECTIVE: To evaluate the effect of a fluoride toothpaste containing nano-sized sodium hexametaphosphate (HMPnano) on enamel demineralization on the biochemical composition and insoluble extracellular polysaccharide (EPS) in biofilm formed in situ. METHODS: This crossover double-blind study consisted of four phases (7 days each), in which 12 volunteers wore intraoral appliances containing four enamel bovine blocks. The cariogenic challenge was performed using 30% sucrose solution (6×/day). Blocks were treated 3×/day with the following toothpastes: no F/HMP/HMPnano (Placebo), conventional fluoride toothpaste, 1100 ppm F (1100F), 1100F + 0.5% micrometric HMP (1100F/HMP), and 1100F + 0.5% nano-sized HMP (1100F/HMPnano). The percentage of surface hardness loss (%SH), integrated loss of subsurface hardness (ΔKHN), and enamel calcium (Ca), phosphorus (P), and fluoride (F) were determined. Moreover, biofilms formed on the blocks were analyzed for F, Ca, P, and insoluble extracellular polysaccharide (EPS) concentrations. Data were analyzed using one-way ANOVA, followed by Student-Newman-Keuls' test (p < 0.001). RESULTS: 1100F/HMPnano promoted the lowest %SH and ΔKHN among all groups (p < 0.001). The addition of HMPnano to 1100F significantly increased Ca concentrations (p < 0.001). The 1100F/HMPnano promoted lower values of EPS when compared with 1100F (~ 70%) (p < 0.001) and higher values of fluoride and calcium in the biofilms (p < 0.001). CONCLUSION: 1100F/HMPnano demonstrated a greater protective effect against enamel demineralization and on the composition of biofilm in situ when compared to 1100F toothpaste. CLINICAL RELEVANCE: This toothpaste could be a viable alternative to patients at high risk of caries.

Fluoride toothpastes containing micrometric or nano-sized sodium trimetaphosphate reduce enamel erosion in vitro.

OBJECTIVE: To evaluate the effect of fluoride toothpastes supplemented with micrometric or nano-sized sodium trimetaphosphate (TMP or TMPnano, respectively) on enamel erosion in vitro, as well as the influence of salivary acquired pellicle and saliva. MATERIAL AND METHODS: Bovine enamel blocks (n = 120) were randomly assigned into the following experimental toothpastes: no F/TMP/TMPnano (Placebo); 1100 ppm F (1100 ppm F); 1100 ppm F plus 3% TMP or 3% TMPnano (1100 TMP or 1100 TMPnano, respectively) and 5000 ppm F (5000 ppm F). Erosive challenge was performed by immersion of the blocks in citric acid for 5 min, followed by 2 h immersion in human or artificial saliva, 4×/day, during 5 days. After each erosive challenge, blocks were exposed to slurries of the toothpastes. Enamel erosion (µm), surface hardness (SHf) and cross-sectional hardness (ΔKHN) were analyzed as response variables and the data were submitted to two-way ANOVA, followed by the Student-Newman-Keuls test (p < .05). RESULTS: 1100 TMPnano significantly reduced enamel loss when compared to 1100 TMP (p = .002), reaching values similar to those promoted by 5000 ppm F (p = .96). 1100 ppm F presented significantly lower enamel loss than Placebo (p < .001), and higher than 1100 TMP (p < .001). Significantly higher SHf and lower ΔKHN was observed for 1100 TMPnano and 5000 ppm F when compared with the other groups (p < .001). The type of saliva did not influence enamel erosion, SHf and ΔKHN for the groups treated with TMP-containing toothpastes. CONCLUSION: The addition of 3% TMPnano to 1100 ppm F toothpastes significantly increases the protective effect against enamel erosion in vitro when compared with its counterparts with micrometric TMP or without TMP. This effect was not influenced by the presence of acquired enamel pellicle and saliva.

Fluoride and calcium concentrations in the biofilm fluid after use of fluoridated dentifrices supplemented with polyphosphate salts.

OBJECTIVES: The present study evaluated fluoride (F) and calcium (Ca) concentrations in the biofilm fluid formed in situ under cariogenic challenge after using F dentifrices supplemented or not with sodium trimetaphosphate (TMP) or calcium glycerophosphate (CaGP). METHODS: Volunteers (n = 12) were randomly divided into 5 groups according to the toothpastes used: placebo (without F, CaGP or TMP), 1100 ppm F (1100F) and low-fluoride dentifrice (LFD, 550 ppm F) with no supplementation (550F) or supplemented with 1 % TMP (550F-TMP) or 0.25 % CaGP (550F-CaGP). In each phase, volunteers wore palatal appliances containing 4 bovine enamel blocks. Cariogenic challenge was performed with 30 % sucrose solution, 6 times/day. On the morning of the eigth day, biofilm samples were collected 12 h and 1 h after brushing and cariogenic challenge. F and Ca analyses in the biofilm fluid were performed with the inverted electrode after buffering with TISAB III and using the Arsenazo III method, respectively. Data were submitted to two-way ANOVA (repeated measures) and Student-Newman-Keuls test (p < 0.05). RESULTS: A dose-response relationship was verified between F concentrations in the dentifrices and in the biofilm fluid. Significant differences were observed among placebo, 550F, and 1100F only 1 h after brushing, without statistical differences among 550F, 550F-TMP, and 550F-CaGP. No defined trend was observed among the groups regarding Ca concentrations, with the highest values seen for placebo and 550F-CaGP. CONCLUSION: The anticaries effect of LFDs supplemented with CaGP or TMP cannot be related to an increased availability of F and Ca in the biofilm fluid. CLINICAL SIGNIFICANCE: The better performance of LFDs containing CaGP or TMP shown in previous studies should be attributed to their ability to interact with tooth enamel and with the biofilm, rather to their effect on the biofilm fluid.

Effect of the addition of nano-sized sodium hexametaphosphate to fluoride toothpastes on tooth demineralization: an in vitro study.

OBJECTIVE: This study evaluated the effect of toothpastes containing 1100 ppm F associated with nano-sized sodium hexametaphosphate (HMPnano) on enamel demineralization in vitro using a pH-cycling model. DESIGN: Bovine enamel blocks (4 mm × 4 mm, n = 72) selected by initial surface hardness (SHi) were randomly allocated into six groups (n = 12), according to the test toothpastes: without fluoride or HMPnano (Placebo), 550 ppm F (550F), 1100 ppm F (1100F), 1100F plus HMPnano at concentrations of 0.25% (1100F/0.25%HMPnano), 0.5% (1100F/0.5%HMPnano), and 1.0% (1100F/1.0%HMPnano). Blocks were treated 2×/day with slurries of toothpastes and submitted to five pH cycles (demineralizing/remineralizing solutions) at 37 °C. Next, final surface hardness (SHf), integrated loss subsurface hardness (ΔKHN), integrated mineral loss (gHAp × cm-3), and enamel fluoride (F) concentrations were determined. Data were analyzed by ANOVA and Student-Newman-Keuls test (p < 0.001). RESULTS: Toothpaste with 1100F/0.5%HMPnano led to the lowest mineral loss and the highest mineral concentration among all groups, which were 26% (SHf) and 21% (ΔKHN) lower and ~58% higher (gHAp × cm-3) when compared to 1100F (p < 0.001). Similar values of enamel F were observed for all fluoridated toothpastes (p > 0.001). CONCLUSION: The addition of 0.5%HMPnano to a 1100 F toothpaste significantly enhances its effects against enamel demineralization when compared to its counterpart without HMPnano in vitro. CLINICAL SIGNIFICANCE: Toothpaste containing 1100 ppm F associated with HMPnano has a higher potential to reduce the demineralization compared to 1100 ppm F. This toothpaste could be a viable alternative to patients at high risk of caries.

Role of tyrosol on Candida albicans, Candida glabrata and Streptococcus mutans biofilms developed on different surfaces.

PURPOSE: To assess the effect of tyrosol on the production of hydrolytic enzymes (by Candida biofilm cells) and acid (by Streptococcus mutans biofilms), as well as to quantify single and mixed biofilms of these species formed on acrylic resin (AR) and hydroxyapatite (HA). METHODS: Candida and S. mutans biofilms were formed on AR and HA in the presence of tyrosol during 48 hours. Next, acid proteinase, phospholipase and hemolytic activities of Candida biofilm cells were determined, while acid production by S. mutans biofilms was assessed by pH determination. The effect of tyrosol on mature biofilms (96 hours) was evaluated through quantification of total biomass, metabolic activity, number of colony-forming units and composition of biofilms' extracellular matrix. Data were analyzed by one- and two-way ANOVA, followed by Tukey's and Holm-Sidak's tests (α = 0.05). RESULTS: Treatments with tyrosol were not able to significantly reduce hydrolytic enzymes and acid production by Candida and S. mutans. Tyrosol only significantly reduced the metabolic activity of single biofilms of Candida species. CLINICAL SIGNIFICANCE: Tyrosol on its own had a limited efficacy against single and mixed-species oral biofilms. Its use as an alternative antimicrobial for topical therapies still demands more investigation.

Effects of pH and fluoride concentration of dentifrices on fluoride levels in saliva, biofilm, and biofilm fluid in vivo.

INTRODUCTION: Acidic dentifrices have been shown to be more effective than neutral ones against dental caries using in vitro, in situ, and clinical protocols. OBJECTIVES: Given the scarcity of studies assessing intraoral fluoride (F) retention after using such formulations, the present study evaluated the influence of pH and F concentration of dentifrices on F uptake by saliva, biofilm, and biofilm fluid. METHODS: Volunteers (n = 22) were randomly assigned to dentifrices containing 0 (placebo), 550 (LFD, low-fluoride dentifrice), and 1100 ppm F (CD, conventional dentifrice) at pH 4.5 and 7.0 and brushed their teeth 3 times/day following a double-blind, crossover protocol. Saliva and biofilm samples were collected after 7 days of using the dentifrices, 1 and approximately 12 h after last brushing. F and calcium (Ca) analyses were performed with the inverted electrode after buffering with TISAB III and the Arsenazo III method, respectively. Data were analyzed by 3-way ANOVA, Tukey's HSD test, and Pearson's correlation coefficient (p < 0.05). RESULTS: F concentrations in biofilm fluid and whole biofilm 1 h after brushing with acidic F-toothpastes were higher than those related to neutral counterparts, although the differences were small and not significant; no increases were observed in salivary F concentrations influenced by dentifrice pH. Moreover, no definite trend was observed for Ca concentrations in these compartments. CONCLUSION: Dentifrice pH had some influence on F uptake by the biofilm fluid, having lesser or no impact on F uptake by the biofilm and saliva, respectively. CLINICAL SIGNIFICANCE: Toothbrushing with acidic toothpastes leads to slight increases in F concentrations in the biofilm fluid when compared to neutral formulations, which may contribute to the higher anticaries effect of acidic formulations.

Fluoride toothpaste supplemented with sodium hexametaphosphate reduces enamel demineralization in vitro.

OBJECTIVE: The aim of this study was to evaluate the effect of fluoride dentifrices combined with sodium hexametaphosphate (HMP) on enamel demineralization in vitro. MATERIAL AND METHODS: Enamel bovine blocks were selected by initial surface hardness (SHi) and then divided into five experimental groups (n = 12): placebo (without fluoride and without HMP); 1100 ppm F (1100F); and 1100F associated with HMP at 0.5 % (1100HMP0.5%), 1 % (1100HMP1%), and 2 % of HMP (1100HMP2%). Blocks were submitted to five pH cycles (demineralizing/remineralizing solutions) at 37 °C. After pH cycling, final surface hardness (SHf), percentage of surface hardness loss (%SH), integrated differential hardness (ΔIH), integrated loss of subsurface hardness (ΔKHN), and enamel firmly bound fluoride (F) were determined. Data were submitted to one-way ANOVA, followed by Student-Newman-Keuls test (p < 0.05). RESULTS: Significant differences were observed among all groups regarding %SH and ΔKHN. 1100HMP1% promoted the lowest mineral loss among all groups (p < 0.001), and led to significantly lower demineralization in the deeper regions of the subsurface lesion when compared with the other HMP-containing toothpastes (p < 0.001). Significantly higher mineral loss was observed for 1100HMP2% when compared to the other fluoridated dentifrices, mainly in the outer part of the lesion (p < 0.001). Enamel F uptake was similar for 1100F and 1100HMP1% but significantly reduced for other HMP concentrations. CONCLUSION: The supplementation of a 1100-ppm F dentifrice with 1 % HMP promoted a higher inhibitory effect against enamel demineralization when compared to a dentifrice containing the same amount of fluoride in vitro. CLINICAL RELEVANCE: This dentifrice could potentially be indicated to patients at high risk of caries.