Five days serum glucose stability at room-temperature in centrifuged fast-clotting serum tubes and the comparability with glucose in heparin-plasma and plasma containing citrate-stabilizer.

Glucose measurement plays a central role in the diagnosis of gestational diabetes mellitus (GDM). Because of earlier reports of overestimation of glucose in the widely used tubes containing granulated glycolysis inhibitor, the study assessed the performance of fast-clotting serum tubes as an alternative sample for the measurement of glucose. Glucose concentration in fast-clotting serum was compared to lithium-heparin plasma placed in an ice-water slurry after sample collection and glucose stability at room-temperature was studied. Blood samples from 30 volunteers were drawn in four different types of tubes (serum separator tubes, fast-clotting serum tubes, lithium-heparin tubes and sodium fluoride, EDTA and a citrate buffer (NaF-EDTA-citrate) tubes, all from Greiner Bio-One). Lithium-heparin tubes were placed in an ice-water slurry until centrifugation in accordance with international recommendations and centrifuged within 10 min. After centrifugation, glucose was measured in all tubes (timepoint T0) and after 24, 48, 72, 96 and 120 h of storage at 20-22 °C. NaF-EDTA-citrate plasma showed significant overestimation of glucose concentration by 4.7% compared to lithium-heparin plasma; fast-clotting serum showed glucose concentrations clinically equivalent to lithium-heparin plasma. In fast-clotting serum tubes, mean bias between glucose concentration after 24, 48, 72, 96 and 120 h and T0 was less than 2.4%. All individual differences compared to T0 were less than 6.5%. The results fulfill the acceptance criteria for sample stability based on biological variation. Fast-clotting serum tubes can be an alternative for the measurement of glucose in diagnosis and management of GDM and diabetes mellitus, especially when prolonged transportation is necessary.

Effect of adhesive components in experimental fluoride varnish on fluoride release within 30 days in vitro study.

We aimed to determine whether adhesive components could increase the release time of effective fluoride concentration from an experimental fluoride varnish applied to bovine teeth. An experimental fluoride varnish containing 5% sodium fluoride (EX1) was prepared and combined with 35% hydroxyethyl methacrylate (HEMA) (EX2), 5% glutaraldehyde (EX3), or 35% HEMA/5% glutaraldehyde mixture (EX4). Two commercially available fluoride varnishes were used for comparison. Each group was applied to bovine incisors, and the fluoride release and pH were monitored for 30 days. Cell viability analysis, scanning electron microscopy, and energy-dispersive spectroscopy were performed. EX4 released the highest and most effective concentration of fluoride for the longest period and reached neutral pH at the earliest; the release was maintained for up to 30 days without cytotoxicity. In conclusion, EX4 is considered to be the most effective varnish to prevent dental caries.

Characteristics of tin-containing fluoride toothpastes related to erosive tooth wear protection.

OBJECTIVES: To assess the effect of different tin-containing toothpastes on the control of erosive tooth wear in enamel and dentin. METHODS: Enamel and dentin slabs were randomly distributed into 7 experimental groups (n = 10/substrate): C-: negative control (Artificial saliva); AmF (regular fluoridated toothpaste without tin); Sn-1 (SnF2/NaF); Sn-2 (SnF2/NaF/SnCl2); Sn-3 (SnCl2/NaF); Sn-4 (SnF2/SnCl2); Sn-5 (SnCl2/AmF/NaF/chitosan). Specimens were submitted to 5-day erosion-abrasion cycling. Surface loss (SL) was determined with an optical profilometer. Tin deposition on the tooth surfaces and some characteristics of the toothpastes (pH, potentially available F-, %weight of solid particles, and RDA) were also assessed. Data were statistically analyzed (α = 0.05). RESULTS: For enamel, the Sn-2 presented the lowest SL, not differing significantly from AmF, C+, and Sn-3. The SL of these groups was significantly lower than the C-, except for Sn-3. Sn-1 and Sn-4 were also not significantly different from C-. For dentin, C- significantly showed the highest SL values, whilst, Sn-1 presented the lowest SL, not differing significantly from AmF, Sn-2, C+, and Sn-3. There was a significant positive association between enamel SL and the pH and tin deposition. Dentin SL was significantly negatively associated with the %weight of solid particles and RDA. CONCLUSIONS: Most of the tin-toothpastes were able to exhibit some protection against ETW. In this process, the toothpastes characteristics play a role, as lower enamel SL was significantly associated with lower pH values and tin deposition; and lower dentin SL was associated with higher %weight of solid particles and RDA of the toothpastes. CLINICAL SIGNIFICANCE: Tin-containing toothpastes can be used for erosive tooth wear protection, but our study showed that their effect depends on the pH, amount of tin deposition, % weight of solid particles and RDA of the toohpastes.

The effect of nano silver fluoride, self-assembling peptide and sodium fluoride varnish on salivary cariogenic bacteria: a randomized controlled clinical trial.

OBJECTIVES: To compare the antibacterial effect of Nanosilver Fluoride varnish (NSF) varnish, P11-4 and Sodium Fluoride (NaF) varnish against salivary Streptococcus mutans (S. mutans) and Lactobacilli. METHODS: 66 patients aged 10-24 years old were randomly assigned to receive single application of NSF, P11-4 or NaF varnish. Baseline unstimulated saliva samples were collected before the agents were applied and S.mutans and Lactobacilli colony forming units (CFU) were counted. After one, three and six months, microbiological samples were re-assessed. Groups were compared at each time point and changes across time were assessed. Multivariable linear regression compared the effect of P11-4 and NSF to NaF on salivary S. mutans and Lactobacilli log count at various follow up periods. RESULTS: There was a significant difference in salivary S. mutans log count after 1 month between P11-4 (B= -1.29, p = 0.049) and NaF but not at other time points nor between NSF and NaF at any time point. The significant reduction in bacterial counts lasted up to one month in all groups, to three months after using P11-4 and NaF and returned to baseline values after six months. CONCLUSION: In general, the antimicrobial effect of P11-4 and NSF on salivary S. mutans and Lactobacilli was not significantly different from NaF varnish. P11-4 induced greater reduction more quickly than the two other agents and NSF antibacterial effect was lost after one month. CLINICAL RELEVANCE: NSF varnish and P11-4 have antimicrobial activity that does not significantly differ from NaF by 3 months. P11-4 has the greatest antibacterial effect after one month with sustained effect till 3 months. The antibacterial effect of NSF lasts for one month. NaF remains effective till 3 months. TRIAL REGISTRATION: This trial was prospectively registered on the clinicaltrials.gov registry with ID: NCT04929509 on 18/6/2021.

Impact of pH-adjusted fluoride and stannous solutions on the protective properties on the pellicle layer in vitro and in situ.

This study evaluates the ideal pH for anti-erosion and anti-adherent efficacy of fluoride and stannous solutions (sodium fluoride (SF), amine fluoride (AF), sodium monofluorophosphate (SMFP), stannous fluoride (SnF2) with 500 ppm fluoride concentration each and stannous chloride (SnCl2, 1563 ppm stannous)). In vitro, solutions were tested at pH 4.5 and 5.5. The main in situ experiments were carried out at the pH of 4.5: For pellicle formation 6 volunteers wore bovine enamel slabs intraorally for 1 min, rinsed with 8 ml solution for 1 min and continued for up to 30 min/8 h. Physiological pellicle samples served as controls. After incubation in HCl (2.0, 2.3) for 2 min mineral release was determined photometrically. Bacterial counts on 8 h biofilms were determined by fluorescence microscopy (BacLight™ and DAPI with Concanavalin A). Modification of the pellicle ultrastructure was examined by TEM. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney-U tests with Bonferroni-correction (p < 0.05). SnF2 showed a significant erosion protection. AF, SnF2, and SnCl2 were most anti-adherent. SnF2 and SnCl2 caused a pronounced basal pellicle with stannous precipitates. Compared to other fluoride monosubstances, stannous ions offer greater protection against erosive acidic attacks. Stannous ions act as crucial co-factor in this process.

Pilot clinical study to evaluate the efficacy of a professionally delivered high fluoride varnish on erosive tooth wear in an in-situ model.

OBJECTIVES: The aim for this pilot study was to investigate the effect of a sodium fluoride varnish on step height measured by a profilometer from human enamel worn by healthy volunteers with a novel in situ/ex vivo erosion design. METHOD: Healthy volunteers aged 18-70 years wore a palatal splint containing 8 human enamel samples and underwent two 3-day treatment periods for 6 h a day with a varnish containing sodium fluoride at 22,600 ppm and the control with the same ingredients but without fluoride. Each splint contained 4 polished and 4 unpolished samples. The interventions were applied to the surface of the enamel samples in randomised order, removed after 6 h, then immersed ex-vivo in 1 %, pH 2.7 citric acid for 2 min, repeated 4 times a day, over 2 days. Measurements of enamel were assessed blindly by microhardness on day 2 and by non-contact laser profilometry on day 3 for the two treatments. RESULTS: 24 volunteers, 2 males and 22 females aged 27-54 years, were screened and recruited. The delta microhardness, from polished samples removed at the end of day 2, for the control and fluoride treatment was 95.7 (22.9) kgf/mm2 and 123.7 (28.9) kgf/mm2, respectively (p < .005). The mean (SD) step height for the control polished enamel surfaces was 3.67 (2.07) µm and for the fluoride varnish was 1.79 (1.01) µm (p < .0005). The control unpolished enamel surfaces had a mean 2.09 (1.53) µm and the fluoride varnish was 2.11 (1.53) µm but no statistical difference was detected. CONCLUSIONS: The results from this pilot study, utilizing an in-situ model where enamel was exposed to acid over the course of 2 days, demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm prevented erosive wear compared to a control on the polished enamel surfaces. CLINICAL SIGNIFICANCE: Intra-oral study demonstrated that a high fluoride varnish containing sodium fluoride at 22,600 ppm reduced erosive tooth wear.

Xylitol associated or not with fluoride: Is the action the same on de- and remineralization?

OBJECTIVES: This study evaluated the effect of xylitol combined or not with fluoride (F) on reduction of demineralization and increase of remineralization of shallow and deep artificial enamel lesions. METHODS: Bovine enamel samples were allocated to the following solutions groups: no xylitol (negative control), 5% xylitol, 10% xylitol, 20% xylitol, 500 ppm F (as NaF), 5% xylitol+F, 10% xylitol+F or 20% xylitol+F (n = 12-15). For the demin study, a pH-cycling model (demineralization-6 h, pH 4.7/remineralization 18 h, pH 7.0) was employed for 7 days. Treatments were applied 2 × 1 min. In the remin study, specimens were pre-demineralized for 2, 5 or 10 days. Afterwards, a pH-cycling protocol was conducted (2 h demineralizing and 22 h remineralizing solution/day for 8 days) and the same treatments were done. The response variables were percentage surface hardness loss (%SHL) and transverse microradiography. Data were analyzed by RM ANOVA/Tukey or Kruskal-Wallis/Dunn (p < 0.05) RESULTS: F and Xylitol combined with F reduced the %SHL (23-30%) compared to the negative control (61.5%). The integrated mineral loss and the lesion depth were not reduced by any treatment. Surface hardness recovery was seen only for shallow lesions in case of 20% xylitol+F compared to negative control. No lesion depth recovery, but significant mineral recovery was seen for F (2-days and 10-days lesion). CONCLUSIONS: All concentrations of xylitol+F reduced enamel surface demineralization, while only 20% xylitol+F improved surface remineralization of shallow lesions in vitro. CLINICAL SIGNIFICANCE: Our results suggest that while F or any concentration of xylitol + F reduces surface demineralization, only 20% xylitol+F improves surface remineralization of shallow lesions in vitro. Therefore, xylitol may be added into oral products, combined to F, to control dental caries.

ERS Mediated by GRP-78/PERK/CHOP Signaling Is Involved in Fluoride-Induced Ameloblast Apoptosis.

Fluoride can be widely ingested from the environment, and its excessive intake could result in adverse effects. Dental fluorosis is an early sign of fluoride toxicity which can cause esthetic and functional problems. Though apoptosis in ameloblasts is one of the potential mechanisms, the specific signal cascade is in-conclusive. High-throughput sequencing and molecular biological techniques were used in this study to explore the underlying pathogenesis of dental fluorosis, for its prevention and treatment. A fluorosis cell model was established. Viability and apoptosis rate of mouse ameloblast-derived cell line (LS8 cells) was measured using cell counting kit-8 (CCK-8) assay and flow cytometry analysis. Cells were harvested with or without 2-mM sodium fluoride (NaF) stimulation for high-throughput sequencing. Based on the sequencing data, subcellular structures, endoplasmic reticulum stress (ERS), and apoptosis related biomarkers were verified using transmission electron microscopy, quantitative real-time polymerase chain reaction, and Western blotting techniques. Expression of ERS markers, apoptosis related proteins, and enamel formation enzymes were detected using Western blotting after addition of 4-phenylbutyrate (4-PBA). NaF-inhibited LS8 cells displayed time- and dose- dependent viability. Additionally, apoptosis and morphological changes were observed. RNA-sequencing data showed that protein processing in endoplasmic reticulum was obviously affected. ERS and apoptosis were induced by excessive NaF. Downregulation of kallikrein-related peptidase 4 (KLK4) was also observed. Inhibition of ERS by 4-PBA rescued the apoptotic and functional protein changes in cells. Excessive fluoride induces apoptosis by activating ERS, which is mediated by GRP-78/PERK/CHOP signaling. Key proteinase is present in maturation-stage enamel; KLK4 was also affected by fluoride, but rescued by 4-PBA. This study presents a possibility for therapeutic strategies for dental fluorosis, while further exploration is required.

The effect of silver nanoparticles in addition to sodium fluoride on remineralization of artificial root dentin caries.

BACKGROUND: Silver nanoparticle was developed to overcome the drawback of silver diamine fluoride. However, evidence is limited, especially in root caries. The aim of this study was to evaluate the remineralization effect of silver nanoparticles on root caries. MATERIALS AND METHODS: Fifty-five root human dentin slices size 5 × 5 mm2 from patients aged over 60 years old were immersed in demineralized solution to create artificial caries. Specimens were allocated into five groups according to the remineralizing agents: silver diamine fluoride (SDF), silver nanoparticles solution (AgNPs), silver nanoparticle solution followed by sodium fluoride varnish (AgNPs+NaF), sodium fluoride varnish (NaF), and tap water. After 8 days of pH-cycling challenge, the microhardness test, lesion depth evaluation, dentin surface morphology, and elemental analysis were performed. Data was analysed using F-test One-way ANOVA followed by Tukey's post hoc test and paired T-test. RESULTS: All test groups demonstrated a significantly higher microhardness value and lower lesion depth compared with the control group. AgNPs+NaF and NaF-treated groups showed lower efficacy than SDF. Crystal precipitation was presented in all groups composed of silver. CONCLUSION: Addition of fluoride varnish did not benefit for silver nanoparticles in preventing further demineralization. SDF provides the highest effectiveness in elderly root carious dentin.

Influence of Different Mouthwashes on the Efficacy of Fluoridated Dentifrices in Prevention of Enamel Erosion: An In Vitro Study.

AIM: The purpose of the current study was to evaluate the impact of three various mouthwashes on the effectiveness of fluoride dentifrices in preventing enamel erosion. MATERIALS AND METHODS: A total of 120 sound intact human premolar teeth which were extracted for orthodontic treatment were selected for the study. A 3 × 3 mm window section was positioned in the middle of the coronal surface of the tooth in order to define the study area. Each sample was placed in a solution of 1% citric acid (pH 3.5) for 10 minutes in order to produce an eroded surface. All samples were divided into two main groups (60 samples each) as follows: Group A for sodium fluoride dentifrices and group B for stannous fluoride dentifrices, again it is subdivided into: CHX: Chlohex ADS®, EO: Listerine®, CPC: Colgate® Plax (20 samples in each subgroup). After that, samples underwent the pH cycling model for 5 days. Samples were examined for surface loss using a scanning electron microscope. RESULTS: In sodium fluoride dentifrices group, before intervention, the surface loss was 3.12 ± 1.03 in CHX group, 3.08 ± 1.20 in EO group, and 3.09 ± 0.96 in CPC group. After intervention, the less surface loss found with CHX group (2.18 ± 0.84), followed by CPC (2.34 ± 0.74) and EO group (2.46 ± 0.97). In stannous fluoride dentifrices group, before intervention, the surface loss in CHX group was 3.26 ± 1.19, in EO group, it was 3.18 ± 1.31, and in CPC group, it was 3.22 ± 1.06. After intervention, the less surface loss found with CHX: group (1.90 ± 0.54), followed by CPC (2.24 ± 0.28) and EO group (2.38 ± 0.20). CONCLUSION: The present study concluded that the fluoride dentifrices' preventive effects against tooth surface loss were unaffected by a different mouthwashes with varying compositions and major constituents. In terms of erosion, fluoridated toothpaste containing stannous fluoride was found to provide better surface loss protection than sodium fluoride. CLINICAL SIGNIFICANCE: Primary prevention and the eradication of contributing causes are the greatest strategies for preventing erosion. Simultaneously, antibacterial agent in the mouthwashes may help in enhancing the effect of fluoride in the enamel, owing to their high affinity for teeth structures. Therefore, in addition to cause-related treatment, further efforts to reduce tooth tissue loss are also necessary.

Influence of the combined effect of desensitizing dentifrices and universal adhesives on dentin bond strength under erosive conditions.

OBJECTIVE: This study aimed to evaluate whether the use of desensitizing dentifrices containing obliterating agents can affect bond strength of eroded/abraded dentin. METHODOLOGY: A total of 100 dentin samples were obtained from human molars. The teeth were cut into 3 mm-thickness discs and allocated in five groups (n=20), according to the toothpaste used: WoF - abrasion with fluoride-free toothpaste (Cocoricó); Arg - toothpaste containing arginine (Colgate Sensitive Pro-Relief); Nov - calcium sodium phosphosilicate toothpaste (Sensodyne Repair and Protect); SnF - fluoride-containing toothpaste (AmF/SnCl2/SnF2 - Elmex Erosion); and Control (no erosive/abrasive process). The erosive/abrasive cycle consisted of immersion in citric acid (1%, pH 2.6, 5 min, 4×/day) and abrasion (2×/day, 120-20 sec abrasion, 100 sec immersion) with each toothpaste. During intervals, samples were immersed in artificial saliva. This cycle was performed for five days. Two resin cylinders (2 mm in diameter) were constructed on each sample for the shear bond strength test using a universal adhesive system. The self-etch and etch-and-rinse (Scotchbond Universal) strategies were employed, each in half of the total sample (n=10). Bond strength (MPa) was measured in a shear test and failure modes were assessed with a stereomicroscope. Statistical analysis was performed using the two-way analysis of variance (ANOVA) and Tukey tests (p<0.05). RESULTS: A statistically significant difference was found between the adhesive strategies tested (p<0.001), with the self-etching form showing higher values than the etch-and-rinse. Moreover, no significant differences were observed between the tested toothpastes (p=0.750) and interactions (p=0.438). CONCLUSION: The use of toothpaste containing obliterating agents does not affect bond strength to dentin subjected to erosive/abrasive conditions when a universal adhesive is used. However, the self-etch strategy might be preferred for eroded/abraded dentin.

Effects of silver diamine fluoride on demineralization protection after a secondary acid challenge.

OBJECTIVE: This investigation describes the effects of 5% sodium fluoride varnish and 38% silver diamine fluoride on demineralization protection of human enamel lesions of three different severities after a secondary acid challenge. STUDY DESIGN: Specimens underwent color and enamel surface microhardness change measurements after demineralization and treatment events. Transverse microradiography was conducted following the secondary demineralization. RESULTS: After treatments, enamel surface microhardness change showed that 24-hour lesions treated with fluoride varnish had less rehardening than 24-hour lesions treated with silver diamine fluoride (p<0.05), whereas 144-hour lesions from both treatment groups showed a beneficial decrease in surface microhardness change that was markedly better in samples treated with silver diamine fluoride (p<0.05). After the secondary demineralization, 24- and 144-hour lesions treated with silver diamine fluoride showed a sustained beneficial decrease in enamel surface microhardness change when compared to fluoride varnish-treated samples of the corresponding lesion severity (p<0.05). Transverse microradiography showed no difference between fluoride varnish- and silver diamine fluoride-treated samples of any corresponding lesion severity, indicating that remineralization in both fluoride varnish- and silver diamine fluoride-treated samples was proportional to each other after a secondary acid challenge. CONCLUSIONS: Using silver diamine fluoride may have comparable benefits to fluoride varnish in mineral loss prevention.

Effect of fluoride varnishes on oral bacteria of preschool children with cavitated and non-cavitated carious lesions: randomized clinical trial.

We compare the effect of calcium and phosphate-containing sodium fluoride (NaF) varnishes to conventional NaF varnish on S. mutans and L. fermentum counts. 3-4 years old children were grouped according to their caries status (n = 45 each): caries-free, with non-cavitated and with cavitated lesions. Each group was randomly subdivided (n = 15 each) into: Group 1- 5% NaF, Group 2- 5% NaF with tricalcium phosphate, Group 3- 5% NaF with casein phosphopeptide- amorphous calcium phosphate. Biofilm and saliva were collected to quantify microorganisms at baseline (T1) and 24-months (T2). Differences between groups were compared using Kruskal-Wallis test, followed by Dunn-Bonferroni post-test, at 0.0167 α-level. Significant difference was found for percentage of children with detectable biofilm L. fermentum (p = 0.013) at T1 and salivary S. mutans (p = 0.011) at T2. Percentage of children increased from T1 to T2 in Group 2 with salivary S. mutans (p = 0.007), salivary L. fermentum (p = 0.035), and biofilm L. fermentum (p = 0.019) and in Group 3 with salivary L. fermentum (p = 0.035). Bacterial change was not significant in both samples of intervention groups, except increase in salivary S. mutans (p = 0.038) in Group 3. Both calcium- and phosphate-containing NaF varnishes demonstrated similar antibacterial effect on S. mutans and L. fermentum compared to conventional NaF varnish.

Film-Forming Polymers for Inhibition of Hydroxyapatite Dissolution: A Screening Study.

The aim of this study was to evaluate the effect of film-forming polymer solutions of different concentrations and pH values, either associated or not with sodium fluoride (F; 225 ppm F-), when applied during the initial stage of salivary pellicle formation, to prevent the dissolution of hydroxyapatite (HA), which was determined by the pH-stat method. Polyacrylic acid (PA), chitosan, sodium linear polyphosphate (LPP), polyvinyl methyl ether/maleic anhydride (PVM/MA), and propylene glycol alginate (PGA) were tested in three concentrations (lower, medium, and higher), two pH values (native or adjusted), and either associated or not with F. Distilled water, F, and stannous ion+fluoride (Sn/F; 225 ppm F- and 800 ppm Sn2+, as SnCl2) solutions were the controls, totalizing 63 groups. HA crystals were pretreated with human saliva for 1 min to allow pellicle formation, then immersed in the experimental solutions (1 min), and exposed to saliva for another 28 min. Subsequently, they were added to a 0.3% citric acid solution (pH = 3.8), connected to a pH-stat system that added aliquots of 28 µL 0.1 N HCl for a total reaction time of 5 min. Data were analyzed with one-way ANOVA and Tukey's tests (α = 0.05). For PA alone, the concentrations of 0.1% (native pH), 0.06%, and 0.08% (both pH adjusted) showed significantly lower HA dissolution than the negative control. PA concentrations of 0.1% and 0.08%, of both pH values, improved the effect of F against HA dissolution to a near-identical value as Sn/F. All solutions containing chitosan and LPP significantly reduced HA dissolution in comparison with the control. For chitosan, the concentration of 0.5% (in both pH values) improved the effect of F. LPP at 0.5% (native pH) and all associations of LPP with F outperformed the effect of F. Some PVM/MA solutions significantly reduced HA dissolution but PVM/MA could not improve the protection of F. PGA was incapable of reducing HA dissolution or improving F effect. It was concluded that chitosan, LPP, and some PA and PVM/MA solutions used alone were capable of reducing HA dissolution. Only PA, chitosan, and LPP were able to enhance fluoride protection, but for PA and chitosan, this was influenced by the polymer concentration.

Multidisciplinary evaluation of the remineralization potential of three fluoride-based toothpastes on natural white spot lesions.

OBJECTIVES: This in vitro study aimed assessing the remineralization potential of three commercial fluoride-based toothpastes in permanent teeth with natural white spot lesions (WSLs). A multidisciplinary approach based on Raman microspectroscopy (RMS), Scanning electron microscopy (SEM), Energy-dispersive x-ray spectroscopy (EDS), and Vickers microhardness (VMH) was exploited. METHODS: N = 12 human molars with natural WSLs in the proximal-vestibular zone were selected and divided into 4 groups (n = 3) according to the different treatments: HAF (hydroxyapatite with fluoride ions); SMF (sodium monofluorophosphate with arginine); SF (sodium fluoride with enzymes), and CTRL (untreated group). All toothpastes tested contained 1450 ppm of fluoride. Teeth samples were submitted to the following protocol: a 7-day pH cycling treatment, with two daily exposures (2 min each time) to the commercial toothpastes described above. The surface micromorphology (SEM), the chemical/elemental composition (RMS and EDS), and the Vickers microhardness (VMH) were evaluated. Statistical analysis was performed. RESULTS: A remarkable remineralization of WSLs in SEM images was observed in all treated groups compared to CTRL. In particular, HAF and SF displayed higher values of VMH, phosphates amount (I960), crystallinity (FWHM960), and lower ones of C/P (I1070/I960) with respect to CTRL. Intermediate values were found in SMF, higher than CTRL but lower with respect to HAF and SF. As regards the Ca/P ratio, statistically significant differences (p < 0.05) were found between SF and the other groups. CONCLUSIONS: All the tested dentifrices have shown to remineralize the WSLs. SF and HAF have comparable capability in hardness recovery and crystallinity; however, SF shows the best remineralizing potential according to both micromorphological and chemical analyses. Clinical relevance The daily use of toothpastes containing hydroxyapatite partially replaced with fluoride, sodium monofluorophosphate with arginine and sodium fluoride toothpaste associated with enzymes represents a preventive, therapeutic, effective, and non-invasive tool for remineralize WSLs.

EFFECT OF CHICKEN EGGSHELL PASTE ON ENAMEL SURFACE MICROHARDNESS AND COLOUR CHANGE OF ARTIFICIAL CARIOUS LESIONS CREATED ON PERMANENTLY EXTRACTED TEETH.

Remineralizing agents such as fluoride and hydroxyapatite (HA) (Ca5 (po4)3OH) are well-known treatment choices for incipient enamel lesions. Hydroxyapatite has been newly presented to return the color of such enamel lesions. The purpose of this prospective in vitro study was to compare commercial sodium fluoride paste to hydroxyapatite paste (HA) made from chicken eggshells powder (CESP) in terms of how it affected the microhardness and color of the enamel surface of artificially demineralized permanent teeth. Fifty healthy maxillary premolars were gathered, decoronated, and the crowns were placed in acrylic moulds with the buccal enamel surfaces exposed. Baseline microhardness evaluation was done for the baseline group, while the colour assessment was done at baseline to three treatment groups. Then specimens were randomly divided into the following five groups (n = 10) based on the treatment of enamel surface: Group 1: Baseline group; Group 2: Acid group demineralized only; Group 3: demineralized followed by the application of hydroxyapatite paste (HA); Group 4: demineralized followed by the application of sodium fluoride toothpaste (Naf); and Group 5: demineralized followed by application of combination treatments (HA paste at morning and Naf paste at evening. The specimens were stored in deionized water at room temperature during treatments, after one week they were subjected to a Vickers microhardness test, and colour assessment to three treatment groups after treatment. One­way ANOVA and Tukey's post hoc multiple comparison tests were used for statistical analysis (P < 0.05). After artificial demineralization, the enamel's surface microhardness was greatly reduced, and after management, it dramatically increased. The combination group had the greatest mean microhardness value when compared to the HA paste group and the Naf paste group. Statistically, there was no significant variance in microhardness values among the Naf paste and HA paste groups. Hydroxyapatite sourced from chicken eggshell was as effective as Naf paste in remineralizing and restoring the lost microhardness of artificially demineralized enamel, hydroxyapatite paste changed tooth color, while sodium fluoride paste, a combination group neither changed nor masked color of early caries lesion.

Influence of bleaching gels formulated with nano-sized sodium trimetaphosphate and fluoride on the physicochemical, mechanical, and morphological properties of dental enamel.

OBJECTIVES: To evaluate in vitro the effects of sodium fluoride (F) and nano-sized sodium trimetaphosphate (TMPnano) added to a 35% hydrogen peroxide (H2O2) bleaching gel on the color alteration, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion. MATERIALS AND METHODS: Bovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 35% H2O2 (HP); 35% H2O2 + 0.1% F (HP/F); 35% H2O2 + 1% TMPnano (HP/TMPnano); 35% H2O2 + 0.1% F + 1% TMPnano (HP/F/TMPnano) and 35% H2O2 + 2% calcium gluconate (HP/Ca). The gels were applied 3 times by 40 min; once each 7-day. The Commission Internationale de l'Eclairage (CIE) L*a*b* total color alteration (ΔE), color alteration by CIEDE2000 (ΔE00), whitening index (ΔWID), surface (SH) and cross-sectional hardness (ΔKHN), surface roughness (Ra), and transamelodentinal diffusion were determined. Enamel surfaces were evaluated by Scanning Electron Microscopy (SEM) and X-ray Dispersive Energy (EDX). Data were submitted to ANOVA, followed by the Student-Newman-Keuls test (p <0.05). RESULTS: ΔE, ΔE00, and ΔWID were similar among the gels that promoted a bleaching effect after treatment (p <0.001). Mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion were lower for HP/F/TMPnano; the HP and HP/Ca groups presented the highest values (p <0.001). For SEM/EDX, surface changes were observed in all bleached groups, but less intense with TMPnano. CONCLUSIONS: Gels containing F/TMPnano do not interfere with the bleaching effect and reduce enamel demineralization, roughness, H2O2 diffusion, and morphological changes. CLINICAL RELEVANCE: Whitening gels containing F/TMPnano can be used as a new strategy to increase safety and maintain clinical performance.

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.

Iron oxide nanozymes stabilize stannous fluoride for targeted biofilm killing and synergistic oral disease prevention.

Dental caries is the most common human disease caused by oral biofilms despite the widespread use of fluoride as the primary anticaries agent. Recently, an FDA-approved iron oxide nanoparticle (ferumoxytol, Fer) has shown to kill and degrade caries-causing biofilms through catalytic activation of hydrogen peroxide. However, Fer cannot interfere with enamel acid demineralization. Here, we show notable synergy when Fer is combined with stannous fluoride (SnF2), markedly inhibiting both biofilm accumulation and enamel damage more effectively than either alone. Unexpectedly, we discover that the stability of SnF2 is enhanced when mixed with Fer in aqueous solutions while increasing catalytic activity of Fer without any additives. Notably, Fer in combination with SnF2 is exceptionally effective in controlling dental caries in vivo, even at four times lower concentrations, without adverse effects on host tissues or oral microbiome. Our results reveal a potent therapeutic synergism using approved agents while providing facile SnF2 stabilization, to prevent a widespread oral disease with reduced fluoride exposure.

Effects of sodium fluoride on neural tube development in chick embryos.

OBJECTIVE: Various environmental factors encountered in daily life are associated with the development of neural tube defects. This study aims to investigate the effects of fluoride on neural tube development in chick embryos. METHODS: A total of 60 specific pathogen-free, fertile, zero-day Leghorn-type eggs were used in the study. Group 1 was the control group, in which only saline was administered. Group 2 was the low-dose group, in which 0.003 mg of fluoride was administered, and Group 3 was the high-dose group, in which 0.006 mg of fluoride was administered. After 72 h of incubation, the embryonic disc was evaluated microscopically. RESULTS: In the control group, the surface ectoderm of all sections was intact, the neural tube was closed, and the neuroepithelium, the basement membrane surrounding the neuroepithelium, the somites, and the notochord displayed standard structure. Neural tube defects were observed in 3 of the chick embryos, that was given low-dose fluoride. In Group 3, which was administered high doses of fluoride, neural tube defects were observed in 4 embryos. It was observed that the development of neural tube defects was no statistically significantly higher in low and high-dose fluoride group compared to the control group. CONCLUSION: Low and high-dose fluoride exposure was associated with developing neural tube defects, but there was no statisticaly significance.