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1.
Arch Oral Biol ; 132: 105275, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34619414

RESUMO

OBJECTIVE: This study evaluated the effect of experimental solutions containing TiF4/NaF and chitosan on bacterial species of microcosm biofilm and on dentin demineralization. DESIGN: Microcosm biofilm was produced from human saliva mixed with McBain medium (0.2% sucrose) on bovine dentin for 5 days, under 5% CO2 and 37 °C. From the 2nd day to 5th day, the treatments were applied (1×60s/day) as following: (1) NaF (500 ppm F-, positive control); (2) TiF4 and NaF (TiF4: 190 ppm Ti4+ and 300 ppm F-; NaF: 190 ppm F-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation). CFU counting was performed for total microorganism, total streptococci, total lactobacilli and mutans streptococci. Dentin demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < 0.05). RESULTS: No differences were found between the treatments with respect to CFU counting (p > 0.05). Dentin treated with TiF4/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF4/NaF solution, being both able to significantly reduce mineral loss. CONCLUSION: TiF4/NaF plus chitosan solution, at suitable pH to be clinically applicable, had no antimicrobial effect, but it was able to reduce dentin caries development under this model.


Assuntos
Biofilmes , Quitosana , Cárie Dentária , Desmineralização do Dente , Animais , Cariostáticos/farmacologia , Bovinos , Quitosana/farmacologia , Cárie Dentária/prevenção & controle , Dentina , Fluoretos/farmacologia , Humanos , Fluoreto de Sódio/farmacologia , Titânio , Desmineralização do Dente/prevenção & controle
2.
Shanghai Kou Qiang Yi Xue ; 30(4): 360-366, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34693427

RESUMO

PURPOSE: To explore the effects of high-concentration fluoride(F) on apoptosis of human periodontal ligament stem cells (PDLSCs). METHODS: PDLSCs were isolated from periodontal ligament tissues of extracted third molars, and treated with different concentrations (0-40 ppm F) of NaF for indicated period of time. CCK-8 assay was performed to detect cell viability. After stained with Annexin V-PI and JC-1, cell apoptosis and mitochondrial membrane potential were analyzed by flow cytometry. Immunofluorescence staining and confocal microscopic assay were used to detect the protein expression level of cyt-c, cleaved-caspase-9 and -3. The mRNA level of caspase -9 and -3 were examined by RT-PCR. The protein expression level of total and phosphate-ERK, JNK and p38 were analyzed by Western blot. SPSS 13.0 software package was used for statistical analysis. RESULTS: Fluoride treatment inhibited cell viability (CCK-8 assay) and induced apoptosis of PDLSCs (Annexin V-PI staining) in a dose- and time-dependent manner. Immunofluorescence assay showed that fluoride with a dose ≥10 ppm significantly induced release of cyt-c from the mitochondria to cytosol, and up-regulation of expression of cleaved-caspase -9 and -3. RT-PCR confirmed that the mRNA level of caspase-9 and -3 increased with the dose of fluoride. Western blot assay confirmed that fluoride induced up-regulation of p-ERK, but not that of p-JNK and p-p38, and specifically blocking ERK pathway with U0126 could partially rescue the fluoride-induced cell apoptosis. CONCLUSIONS: High concentrations of fluoride induces apoptosis of PDLSCs via intrinsic mitochondrial pathway, and phosphation of MAPK/ERK is involved in the F-induce cell apoptosis.


Assuntos
Fluoretos , Ligamento Periodontal , Apoptose , Células Cultivadas , Fluoretos/farmacologia , Humanos , Células-Tronco
3.
Chem Biol Interact ; 349: 109659, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536393

RESUMO

Fluorine is an essential trace element for human health. However, excessive fluoride intake causes skeletal fluorosis which affects cartilage development. Fluoride inhibited chondrocyte proliferation which is the initial and critical step of endochondral ossification, but the underlying mechanism has not been clearly illustrated. Mammalian target of rapamycin (mTOR) is an important protein kinase which modulates various cellular processes and is believed to be a central regulator of chondrocyte proliferation and autophagy. In this study, we explored the effect of fluoride on the proliferation and autophagy of chondrocytes and the regulatory role of mTOR signaling pathway. Our results suggested that NaF inhibited the protein expressions of proliferating cell nuclear antigen (PCNA) and pS6 in cultured fetal rat tibias. Furthermore, NaF significantly downregulated the expressions of mTOR signaling pathway-related genes, including PI3K, AKT, mTOR, 4EBP1 and S6K1 in mouse ATDC5 chondrogenic cell line. We also found that NaF increased autophagy in ATDC5 cells. The mRNA and protein levels of autophagy-related genes LC3, Beclin1 and p62 were significantly changed after NaF treatment. Further studies demonstrated that MHY1485, a small-molecular mTOR activator, totally reversed fluoride-induced promotion of autophagy. MHY1485 also recovered the downregulation of proliferative chondrocytes markers Sox9 and Type Ⅱ Collagen (Col2a1) induced by fluoride in ATDC5 cells. Taken together, our result demonstrate that fluoride suppressed proliferation and facilitated autophagy via PI3K/AKT/mTOR signaling pathway in chondrogenesis.


Assuntos
Autofagia/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Condrócitos/efeitos dos fármacos , Fluoretos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Condrócitos/citologia , Humanos
4.
Biomed Res Int ; 2021: 3304553, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34337003

RESUMO

Background: Diet and lifestyle can destroy tooth structure due to the dissolution of enamel by acidic beverages. The present study evaluated the effect of CO2 laser irradiation and CPP-ACFP (casein phosphopeptide and amorphous calcium phosphate with fluoride) paste on the remineralization of enamel eroded by carbonated soft drinks. Methods: In the present in vitro study, 46 human sound premolar teeth were sectioned mesiodistally to achieve 84 samples. Fourteen samples were assigned to the positive control group (G1), and the remaining samples were immersed in 500 mL of cola drink for 2 minutes, followed by rinsing with distilled water for 10 seconds. This procedure was carried out three times to create erosive lesions. Then, the 60 eroded samples were randomly assigned to five groups of G2 to G6 in terms of the treatment as follows: negative control (G2), CO2 laser irradiation (G3), CPP-ACFP paste (G4), CO2 laser irradiation followed by CPP-ACFP paste application (G5), and CPP-ACFP paste application followed by CO2 laser irradiation (G6). The mean surface microhardness of the enamel surface was evaluated and determined at three points for each sample. Data were analyzed with one-way ANOVA and Tukey HSD tests (α = 0.05). Results: The highest and the lowest hardness values were recorded in the G1 (314 ± 12 kg/mm2) and G2 (213.7 ± 12 kg/mm2) groups, respectively. ANOVA revealed significant differences between the study groups (P < 0.001). Two-by-two comparisons showed significant differences between the G2 group and the other groups, indicating the efficacy of all the treatment modalities in tooth remineralization and rehardening procedures (P < 0.05). Only in group G6, the enamel microhardness was not significantly different from the G1 positive control group (P > 0.05). Conclusion: Considering the parameters used in the present study, CO2 laser irradiation or CPP-ACFP paste application alone increased eroded enamel's surface hardness; however, their sequential application was more effective in rehardening the eroded enamel's surface to near-normal levels.


Assuntos
Dióxido de Carbono/farmacologia , Caseínas/farmacologia , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/efeitos da radiação , Fluoretos/farmacologia , Lasers de Gás , Fragmentos de Peptídeos/farmacologia , Erosão Dentária/patologia , Erosão Dentária/cirurgia , Dureza , Humanos
5.
J Dent ; 113: 103789, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34455017

RESUMO

OBJECTIVE: Composites with remineralizing and antibacterial properties are favorable for caries inhibition. The objectives of this study were to develop a new bioactive nanocomposite with remineralizing and antibiofilm properties by incorporating dimethylaminohexadecyl methacrylate (DMAHDM) and nano-calcium fluoride (nCaF2). METHODS: nCaF2 was produced via a spray-drying method and integrated at 15% mass fraction into composite. DMAHDM was added at 3% mass fraction. Mechanical properties and F and Ca ion releases were assessed. Colony-forming units (CFU), lactic acid and metabolic activity of biofilms on composites were performed. RESULTS: The new composites had flexural strengths of (95.28±6.32) MPa and (125.93±7.49) MPa, which were within the ISO recommendations. Biofilm CFU were reduced by 3-4 log (p<0.05). The composites achieved high F releases of (0.89±0.01) mmol/L and (0.44±0.01) mmol/L, and Ca releases of (1.46±0.05) mmol/L and (0.54±0.005) mmol/L. CONCLUSIONS: New nanocomposites were developed with good mechanical properties, potent antibacterial activity against salivary biofilms, and high F and Ca ion releases with potential for remineralization. CLINICAL SIGNIFICANCE: Novel nanocomposites using nCaF2 and DMAHDM were developed with potent antibacterial and remineralizing effects and high F and Ca ion releases. They are promising to inhibit recurrent caries, promote remineralization, and possess long-term sustainability.


Assuntos
Fluoretos , Nanocompostos , Antibacterianos/farmacologia , Biofilmes , Fluoreto de Cálcio , Fosfatos de Cálcio/farmacologia , Fluoretos/farmacologia , Metacrilatos
6.
J Contemp Dent Pract ; 22(3): 237-241, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210921

RESUMO

AIM AND OBJECTIVE: The present study aimed at evaluating the effectiveness of diverse remineralizing agents on artificial enamel lesion using confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: Totally 80 mandibular premolars which were single rooted were included. All teeth were suspended in a demineralizing solution to create artificial enamel lesions on the exposed enamel. The samples were separated randomly into four groups (20 each) depending on the application of the remineralizing agents as follows: group 1: control; group 2: calcium sucrose phosphate (CaSP); group 3: fluoride varnish; and group 4: casein phosphopeptides-amorphous calcium phosphate (CPP-ACP). The samples in individual group were treated with the corresponding remineralizing agent (except for the control group) two times a day for 14 days. The experimental and control groups were exposed to CLSM assessment to analyze the data of remineralization and demineralization. RESULTS: The mean depth of remineralization of fluoride varnish group was slightly more compared to other groups. The highest mean depth of remineralization was found in the fluoride varnish group (122.26 ± 0.28) followed by CaSP (110.58 ± 1.34), CPP-ACP (107.08 ± 0.48), and control (157.78 ± 0.46) groups. The different comparisons among the remineralization material groups showed a statistically significant difference (p < 0.05) in almost all groups except group 2 vs group 4. CONCLUSION: This study concluded that improved remineralization of artificial enamel lesion could be achieved with the fluoride varnish group when compared to the CaSP and CPP-ACP groups. CLINICAL SIGNIFICANCE: Remineralization as a treatment technique has received a lot of consideration from clinicians. The process of remineralization and demineralization is considered an active process categorized by the movement of calcium and phosphate in and out of the enamel. Presently, the attention has changed toward increasing the resistance of the tooth by applying remineralizing agents topically, which has led to the notable fall in dental caries.


Assuntos
Cárie Dentária , Remineralização Dentária , Cariostáticos/farmacologia , Caseínas , Cárie Dentária/tratamento farmacológico , Esmalte Dentário , Fluoretos/farmacologia , Humanos , Lasers
7.
Clin Oral Investig ; 25(10): 5929-5944, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34115201

RESUMO

OBJECTIVE: The purpose of this in situ study was to evaluate different dentifrices on enamel after bleaching under normal and hyposalivatory conditions. MATERIALS AND METHODS: Twenty-four participants were assigned of which 12 had normal and 12 had low salivary flow. The study was conducted in 6 in situ experimental phases of 24 h duration: placebo, NaF, SnF2, F/Sn/Chitosan, F/Arginine, and F/Bioactive Glass. The specimens were previously bleached in vitro. Microhardness (SMH), roughness (Ra), and color analyses (CIELAB and ΔE00) were performed at baseline (T1), after bleaching (T2) and after in situ phase (T3). Scanning electron microscopy (SEM) and the elemental levels (wt%) of Ca, P, and Na and the proportion between Ca and P were determined using an energy-dispersive X-ray spectrometer (EDS) in T3. The SMH and Ra were analyzed by mixed models for repeated measures and Tukey Kramer. The color and Na% were analyzed by split-plot ANOVA and Tukey test. The EDS were analyzed by Mann's Whitney nonparametric, Friedman, and Nemenyi tests (p<0.05). RESULTS: The dentifrices placebo and NaF in the low flow presented lower SMH and higher Ra in T3 and lower Ca% compared to the same dentifrices in normal flow. For normal flow, SnF2 resulted in greater SMH. For low flow, SnF2, F/Sn/Chitosan, and F/Bioactive Glass resulted in higher SMH in T3 and did not differ from T1. F/Bioactive Glass showed lower Ra among the dentifrices evaluated for both salivary flows, whereas SnF2 showed the highest. F/Bioactive Glass showed a statistically significant difference from placebo for Ca%, P%, Na%. For ΔE*ab and ΔE00 (T1×T3), no differences were found for the dentifrices and salivary flows. CONCLUSION: The low salivary flow had less capacity for remineralization of bleached enamel compared to normal flow. Overall, the dentifrice with bioactive glass had the best performance in bleached enamel under low and normal salivary flow condition. CLINICAL RELEVANCE: It is recommended to use a bioactive glass-based dentifrice after bleaching to promote tooth enamel recovery for patients with or without impaired salivary flow.


Assuntos
Dentifrícios , Clareamento Dental , Xerostomia , Esmalte Dentário , Dentifrícios/farmacologia , Fluoretos/farmacologia , Humanos , Remineralização Dentária
8.
J Dent ; 111: 103732, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34174348

RESUMO

OBJECTIVES: To evaluate the effect of experimental solutions containing TiF4/NaF and chitosan on bacterial species and on enamel caries prevention. METHODS: Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel for five days, under 5% CO2 and 37 °C. From the second day until the end, the treatments were applied (1 × 60 s/day): (1) NaF (500 ppm F-, positive control); (2) TiF4 and NaF (TiF4: 190 ppm Ti4+ and 300 ppm F-; NaF: 190 ppm F-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPas, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPas, 75% deacetylation). CFU counting was performed for total microorganism, total streptococcus, total lactobacillus and Streptococcus mutans. Enamel demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < .050). RESULTS: No differences were found between the treatments with respect to CFU counting (ANOVA, p > .050). Enamel treated with TiF4/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF4/NaF and NaF solutions, being all of them able to significantly reduce mineral loss (50-74%), but only TiF4/NaF plus chitosan reduced lesion depth (55%) compared to the negative control (p = .001). CONCLUSION: TiF4/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development in 79% compared to control under this model. CLINICAL SIGNIFICANCE: This study showed that TiF4/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development under a microcosm biofilm model.


Assuntos
Quitosana , Cárie Dentária , Desmineralização do Dente , Animais , Biofilmes , Cariostáticos/uso terapêutico , Bovinos , Quitosana/farmacologia , Cárie Dentária/prevenção & controle , Suscetibilidade à Cárie Dentária , Fluoretos/farmacologia , Fluoretos/uso terapêutico , Humanos , Fluoreto de Sódio/farmacologia , Fluoreto de Sódio/uso terapêutico , Desmineralização do Dente/prevenção & controle
9.
J Dent ; 111: 103724, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34118282

RESUMO

OBJECTIVE: To evaluate the effect of low-fluoride (F-) toothpaste and sodium trimetaphosphate (TMP) associated with xylitol and erythritol (XE) on enamel demineralization and biofilm composition. METHODS: This crossover double-blind in situ study consisted of five phases (seven days each), in which 14 volunteers wore oral appliances containing four enamel bovine blocks. The cariogenic challenge was performed by exposure to a 30% sucrose solution (6x/day). The toothpaste treatments (3x/day) were as follows: placebo (no F-/TMP/XE); 200 ppm F- (NaF) (200F); 1,100 ppm F- (1100F); 16% Xylitol and 4% Erythritol (XE); and 200 ppm F-, 0.2% TMP, 16% xylitol, and 4% erythritol (200F-TMP-XE). Percentage of surface hardness loss (%SH) and integrated loss of subsurface hardness (ΔKHN), and calcium (Ca2+), phosphate (PO43-), and F- on enamel and biofilm were determined; as well as insoluble extracellular polysaccharide (EPS). RESULTS: XE and 1100F groups showed no significant difference for %SH and ΔKHN values (p = 0.220 and p = 0.886), and the 200F-TMP-XE group had the lowest mineral loss (p < 0.001). Ca2+ and PO43- in the enamel showed the highest values (p < 0.001) for the 200F-TMP-XE group. Higher values of F- in the enamel and biofilm were observed for the 1100F group (p < 0.001). There was no difference for Ca2+ (p = 1.00) and EPS (p =0.918) values between XE and 200-TMP-XE groups in the biofilm, but their values were higher and lower than the 1100F (p = 0.002 and p = 0.029), respectively. CONCLUSIONS: 200F-TMP-XE promoted a greater protective effect against enamel demineralization and significantly affected the composition of biofilm formed in situ compared to 1100F toothpaste. CLINICAL SIGNIFICANCE: Low-F- toothpaste containing TMP and polyols can be considered an effective and safe measure to improve the oral health of individuals, especially patients with high caries activity.


Assuntos
Desmineralização do Dente , Cremes Dentais , Animais , Biofilmes , Cariostáticos/farmacologia , Bovinos , Estudos Cross-Over , Esmalte Dentário , Método Duplo-Cego , Eritritol , Fluoretos/farmacologia , Dureza , Humanos , Desmineralização do Dente/prevenção & controle , Cremes Dentais/farmacologia , Xilitol/farmacologia
10.
Folia Microbiol (Praha) ; 66(4): 569-578, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33821405

RESUMO

In our previous study, all Pseudomonas strains THP6, THP41, and OHP5 were identified as fluoride-resistant bacteria isolated from Dindigul district, Tamilnadu, India. The selected strains exhibiting a high level of fluoride resistance was determined in Luria broth (LB) medium and LB agar plates. In a further effort, fluoride-resistant organisms were tested for hemolytic activity and showed ß-hemolysis on blood agar plates. The virulence factors such as gyrB, toxA, algD and lasB, plcH, rhlC and biofilm response genes (pslA, pelA, ppyR) were detected by PCR analysis. The putative genus-specific and species-specific PCR also confirmed that the selected fluoride-resistant strains were belonging to Pseudomonas aeruginosa species. Fluoride-resistance gene crcB was amplified by gene-specific primers. The crcB gene was cloned in TA vector and transformed into E. coli DH5α. Comparative and blast analysis of THP6, THP41, and OHP5 strains crcB gene sequences were high homology with P. aeruginosa fluoride efflux transporter crcB and P. aeruginosa putative fluoride ion transporter crcB. The recombinants were efficiently growing in the NaF containing LB agar plates. The fluoride tolerance of these strains was also associated with resistance to multiple antibiotics. These results can lead to the use of the fluoride resistance gene of P. aeruginosa for the development of a biosensor for fluoride detection.


Assuntos
Farmacorresistência Bacteriana , Fluoretos , Pseudomonas , Fatores de Virulência , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Fluoretos/análise , Fluoretos/farmacologia , Índia , Pseudomonas/classificação , Pseudomonas/efeitos dos fármacos , Pseudomonas/genética , Pseudomonas/patogenicidade , Pseudomonas aeruginosa/classificação , Pseudomonas aeruginosa/genética , Fatores de Virulência/genética , Água/química , Microbiologia da Água
11.
Caries Res ; 55(3): 225-233, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33827100

RESUMO

Fluorosis is a defect in the enamel mineral content caused by excessive fluoride intake during amelogenesis; the interaction of various factors in the development and progression of fluorosis has not been defined. Casein kinase 1α (CK1α) is constitutively active in cells and is involved in diverse cellular processes; however, its expression in fluorosis has not been measured. This study aimed to investigate the effects of fluoride on CK1α expression and to assess the regulation of molecular signaling involving fluoride and CK1α during enamel development. Kunming mice were randomly divided into the control and F groups with induced clinical features of fluorosis. The F group mice, including mothers and newborns, were treated with 50 ppm fluoridated water. Immunohistochemical staining of the sections of the embryonic mandible regions was performed at the bell stage. Protein expression and signaling pathways in a mouse-derived ameloblast-like cell line (LS8) exposed to fluoride or a Jun N-terminal kinase (JNK) inhibitor were compared to those in control cells without exposure. CK1α and proteins of the JNK signaling pathways were assayed by quantitative real-time PCR and Western blotting. Mice of the F group developed dental fluorosis. Scanning electron microscopy showed a significant reduction in the degree of mineralization in the F group mice, which manifested as thin, loosely arranged, and disorganized enamel rods. Additional analysis revealed that the expression of CK1α in the F group was significantly elevated compared with that in the control group; LS8 cells responded to fluoride by upregulation of CK1α expression through the JNK pathway. Our findings identified the potential effects of CK1α on fluorosis using a mouse model and revealed that a high fluoride level increases the expression of CK1α and that JNK can be a key regulatory factor in CK1α expression.


Assuntos
Caseína Quinase Ialfa , Fluorose Dentária , Esmalte Dentário , Fluoretos/farmacologia , Humanos , Recém-Nascido , Sistema de Sinalização das MAP Quinases , Regulação para Cima
12.
Biomed Res Int ; 2021: 5544196, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33834066

RESUMO

Objectives: The aim of this study was to evaluate the protective effect of using four different fluoride bioactive enamel sealers against an acidic erosion challenge. Materials and Methods: A sample of 50 freshly extracted sound upper premolars had their buccal surface bonded to 50 orthodontic brackets using Transbond PLUS color change adhesive; the first four groups had four compositions of fluoride bioactive glasses based on 37 mol% SiO2, 43.9-53.9 mol% CaO, 6.1 mol% P2O5 and CaF2, and 0-10 mol% of Na2O applied to their surfaces and the fifth group served as control (which was not treated by any bioactive sealer). All specimens were challenged by 1% citric acid for 18 minutes which was stirred by a magnetic stirrer. The enamel surfaces next to the orthodontic brackets were examined by SEM. The Wilcoxon signed-rank test was used to compare the area covered by the fluoride bioactive pastes before/after erosion (p < 0.05). Samples from the layer formed on top of the examined teeth were tested before/after erosion to be examined by the attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR/ATR). Results: The FTIR/ATR test showed that fluoride bioactive pastes' applications resulted in the formation of a hydroxyapatite-rich layer; the SEM analysis showed that the aforementioned layer significantly resisted erosion challenge when compared to the control group (p < 0.05). Conclusions: Fluoride bioactive pastes can efficiently protect the enamel surfaces next to orthodontic brackets from acidic erosion challenges.


Assuntos
Esmalte Dentário/efeitos dos fármacos , Fluoretos/farmacologia , Vidro/química , Braquetes Ortodônticos , Substâncias Protetoras/farmacologia , Simulação por Computador , Cristalização , Esmalte Dentário/ultraestrutura , Selantes de Fossas e Fissuras , Resinas Sintéticas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
13.
Biol Trace Elem Res ; 199(11): 4145-4153, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33660200

RESUMO

Fluoride had been shown to inhibit collagen-induced in vitro mineralization without affecting demineralization at its lower concentrations (> 1X10-5 and < 1X10-4 M) and stimulate mineralization in addition to inhibiting demineralization at its concentration > 1X10-4 M. The present studies were designed to investigate the mechanism by which fluoride acts to produce these concentration-dependent effects. The inhibition of mineralization occurring at the lower concentrations of fluoride was found to be due to the inactivation of the specific calcium binding sites of collagen involved in initiating the process of mineralization. Stimulation of mineralization obtained at the higher concentrations of fluoride was found to be due to the activation of the specific phosphate-binding sites of the collagen and the formation of a relatively less soluble and highly stable fluorapatite instead of hydroxyapatite. At its higher concentrations, fluoride was also found to inhibit demineralization by binding to the mineral phase associated with collagen. A model has been presented to explain the mechanisms whereby fluoride may act to produce the above observed effects.


Assuntos
Colágeno , Fluoretos , Durapatita , Fluoretos/farmacologia
14.
J Dent ; 108: 103631, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33711406

RESUMO

OBJECTIVE: To examine the biochemical components of multi-species biofilm on the arginine (Arg)-sodium fluoride (NaF) varnish-treated enamel following bacterial pH-cycling. METHODS: l-arginine (at 1%, 2%, & 4% w/v.) was incorporated in a 5% NaF varnish. The experimental and control groups were: 1%, 2%, 4% Arg-NaF, NaF, and no treatment. Enamel blocks were prepared, acid-etched, varnish-treated and then subjected to 72 h bacterial pH-cycling in an oral biofilm reactor. The organic (carbohydrates, proteins, amyloids, and eDNA) and inorganic components (calcium, inorganic phosphate, F) were assayed for the obtained biofilm suspensions. The biofilms were stained for exopolysaccharides (EPS)/bacteria and the respective proportions of live/dead bacteria was determined using confocal imaging. RESULTS: The total carbohydrate content of the biofilm was the lowest for the 2% and 4% Arg-NaF (p < 0.05). Except for 2% Arg-NaF, the biofilm proteins for 4% Arg-NaF were significantly higher than the other groups (p < 0.05). The amyloids for Arg-NaF groups were significantly lower than the controls (p < 0.05). The eDNA for 4% Arg-NaF was significantly higher than the controls (p < 0.05). The 2% and 4% Arg-NaF-treated enamel had increased biofilm Pi and F compared to the NaF-treated enamel (p < 0.05). The proportion of biofilm EPS matrix to bacteria was significantly reduced in Arg-NaF groups compared to the controls (p < 0.05). The dead bacterial proportions of 4% Arg-NaF were significantly higher than the controls (p < 0.05). CONCLUSION: Higher concentrations (i.e. 2%/4%) of Arg in 5% NaF varnish have the potential to modulate the biochemical composition of the biofilm growing on the treated enamel.


Assuntos
Fluoretos Tópicos , Fluoretos , Arginina , Biofilmes , Cariostáticos/farmacologia , Fluoretos/farmacologia , Fluoreto de Sódio/farmacologia
15.
Dent Mater J ; 40(4): 1041-1048, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33775984

RESUMO

This study evaluated the ability of different types of silver diammine fluoride (SDF) to inhibit dentin demineralization using micro-focused X-ray computed-tomography (µCT). Dentin specimens were divided into five groups (n=10); no-treatment (control), 3.8% SDF (RC), 38% SDF, 38% SDF with potassium iodide (SDF/KI), and potassium fluoride (KF). The treated-dentin surfaces were subjected to demineralization for 7-days and assessed using µCT to determine mineral loss (ML) values. Specimens were also analyzed with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The ML values of the SDF and KF groups were significantly lower than those of the RC and SDF/KI groups. EDS detected fluoride ions in the SDF and KF groups but not in the RC and SDF/KI groups. It was concluded that 38% SDF demonstrated a high ability to inhibit dentin demineralization while additional application of KI may diminish the inhibitory effect of SDF. The amount of dentin demineralization with SDF treatments was material dependent.


Assuntos
Fluoretos , Desmineralização do Dente , Amônia , Dentina , Fluoretos/farmacologia , Fluoretos Tópicos/farmacologia , Humanos , Compostos de Prata/farmacologia , Desmineralização do Dente/prevenção & controle , Microtomografia por Raio-X
16.
J Dent ; 108: 103633, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33716101

RESUMO

OBJECTIVE: To investigate the remineralizing effect of a strontium-doped bioactive glass (HX-BGC) and fluoride on demineralized enamel and dentine. MATERIALS: Sixty demineralized human tooth specimens were allocated to four groups. Group 1 received 5% HX-BGC, Group 2 received 5% HX-BGC and 1450 ppm fluoride, Group 3 received 1450 ppm fluoride, and Group 4 received deionized water as negative control. The specimens were subjected to pH cycling for 14 days. The surface morphology, lesion depths, crystal characteristics and collagen matrix degradation of the specimens were assessed by scanning electron microscopy (SEM), micro-computed tomography (mico-CT), X-ray diffraction (XRD), and spectrophotometry with a hydroxyproline (HYP) assay, respectively. RESULTS: SEM images showed the enamel surface was smooth with regularly arranged enamel rods in Groups 1-3. Granular grains were observed in both inter-tubular and intra-tubular dentine in Groups 1-3. The mean lesion depths in enamel were 80.8 µm, 50.6 µm, 72.7 µm and 130.7 µm in Groups 1-4, respectively (p < 0.001), and those in dentine were 152.6 µm, 140.9 µm, 165.4 µm and 214.1 µm, respectively (p < 0.001). The differences in mean mineral loss in enamel and in dentine between the four study groups follow the same pattern as that of the differences in lesion depth. XRD illustrated apatite formation in each group. There were no significant differences in the HYP concentrations among the four groups (p = 0.261). CONCLUSION: Combined use of HX-BGC and fluoride can reduce mineral loss and promote remineralization of demineralized enamel and dentine through the precipitation of newly formed apatite. CLINICAL SIGNIFICANCE: Adjunctive use of HX-BGC may enhance the remineralization effect of fluoride in the management of early dental caries lesions.


Assuntos
Cárie Dentária , Fluoretos , Cariostáticos/farmacologia , Cárie Dentária/tratamento farmacológico , Esmalte Dentário , Dentina , Fluoretos/farmacologia , Humanos , Estrôncio/farmacologia , Remineralização Dentária , Microtomografia por Raio-X
17.
Sci Rep ; 11(1): 973, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441658

RESUMO

The objectives of the in vitro study were: (1) to investigate the effect of combining L-arginine (Arg) and NaF on the growth of Lactobacillus rhamnosus GG (LRG); and (2) to identify an optimum synergistic concentration for the synbiotic (Arg + LRG)-fluoride (SF) therapy. 1% Arg + 2000-ppm NaF (A-SF) and 2% Arg + 2000-ppm NaF (B-SF) demonstrated antagonism against LRG (FIC > 4.0). Both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assays showed that A-SF and B-SF enhanced the growth of LRG when compared to 2000-ppm NaF and LRG control. Colony forming units, bacterial weight, and biofilm thickness of A-SF and B-SF were significantly higher than 2000-ppm NaF and LRG control. Biofilm imaging depicted that 2000-ppm NaF inhibited biofilm formation; while 1%/2% Arg, A-SF, and B-SF increased biofilm growth of LRG. Lactic acid formation was the lowest for 2000-ppm NaF, followed by A-SF and then B-SF. The SF buffer potential after 24 h was the highest for B-SF, and then A-SF. Biofilm pH for B-SF was closest to neutral. Fluoride, Arg and LRG bioavailability remained unaffected in B-SF. The relative gene expression for arcA, argG, and argH was significantly higher for B-SF than the respective controls. In conclusion, combining 2% Arg, 2000-ppm NaF, and LRG provides an optimum synbiotic-fluoride synergism.


Assuntos
Arginina/farmacologia , Biofilmes/efeitos dos fármacos , Fluoretos/farmacologia , Lactobacillus rhamnosus/efeitos dos fármacos , Fluoreto de Sódio/farmacologia , Cariostáticos/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Lactobacillus rhamnosus/genética , Simbióticos , Sais de Tetrazólio/farmacologia
18.
Clin Oral Investig ; 25(4): 2069-2076, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32808179

RESUMO

OBJECTIVES: To evaluate the hydraulic conductance of dentin after treatment with fluoride toothpastes containing sodium trimetaphosphate microparticles (TMPmicro) or nanoparticles (TMPnano). MATERIALS AND METHODS: The dentinal tubules of bovine dentin blocks (4 × 4 × 1 mm) were unobstructed for determination of the maximum hydraulic conductance of the dentin. The dentin blocks were randomized into four groups (n = 15/group) of toothpastes (placebo, 1100 ppm F, and 1100 with 3% TMPmicro or 3% TMPnano) which were applied for 7 days (2×/day) using a brushing machine. The dentin surface (5/group) was analyzed by scanning electron microscopy. The hydraulic conductance post-treatment was measured in the other ten blocks. Thereafter, the same blocks were immersed in citric acid (pH 3.2) for 1 min, and the conductance was determined again. The data were submitted to 2-way ANOVA repeated measures, followed by the Student-Newman-Keuls test (p < 0.05). RESULTS: The percentage conductance reduction post-treatment for the groups were placebo = 1100 ppm F < 1100 TMPnano < 1100 TMPmicro (p < 0.001). After acid attack, the percentage reduction was placebo < 1100 ppm F < 1100 TMPnano < 1100 TMPmicro (p < 0.001). The toothpastes containing TMP showed the highest obliteration of dentinal tubules. CONCLUSIONS: The addition of TMPmicro to fluoride toothpaste produced a greater reduction in hydraulic conductance when compared with 1100 ppm F toothpaste. CLINICAL RELEVANCE: The increased capacity of toothpastes containing TMP to reduce hydraulic conductance indicates their potential to reduce symptoms of dentinal hypersensitivity.


Assuntos
Nanopartículas , Cremes Dentais , Animais , Bovinos , Dentina , Fluoretos/farmacologia , Humanos , Polifosfatos , Fluoreto de Sódio , Cremes Dentais/farmacologia
19.
Arch Oral Biol ; 122: 105001, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316658

RESUMO

OBJECTIVE: To evaluate the effects of combination of treatments with fluoridated toothpastes supplemented with sodium trimetaphosphate (TMP) and casein phosphopeptide-amorphous calcium phosphate (MI Paste Plus®), on the remineralization of dental enamel. DESIGN: Enamel blocks with artificial caries were randomly allocated into six groups (n = 12), according to the toothpastes: 1) without F-TMP-MI Paste Plus® (Placebo); 2) 1100 ppm F (1100 F), 3) MI Paste Plus®, 4) 1100 F + MI Paste Plus® (1100 F-MI Paste Plus®), 5) 1100 F + 3% TMP (1100 F-TMP) and 6) 1100 F-TMP + MI Paste Plus® (1100 F-TMP-MI Paste Plus®). Blocks were treated 2×/day with slurries of toothpastes (1 min). Furthermore, groups 4 and 6 received the application of MI Paste Plus® for 3 min. After pH cycling, the percentage of surface hardness recovery (%SHR); integrated loss of subsurface hardness (ΔKHN); profile analysis and lesion depth subsurface through polarized light microscopy (PLM), confocal laser scanning microscopy (LSCM), scanning electron microscopy (SEM), fluoride (F), calcium (Ca), phosphorus (P) concentrations in the enamel were determined. The data were analyzed by ANOVA (1-criterion) and Student-Newman-Keuls test (p < 0.001). RESULTS: 1100 F-TMP-MI Paste Plus® group showed the best results of %SHR, ΔKHN and PLM (p < 0.001). F concentration was similar between the 1100 F, 1100 F-MI Paste Plus®, and 1100 F-TMP-MI Paste Plus® groups (p > 0.001). 1100 F-TMP-MI Paste Plus® group showed the highest concentration of Ca and P in the enamel (p < 0.001). CONCLUSION: The association of 1100 F-TMP and MI Paste Plus® led to a significant increase in the remineralization of initial carious lesions.


Assuntos
Fosfatos de Cálcio/farmacologia , Cariostáticos/farmacologia , Esmalte Dentário/efeitos dos fármacos , Fluoretos/farmacologia , Polifosfatos/farmacologia , Remineralização Dentária , Caseínas/farmacologia , Cárie Dentária/tratamento farmacológico , Humanos , Técnicas In Vitro , Fosfopeptídeos/farmacologia , Distribuição Aleatória , Cremes Dentais/farmacologia
20.
Biol Trace Elem Res ; 199(6): 2208-2214, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32856250

RESUMO

An in vitro system employing collagen isolated from the sheep tendons to induce mineralization and demineralization reactions was used not only to study the effect of various concentrations of fluoride on the collagen-induced mineralization and demineralization reactions but also to compare their action with the inhibitors of mineralization and/or demineralization. Studies demonstrated that under physiological conditions, at lower concentrations (5 × 10-6 to 5 × 10-5 M) fluoride inhibited while at higher concentrations (> 10-4 M), it stimulated the collagen-induced in vitro mineralization. At higher concentrations, fluoride was also found to inhibit the demineralization of the collagen bound preformed mineral phase. At low concentrations, fluoride acted like Mg2+ to inhibit mineralization while at higher concentration, it acted like crystal poisons (e.g., pyrophosphate phosphonates, citrate) to inhibit demineralization. However, unlike magnesium and pyrophosphate, fluoride at its higher concentrations was found to stimulate rather than inhibit the process of mineralization.


Assuntos
Colágeno , Fluoretos , Animais , Fluoretos/farmacologia , Magnésio/farmacologia , Minerais , Ovinos
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