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OBJECTIVE: To evaluate the protective effect of an experimental solution containing TiF4/NaF on the development of radiation-induced dentin caries lesions. METHODOLOGY: bovine root samples were irradiated (70Gy) and distributed as following (n=12/group): Commercial Saliva (BioXtra), NaF (500 ppm F-), TiF4 (500 ppm F), TiF4/NaF (TiF4: 300 ppm F-, NaF: 190 ppm F-), and Phosphate buffer solution (PBS, negative control). Biofilm was produced using biofilm from irradiated patients and McBain saliva (0.2% of sucrose, at 37oC and 5% CO2) for five days. The treatments were applied 1x/day. Colony-forming units (CFU) were counted and demineralization was quantified by transversal microradiography. The ANOVA/Tukey test was applied for all parameters. RESULTS: All treatments reduced CFU for total microorganisms. TiF4 reduced Lactobacillus sp. (7.04±0.26 log10 CFU/mL) and mutans streptococci (7.18±0.28) CFU the most, when compared to PBS (7.58±0.21 and 7.75±0.17) and followed by NaF (7.12±0.31 and 7.34±0.22) and TiF4/NaF (7.16±0.35 and 7.29± 0.29). TiF4 and Commercial saliva showed the lowest integrated mineral loss (ΔZ-vol%.mm) (1977±150 and 2062±243, respectively) when compared to PBS (4540±335), followed by NaF (2403±235) and TiF4/NaF (2340±200). Commercial saliva was the only to significantly reduce mineral loss (LD-µm) (111±25) compared to PBS (153±24).Mean mineral loss (R-vol%) decreased by 35.2% for TiF4 (18.2±3.3) when compared to PBS (28.1±2.9) Conclusion: TiF4/NaF has a comparable anti-cariogenic effect to TiF4 and Commercial saliva under the model in this study.
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Biofilmes , Cárie Dentária , Dentina , Fluoretos , Saliva , Fluoreto de Sódio , Streptococcus mutans , Fluoreto de Sódio/farmacologia , Bovinos , Animais , Dentina/efeitos dos fármacos , Dentina/efeitos da radiação , Dentina/microbiologia , Cárie Dentária/prevenção & controle , Cárie Dentária/microbiologia , Biofilmes/efeitos dos fármacos , Fluoretos/farmacologia , Saliva/microbiologia , Saliva/química , Saliva/efeitos dos fármacos , Streptococcus mutans/efeitos dos fármacos , Fatores de Tempo , Análise de Variância , Microrradiografia , Cariostáticos/farmacologia , Reprodutibilidade dos Testes , Lactobacillus/efeitos dos fármacos , Contagem de Colônia Microbiana , Desmineralização do Dente/prevenção & controle , Humanos , Teste de Materiais , Valores de Referência , Resultado do Tratamento , Estatísticas não Paramétricas , TitânioRESUMO
INTRODUCTION: Visual imaging of subsurface caries lesions is of vital interest in dentistry, which can be obtained by invasive radiography technique as well as by available non-destructive imaging approaches. Thus, as a first step toward the development of a new innovative approach, Spectral-domain optical coherence tomography (SD-OCT) was applied to detect the lesion depth in comparison to the established reference technique (transverse microradiography [TMR]). METHODS: Bovine enamel specimens were demineralized for 5 days, following previous studies. For OCT, the resulting artificial lesions were scanned three-dimensionally (SD-OCT) and semi-automated measured (CarLQuant). For TMR, specimens were sectioned and the lesion depth was manually determined (Inspektor Research System). RESULTS: The range of lesion depth detected with OCT was 24.0-174.0 µm (mouth rinse study), 18.0-178.0 µm (toothpastes study) and with TMR 59.2-198.0 µm (mouth rinse study), 33.2-133.4 µm (toothpastes study). We found a strong correlation between both methods in terms of lesion depth (Spearman rankwith outlierp < 0.001, Rho = 0.75, Spearman rankwithout outlierp = 0.001, Rho = 0.79). The two methods produce similar results (Passing-Bablok regression, 1.16). As deeper is the lesion, the smallest is the difference between both methods as indicated by Bland-Altman-plots. CONCLUSION: Especially in the case of deep lesions, the values obtained by both methods are in agreement, and OCT can potentially substitute TMR to detect and assess lesion depth with the benefit of being non-destructive.
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Cárie Dentária , Esmalte Dentário , Microrradiografia , Tomografia de Coerência Óptica , Tomografia de Coerência Óptica/métodos , Animais , Bovinos , Cárie Dentária/diagnóstico por imagem , Cárie Dentária/patologia , Microrradiografia/métodos , Esmalte Dentário/diagnóstico por imagem , Esmalte Dentário/patologia , Imageamento Tridimensional/métodos , Desmineralização do Dente/diagnóstico por imagem , Desmineralização do Dente/patologiaRESUMO
The initial characteristics of white spot lesion (WSLs), such as the degree of integrated mineral loss (ΔZ), depth and pattern of mineral distribution, have an impact on further demineralization and remineralization. However, these lesion parameters have not been evaluated in WSLs produced from microcosm biofilms. OBJECTIVE: This study characterized artificial white spot lesions produced on human enamel under microcosm biofilm for different experimental periods. METHODOLOGY: In total, 100 human enamel specimens (4x4mm) were assigned to 5 distinct groups (n=20/group) differing according to the period of biofilm formation (2, 4, 6, 8 or 10 days). Microcosm biofilm was produced on the specimens from a mixture of human and McBain saliva at the first 8h. Enamel samples were then exposed to McBain saliva containing 0.2% sucrose. WSLs formed were characterized by quantitative light-induced fluorescence (QLF) and transverse microradiography (TMR). Data were analyzed by ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p<0.05). RESULTS: A clear time-response pattern was observed for both analyses, but TMR was able to better discriminate among the lesions. Regarding QLF analysis, median (95%CI; %) changes in fluorescence ∆Z were -7.74(-7.74:-6.45)a, -8.52(-8.75:-8.00)ab, -9.17(-10.00:-8.71)bc, -9.58(-10.53:-8.99)bc and -10.01(-11.44:-9.72)c for 2, 4, 6, 8, and 10 days, respectively. For TMR, median (95%CI; vol%.µm) ∆Z were 1410(1299-1479)a, 2420(2327-2604)ab, 2775(2573-2899)bc, 3305(3192-3406)cd and 4330(3972-4465)d, whereas mean (SD; µm) lesion depth were 53.7(12.3)a, 71.4(12.0)a, 103.8(24.8)b, 130.5(27.2)bc, 167.2(39.3)c for 2, 4, 6, 8 and 10 days, respectively. CONCLUSION: The progression of WSLs formed on human enamel under microcosm biofilm can be characterized over 2-10 days, both by QLF and TMR analyses, although the latter provides better discrimination among the lesions.
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Cárie Dentária , Desmineralização do Dente , Biofilmes , Esmalte Dentário , Humanos , Microrradiografia , Saliva , Remineralização DentáriaRESUMO
OBJETIVES: The neonatal line (NNL) in enamel is hypomineralized, but quantitative data on the enamel component volumes of the NNL are lacking. This study aimed at quantifying the variation in the mineral, organic, and water volumes at the NNL and in pre- and postnatal enamel. MATERIALS AND METHODS: In buccal enamel longitudinal ground sections of exfoliated primary incisors (upper and lower; n = 17), the enamel component volumes were quantified at five histological sites (located at 40 µm intervals along a transversal line): the NNL, two sites in prenatal enamel, and two sites in postnatal enamel. Mineral volume was quantified using microradiography, and non-mineral volumes were quantified using polarizing microscopy. RESULTS: Differences in component volumes between the NNL and pre- and postnatal enamel had high effect sizes (Hedge's G ranging from 0.89, for the water volume, to 1.88, for the mineral volume; power > 90 %). The distance from the NNL correlated with the normalized component volume: r = 0.459, 95 % CI = 0.274/0.612 (mineral); r = -0.504; 95 % CI= -0.328/-0.647 (organic), and r = -0.294; 95 % CI= -0.087/-0.476 (water). Approaching the NNL from postnatal enamel, the percentage differences in component volumes were: -1.93 to -3.22 % for the mineral volume, +21.26 to +35.42 % for the organic volume, and +3.86 to +6.03 % for the water volume. Towards postnatal enamel, the percentage differences had the opposite trend. CONCLUSIONS: The enamel NNL is slightly hypomineralized with an increased organic volume one order of magnitude higher than the percentage differences in both mineral and water volumes.
Assuntos
Esmalte Dentário/química , Minerais , Água , Esmalte Dentário/embriologia , Feminino , Humanos , Microrradiografia , Gravidez , Dente Decíduo/químicaRESUMO
INTRODUCTION: The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. OBJECTIVE: To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. METHODOLOGY: Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. RESULTS: The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). CONCLUSION: Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.
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Biofilmes/crescimento & desenvolvimento , Esmalte Dentário/microbiologia , Saliva/química , Sacarose/química , Desmineralização do Dente/microbiologia , Animais , Bovinos , Esmalte Dentário/química , Película Dentária/microbiologia , Dureza , Microrradiografia/métodos , Pasteurização , Valores de Referência , Saliva/microbiologia , Sacarose/análise , Propriedades de SuperfícieRESUMO
Abstract The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. Objective To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. Methodology Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. Results The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). Conclusion Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.
Assuntos
Animais , Bovinos , Saliva/química , Sacarose/química , Desmineralização do Dente/microbiologia , Biofilmes/crescimento & desenvolvimento , Esmalte Dentário/microbiologia , Valores de Referência , Saliva/microbiologia , Sacarose/análise , Propriedades de Superfície , Microrradiografia/métodos , Esmalte Dentário/química , Película Dentária/microbiologia , Pasteurização , DurezaRESUMO
The study aimed to apply micro-computed tomography (micro-CT) and transverse microradiography (TMR) to measure dentine demineralization and to test the preventive effect of titanium tetrafluoride (TiF4 ) under microcosm biofilm. Sound dentine specimens from bovine root were treated for 6 h with: (i) 4.0% titanium tetrafluoride (TiF4 ) varnish [pH 1.0, 2.45% fluoride (F-); (ii) 5.42% sodium fluoride (NaF) varnish (pH 5.0, 2.45% F); (iii) 2% chlorhexidine (CHX) gel (pH 7.0); (iv) placebo varnish (pH 5.0); or (v) no agent (untreated). Dentine specimens were then exposed to human saliva mixed with McBain saliva for 8 h. Thereafter, McBain saliva containing 0.2% sucrose was applied daily, for 5 d, onto dentine specimens to stimulate formation of microcosm biofilm. Although a high correlation was found between the results of both methods regarding integrated mineral loss, the results of the methods did not show good agreement in Bland-Altman plots, with significant biases in calculations of lesion depth. Fluoride varnishes were able to reduce dentine demineralization (P < 0.05), while CHX failed to do so. Fluorides are still the best option to reduce dentine demineralization. Micro-CT may be used to measure dentine mineral loss, but not the lesion depth, for which TMR is superior.
Assuntos
Biofilmes/crescimento & desenvolvimento , Cariostáticos/farmacologia , Dentina , Fluoretos Tópicos/farmacologia , Microrradiografia , Desmineralização do Dente , Microtomografia por Raio-X , Animais , Bovinos , Cárie Dentária/prevenção & controle , Fluoretos , Humanos , Fluoreto de Sódio/farmacologiaRESUMO
There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Label="OBJECTIVE">To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. METHODOLOGY Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. RESULTS%SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. CONCLUSIONS The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.
Assuntos
Biofilmes/crescimento & desenvolvimento , Candida albicans/fisiologia , Esmalte Dentário/microbiologia , Streptococcus mutans/metabolismo , Desmineralização do Dente/microbiologia , Ácidos/metabolismo , Animais , Bovinos , Contagem de Colônia Microbiana , Esmalte Dentário/química , Testes de Dureza , Concentração de Íons de Hidrogênio , Microrradiografia/métodos , Valores de Referência , Propriedades de Superfície , Fatores de TempoRESUMO
OBJECTIVES: The aim of this study was to assess the effect of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves hydroalcoholic extracts on viability and metabolism of a microcosm biofilm and on enamel demineralization prevention. METHODOLOGY: Microcosm biofilm was produced on bovine enamel using inoculum from pooled human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. The biofilm was daily-treated with the extracts for 1 min. At the end, it was analyzed with respect to viability by fluorescence, CFU counting and extracellular polysaccharides (phenol-sulphuric acid colorimetric assay) and lactic acid (enzymatic assay) production. The demineralization was measured by TMR. The data were compared using ANOVA or Kruskal-Wallis (p<0.05). RESULTS: M. urundeuva All. at 100, 10 and 0.1 µg/mL and Q. grandiflora Mart. at 100 and 0.1 µg/mL reduced biofilm viability similarly to positive control (chlorhexidine) and significantly more than the negative-vehicle control (35% ethanol). M. urundeuva at 1000, 100 and 0.1 µg/mL were able to reduce both lactobacilli and mutans streptococci CFU counting, while Q. grandiflora (1000 and 1.0 µg/mL) significantly reduced mutans streptococci CFU counting. On the other hand, the natural extracts were unable to significantly reduce extracellular polysaccharides and lactic acid productions neither the development of enamel carious lesions. CONCLUSIONS: The extracts showed antimicrobial properties on microcosm biofilm, however, they had no effect on biofilm metabolism and caries protection.
Assuntos
Anacardiaceae/química , Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Myrtales/química , Extratos Vegetais/farmacologia , Desmineralização do Dente/prevenção & controle , Animais , Cariostáticos/farmacologia , Bovinos , Contagem de Colônia Microbiana , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/microbiologia , Ácido Láctico/metabolismo , Lactobacillus/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Microrradiografia/métodos , Folhas de Planta/química , Polissacarídeos Bacterianos/metabolismo , Reprodutibilidade dos Testes , Saliva/química , Streptococcus mutans/efeitos dos fármacosRESUMO
OBJECTIVE: Microcosm biofilm has been applied to induce carious lesions in dentin. However, no study has been done to compare the impact of the type of model for providing nutrients to microcosm biofilm formation on dentin. This study compared the performance of two kinds of models (static and semi-dynamic) on the biofilm formation and the development of dentin carious lesions. MATERIAL AND METHODS: In both models, biofilm was produced using inoculum from pooled human saliva mixed with McBain saliva for the first 8 h (5% CO2 and 37°C). Afterwards, for the static model, the samples were placed in 24-wells microplate containing McBain saliva with 0.2% sucrose, which was replaced at 24 h. In the semi-dynamic model, the samples were submitted to artificial mouth system with continuous flow of McBain saliva with 0.2% sucrose (0.15 ml/min, 37°C) for 10 h a day (for the other 14 h, no flow was applied, similarly to the static model). After 5 days, biofilm viability was measured by fluorescence and dentin demineralization by transverse microradiography. RESULTS: Biofilm viability was significantly lower for the static compared with semi-dynamic model, while dentin demineralization was significantly higher for the first one (p<0.05). The static model was able to produce a higher number of typical subsurface lesions compared with the semi-dynamic model (p<0.05). CONCLUSIONS: The type of model (static and semi-dynamic) applied in the microcosm biofilm may have influence on it's viability and the severity/profile of dentin carious lesions.
Assuntos
Biofilmes/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Dentina/microbiologia , Modelos Biológicos , Animais , Bovinos , Humanos , Viabilidade Microbiana , Microrradiografia , Saliva/microbiologia , Propriedades de Superfície , Fatores de Tempo , Desmineralização do Dente/microbiologiaRESUMO
The aim of the study was to evaluate the effect of experimental composites containing dicalcium phosphate dihydrate (DCPD) on remineralization of enamel lesions. Five resin-based composites containing equal parts (in mols) of bisphenol-A glycidyl dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), and 60 vol % of fillers were manipulated. Filler phase was constituted by silanized barium glass and 0, 10, or 20 vol % of DPCD particles, either functionalized (F) or nonfunctionalized (NF) with TEGDMA. Artificial subsurface lesions were produced in human enamel fragments and divided according to the resin composite applied on the lesion (no DCPD, 20% NF, 20% F, 10% NF, 10% F) plus a group without composite build-up (nontreated, NT). Fragments were exposed to 16 days of pH cycling. Specimens were evaluated using transverse microradiography (TMR). Calcium and phosphate concentrations in pH-cycling solutions were determined by spectrophotometry. TMR and ionic concentrations were analyzed using one-way ANOVA/Tukey and Kruskal-Wallis/Dunn test, respectively (alpha: 0.05). All composite groups showed enamel remineralization (3%-23%). Higher mineral recovery in the middle (7%-11%) and bottom (2%-7%) thirds of the lesion was observed in groups with DCPD-containing composites compared to the "no DCPD" group (middle: 1%, bottom: -3%). Lesion depth was significantly reduced in groups using DCPD-containing composites compared to NT group. No noticeable increase in calcium and phosphate ions was observed in the pH-cycling solutions due to the presence of DCPD in the composites. In conclusion, composites with DCPD fractions as low as 10%, regardless of functionalization, were able to promote mineral recovery and reduce lesion depth of enamel lesions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1542-1550, 2019.
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Fosfatos de Cálcio/química , Resinas Compostas/química , Cárie Dentária/terapia , Esmalte Dentário/química , Metacrilatos/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Compostos de Bário/química , Bis-Fenol A-Glicidil Metacrilato/química , Humanos , Íons/química , Teste de Materiais , Microrradiografia , Minerais/química , Dente Serotino/metabolismo , Silanos/química , Dióxido de Silício/química , Propriedades de Superfície , Remineralização DentáriaRESUMO
Abstract Microcosm biofilm has been applied to induce carious lesions in dentin. However, no study has been done to compare the impact of the type of model for providing nutrients to microcosm biofilm formation on dentin. Objective This study compared the performance of two kinds of models (static and semi-dynamic) on the biofilm formation and the development of dentin carious lesions. Material and Methods In both models, biofilm was produced using inoculum from pooled human saliva mixed with McBain saliva for the first 8 h (5% CO2 and 37°C). Afterwards, for the static model, the samples were placed in 24-wells microplate containing McBain saliva with 0.2% sucrose, which was replaced at 24 h. In the semi-dynamic model, the samples were submitted to artificial mouth system with continuous flow of McBain saliva with 0.2% sucrose (0.15 ml/min, 37°C) for 10 h a day (for the other 14 h, no flow was applied, similarly to the static model). After 5 days, biofilm viability was measured by fluorescence and dentin demineralization by transverse microradiography. Results Biofilm viability was significantly lower for the static compared with semi-dynamic model, while dentin demineralization was significantly higher for the first one (p<0.05). The static model was able to produce a higher number of typical subsurface lesions compared with the semi-dynamic model (p<0.05). Conclusions The type of model (static and semi-dynamic) applied in the microcosm biofilm may have influence on it's viability and the severity/profile of dentin carious lesions.
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Humanos , Animais , Bovinos , Biofilmes/crescimento & desenvolvimento , Cárie Dentária/microbiologia , Dentina/microbiologia , Modelos Biológicos , Saliva/microbiologia , Propriedades de Superfície , Fatores de Tempo , Microrradiografia , Desmineralização do Dente/microbiologia , Viabilidade MicrobianaRESUMO
Abstract Objectives: The aim of this study was to assess the effect of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves hydroalcoholic extracts on viability and metabolism of a microcosm biofilm and on enamel demineralization prevention. Methodology: Microcosm biofilm was produced on bovine enamel using inoculum from pooled human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. The biofilm was daily-treated with the extracts for 1 min. At the end, it was analyzed with respect to viability by fluorescence, CFU counting and extracellular polysaccharides (phenol-sulphuric acid colorimetric assay) and lactic acid (enzymatic assay) production. The demineralization was measured by TMR. The data were compared using ANOVA or Kruskal-Wallis (p<0.05). Results: M. urundeuva All. at 100, 10 and 0.1 μg/mL and Q. grandiflora Mart. at 100 and 0.1 μg/mL reduced biofilm viability similarly to positive control (chlorhexidine) and significantly more than the negative-vehicle control (35% ethanol). M. urundeuva at 1000, 100 and 0.1 μg/mL were able to reduce both lactobacilli and mutans streptococci CFU counting, while Q. grandiflora (1000 and 1.0 μg/mL) significantly reduced mutans streptococci CFU counting. On the other hand, the natural extracts were unable to significantly reduce extracellular polysaccharides and lactic acid productions neither the development of enamel carious lesions. Conclusions: The extracts showed antimicrobial properties on microcosm biofilm, however, they had no effect on biofilm metabolism and caries protection.
Assuntos
Animais , Masculino , Bovinos , Extratos Vegetais/farmacologia , Desmineralização do Dente/prevenção & controle , Biofilmes/efeitos dos fármacos , Anacardiaceae/química , Myrtales/química , Anti-Infecciosos/farmacologia , Polissacarídeos Bacterianos/metabolismo , Saliva/química , Streptococcus mutans/efeitos dos fármacos , Microrradiografia/métodos , Contagem de Colônia Microbiana , Cariostáticos/farmacologia , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes , Folhas de Planta/química , Ácido Láctico/metabolismo , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/microbiologia , Viabilidade Microbiana/efeitos dos fármacos , Lactobacillus/efeitos dos fármacosRESUMO
Abstract There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Objective: To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. Methodology: Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. Results: %SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. Conclusions: The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.
Assuntos
Animais , Bovinos , Streptococcus mutans/metabolismo , Candida albicans/fisiologia , Desmineralização do Dente/microbiologia , Biofilmes/crescimento & desenvolvimento , Esmalte Dentário/microbiologia , Valores de Referência , Propriedades de Superfície , Fatores de Tempo , Ácidos/metabolismo , Microrradiografia/métodos , Contagem de Colônia Microbiana , Esmalte Dentário/química , Testes de Dureza , Concentração de Íons de HidrogênioRESUMO
Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect. OBJECTIVES: This study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model. MATERIAL AND METHODS: A microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography - TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). RESULTS: Only chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% µm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% µm). CONCLUSIONS: TiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cariostáticos/farmacologia , Esmalte Dentário/microbiologia , Fluoretos/farmacologia , Streptococcus/efeitos dos fármacos , Titânio/farmacologia , Análise de Variância , Animais , Bovinos , Clorexidina/farmacologia , Contagem de Colônia Microbiana , Cárie Dentária/prevenção & controle , Esmalte Dentário/efeitos dos fármacos , Humanos , Viabilidade Microbiana/efeitos dos fármacos , Microrradiografia , Efeito Placebo , Distribuição Aleatória , Reprodutibilidade dos Testes , Saliva/microbiologia , Fluoreto de Sódio/farmacologia , Estatísticas não Paramétricas , Streptococcus/crescimento & desenvolvimentoRESUMO
This study aimed to test the hypotheses that (i) a parameter related to permeability, αd (ratio of squared water volume by the nonmineral volume) is, among all major component volumes (mineral, water, and organic volumes) the best predictor of quinoline infiltration in natural enamel caries (NEC), and (ii) the pore volume fraction infiltrated by quinoline (Vqui ) in NEC is much lower than previous estimates that neglected water and organic enamel volumes. Mineral and nonmineral volumes and αd were measured at 341 histological points (from 20 approximal NEC lesions), and transport of quinoline was tracked by orientation-independent polarizing microscopy. R2 values of Vqui were 0.596 (αd ), 0.033 (mineral volume), 0.474 (water volume), and 0.011 (organic volume). Vqui values were 23% (body of the lesion), 7% (dark zone), and 9% (translucent zone), lower than previous estimates (with high effect size). Transport of quinoline occurred both parallelly and perpendicularly to prism paths, and dark zones were seen where only transport parallel to prisms occurred. In conclusion, αd was the main predictor of quinoline infiltration, but it differed from the water volume with a small effect size, and the pore volume fraction with quinoline was much lower than previous estimates.
Assuntos
Cárie Dentária/diagnóstico por imagem , Esmalte Dentário/diagnóstico por imagem , Microscopia de Polarização/métodos , Quinolinas/farmacocinética , Dente/diagnóstico por imagem , Humanos , Microrradiografia/métodos , Minerais/farmacocinética , PermeabilidadeRESUMO
Abstract Titanium tetrafluoride (TiF4) is known for interacting with enamel reducing demineralization. However, no information is available about its potential antimicrobial effect. Objectives This study evaluated the antimicrobial and anti-caries potential of TiF4 varnish compared to NaF varnish, chlorhexidine gel (positive control), placebo varnish and untreated (negative controls) using a dental microcosm biofilm model. Material and Methods A microcosm biofilm was produced on bovine enamel previously treated with the varnishes, using inoculum from human saliva mixed with McBain saliva, under 0.2% sucrose exposure, for 14 days. All experiments were performed in biological triplicate (n=4/group in each experiment). Factors evaluated were: bacterial viability (% dead and live bacteria); CFU counting (log10 CFU/mL); and enamel demineralization (transverse microradiography - TMR). Data were analysed using ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). Results Only chlorhexidine significantly increased the number of dead bacteria (68.8±13.1% dead bacteria) compared to untreated control (48.9±16.1% dead bacteria). No treatment reduced the CFU counting (total microorganism and total streptococci) compared to the negative controls. Only TiF4 was able to reduce enamel demineralization (ΔZ 1110.7±803.2 vol% μm) compared to both negative controls (untreated: ΔZ 4455.3±1176.4 vol% μm). Conclusions TiF4 varnish has no relevant antimicrobial effect. Nevertheless, TiF4 varnish was effective in reducing enamel demineralization under this model.
Assuntos
Humanos , Animais , Bovinos , Streptococcus/efeitos dos fármacos , Titânio/farmacologia , Cariostáticos/farmacologia , Biofilmes/efeitos dos fármacos , Esmalte Dentário/microbiologia , Fluoretos/farmacologia , Antibacterianos/farmacologia , Saliva/microbiologia , Fluoreto de Sódio/farmacologia , Streptococcus/crescimento & desenvolvimento , Microrradiografia , Contagem de Colônia Microbiana , Distribuição Aleatória , Efeito Placebo , Clorexidina/farmacologia , Reprodutibilidade dos Testes , Análise de Variância , Estatísticas não Paramétricas , Cárie Dentária/microbiologia , Cárie Dentária/prevenção & controle , Esmalte Dentário/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacosRESUMO
The objective of this study was to evaluate the antimicrobial and anti-caries effects of two plant extracts. The first chapter dealt with a review of the literature whose objective was to discuss the antimicrobial potential of Brazilian natural agents on the biofilm related to dental caries and gingivitis/periodontal disease. The research of the articles was carried out using PubMed. We found a total of 23 papers. Most of the studies were performed using planktonic microorganisms or under clinical trials. Nineteen articles were focused on cariogenic bacteria. From these nineteen articles, eleven were also about periodontopathogenic bacteria. Four studies addressed only periodontopathogenic bacteria. The most tested Brazilian natural agents were green propolis, essential oils of Lippia sidoides and Copaifera sp. Most of the tested agents showed similar results when compared to positive control (essential oils and extracts) or better effect than negative control (green propolis). More studies involving protocols closer to the clinical condition and the use of response variables that allows understanding the mechanism of action of natural agents are necessary before the incorporation of these natural agents into dental products. The second chapter aimed to test the effect of the hydroalcoholic extracts of Myracrodruon urundeuva All. and Qualea grandiflora Mart. leaves on the viability of the microcosm biofilm and on the prevention of enamel demineralization. The microcosm biofilm was produced on bovine enamel, using human saliva pool mixed with McBain saliva (0.2% sucrose) for 14 days. The biofilm was treated daily with the extracts for 1 min. M. urundeuva at 100, 10 and 0.1 µg/ml and Q. grandiflora at 100 and 0.1 µg/ml reduced cell viability similarly to the positive control and significantly more than negative control. M. urundeuva at 1000, 100 and 0.1 µg/ml were able to reduce the counting formation unit-CFU counting of lactobacilli sp. and Streptococcus mutans, while Q. grandiflora at 1000 and 1.0 µg/ml significantly reduced the S. mutans CFU counting. On the other hand, the natural extracts did not reduce the production of extracellular polyssacharides, lactic acid and the development of enamel caries lesions. The third chapter aimed to evaluate the effect of hydroalcoholic extracts of M. urundeuva and Q. grandiflora (alone or combined) on the viability of S. mutans biofilm and the prevention of enamel demineralization. S. mutans strain (ATCC 21175) was reactivated in BHI broth. Minimum inhibitory concentration, minimum bactericidal concentration, minimum biofilm inhibitory concentration and minimum biofilm eradication concentration were determined to choose the concentrations to be tested under the biofilm model. S. mutans biofilm (5x105 CFU/ml) was produced on bovine enamel using McBain saliva with 0.2% sucrose for 3 days. The biofilm was treated daily with the extracts for 1 min. M. urundeuva (isolated or combined) at concentrations equal or higher than 0.625 mg/ml was able to reduce the bacteria viability, whereas Q. grandiflora extract alone showed antimicrobial effect at 5 mg/ml only (p<0.05). On the other hand, none of the extracts was able to reduce the development of enamel caries lesions. Despite the tested natural extracts have antimicrobial effect; they are unable to prevent caries in enamel.(AU)
O objetivo foi avaliar os efeitos antimicrobiano e anti-cárie de dois extratos de plantas. O primeiro capítulo se referiu a uma revisão da literatura cujo objetivo foi discutir o potencial antimicrobiano dos agentes naturais brasileiros sobre o biofilme relacionado à cárie dentária e à gengivite/doença periodontal. A pesquisa dos artigos foi realizada usando o PubMed. Foram encontrados 23 trabalhos. A maioria dos estudos foi realizada utilizando microorganismos na fase planctônica ou ensaios clínicos. Dezenove artigos foram focados em bactérias cariogênicas. Dos dezenove artigos, onze também eram sobre bactérias periodontopatogênicas. Quatro estudos abordaram apenas bactérias periodontopatogênicas. Os agentes naturais brasileiros mais testados foram própolis verde, óleos essenciais de Lippia sidoides e Copaifera sp. Os agentes testados apresentaram resultados similares quando comparados ao controle positivo (óleos essenciais e extratos) ou melhor efeito que o controle negativo (própolis verde). Mais estudos próximos da condição clínica e o uso de variáveis de resposta que permitam entender o mecanismo de ação são necessários, para permitir a incorporação desses agentes naturais em produtos odontológicos. O segundo capítulo teve como objetivo testar o efeito dos extratos hidroalcoólicos de Myracrodruon urundeuva All. e Qualea grandiflora Mart. sobre a viabilidade do biofilme microcosmo e na prevenção da desmineralização do esmalte. O biofilme microcosmo foi produzido em esmalte bovino, utilizando pool de saliva humana misturada à saliva de McBain (0,2% de sacarose) durante 14 dias. O biofilme foi tratado diariamente com os extratos durante 1 min. M. urundeuva a 100, 10 e 0,1 µg/ml e Q. grandiflora a 100 e 0,1 µg/ml reduziram a viabilidade dos microrganismos de forma semelhante ao controle positivo e significativamente maior do que o controle negativo. M. urundeuva a 1000, 100 e 0,1 µg/ml foi capaz de reduzir a contagem de Unidade formadora de colônia-UFC para Lactobacilos totais e Streptococcus mutans, enquanto a Q. grandiflora a 1000 e 1,0 µg/ml reduziu significativamente a contagem de UFC para S. mutans. Os extratos naturais não conseguiram reduzir a produção de polissacarídeos extracelulares-PEC, ácido lático e o desenvolvimento da lesão cariosa em esmalte. O terceiro capítulo teve como objetivo avaliar o efeito dos extratos hidroalcoólicos de M. urundeuva. e Q. grandiflora (sozinhos ou combinados) sobre a viabilidade do biofilme de S. mutans e na prevenção da desmineralização do esmalte. Cepa de S. mutans (ATCC 21175) foi reativada em caldo BHI. Concentração inibitória mínima, concentração bactericida mínima, concentração inibitória mínima de biofilme e concentração de erradicação mínima de biofilme foram determinadas para escolher as concentrações a serem testadas sob o modelo de biofilme. O biofilme de S. mutans (5x105 CFU/ml) foi produzido em esmalte bovino, utilizando saliva de McBain com 0,2% de sacarose durante 3 dias. O biofilme foi tratado diariamente com os extratos durante 1 min. M. urundeuva (isolada ou combinada) nas concentrações iguais ou superiores a 0,625 mg/ml foi capaz de reduzir a viabilidade das bactérias, enquanto que o extrato da Q. grandflora apresentou efeito antimicrobiano somente a 5 mg/ml (p<0,05). Nenhum dos extratos reduziu o desenvolvimento da lesão da cárie. Apesar dos extratos naturais terem efeito antimicrobiano, são incapazes de prevenir o desenvolvimento da lesão cariosa em esmalte.(AU)
Assuntos
Humanos , Animais , Bovinos , Anacardiaceae/química , Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Esmalte Dentário/microbiologia , Magnoliopsida/química , Extratos Vegetais/farmacologia , Desmineralização do Dente/prevenção & controle , Testes de Sensibilidade Microbiana , Microrradiografia , Reprodutibilidade dos Testes , Saliva/microbiologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus mutans/crescimento & desenvolvimento , Fatores de TempoRESUMO
This in vitro study investigated the development of dentin wall lesions next to resin composite containing very small gap sizes using an in vitro biofilm model, and evaluated whether a relevant threshold for the gap size could be established. Microcosm biofilms were grown for 14 days within small interfacial gaps between dentin-resin composite discs under intermittent cariogenic challenge. The factor under study was gap size: samples were either restored with composite resin without adhesive procedure (no intentional gap; no bonding [NB] group) or with intentional gaps of 30, 60, or 90 µm, or with complete adhesive procedure (no gap; bonding [B] group). Secondary caries wall lesion progression was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography at 3 locations: outer surface lesion and wall lesions at 200 and 500 µm distance from gap entrance. Results from linear regression analysis showed that the presence of an intentional gap (30, 60, and 90 µm) affected the secondary caries progression at 200 µm from the gap entrance (p ≤ 0.013). The NB group did not show significant wall lesion development (ML and LD, p ≥ 0.529). At 500 µm distance almost no wall caries development was observed. In conclusion, dentin wall lesions developed in minimal gap sizes, and the threshold for secondary wall lesion development was a gap of around 30 µm in this microcosm biofilm model.
Assuntos
Resinas Acrílicas/farmacologia , Biofilmes , Resinas Compostas/farmacologia , Cárie Dentária/patologia , Restauração Dentária Permanente , Adesivos Dentinários/farmacologia , Dentina/patologia , Poliuretanos/farmacologia , Saliva/microbiologia , Condicionamento Ácido do Dente , Animais , Bovinos , Cárie Dentária/diagnóstico por imagem , Dentina/diagnóstico por imagem , Humanos , Técnicas In Vitro , Teste de Materiais , Microrradiografia , Propriedades de SuperfícieRESUMO
Detection of occlusal caries with visual examination using ICDAS correlates strongly with histology under stereomicroscopy (SM), but dentin aspects under SM are ambiguous regarding mineral content. Thus, our aim was to test two null hypotheses: SM and microradiography result in similar correlations between ICDAS and histology; SM and microradiography result in similar positive (PPV) and negative predictive values (NPV) of ICDAS cut-off 1-2 (scores 0-2 as sound) with histological threshold D3 (demineralization in the inner third of dentin). Occlusal surfaces of extracted permanent teeth (n = 115) were scored using ICDAS. Undemineralized ground sections were histologically scored using both SM without contrast solution and microradiography after immersion in Thoulet's solution 1.47 for 24 h (MRC). Correlation between ICDAS and histology differed from SM (0.782) to MRC (0.511) (p = 0.0002), with a large effect size "q" of 0.49 (95% CI: 0.638/0.338). For ICDAS cut-off 1-2 and D3, PPV from MRC (0.56) was higher than that from SM (0.28) (p< 0.00001; effect size h = 0.81), and NPV from MRC (0.72) was lower than that from SM (1,00) (p < 0.00001; effect size h = 1.58). In conclusion, SM overestimated the correlation between ICDAS and lesion depth, and underestimated the number of occlusal surfaces with ICDAS cut-off 1-2 and deep dentin demineralization.