Comparison between static and semidynamic models for microcosm biofilm formation on dentin

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 370C). 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, 370C) 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

Efeitos antimicrobiano e anti-cárie do verniz tetrafluoreto de titânio a 4% sob um modelo de biofilme microcosmo em dentina

The study aimed: 1) to compare the effect of two different nutrients supply models (static and semi-dynamic) on the microcosm biofilm viability and dentin carious lesions formation; 2) to compare micro-CT versus TMR to measure dentin demineralization; and 3) to evaluate the effect of 4% TiF4 varnish on the viability and metabolism of a microcosm biofilm and on development of dentin carious lesions. Microcosm biofilm was produced using pooled human saliva mixed with McBain saliva for the first 8 h; thereafter, only McBain saliva with 0.2% sucrose was applied daily (37°C, 5% CO2), for a total time of 5 days. In the study 1, the static model consisted of 24-wells microplate, where bovine root dentin samples were submitted to biofilm formation. The semi-dynamic model, consisted of artificial mouth with continuous flow of McBain saliva with 0.2% sucrose (0.15 ml/min, 37°C) during 10 h a day (for the other 14 h, no flow was applied). Biofilm viability was measured by fluorescence and dentin demineralization by TMR. For the studies 2 and 3, bovine root dentin samples were treated for 6 h: A) 4% TiF4 (pH 1.0, 2.45% F); B) 5.42% NaF (pH 5.0, 2.45% F); C) 2% CHX gel positive control D) placebo or E) untreated negative control. Treated samples were submitted to biofilm formation under static model as described above. Demineralization was measured using micro-CT (study 2) and TMR (studies 2 and 3). In the study 3, biofilm was analyzed with respect to viability by fluorescence and CFU counting for total microorganisms, total streptococci, mutans streptococci and Lactobacillus sp., and lactic acid and EPS production. In study 1, biofilm viability was lower for the static model (0.420±0.138) compared to semi-dynamic one (0.944±0.599). Both models were able to provoke dentin demineralization; however, the static model produced a higher number of typical subsurface lesions (83%) compared to the semi-dynamic (45%). In study 2, both fluorides were able to reduce dentin demineralization. Data obtained from micro- CT and TMR presented a significant and positive correlation (Z: r=0.78 p<0.0001 and LD: r=0.57 p<0.0001) In study 3, all treatments reduced the biofilm viability, but not the CFU counting, except NaF that significantly reduced the number of Lactobacillus sp. compared to control. No treatment was able to decrease the lactic acid production neither EPS production, except CHX that reduced the amount of insoluble EPS. Fluorides were able to reduce dentin demineralization compared to control, but TiF4 had the best effect in reducing mineral loss and lesion depth (reduction of Z: 70% and LD: 45%). In conclusion, 1) the nutrient supply model may have influence on the biofilm viability and the profile of dentin carious lesions; 2) micro-CT may be a suitable non-destructive method to measure dentin demineralization; and 3) despite TiF4 varnish has no relevant antimicrobial effect, it is the best option to reduce the development of dentin carious lesions under this model.O estudo objetivou: 1) comparar o efeito de dois modelos diferentes de disponibilidade de nutrientes (estático e semi-dinâmico) sobre a viabilidade do biofilme microcosmo e formação de lesões de cárie em dentina; 2) comparar micro- CT versus TMR para mensurar a desmineralização da dentina; e 3) avaliar o efeito do verniz TiF4 4% na viabilidade e metabolismo do biofilme microcosmo e no desenvolvimento de lesões de cárie em dentina. O biofilme microcosmo foi produzido utilizando saliva humana misturada com saliva de McBain durante as primeiras 8 h; depois, apenas saliva de McBain com sacarose 0,2% foi aplicada diariamente (37°C, 5% de CO2), totalizando 5 dias. No estudo 1, o modelo estático consistiu de placa de 24 poços, onde amostras de dentina radicular bovina foram submetidas à formação do biofilme. O modelo semi-dinâmico, consistiu de boca artificial com fluxo contínuo de saliva de McBain com sacarose 0,2% (0,15 ml/min, 37°C) durante 10 h por dia (nas demais 14 h, não foi aplicado fluxo). A viabilidade do biofilme foi mensurada por fluorescência e a desmineralização da dentina por TMR. Para os estudos 2 e 3, as amostras de dentina radicular bovina foram tratadas por 6 h: A) TiF4 4% (pH 1,0, 2,45% F); B) NaF 5,42% (pH 5,0, 2,45% F); C) gel CHX 2% - controle positivo D) placebo ou E) não tratado - controle negativo. As amostras tratadas foram submetidas à formação do biofilme sob modelo estático conforme descrito acima. A desmineralização foi mensurada utilizando micro-CT (estudo 2) e TMR (estudos 2 e 3). No estudo 3, o biofilme foi analisado quanto à viabilidade por fluorescência e contagem das UFC para microrganismos totais, Streptococcus totais, Streptococcus mutans e Lactobacillus, e quanto à produção de ácido lático e PEC. No estudo 1, a viabilidade do biofilme foi menor para o modelo estático (0,420±0,138) comparado ao semi-dinâmico (0,944±0,599). Ambos os modelos provocaram desmineralização da dentina; entretanto, o modelo estático produziu maior número de lesões de subsuperfície (83%) comparado ao semi-dinâmico (45%). No estudo 2, ambos os fluoretos reduziram a desmineralização da dentina. Dados obtidos por micro-CT e TMR apresentaram uma correlação significativa e positiva (Z: r=0,78 p<0,0001 e LD: r=0,57 p<0,0001). No estudo 3, todos os tratamentos reduziram a viabilidade do biofilme, mas não a contagem de UFC, exceto o NaF que reduziu o número de Lactobacillus comparado ao controle. Nenhum tratamento diminuiu a produção de ácido lático e PEC, exceto a CHX que reduziu PEC insolúvel. Os fluoretos reduziram a desmineralização da dentina comparado ao controle, mas o TiF4 apresentou o melhor efeito em reduzir perda mineral e profundidade da lesão (redução de Z: 70% e LD: 45%). Em conclusão, 1) o modelo de disponibilidade de nutrientes pode influenciar a viabilidade do biofilme e o perfil das lesões de cárie em dentina; 2) micro-CT pode ser um método não destrutivo adequado para mensurar desmineralização da dentina; e 3) apesar do verniz TiF4 não apresentar efeito antimicrobiano relevante, é a melhor opção para reduzir o desenvolvimento de lesões de cárie em dentina neste modelo

Comparison between static and semi-dynamic models for microcosm biofilm formation on dentin

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

NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data