Características histológicas da lesão inicial da cárie secundária adjacente a restaurações de resina composta

The aim of this study was to analyse morphologically the initiation of the secondary caries lesion. Thirty-three proximal surfaces adjacent to Class II resin restorations were examined by stereomicroscope (x40) for the presence of caries and gap. Sixty sites (39 sound, 7 with lesions, 14 adjacent to lesions) were prepared for examination using polarized light microscopy in water and after air drying. Lesions were observed in 52.7% of the wet sections and 85.0% of the dried sections. The dried ground sections displayed larger lesions. Further analyses were performed on the dried sections. One hundred per cent of the ground sections from the stereomicroscope carious sites, 87.2% from sound sites, and 71.4% from sites adjacent to lesions displayed demineralized areas. Morphological analysis indicated that caries lesion initiates at the external enamel surface in the interface between tooth and restoration. Two distinct patterns of caries development were observed, related to the direction of enamel rods: (1) the direction of the rods in the adjacent enamel was parallel to the cavity wall (the deepest part of caries penetration was located at the cavity wall), and (2) the direction of the rods ran in the apical direction (the deepest part of caries penetration was oblique to the cavity wall). The pattern 1 could be mistaken for a wall lesion. The prevalence of lesions adjacent to restorations was similar in the sites with (85.7%) and without (84.0%) gaps. The findings support the assumption that secondary caries initiation in vivo is not related to the presence of a gap and follows the direction of the enamel rods.O objetivo deste estudo foi analisar morfologicamente o início da lesão de cárie secundária. Trinta e três superfícies proximais adjacentes a restaurações de resina classe II foram examinadas ao estereomicroscópio (40x) para a presença de carie e gap. Sessenta sítios (39 sadios, 7 com lesões, 14 adjacentes a lesões) foram preparados para exame utilizando microscopia de luz polarizada. As lesões foram observadas em 52,7% dos corte úmidos e 85,0% dos cortes secos. Os cortes secos demonstraram lesões maiores. Analises posteriores foram realizadas nos cortes secos. Cem por cento das secções observadas no estereomicroscópio, 87,2% das lesões hígidas, e 71,4% dos sítios adjacentes a lesões demonstraram áreas desmineralizadas. A análise morfológica indicou que a lesão cariosa inicia na superfície de esmalte externa na interface entre dente e restauração. Dois padrões distintos de desenvolvimento de carie foram observados, relacionados à direção dos prismas de esmalte: (1) a direção dos prismas no esmalte adjacente foi paralela à parede da cavidade (a parte mais profunda da penetração da cárie foi localizada na parede da cavidade), e (2) a direção dos prismas corria na direção apical (a parte mais profunda da penetração da cárie foi obliqua à parede da cavidade). O padrão 1 pode ser confundido por uma parede da lesão. A prevalência de lesões adjacentes às restaurações foi similar em sítios com (85,7%) e sem (84,0%) gaps. Os achados suportam o pressuposto de que o inicio da lesão de cárie secundária in vivo não está relacionado à presença de um gap e segue a direção dos prismas de esmalte

Características da cárie secundária adjacente a restaurações de resina composta

The aim of this study was to analyze the features of secondary caries and their relationship with the presence of restorations marginal defects as gap, negative ledge (NL, lack of restorative material) and positive ledge (PL, overhang). Eighty proximal surfaces of Class II resin restorations were photographed and analyzed using a stereomicroscope (X40). It was recorded the presence of external secondary caries, gap, NL, PL and after the restorations removal, the presence of internal lesion. All the exams were done in 10 well-defined points. The reproducibility (Kappa Index) of the exams of external caries, presence of gaps, restorations marginal defects and internal caries were, respectively: 0.88 e 0.94; 0.80 e 0.87; 0.83 e 0.90 e 0.82 e 0.94. As reprodutibilidades (Kappa) dos exames de cárie externa, EDR, presença de degraus e cárie interna no início e depois da análise de 50% da amostra foram, respectivamente: 0,88 e 0,94; 0,80 e 0,87; 0,83 e 0,90 e 0,82 e 0,94. The prevalence of secondary caries (p < 0.05) and gap (p < 0.01) were associated with gingival margin. The restorations marginal defects (NL and PL) were not associated with any specific location (buccal, lingual or gingival) (p= 0.073). It was observed a relationship between these defects with secondary caries prevalence (gap: p= 0.004; NL and PL: p= 0.017). This association could be explained by the biofilm accumulation usually observed in the interface tooth surface/ restoration marginal defects. The presence of internal lesion was associated with external lesion (p< 0.001). Although, in 141 points was observed internal lesion without the presence of external lesion. The majority of these lesions showed internal enamel involvement. Only 8% had emineralization restricted to dentine, which could suggest residual caries. The results of this study showed that secondary caries lesion frequently began externally on the interface tooth/restoration, where diagnose, control and arrestment of the lesions is possible.Objetivo: O objetivo deste estudo foi analisar as características de cárie secundária e sua relação com a presença de restaurações com defeitos marginais como gap, degrau negativa (NL, a falta de material restaurador) e degrau positiva (PL, saliência). Materiais e Métodos: Oitenta superfícies proximais de restaurações de resina classe II foram fotografados e analisados utilizando um microscópio estereoscópico (X40). Foi registrada a presença de cáries secundárias externas, gaps, NL, PL e após a remoção de restaurações, a presença de lesão interna. Todos os exames foram realizados em 10 pontos bem definidos. Resultados: A prevalência de cárie secundária e gap foram associados com margem gengival. As restaurações com defeitos marginais (NL e PL) não foram associados a qualquer local específico (vestibular, lingual ou gengival). Observou-se uma relação entre esses defeitos com a prevalência de cárie secundária. A presença da lesão interna foi associada com lesão externa. Embora, em 141 pontos foi observada lesão

Fluoridated elastomers: Effect on the microbiology of plaque

The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P = < .001) for the percentage of streptococcal and anaerobic bacterial count and the visit variable for the percentage of streptococcal count (P = < .001). The use of fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P = .288) or anaerobic count (P = .230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth

Prevalência de cárie, gengivite e fluorose em escolares de 12 anos de Porto Alegre - RS, Brasil, 1998/1999

The aim of the study was to evaluate the prevalence of dental caries, gingival bleeding and fluorosis in twelve-year-old schoolchildren from Porto Alegre, Brazil. One thousand students from private and public schools were examined. The indexes used were BI, DMF and TFI. The data pertaining to BI were the first to be collected. After that, the children were submitted to plaque removal and their teeth were dried prior to the examination for caries and fluorosis. The average value for DMFT, including cavitated and non-cavitated lesions, was 2.22 ± 0.08 (standard error). The average value for BI was 19.76% ± 0.54% (standard error) and the prevalence of students with fluorosis was 52.9%. Regarding the severity of fluorosis, 45.9% of the children had TFI 1, 6.1% TFI 2 and 0.9% TFI 3. A polarization of the experience of caries and gingivitis was observed in the studied population. Only 14.4% of the students had DMFS higher than 7. A small percentage of children (12%) presented with BI ³ 40%. The experience of caries and gingivitis of 12-year-old schoolchildren in Porto Alegre is comparable to that of children from developed countries. That probably results from the intense utilization of fluoride, which is also causing an increased prevalence of fluorosis. The severity of fluorosis does not justify any public health measure. The results show that the employed public health measures are effective, although part of the population still needs additional care.O objetivo do estudo foi avaliar a prevalência de cárie, gengivite e fluorose em escolares de 12 anos de Porto Alegre - RS. Foram examinados 1.000 escolares da rede de ensino público e particular da cidade. Os índices utilizados foram o ISG, CPO e o ITF. Após a coleta do ISG, a criança foi submetida à remoção da placa e secagem dos dentes para proceder-se aos exames de cárie e fluorose. A média e erro padrão do CPOD, incluindo as lesões não cavitadas, foi de 2,22 ± 0,08, o ISG foi de 19,76% ± 0,54% e a prevalência de escolares com fluorose foi de 52,9%. Em relação à severidade, 45,9% das crianças apresentaram ITF 1, 6,1%, ITF 2 e 0,9%, ITF 3. Os escolares com CPOS maior que 7 (51,2%) compreenderam 14,4% da amostra. Quanto ao sangramento gengival, observou-se que 12% das crianças apresentavam ISG >; ou = 40%. O CPOD de Porto Alegre é comparável ao de países desenvolvidos, resultado provavelmente em decorrência do uso intensivo de flúor, que também está ocasionando a fluorose. A severidade da fluorose encontrada não justifica qualquer medida de saúde pública. As medidas de saúde pública de impacto populacional estão sendo efetivas, porém, existe uma parcela da população que necessita de cuidados adicionais

Presença de lesões externas de cárie adjacentes a restaurações de resina composta versus defeitos nestas restaurações

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2 Contribution Number 1328-E from the Agricultural Research Organization, The Volcani Center

ABSTRACT We studied the balance of Na + , K + , Cl -, and water in six high yielding (&gt;39 kg/d of milk) cows between wk 2 to 1 prepartum and at 2 and 7 wk postpartum during winter in Israel. Cows were fed complete diets; Na + and Cl -contents exceeded dietary recommendations, and K + content was equal to dietary recommendations. Milk yield was related positively and significantly to retention of Cl -and K + , indicating that ions that are the main constituents of sweat can limit the ability of cows to express full genetic potential. The highest ion retention was recorded for cows that had the highest dry matter intake and, hence, the highest ion intake. Retention of Cl -was highest for cows that were most efficient in retaining Cl -in the kidney. In hot climates, increasing the concentrations of ions in the diet of early lactation cows according to the actual dry matter intake could prevent or reduce the severity of ion deficiencies. Water turnover rate of the cows was dependent on dry matter intake, milk yield, and respiratory-cutaneous water loss. The milk-free water balance (water turnover rate minus water secreted in milk) could be very efficiently predicted for lactating and nonlactating cows by the following equation: milk-free water balance (kilograms per day) = digestible energy intake (megacalories per day) × 0.58 + respiratory-cutaneous loss (kilograms per day) × 0.97 ( n = 18; R 2 = 0.97). This formula provides a tool to assess the evaporative-cutaneous water loss from feed and water intake measurements to evaluate the severity of heat stress. ( Key words: water, ions, metabolism, lactation) Abbreviation key: FWI = free water intake, MFWB = milk-free water balance, RCW = respiratorycutaneous water, WTO = water turnover

ToMRobot 2.0: real mobility mechanism in MANET testbed using mobile robot

This paper is a continuation of our previous paper under the same topic, ToMRobot 1.0. Our main goal of developing ToMRobot 2.0 is to improve the ToMRobot 1.0 that we developed earlier. ToMRobot was developed because we think mobile robot technology is more practical than other approaches as a real world mobility mechanism in MANET testbed. But to develop our own mobile robot at low cost and at the same time not complex is very challenging. The challenge is overcome through the use of easy-to-use components, self-built components using 3D printers and the use of mobile robot designs that have proven to be easily developed, cheap and effective. The use of the Robot Operating System (ROS) as the main robot software framework greatly helps to reduce the complexity of developing control system for mobile robot

Efficacy of 1.23% acidulated phosphate fluoride gel on non-cavitated enamel lesions : a randomized clinical trial

A randomized controlled parallel clinical trial was conducted to evaluate the efficacy of the association of 1.23% topical professional acidulated phosphate fluoride (APF) gel with oral hygiene and dietary instructions on the arrest of active non-cavitated lesions in permanent, mixed, and temporary dentition in children between 3 and 12 years of age. Ninety-eight caries-active children were randomly divided into two groups: a fluoride gel group (n = 49) and a non-fluoridated gel group (n = 49). Each group received up to eight weekly applications of gel, weekly professional toothbrushing with oral hygiene instructions and dietary counselling. Caries lesions were assessed qualitatively through visual-tactile criteria performed in three stages: initial, intermediate, and final. Regression models were applied to identify risk indicators for caries control. Between-group comparison regarding the time taken to arrest the lesions was performed using Chi-squared and Fisher's exact tests. Seventeen children did not receive the allocated intervention, and one was lost to follow-up (n = 80). There was no difference between the control and placebo groups regarding the time to the arrest of the lesion (p >.05). The treatments showed similar results without significant statistical difference (p = 0.33; 95%CI: 0.32–1.48). No adverse effects were observed. It can be concluded that no additional effect of the association of 1.23% APF gel with oral hygiene using fluoride dentifrice and dietary instructions on the arrest of active non-cavitated lesions could be established. We can also confirm the importance of toothbrushing frequency and, consequently, the visible plaque reduction in the control of caries activity. RBR-37V5S

Ecological and Genomic Attributes of Novel Bacterial Taxa That Thrive in Subsurface Soil Horizons.

While most bacterial and archaeal taxa living in surface soils remain undescribed, this problem is exacerbated in deeper soils, owing to the unique oligotrophic conditions found in the subsurface. Additionally, previous studies of soil microbiomes have focused almost exclusively on surface soils, even though the microbes living in deeper soils also play critical roles in a wide range of biogeochemical processes. We examined soils collected from 20 distinct profiles across the United States to characterize the bacterial and archaeal communities that live in subsurface soils and to determine whether there are consistent changes in soil microbial communities with depth across a wide range of soil and environmental conditions. We found that bacterial and archaeal diversity generally decreased with depth, as did the degree of similarity of microbial communities to those found in surface horizons. We observed five phyla that consistently increased in relative abundance with depth across our soil profiles: Chloroflexi, Nitrospirae, Euryarchaeota, and candidate phyla GAL15 and Dormibacteraeota (formerly AD3). Leveraging the unusually high abundance of Dormibacteraeota at depth, we assembled genomes representative of this candidate phylum and identified traits that are likely to be beneficial in low-nutrient environments, including the synthesis and storage of carbohydrates, the potential to use carbon monoxide (CO) as a supplemental energy source, and the ability to form spores. Together these attributes likely allow members of the candidate phylum Dormibacteraeota to flourish in deeper soils and provide insight into the survival and growth strategies employed by the microbes that thrive in oligotrophic soil environments.IMPORTANCE Soil profiles are rarely homogeneous. Resource availability and microbial abundances typically decrease with soil depth, but microbes found in deeper horizons are still important components of terrestrial ecosystems. By studying 20 soil profiles across the United States, we documented consistent changes in soil bacterial and archaeal communities with depth. Deeper soils harbored communities distinct from those of the more commonly studied surface horizons. Most notably, we found that the candidate phylum Dormibacteraeota (formerly AD3) was often dominant in subsurface soils, and we used genomes from uncultivated members of this group to identify why these taxa are able to thrive in such resource-limited environments. Simply digging deeper into soil can reveal a surprising number of novel microbes with unique adaptations to oligotrophic subsurface conditions