Nathalia Carolina Fernandes Fagundes

Binge Drinking of Ethanol during Adolescence Induces Oxidative Damage and Morphological Changes in Salivary Glands of Female Rats

This study investigates morphological and biochemistry effects of binge ethanol consumption in parotid (PG) and submandibular (SG) salivary glands of rats from adolescence to adulthood. Female Wistar rats (n = 26) received ethanol at 3 g/kg/day (20% w/v) for 3 consecutive days/week from the 35th until the 62nd day of life. Animals were treated in two periods: 1 week (G1) and 4 weeks (G2), with a control (treated with distilled water) and an ethanol group to each period. In morphological analysis, morphometric and immunohistochemistry evaluation for smooth muscle actin (αSMA), cytokeratin-18 (CK-18), and vimentin (VIM) were made. Biochemical changes were analyzed by concentration of nitrites and levels of malondialdehyde (MDA). The difference between groups in each analysis was evaluated by Mann-Whitney U test or Students t-test (p ≤ 0.05). PG showed, at one week of ethanol exposure, lower CK-18 and α-SMA expression, as well as MDA levels. After four weeks, lower CK-18 and higher MDA levels were observed in PG exposed to ethanol, in comparison to control group. SG showed lower α-SMA expression after 1 and 4 weeks of ethanol exposure as well as higher MDA levels after 1 week. Ethanol binge consumption during adolescence promotes tissue and biochemical changes with only one-week binge in acinar and myoepithelial PG cells.

Cleansing orthodontic brackets with air-powder polishing: effects on frictional force and degree of debris

ABSTRACT Introduction: Debris buildup on the bracket-wire interface can influence friction. Cleansing brackets with air-powder polishing can affect this process. Objective: The aim of this study was to evaluate the frictional force and amount of debris remaining on orthodontic brackets subjected to prophylaxis with air-powder polishing. Methods: Frictional force and debris buildup on the surface of 28 premolar brackets were evaluated after orthodontic treatment. In one hemiarch, each bracket was subjected to air-powder polishing (n = 14) for five seconds, while the contralateral hemiarch (n = 14) served as control. Mechanical friction tests were performed and images of the polished bracket surfaces and control surfaces were examined. Wilcoxon test was applied for comparative analysis between hemiarches at p < 0.05. Results: Brackets that had been cleaned with air-powder polishing showed lower friction (median = 1.27 N) when compared to the control surfaces (median = 4.52 N) (p < 0.01). Image analysis showed that the control group exhibited greater debris buildup (median = 2.0) compared with the group that received prophylaxis with air-powder polishing (median = 0.5) (p < 0.05). Conclusion: Cleansing orthodontic brackets with air-powder polishing significantly reduces debris buildup on the bracket surface while decreasing friction levels observed during sliding mechanics.

Avaliação comparativa da ultraestrutura e propriedades físicas do esmalte bovino, bubalino e humano

This study aimed to compare the morphology and physical properties of the enamel structure of bovine, buffalo and human teeth. Analysis of this tissue was performed by scanning electron microscopy, mineral composition, microhardness and surface roughness of enamel in 41 buffalo incisors (Bos taurus indicus), 41 bovine incisors (Pelorovis antiques), and 30 human permanent incisors. The results showed a significant similarity between the ultrastructure of enamel in these animal species and the one found in human samples. The chemical elements which presented higher concentration in bovine and buffalo enamel were: O,Ca and P, precisely those that form hydroxyapatite crystals - Ca10 (PO4)6 (OH)2. Knoop microhardness values showed no statistically significant differences between the three species. However, the surface roughness of buffalo enamel (2.16µm ±0.23) was significantly higher when compared with human (0.36µm ±0.05) and bovine teeth (0.41µm ±0.07). It is concluded that the characteristics and properties of bovine and buffalo enamel, as obtained from our analysis and testing, showed a similar morphology to that of humans. They showed a similar ultrastructural architecture, microhardness and mineral composition equivalent to the human dental tissue, becoming reference models for research.

Anatomical and histological characteristics of teeth in agouti (Dasyprocta prymnolopha Wagler, 1831)

The agouti species Dasyprocta prymnolopha (D. prymnolopha) is a medium-sized rodent, diurnal, and characteristic of northeastern Brazil, south of the Amazon. Several studies have been made on these rodents. However, there is a lack of analysis of masticatory system, in particular morphology of the teeth. Thus, this research seeks to describe anatomical and histological aspects of the agouti teeth. For this purpose, we used adult agouti, in which measurements and descriptions of teeth and dental tissues were made. It was observed that the dental arch of D. prymnolopha comprises of twenty teeth, evenly distributed in the upper and lower arch, being inferior teeth larger than their corresponding higher. The incisors are larger, and between the posterior premolars and molars, there is a gradual increase in length in the anterior-posterior arch. In microscopic examination, a prismatic appearance was observed consisting of enamel prisms arranged in different directions, behind the enamel and dentin with standard tubular dentinal tubules with variable diameter and far between, also showing a sinuous path from the inner portion to the junction with more superficial enamel. Morphological analysis of dental tissues showed that an enamel with structural organization adapted to the act of chewing and high impact dentin compatible with standard tubular function resilience and mechanical damping of masticatory forces, as found in larger animals, confirming the understanding of eating habits that define much of its ecological functions within the ecosystem they inhabit.

Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex

Mercury is a toxic metal that can be found in the environment in three different forms – elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood–brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2), an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.

Is there an Association Between Periodontitis and Atherosclerosis in Adults? A Systematic Review

BACKGROUND Atherosclerosis is a multifactorial inflammatory disease of the cardiovascular system. It has been suggested that periodontitis, an infectious disease of oral cavity caused by gramnegative anaerobic bacteria, could be linked to atherosclerosis. OBJECTIVE The objective of this systematic review was to assess the evidence between the association of periodontitis and atherosclerosis in adults. METHODS A systematic literature search was conducted in 7 databases up to January 2017, according to the Preferential Reports for Systematic Review and Meta-analysis (PRISMA) guidelines. Studies in humans with atherosclerosis were considered eligible when considering a group exposed to periodontitis and a control group (absence of periodontitis), in which the primary outcome was the association between the 2 diseases (atherosclerosis and periodontitis). The synthesis of the qualitative studies included was evaluated using previously validated checklist for assessing the risk of bias. RESULTS Among the 2138 studies found, 4 observational studies met the eligibility criteria and were included in the qualitative synthesis. All articles were considered adequate, presenting consistent and valid information. The results of the selected studies show the expected effects, being considered as low risk of bias. CONCLUSION The available evidence indicates an association between the 2 diseases, with elevated levels of inflammatory markers, mainly C-reactive protein and interleukin 6.

Analysis of the effectiveness of calcium hydroxide removal with variation of technique and solvent vehicles.

CONTEXT Calcium hydroxide (Ca(OH)2) paste filling is largely used as intra-canal medication and can be combined with different vehicles. Removal of that paste should be preceded by obturation, to avoid the occurrence of apical microleakage. AIMS To evaluate the efficiency of removal of pulp Ca(OH)2, from using different vehicles (water, propylene glycol) and removal techniques (mechanical and ultrasonic). STUDY DESIGN Twenty-four premolars and four human incisors were prepared with step-back technique and divided into six groups according to the removal techniques and vehicles used: Group distilled water/mechanical removal, Group distilled water/ultrasonic removal, Group propylene/mechanical removal, Group propylene/ultrasonic removal, negative control group, and positive control group. The differences between groups were analyzed. MATERIALS AND METHODS The teeth were prepared by step-back technique. The samples were evaluated by stereomicroscopy, using a scoring system for the evaluation of residues in the canal. STATISTICAL ANALYSIS Mann-Whitney test was used to a comparison between groups with the same vehicle. For comparison between groups, regardless of the vehicle, we used the Kruskal-Wallis test, considering P < 0.05 for both tests. RESULTS Groups using distilled water or propylene glycol did not show statistically significant results. When the groups were compared, differences were detected between groups distilled water/propylene and mechanical removal/removal ultrasonic, with the first featuring superior performance. CONCLUSION None of the removal techniques employed in this study was able to completely remove Ca(OH)2 from the root canal. However, the use of distilled water as a vehicle and ultrasonic removal presented the best performance.

Hippocampal Dysfunction Provoked by Mercury Chloride Exposure: Evaluation of Cognitive Impairment, Oxidative Stress, Tissue Injury and Nature of Cell Death

Mercury (Hg) is a highly toxic metal, which can be found in its inorganic form in the environment. This form presents lower liposolubility and lower absorption in the body. In order to elucidate the possible toxicity of inorganic Hg in the hippocampus, we investigated the potential of low doses of mercury chloride (HgCl2) to promote hippocampal dysfunction by employing a chronic exposure model. For this, 56 rats were exposed to HgCl2 (0.375 mg/kg/day) via the oral route for 45 days. After the exposure period, the animals were submitted to the cognitive test of fear memory. The hippocampus was collected for the measurement of total Hg levels, analysis of oxidative stress, and evaluation of cytotoxicity, apoptosis, and tissue injury. It was observed that chronic exposure to inorganic Hg promotes an increase in mercury levels in this region and damage to short- and long-term memory. Furthermore, we found that this exposure model provoked oxidative stress, which led to cytotoxicity and cell death by apoptosis, affecting astrocytes and neurons in the hippocampus. Our study demonstrated that inorganic Hg, even with its low liposolubility, is able to produce deleterious effects in the central nervous system, resulting in cognitive impairment and hippocampal damage when administered for a long time at low doses in rats.

The Effects of Moderate Physical Exercise on Adult Cognition: A Systematic Review

Background: Physical exercise is a systematic sequence of movements executed with a predefined purpose. This muscular activity impacts not only on circulatory adaptations, but also neuronal integration with the potential to influence cognition. The aim of this review was to determine whether the literature supports the idea that physical exercise promotes cognitive benefits in healthy adults. Methods: A systematic search for relevant articles was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis criteria using available databases (PubMed, LILACS, Scopus, Web of Science, The Cochrane Library, OpenGrey, Google Scholar and CENTRAL). The search terms included “humans” or “adults” or “cognition” or “awareness” or “cognitive dissonance” or “cognitive reserve” or “comprehension” or “consciousness” and “motor activity” or “exercise” or “physical fitness,” and not “aged” or “nervous system diseases,” with the purpose of finding associations between moderate physical exercise and cognition. A methodological quality and risk of bias unit assessed the eligibility of articles. Results: A total of 7179 articles were identified. Following review and quality assessment, three articles were identified to fulfill the inclusion criteria. An association between moderate physical exercise and cognition was observed. Improvements in cognitive parameters such as reduced simple reaction time, improved response precision and working memory were identified among the included articles. Conclusion: This systematic review found that moderate physical exercise improves cognition.

Effect of a resin-based and a glass-ionomer sealant on the treatment of noncavitated occlusal caries lesions in teenagers

Objectives: The aim of the study was to use clinical outcomes and digital radiographs to compare the effects of two types of sealant materials on the treatment of noncavitated occlusal caries lesions regarding their progression or arrest in teenage permanent molars. Methods: The sample consisted of 28 teeth from 20 patients aged 11-15 years with random distribution to receive either a resin-based sealant (Fluroshield ® , Dentsply, Philadelphia, PA, USA; Gres group) or a glass-ionomer sealant (RIVA Protect ® , SDI, São Paulo, Brazil; Ggis group). Caries progression was monitored by clinical evaluation and radiographic examination. Clinical outcomes were analyzed using the Mann-Whitney and Fisher′s exact test, and radiographic data were analyzed by Student′s t-test for paired data (P ≤ 0.05). Results: There were no significant differences between the clinical outcomes of both groups regarding the sealant retention, thermal sensitivity, and development of new caries lesions adjacent to the sealed surface. There was an increase in the radiographic density coefficient (carious dentin density/sound dentin density) at the end of the study for the Gres group (P = 0.003), but the coefficient for the Ggis group was similar for both time points (P = 0.49). Conclusions: Radiographic features showed an increase in the mineralization of the caries lesions when the teeth were sealed with a resin-based sealant; however, both techniques may be considered an adequate clinical approach for controlling the progression of the lesions.