Effect of the molecular weight on the sensing mechanism in polyethylene glycol diacrylate/gold nanocomposite optical transducers.

The combination of plasmonic nanoparticles and hydrogels results in nanocomposite materials with unprecedented properties that give rise to powerful platforms for optical biosensing. Herein, we propose a physicochemical characterization of plasmonic hydrogel nanocomposites made of polyethylene glycol diacrylate (PEGDA) hydrogels with increasing molecular weights (700-10000 Da) and gold nanoparticles (AuNPs, ∼60 nm). The swelling capability, mechanical properties, and thermal responses of the nanocomposites are analyzed and the combination with the resulting optical properties is elucidated. The different optomechanical properties of the proposed nanocomposites result in different transduction mechanisms, which can be exploited for several biosensing applications. A correlation between the polymer molecular weight, the effective refractive index of the material, and the optical response is found by combining experimental data and numerical simulations. In particular, the localized surface plasmon resonance (LSPR) position of the AuNPs was found to follow a parabolic profile as a function of the monomer molecular weight (MW), while its absorbance intensity was found as inversely proportional to the monomer MW. Low MW PEGDA nanocomposites were found to be responsive to refractive index variations for small molecule sensing. Differently, high MW PEGDA nanocomposites exhibited absorbance intensity increase/decrease as a function of the hydrophobicity/hydrophilicity of the targeted small molecule. The proposed optomechanical model paves the way to the design of innovative platforms for real-life applications, such as wearable sensing, point-of-care testing, and food monitoring via smart packaging devices.

Protocol for synthesis of spherical silver nanoparticles with stable optical properties and characterization by transmission electron microscopy.

The synthesis of metallic plasmonic nanoparticles (NPs) faces challenges in stability and reproducibility, especially with silver. Here, we present a protocol for tunable synthesis of spherical silver NPs (AgNPs) with stable optical properties. We describe steps for preparing solutions, morphological characterization of AgNPs by transmission electron microscopy, and testing stability. AgNPs exhibit enduring stability and compatibility with various pH values. Moreover, they can be functionalized for optical biosensing applications, offering versatility in nanomaterial applications.

Distributional reinforcement learning in prefrontal cortex.

The prefrontal cortex is crucial for learning and decision-making. Classic reinforcement learning (RL) theories center on learning the expectation of potential rewarding outcomes and explain a wealth of neural data in the prefrontal cortex. Distributional RL, on the other hand, learns the full distribution of rewarding outcomes and better explains dopamine responses. In the present study, we show that distributional RL also better explains macaque anterior cingulate cortex neuronal responses, suggesting that it is a common mechanism for reward-guided learning.

Is there a tolerance for extension of the first metatarsal after the Lapidus procedure? A clinical, functional, and hindfoot radiographic analysis.

PURPOSE: Based on the tripod concept of load distribution, our study aimed to evaluate whether a slight extension of first metatarsal (M1) that may occur after the Lapidus procedure (LP) could alter the radiographic measurements of the hindfoot and influence clinical and functional outcomes. METHODS: Twenty-five patients (27 feet) were reviewed. Hindfoot radiographic analysis was based on seven measurements. Clinical and functional outcomes were evaluated with self-reported questionnaires. Transfer metatarsalgia was also assessed. Correlation analysis was performed according to variations of the studied variables. RESULTS: The average extension of the M1 was 4.26 degrees (p < 0.001). None of the hindfoot radiographic measurements changed significantly (p = 0.13, p = 0.50, p = 0.19, p = 0.70, p = 0.11, p = 0.36, p = 0.83). Patients improved on most questionnaires (p < 0.001). None presented transfer metatarsalgia. No correlation between M1 extension and clinical and functional outcomes was found. CONCLUSION: Possibly there is a tolerance of M1 extension in which it does not alter the radiographic measurements of the hindfoot, overload the lesser metatarsals, or compromise clinical and functional outcomes.

Antimicrobial activity, membrane interaction and structural features of short arginine-rich antimicrobial peptides.

Antimicrobial activity of many AMPs can be improved by lysine-to-arginine substitution due to a more favourable interaction of arginine guanidinium moiety with bacterial membranes. In a previous work, the structural and functional characterization of an amphipathic antimicrobial peptide named RiLK1, including lysine and arginine as the positively charged amino acids in its sequence, was reported. Specifically, RiLK1 retained its ß-sheet structure under a wide range of environmental conditions (temperature, pH, and ionic strength), and exhibited bactericidal activity against Gram-positive and Gram-negative bacteria and fungal pathogens with no evidence of toxicity on mammalian cells. To further elucidate the influence of a lysine-to-arginine replacement on RiLK1 conformational properties, antimicrobial activity and peptide-liposome interaction, a new RiLK1-derivative, named RiLK3, in which the lysine is replaced with an arginine residue, was projected and characterised in comparison with its parental compound. The results evidenced that lysine-to-arginine mutation not only did not assure an improvement in the antimicrobial potency of RiLK1 in terms of bactericidal, virucidal and fungicidal activities, but rather it was completely abolished against the hepatitis A virus. Therefore, RiLK1 exhibited a wide range of antimicrobial activity like other cationic peptides, although the exact mechanisms of action are not completely understood. Moreover, tryptophan fluorescence measurements confirmed that RiLK3 bound to negatively charged lipid vesicles with an affinity lower than that of RiLK1, although no substantial differences from the structural and self-assembled point of view were evidenced. Therefore, our findings imply that antimicrobial efficacy and selectivity are affected by several complex and interrelated factors related to substitution of lysine with arginine, such as their relative proportion and position. In this context, this study could provide a better rationalisation for the optimization of antimicrobial peptide sequences, paving the way for the development of novel AMPs with broad applications.

Fitness checklist model for spontaneous breathing tests in pediatrics.

OBJECTIVE: To evaluate whether a model of a daily fitness checklist for spontaneous breathing tests is able to identify predictive variables of extubation failure in pediatric patients admitted to a Brazilian intensive care unit. METHODS: This was a single-center, cross-sectional study with prospective data collection. The checklist model comprised 20 items and was applied to assess the ability to perform spontaneous breathing tests. RESULTS: The sample consisted of 126 pediatric patients (85 males (67.5%)) on invasive mechanical ventilation, for whom 1,217 daily assessments were applied at the bedside. The weighted total score of the prediction model showed the highest discriminatory power for the spontaneous breathing test, with sensitivity and specificity indices for fitness failure of 89.7% or success of 84.6%. The cutoff point suggested by the checklist was 8, with a probability of extubation failure less than 5%. Failure increased progressively with increasing score, with a maximum probability of predicting extubation failure of 85%. CONCLUSION: The extubation failure rate with the use of this model was within what is acceptable in the literature. The daily checklist model for the spontaneous breathing test was able to identify predictive variables of failure in the extubation process in pediatric patients.

A comparative analysis of clinical, functional and radiographic outcomes of patients with and without fusion between the first and second metatarsals after the lapidus procedure.

BACKGROUND: The aim of this study was to compare the clinical, functional and radiographic outcomes in patients who underwent the original Lapidus procedure (OLP) with fusion and undesired non-fusion between the first (M1) and second (M2) metatarsals. METHODS: A retrospective and comparative analysis of 29 patients (38 feet) who underwent the OLP was performed. They were divided in two groups: (1) 23 feet in which fusion occurred and (2) 15 with undesired non-fusion. Clinical and functional data were assessed with the VAS for pain, AOFAS, LEFS and SF-12. SF-12 comprises physical and mental health scales (PCS-12 and MCS-12). Radiographic parameters assessed were bony and soft tissue forefoot widths (BSFW), intermetatarsal-angle (IMA) and HV-angle (HVA). RESULTS: Separately, the groups presented significant improvements in all questionnaires (p < 0.001), except on MCS-12 (fusion p = 0.08 and non-fusion p = 0.27). When comparing both groups, patients with fusion had higher AOFAS scores (p < 0.05). Both groups presented the same improvements on BSFW, IMA and HVA (p = 0.09, p = 0.16, p = 0.52 and p = 0.63). CONCLUSION: Excellent results were observed, even when without fusion between M1 and M2. Patients who evolved with fusion between the M1 and M2 showed greater improvements in the AOFAS score. LEVEL OF EVIDENCE: III, retrospective comparative study.

Pediatric unplanned extubation risk score: A predictive model for risk assessment.

BACKGROUND: Unplanned extubation is one of the most common preventable adverse events associated with invasive mechanical ventilation. OBJECTIVE: This research study aimed to develop a predictive model to identify the risk of unplanned extubation in a pediatric intensive care unit (PICU). METHODS: This single-center, observational study was conducted at the PICU of the Hospital de Clínicas. Patients were included based on the following criteria: aged between 28 days and 14 years, intubated, and using invasive mechanical ventilation. RESULTS: Over 2 years, 2,153 observations were made using the Pediatric Unplanned Extubation Risk Score predictive model. Unplanned extubation occurred in 73 of 2,153 observations. A total of 286 children participated in the application of the Risk Score. This predictive model was created to categorize the following significant risk factors: 1) inadequate placement and fixation of the endotracheal tube (odds ratio 2.00 [95%CI,1.16-3.36]), 2) Insufficient level of sedation (odds ratio 3.00 [95%CI,1.57-4.37]), 3) age ≤ 12 months (odds ratio 1.27 [95%CI,1.14-1.41]), 4) presence of airway hypersecretion (odds ratio 11.00 [95%CI,2,58-45.26]) inadequate family orientation and/or nurse to patient ratio (odds ratio 5.00 [95%CI,2.64-7.99]), and 6) weaning period from mechanical ventilation (odds ratio 3.00 [95%CI,1.67-4.79]) and 5 risk enhancement factors. CONCLUSIONS: The scoring system demonstrated effective sensitivity for estimating the risk of UE with the observation of six aspects, which overlap as an isolated risk factor or are associated with a risk enhancement factors.

Artificial intelligence and statistical methods for stratification and prediction of progression in amyotrophic lateral sclerosis: A systematic review.

BACKGROUND: Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disorder characterised by the progressive loss of motor neurons in the brain and spinal cord. The fact that ALS's disease course is highly heterogeneous, and its determinants not fully known, combined with ALS's relatively low prevalence, renders the successful application of artificial intelligence (AI) techniques particularly arduous. OBJECTIVE: This systematic review aims at identifying areas of agreement and unanswered questions regarding two notable applications of AI in ALS, namely the automatic, data-driven stratification of patients according to their phenotype, and the prediction of ALS progression. Differently from previous works, this review is focused on the methodological landscape of AI in ALS. METHODS: We conducted a systematic search of the Scopus and PubMed databases, looking for studies on data-driven stratification methods based on unsupervised techniques resulting in (A) automatic group discovery or (B) a transformation of the feature space allowing patient subgroups to be identified; and for studies on internally or externally validated methods for the prediction of ALS progression. We described the selected studies according to the following characteristics, when applicable: variables used, methodology, splitting criteria and number of groups, prediction outcomes, validation schemes, and metrics. RESULTS: Of the starting 1604 unique reports (2837 combined hits between Scopus and PubMed), 239 were selected for thorough screening, leading to the inclusion of 15 studies on patient stratification, 28 on prediction of ALS progression, and 6 on both stratification and prediction. In terms of variables used, most stratification and prediction studies included demographics and features derived from the ALSFRS or ALSFRS-R scores, which were also the main prediction targets. The most represented stratification methods were K-means, and hierarchical and expectation-maximisation clustering; while random forests, logistic regression, the Cox proportional hazard model, and various flavours of deep learning were the most widely used prediction methods. Predictive model validation was, albeit unexpectedly, quite rarely performed in absolute terms (leading to the exclusion of 78 eligible studies), with the overwhelming majority of included studies resorting to internal validation only. CONCLUSION: This systematic review highlighted a general agreement in terms of input variable selection for both stratification and prediction of ALS progression, and in terms of prediction targets. A striking lack of validated models emerged, as well as a general difficulty in reproducing many published studies, mainly due to the absence of the corresponding parameter lists. While deep learning seems promising for prediction applications, its superiority with respect to traditional methods has not been established; there is, instead, ample room for its application in the subfield of patient stratification. Finally, an open question remains on the role of new environmental and behavioural variables collected via novel, real-time sensors.

An All-Green Photo-Electrochemical Biosensor Using Microalgae Immobilized on Eco-Designed Lignin-Based Screen-Printed Electrodes to Detect Sustainable Nanoherbicides.

Herein, a novel completely green biosensor was designed exploiting both the biological and instrumental components made of eco-friendly materials for the detection of herbicides encapsulated into biodegradable nanoparticles for a sustainable agriculture. Similar nanocarriers, indeed, can deliver herbicides to the correct location, reducing the amount of active chemicals deposited in the plant, impacting the agricultural and food industries less. However, handling measurements of nanoherbicides is crucial to provide comprehensive information about their status in the agricultural fields to support farmers in decision-making. In detail, whole cells of the unicellular green photosynthetic alga Chlamydomonas reinhardtii UV180 mutant were immobilized by a green protocol on carbonized lignin screen-printed electrodes and integrated into a photo-electrochemical transductor for the detection of nanoformulated atrazine. Specifically, atrazine encapsulated into zein and chitosan doped poly-ε-caprolactone nanoparticles (atrazine-zein and atrazine-PCL-Ch) were analyzed following the current signals at a fixed applied potential of 0.8 V, in a range between 0.1 and 5 µM, indicating a linear relationship in the measured dose-response curves and a detection limit of 0.9 and 1.1 nM, respectively. Interference studies resulted in no interference from 10 ppb bisphenol A, 1 ppb paraoxon, 100 ppb arsenic, 20 ppb copper, 5 ppb cadmium, and 10 ppb lead at safety limits. Finally, no matrix effect was observed on the biosensor response from wastewater samples and satisfactory recovery values of 106 ± 8% and 93 ± 7% were obtained for atrazine-zein and atrazine-PCL-Ch, respectively. A working stability of 10 h was achieved.

Impact of forefoot width variation on clinical and functional outcomes following the Lapidus procedure.

PURPOSE: This study aimed to evaluate the effect of variations in bony and soft tissue foot widths on clinical and functional outcomes after hallux valgus correction with the Lapidus procedure. METHODS: Forty-three feet in 35 patients with a mean follow-up of 18.5 months undergoing the LP were reviewed. Clinical and functional data were assessed with the VAS for pain, AOFAS Scale, LEFS and SF-12 health survey, which is divided into physical and mental health composite scales (PCS-12 and MCS-12). Radiographic analysis of forefoot width was based on bony and soft tissue limits. Intermetatarsal-angle and HV-angle were also assessed. RESULTS: Bony width changed significantly from 95.5 mm to 84.2 mm (11.8%) and soft tissue width from 107.12 mm to 100.84 mm (5.86%) (p < 0.001). IMA and HVA improved significantly. Significant clinical and functional improvements were observed, except in MCS-12. In simple linear regression, correlation was found between variations of bony width with Δ-AOFAS and Δ-PCS-12, meaning that as the forefoot narrows, their values increase (p = 0.02 and p = 0.005, respectively). It was also related to Δ-IMA, meaning that the forefoot narrows as these parameters improve (p < 0.001 and p < 0.001). Soft tissue width was related to Δ-PCS-12 and Δ-AIM. In multiple linear regression, the strongest correlation was between bony width variation and Δ-IMA (p = 0.029, r2 = 0.22). CONCLUSION: Forefoot narrowing was correlated with improved clinical and functional outcomes, as measured by AOFAS and PCS-12. In addition, correction of the radiographic parameters, mainly IMA, reflected on a significant decrease in the forefoot width.

Fitness checklist model for spontaneous breathing tests in pediatrics / Modelo de checklist de, aptidão para teste de respiração espontânea em pediatria

ABSTRACT Objective: To evaluate whether a model of a daily fitness checklist for spontaneous breathing tests is able to identify predictive variables of extubation failure in pediatric patients admitted to a Brazilian intensive care unit. Methods: This was a single-center, cross-sectional study with prospective data collection. The checklist model comprised 20 items and was applied to assess the ability to perform spontaneous breathing tests. Results: The sample consisted of 126 pediatric patients (85 males (67.5%)) on invasive mechanical ventilation, for whom 1,217 daily assessments were applied at the bedside. The weighted total score of the prediction model showed the highest discriminatory power for the spontaneous breathing test, with sensitivity and specificity indices for fitness failure of 89.7% or success of 84.6%. The cutoff point suggested by the checklist was 8, with a probability of extubation failure less than 5%. Failure increased progressively with increasing score, with a maximum probability of predicting extubation failure of 85%. Conclusion: The extubation failure rate with the use of this model was within what is acceptable in the literature. The daily checklist model for the spontaneous breathing test was able to identify predictive variables of failure in the extubation process in pediatric patients.

RESUMO Objetivo: Avaliar se um modelo de checklist diário de aptidão para o teste de respiração espontânea é capaz de identificar variáveis preditivas de falha no processo de extubação em pacientes pediátricos internados em uma unidade de terapia intensiva brasileira. Métodos: Estudo unicêntricotransversal, com coleta prospectiva de dados. O modelo de checklist foi elaborado com 20 itens e aplicado para avaliação de aptidão para o teste de respiração espontânea. Resultados: A amostra foi composta de 126 pacientes pediátricos em ventilação mecânica invasiva, 85 do sexo masculino (67,5%), para os quais foram aplicadas 1.217 avaliações diárias à beira do leito. A pontuação total ponderada do modelo de predição apresentou o maior poder de discriminação para a realização do teste de respiração espontânea, com índices de sensibilidade e especificidade para a falha de aptidão de 89,7% ou sucesso de 84,6%. O ponto de corte sugerido pelo checklist foi 8, com probabilidade de falha de extubação inferior a 5%. Observou-se que a falha aumentou progressivamente com o aumento da pontuação obtida, com probabilidade máxima de predição de falha de extubação de 85%. Conclusão: A taxa de falha de extubação com a utilização desse modelo ficou dentro do que é aceitável na literatura. O modelo de checklist diário para aptidão do teste de respiração espontânea foi capaz de identificar variáveis preditivas de falha no processo de extubação em pacientes pediátricos.

Cities and neuroscience research: A systematic literature review.

Background: Cities are becoming the socio-economic hubs for most of the world's population. Understanding how our surroundings can mentally affect everyday life has become crucial to integrate environmental sustainability into urban development. The present review aims to explore the empirical studies investigating neural mechanisms underlying cognitive and emotional processes elicited by the exposure to different urban built and natural spaces. It also tries to identify new research questions and to leverage neurourbanism as a framework to achieve healthier and sustainable cities. Methods: By following the PRISMA framework, we conducted a structured search on PubMed, ProQuest, Web of Science, and Scopus databases. Only articles related to how urban environment-built or natural-affects brain activity through objective measurement (with either imaging or electrophysiological techniques) were considered. Further inclusion criteria were studies on human adult populations, peer-reviewed, and in English language. Results: Sixty-two articles met the inclusion criteria. They were qualitatively assessed and analyzed to determine the main findings and emerging concepts. Overall, the results suggest that urban built exposure (when compared to natural spaces) elicit activations in brain regions or networks strongly related to perceptual, attentional, and (spatial) cognitive demands. The city's-built environment also triggers neural circuits linked to stress and negative affect. Convergence of these findings was observed across neuroscience techniques, and for both laboratory and real-life settings. Additionally, evidence also showed associations between neural social stress processing with urban upbringing or current city living-suggesting a mechanistic link to certain mood and anxiety disorders. Finally, environmental diversity was found to be critical for positive affect and individual well-being. Conclusion: Contemporary human-environment interactions and planetary challenges imply greater understanding of the neurological underpinnings on how the urban space affects cognition and emotion. This review provides scientific evidence that could be applied for policy making on improved urban mental health. Several studies showed that high-quality green or blue spaces, and bio-diverse urban areas, are important allies for positive neural, cognitive, and emotional processes. Nonetheless, the spatial perception in social contexts (e.g., city overcrowding) deserves further attention by urban planners and scientists. The implications of these observations for some theories in environmental psychology and research are discussed. Future work should take advantage of technological advancements to better characterize behavior, brain physiology, and environmental factors and apply them to the remaining complexity of contemporary cities.

Effects of Dermatan Sulfate from Marine Invertebrate Styela plicata in the Wound Healing Pathway: A Natural Resource Applied to Regenerative Therapy.

Acute and chronic dermatological injuries need rapid tissue repair due to the susceptibility to infections. To effectively promote cutaneous wound recovery, it is essential to develop safe, low-cost, and affordable regenerative tools. Therefore, we aimed to identify the biological mechanisms involved in the wound healing properties of the glycosaminoglycan dermatan sulfate (DS), obtained from ascidian Styela plicata, a marine invertebrate, which in preliminary work from our group showed no toxicity and promoted a remarkable fibroblast proliferation and migration. In this study, 2,4-DS (50 µg/mL)-treated and control groups had the relative gene expression of 84 genes participating in the healing pathway evaluated. The results showed that 57% of the genes were overexpressed during treatment, 16% were underexpressed, and 9.52% were not detected. In silico analysis of metabolic interactions exhibited overexpression of genes related to: extracellular matrix organization, hemostasis, secretion of inflammatory mediators, and regulation of insulin-like growth factor transport and uptake. Furthermore, in C57BL/6 mice subjected to experimental wounds treated with 0.25% 2,4-DS, the histological parameters demonstrated a great capacity for vascular recovery. Additionally, this study confirmed that DS is a potent inducer of wound-healing cellular pathways and a promoter of neovascularization, being a natural ally in the tissue regeneration strategy.

Recurrence after stopping anticoagulants in women with combined oral contraceptive-associated venous thromboembolism: A systematic review and meta-analysis.

The risk of recurrence after discontinuation of anticoagulation for a combined oral contraceptive (COC)-associated venous thromboembolism (VTE) is unclear. Therefore, we conducted a systematic review and meta-analysis to estimate the incidence of recurrent VTE among women with COC-associated VTE, unprovoked VTE and to compare the incidence of recurrent VTE between the two groups. The Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase Classic +Embase and Medline ALL to July 2020 and citations from included studies were searched. Randomized controlled trials, prospective cohort studies and meta-analyses of these study types were selected. The analysis was conducted by random-effects model. Nineteen studies were identified including 1537 women [5828 person-years (PY)] with COC-associated VTE and 1974 women (7798 PY) with unprovoked VTE. Studies were at low risk of bias. The incidence rate of VTE recurrence was 1.22/100 PY [95% confidence interval (CI) 0.92-1.62, I2  = 6%] in women with COC-associated VTE, 3.89/100 PY (95% CI 2.93-5.17, I2  = 74%) in women with unprovoked VTE and the unadjusted incidence rate ratio was 0.34 (95% CI 0.26-0.46, I2  = 3%). The recurrence risk in women after COC-associated VTE is low and lower than after an unprovoked VTE.

Complete genome sequence of a novel bipartite begomovirus infecting the legume weed Macroptilium erythroloma.

The natural occurrence of mixed infections and large populations of the polyphagous vector (Bemisia tabaci) are the main factors associated with the intensification of the genetic flow among begomoviruses in Neotropical areas, contributing to the emergence of novel recombinants. Here, high-throughput sequencing and metagenomic analyses were employed to discover and characterize a novel recombinant bipartite begomovirus, tentatively named "macroptilium bright yellow interveinal virus" (MaBYIV) in the weed Macroptilium erythroloma (Fabaceae). Recombination signals were detected in MaBYIV, involving bean golden mosaic virus (BGMV) and tomato mottle leaf curl virus (ToMoLCV) genome components. All of the original MaBYIV-infected M. erythroloma plants were found to have mixed infections with BGMV. MaBYIV was transmitted to bean and soybean cultivars via B. tabaci MEAM 1, indicating that M. erythroloma may play a role as a year-round reservoir of a potential new viral pathogen of economically important legume crops.

Doenças peri-implantares e fatores de risco associados ao paciente, que levam a perda do implante - uma revisão / Peri-implant diseases and risk fatores associated with the patient, leading to loss of the implant - a review

Os tecidos moles periodontais e peri- implantares possuem muitas características em comum, tanto clínicas como histológicas. Para controle e manutenção adequados destes tecidos, é necessário melhor entendimento das diferenças e similaridades que existem entre eles. Os biofilmes se formam em todas as superfícies aderentes em sistemas fluidos, tanto em dentes como em implantes orais. Como um resultado da presença bacteriana, o hospedeiro responde desenvolvendo um mec anismo de defesa que levará à inflamaç ão dos tecidos moles. Na unidade dentogengival, os resultados são as lesões de gengivite. Na unidade implantar, essa inflamaç ão é denominada de muc osite. Se for permitido o acúmulo de placa por períodos prolongados de tempo, pesquisas experimentais demonstraram que a muc osite pode evoluir para peri-implantite, isto na dependência dos fatores e indicadores de risc o, afetando o osso peri- implantar de suporte circunferencialmente. Embora o osso de suporte seja perdido coronalmente, o implante ainda permanec erá ósseo integrado e, portanto, clinicamente estável. Essa é a razão pela qual a mobilidade representa uma característica de diagnóstico de peri-implantite pouco sensível, mas específica. Parâmetros mais sensíveis e confiáveis do desenvolvimento e da presença de infecções peri- implantares são o sangramento a sondagem, profundidade de sondagem e a interpretações radiográficas , visam detectar o mais cedo possível as lesões peri-implantares, possibilitando assim que o tratamento, que nessa revisão é descrito como sendo cumulativo, começ ando por procedimentos mais simples até os mais avançados, tendo em vista, paralisar e evitar a progressão dessas lesões, o que fatalmente resultaria no fracasso do implante.

Implantes imediatos, e seus defeitos peri-implantares (GAP) preenchidos com o uso de biomateriais sintéticos / Implants, and their peri-implant defects (GAP) filled with the use of synthetic biomaterials

A colocação de implantes osseointegráveis requer volume ósseo adequado, porém, a extração de dentes leva a diferentes padrões de remodelaç ão e reabsorção óssea. A reabsorção do rebordo alveolar tem sido considerada uma consequência inevitável da extração dentária e pode ser um problema significativo em Implantodontia. Após a extração dentária, mesmo com a instalação de implantes imediatos, o sítio desdentado do processo alveolar sofre substancial modelagem óssea, com a diminuiç ão das dimensões da crista alveolar. Após a inserção de um implante em um local de extração fresco, um defeito marginal (GAP) ocorre, frequentemente, entre o rebordo e a superfície do implante, A fim de superar esse problema e para facilitar a formaç ão de osso no defeito marginal, vários processos de enxerto têm sido utilizados, associados ou não ao uso de membranas de barreira, bem como diversos tipos de substitutos ósseos que podem ser utilizados para tal procedimento. Esse trabalho tem por objetivo revisar e discutir a literatura relacionada ao uso de biomateriais sintéticos para preenchimento desses defeitos que se formam ao redor de implantes instalados em alvéolos frescos. No entanto, ainda não existe um biomaterial ideal que possua todas as pro- priedades desejáveis. Além disso, o volume de osso residual deve ser avaliado antes da extração de dentes, de modo que os cirurgiões possam utilizar técnicas diferentes para preservar o osso alveolar.

Regeneração óssea guiada de alveolos de extração dentária - uma revisão / Guided bone regeneration of alveoli tooth extraction - a review

O osso é um tecido conjuntivo especializado, vascularizado e dinâmico que se modifica ao longo do organismo. Quando lesado, possui uma capacidade única de regeneração e reparação sem a presença de cicatrizes, mas em algumas situações devido tamanho do defeito ósseo não se regenera por completo. Assim, se faz necessária a realização de procedimentos de regeneração óssea guiada. Para isso, o implantodontista deve conhecer as bases biológicas da regeneração óssea guiada alveolar e suas indicações. Nesta revisão foram abordadas indicações, vantagens e tipos de biomateriais utilizados para preenchimento do alvéolo dentário imediatamente após a extração dentária sempre que o objetivo for à reabilitação através da instalação de implantes. Mesmo este, biomateriais, apresentando inúmeras qualidades, estudos ainda devem ser feitos a fim de obter a cada dia, um material sintético compatível com o tecido ósseo perdido em quantidades adequadas sem necessitar de cirurgias extra-bucais.

Bone is a specialized vascularized connective tissue that dynamic changes throughout the body. When injured, it has a unique ability to regenerate and repair without the presence of scars, but in some situations due to size of the bone defect does not regenerate completely. Thus, it is necessary to perform guided bone regeneration procedures. For this, the implant dentistry must know the biological bases of alveolar guided bone regeneration and its indications. In this review were addressed indications, advantages and types of biomaterials used for filling the tooth socket immediately after the tooth extraction whenever the goal is rehabilitation through implants installation. Even this, biomaterials, having several qualities, further studies must be done to obtain each day, a synthetic material compatible with the bone tissue lost in proper amounts without the need of extra-oral surgery.