EXTRAÇÕES EM ORTODONTIA: REVISÃO DE LITERATURA

As extrações dentárias para fins ortodônticos compõe um tema debatido há mais de cem anos e, atualmente, os critérios que determinam a escolha dessa forma de tratamento vão além de análise de modelos e da posição que os dentes se encontram na base óssea. O objetivo deste estudo foi analisar as indicações das extrações, quais dentes são extraídos com maior frequência, e a estabilidade pós-tratamento. O estudo foi desenvolvido a partir de uma busca eletrônica nas bases de dados PubMed/Medline e Google Scholar. Foram selecionados artigos publicados no período de 10 anos que tivessem como abordagem as extrações no plano de tratamento. Foram excluídos artigos duplicados em ambas as bases de dados e aqueles que não abordassem o tema Extrações. Foram encontrados 468 artigos no PubMed e 152 no Google Scholar, sendo excluídos 472, examinados 153 artigos, chegando à seleção de 37 artigos e, destes, apenas 12 foram utilizados para o desenvolvimento deste trabalho. As exodontias são indicadas em casos de discrepâncias dentárias e esqueléticas, protrusão ou biprotrusão e tratamentos orto-cirúrgicos. Os principais dentes a serem extraídos são os pré-molares superiores devido à sua localização no arco e a estabilidade pós-tratamento se mostrou semelhante a casos onde não se optam por extrações no plano de tratamento.Las extracciones dentales con fines de ortodoncia han sido un tema debatido durante más de cien años y, en la actualidad, los criterios que determinan la elección de esta forma de tratamiento van más allá del análisis de modelos y la posición que ocupan los dientes en la base ósea. El objetivo de este estudio fue analizar las indicaciones de exodoncia, qué dientes se extraen con mayor frecuencia y la estabilidad postratamiento. El estudio se desarrolló a partir de una búsqueda electrónica en las bases de datos PubMed/Medline y Google Scholar. Se seleccionaron artículos publicados durante un período de 10 años que abordaran las extracciones en el plan de tratamiento. Se excluyeron los artículos duplicados en ambas bases de datos y aquellos que no abordaban el tema de las extracciones. Se encontraron 468 artículos en PubMed y 152 en Google Scholar, se excluyeron 472, se examinaron 153 artículos, llegando a la selección de 37 artículos y, de estos, solo 12 fueron utilizados para el desarrollo de este trabajo. Las extracciones están indicadas en casos de discrepancias dentales y esqueléticas, protrusión o biprotrusión y tratamientos ortoquirúrgicos. Los principales dientes a extraer son los premolares superiores debido a su ubicación en la arcada y la estabilidad postratamiento fue similar a los casos en los que no se optó por extracciones en el plan de tratamiento.Tooth extractions for orthodontic purposes has been a topic discussed for over a hundred years and, currently, the criteria that determine the choice of this form of treatment go beyond the analysis of models and the position that the teeth are in the bone base. The aim of this study was to analyze the indications for extractions, which teeth are extracted most frequently, and post-treatment stability. The study was developed from an electronic search in PubMed/Medline and Google Scholar databases. Articles published over a 10-year period were selected that addressed extractions in the treatment plan. Duplicate articles in both databases and those that did not address the topic of Extractions were excluded. 468 articles were found in PubMed and 152 in Google Scholar, 472 were excluded, 153 articles were examined, reaching the selection of 37 articles and, of these, only 12 were used for the development of this work. The extractions are indicated in cases of dental and skeletal discrepancies, protrusion or biprotrusion and ortho-surgical treatments. The main teeth to be extracted are the maxillary premolars due to their location in the arch and post-treatment stability was similar to cases where extractions are not chosen in the treatment plan.As extrações dentárias para fins ortodônticos compõe um tema debatido há mais de cem anos e, atualmente, os critérios que determinam a escolha dessa forma de tratamento vão além de análise de modelos e da posição que os dentes se encontram na base óssea. O objetivo deste estudo foi analisar as indicações das extrações, quais dentes são extraídos com maior frequência, e a estabilidade pós-tratamento. O estudo foi desenvolvido a partir de uma busca eletrônica nas bases de dados PubMed/Medline e Google Scholar. Foram selecionados artigos publicados no período de 10 anos que tivessem como abordagem as extrações no plano de tratamento. Foram excluídos artigos duplicados em ambas as bases de dados e aqueles que não abordassem o tema Extrações. Foram encontrados 468 artigos no PubMed e 152 no Google Scholar, sendo excluídos 472, examinados 153 artigos, chegando à seleção de 37 artigos e, destes, apenas 12 foram utilizados para o desenvolvimento deste trabalho. As exodontias são indicadas em casos de discrepâncias dentárias e esqueléticas, protrusão ou biprotrusão e tratamentos orto-cirúrgicos. Os principais dentes a serem extraídos são os pré-molares superiores devido à sua localização no arco e a estabilidade pós-tratamento se mostrou semelhante a casos onde não se optam por extrações no plano de tratamento

Histomorphometric evaluation of periodontal compression and tension sides during orthodontic tooth movement in rats

Objective: The purpose of this study was to evaluate the thickness of the periodontal ligament of rat molars during orthodontic tooth movement (OTM). Methods: Thirty Wistar rats were divided into three groups of 10 animals each: GI, GII and GIII and the mice were euthanized at 7, 14 and 21 days, respectively. Experimental subjects were compared to their respective controls by the Mann-Whitney test. Comparison of values between compression and tension sides were performed during the same and different time periods through Analysis of Variance (ANOVA), Kruskal-Wallis test and, subsequently, Tukey’s test. Results: Groups GI and GII showed decreased PDL size in the apical regions of the mesiobuccal root and in the cervical region of the distobuccal root. There was also an increased PDL in the cervical regions of the mesiobuccal root, apical region of the distobuccal root and middle region of both roots. Conclusion: The reduction and increase in PDL size were seen in the same root, which characterizes tooth inclination. The apical, middle and cervical regions were compared with one another in each time period and at three times: 7, 14 and 21 days. They were also compared in each region, confirming a tipping movement in GI and GII and a gradual decreased intensity between GI to GII, reaching normal dimension in GIII

Pulp analysis of teeth submitted to different types of forces: a histological study in rats

Objective: The purpose of this study was to histologically evaluate pulp and dentin under induced tooth movement (ITM) with different types of forces. Material and Methods: The maxillary right first molars of rats were submitted to movement with continuous (CF), continuous interrupted (CIF) and intermittent (IF) forces during 5, 7 and 9 days with nickel-titanium (NiTi) closed-coil springs exerting 50cN force magnitude. The groups were histologically evaluated as for cellularity pattern, presence of dystrophic, hemodynamic alterations in the pulp as well dentin alterations. The main observed alterations were related to hemodynamic pulp characteristics, such as presence of thrombosis, vascular congestion and hemorrhages. The hemodynamic alterations were statistically evaluated by Shapiro-Wilk normality test and analysis of variance by the Kruskall-Wallis test. Results: There was no significant differences observed between groups in the different types of applied forces and duration of ITM (vascular congestion, p=1.000; hemorrhage, p=0.305; thrombosis, p=1.000). Conclusions: Pulp tissue alterations resulting from ITM were limited to hemodynamic events, without progressing to irreversible degeneration, regardless of the type of force applied. &nbsp

Tomografia computadorizada Cone Beam em Ortodontia – evolução ou revolução? Visão geral, aplicações, vantagens/desvantagens e dose de radiação / Cone Beam computed tomography in orthodontia - evolution or revolution? Overview, applications, advantages/dis

Introdução: A requisição de imagens tridimensionais (3D) do complexo dentomaxilofacial tem aumentado. Com isso, novas possibilidades para avaliações, tratamento e acompanhamento pós-tratamento tem ganhando notoriedade com o emprego da tomografia computadoriza cone beam (TCCB). As imagens em duas dimensões (2D) apresentam problemas inerentes que podem ser resolvidos com avaliações tridimensionais (3D). Objetivos: Esclarecer as principais dúvidas acerca do mecanismo de funcionamento desse método de diagnóstico complementar, expor as vantagens/desvantagens, discutir sobre a dose de radiação efetiva e possibilidades de aplicação em Ortodontia. Conclusão: As informações geradas pelas imagens em 2D derivadas da TCCB não apresentam diferenças que possam comprometer o planejamento ortodôntico quando comparadas com as imagens das radiografias convencionais em 2D. A dose efetiva de radiação recebida pelo paciente não deve ser considerada como fator limitante da solicitação do exame tomográfico.Palavras-chave: Tomografia. Radiografia. Ortodontia. Radiação.AbstractIntroduction: The request of three-dimensional images (3D) of the dentomaxillofacial complex has increased. Hence, new possibilities for assessment, treatment as well as follow-up after treatment have increased their importance with the use of cone beam computed tomography (CBCT). The images in two dimensions (2D) have inherent problems that can be solved with treedimensional images assessment. Objectives: To clarify the main doubts about the operational mechanism of complementary diagnostic method; to explain the advantages and disadvantages, to discuss the effective radiation dose and possible applications in orthodontia. Conclusion: The information generated by 2D images from the CBCT does not show differences that may endanger the orthodontic planning when compared with the images of 2D conventional radiographs. The effective radiation dose received by the patient should not be considered as a limiting factor of the tomography exam request.Keywords: Tomagraphy. Radiography. Orthodontia. Radiation

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost