Effect of plant trichomes on the vertical migration of Haemonchus contortus infective larvae on five tropical forages

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Three-Dimensional Finite Element Analysis of Vertical and Angular Misfit in Implant-Supported Fixed Prostheses

Purpose: Three-dimensional finite element analysis was used to evaluate the effect of vertical and angular misfit in three-piece implant-supported screw-retained fixed prostheses on the biomechanical response in the peri-implant bone, implants, and prosthetic components. Materials and Methods: Four three-dimensional models were fabricated to represent a right posterior mandibular section with one implant in the region of the second premolar (2PM) and another in the region of the second molar (2M). The implants were splinted by a three-piece implant-supported metal-ceramic prosthesis and differed according to the type of misfit, as represented by four different models: Control = prosthesis with complete fit to the implants; UAM (unilateral angular misfit) = prosthesis presenting unilateral angular misfit of 100 pm in the mesial region of the 2M; UVM (unilateral vertical misfit) = prosthesis presenting unilateral vertical misfit of 100 pm in the mesial region of the 2M; and TVM (total vertical misfit) = prosthesis presenting total vertical misfit of 100 pm in the platform of the framework in the 2M. A vertical load of 400 N was distributed and applied on 12 centric points by the software Ansys, ie, a vertical load of 150 N was applied to each molar in the prosthesis and a vertical load of 100 N was applied at the 2PM. Results: The stress values and distribution in peri-implant bone tissue were similar for all groups. The models with misfit exhibited different distribution patterns and increased stress magnitude in comparison to the control. The highest stress values in group UAM were observed in the implant body and retention screw. The groups UVM and TVM exhibited high stress values in the platform of the framework and the implant hexagon, respectively. Conclusions: The three types of misfit influenced the magnitude and distribution of stresses. The influence of misfit on peri-implant bone tissue was modest. Each type of misfit increased the stress values in different regions of the system. INT J ORAL MAXILLOFAC IMPLANTS 2011;26:788-796

Influence of Implant Inclination Associated With Mandibular Class I Removable Partial Denture

The aim of this study was to use two-dimensional finite element method to evaluate the displacement and stress distribution transmitted by a distal extension removable partial denture (DERPD) associated with an implant placed at different inclinations (0, 5, 15, and 30 degrees) in the second molar region of the edentulous mandible ridge. Six hemimandibular models were created: model A, only with the presence of the natural tooth 33; model B, similar to model A, with the presence of a conventional DERPD replacing the missing teeth; model C, similar to the previous model, with a straight implant (0 degrees) in the distal region of the ridge, under the denture base; model D, similar to model C, with the implant angled at 5 degrees in the mesial direction; model E, similar to model C, with the implant angled at 15 degrees in the mesial direction; and model F, similar to ME, with the implant angled at 30 degrees in the mesial direction. The models were created with the use of the AutoCAD 2000 program (Autodesk, Inc, San Rafael, CA) and processed for finite element analysis by the ANSYS 8.0 program (Swanson Analysis Systems, Houston, PA). The force applied was vertical of 50 N on each cusp tip. The results showed that the introduction of the RPD overloaded the supporting structures of the RPD and that the introduction of the implant helped to relieve the stresses of the mucosa alveolar, cortical bone, and trabecular bone. The best stress distribution occurred in model D with the implant angled at 5 degrees. The use of an implant as a support decreased the displacement of alveolar mucosa for all inclinations simulated. The stress distribution transmitted by the DERPD to the supporting structures was improved by the use of straight or slightly inclined implants. According to the displacement analysis and von Mises stress, it could be expected that straight or slightly inclined implants do not represent biomechanical risks to use.

Evaluation of the influence of location of osseointegrated implants associated with mandibular removable partial dentures

Purpose: The aim of this research was to assess, by means of, the bi-dimensional finite element method, the best implant location in the alveolar edge, through stress distribution and support structure displacement of a distal extension removable partial denture associated with an osseointegrated implant of 10.0 x .75 mm, acting as abutment for the denture base.Methods and Materials: Five models in sagittal cut were used to represent: model A-hemi arch containing natural tooth 33 and the distal alveolar edge; model B-similar to model A, but with a conventional removable partial denture to replace the absent teeth; model C (MC)-similar to the previous one, with an implant in the distal region of the edge under the denture base; model D-similar to MC, with the implant in the central region of the edge; model E-similar to MC, with an implant in the mesial region of the edge. With the aid of the finite element program ANSYS 8.0, the models were loaded with strictly vertical forces of 50 N on each cusp tip. Displacement and von Mises Maps were plotted for visualization of results.Results: The introduction of implant diminished the tendency of intrusion of the removable partial denture in all situations. The maximum stress was observed on implant in all situations. Approximating implant in direction of support teeth was benefit for stress distribution.Conclusion: Model D presented the lowest value for maximum tendency to displacement when compared with those found in the other models; model E demonstrated better relief with regard to demand from the abutment tooth; locating the implant near of the abutment tooth influenced positively the distribution of stresses on the analyzed structures.

Oral rehabilitation of severely worn dentition using an overlay for immediate re-establishment of occlusal vertical dimension

The aim of this study was to describe the treatment used in an elderly patient presenting with bruxism and dental erosion, with good gingival health and bone support, but with decreased occlusal vertical dimension (OVD). The oral rehabilitation of elderly patients presenting with bruxism in association with tooth erosion has been a great challenge for dentists. The loss of OVD, the presence of occlusal instability and the absence of an effective anterior guide due excessive dental wear, can damage stomatognathic system (SS) biology, the function and the aesthetics. In the first treatment stage, an overlay removable partial denture (ORPD) was fabricated for the immediate re-establishment of function and aesthetics. After a 2-month follow up, with the patient presenting no symptoms, a second rehabilitation stage was accomplished, with fixed and removable prostheses. Oral rehabilitation with an ORPD was able to re-establish the SS biology, but a correct diagnosis and treatment plan are essential for success. The ORPD is a non-invasive and reversible restoring modality for general dentists that allow the re-establishment of the patient's immediate aesthetics and function at low cost.

Effect of Vertical Misfit on Screw Joint Stability of Implant-Supported Crowns

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação cefalométrica do tratamento da Classe II, divisão 1, de Angle com os aparelhos extrabucal de Kloehn e fixo edgewise: influência do padrão facial

O presente estudo foi realizado com o propósito de avaliar respostas cefalométricas ao tratamento com aparelho extrabucal de Kloehn associado ao aparelho fixo edgewise convencional. Telerradiografias iniciais (T1) e finais (T2) de dois grupos de 30 pacientes tratados com estes aparelhos foram selecionadas e definidas pelo índice cefalométrico de Jarabak para determinação do padrão esquelético craniofacial. Os grupos foram denominados favorável (hipodivergente) e desfavorável (hiperdivergente). A idade média, no início do tratamento, foi de 11,03 anos e final de 14,72 com o tempo médio de tratamento de 3,6 anos para o grupo favorável. No grupo desfavorável a idade inicial foi de 11,51 anos e final de 15,17 anos com tempo médio de tratamento de 3,4 anos. Foi utilizado um sistema de análise de resposta de tratamento em coordenadas X e Y representativos dos movimentos dentários e das bases ósseas decompondo-os em seus vetores horizontais e verticais. Os resultados e respostas do tratamento foram analisados e comparados entre os grupos favorável e desfavorável utilizando o teste t-Student. Os resultados mostraram não haver diferenças estatisticamente significantes na resposta cefalométrica no tratamento com o aparelho extrabucal de Kloehn associados ao aparelho fixo edgewise quanto aos padrões faciais favorável e desfavorável. O tratamento promoveu uma restrição do deslocamento anterior maxilar e um menor deslocamento anterior mandibular. Quanto à movimentação dentária maxilar, houve uma restrição do movimento mesial e extrusivo dos molares superiores no grupo favorável, enquanto que o movimento dos dentes inferiores foi mínimo no sentido anterior e vertical.

Avaliação transversal e vertical da maxila, após expansão rápida, utilizando um método de padronização das radiografias póstero-anteriores

OBJETIVO: na presente pesquisa utilizou-se o aparelho Hyrax tendo como objetivo avaliar as alterações transversais e verticais da maxila. Foram selecionados 20 pacientes de ambos os gêneros, entre 7 e 11 anos de idade, que apresentavam mordida cruzada posterior uni ou bilateral. METODOLOGIA: foram realizadas telerradiografias em norma frontal (PA) antes e após a expansão. A fim de evitar que a falta de padronização dessas radiografias pudesse influenciar nos resultados, idealizou-se um método de padronização para tais radiografias. RESULTADOS E CONCLUSÕES: os resultados mostraram que a correção da mordida cruzada posterior com o aparelho Hyrax, que ocorreu em todos os casos, foi em função tanto da abertura da sutura palatina mediana como também da inclinação dos molares. A medida JgE-JgD relacionada com a expansão maxilar aumentou significantemente em todos os casos tratados. Nas avaliações dentárias, as medidas verticais não apresentaram diferenças significantes, ao contrário das medidas transversais (FTE-FTD; FBE-FBD; LO.BTE; LO.BTD; BTE.BTD). A largura da cavidade nasal também aumentou significantemente (CNE-CND). O método de padronização proposto permite, portanto, utilizar as medidas que avaliam a expansão rápida da maxila, através das radiografias póstero-anteriores, com segurança, também no sentido vertical.

Comparison of the occlusal vertical dimension after processing complete dentures made with lingualized balanced occlusion and conventional balanced occlusion

Statement of problem. An increase in occlusal vertical dimension (OVD) may occur after processing complete dentures. Although many factors that generate this change are known, no information is available in the dental literature regarding the effect that the occlusal scheme may have on the change in OVD.Purpose. This in vitro study compared the increase in OVD, after processing, between complete dentures with teeth arranged in lingualized balanced occlusion and conventional balanced occlusion.Material and methods. Thirty sets of complete dentures were evaluated as follows: 15 sets of complete dentures were arranged in conventional balanced occlusion (control) and 15 sets of complete dentures were arranged in lingualized balanced occlusion. All dentures were compression molded with a long polymerization cycle. The occlusal vertical dimension was measured with a micrometer (mm) before and after processing each set of dentures. Data were analyzed using an independent t test (alpha=.05).Results. The mean increase in the OVD, after processing, was 0.87 +/- 0.21 mm for the control group and 0.90 +/- 0.27 mm for the experimental group. There was no significant difference between the groups.Conclusion. After processing, dentures set in lingualized balanced occlusion showed an increase in OVD similar to those set in conventional balanced occlusion.

Evaluation of the occlusion vertical dimension of complete dentures after microwave disinfection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Calcaneal Tendon Regions Exhibit Different MMP-2 Activation After Vertical Jumping and Treadmill Running

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vertical migration of Haemonchus contortus third stage larvae on Brachiaria decumbens grass

The present study aimed at evaluating the vertical migration of Haemonchus contortus third stage larvae (1-3) on Brachiaria decumbens grass, as well as at verifying whether larval numbers on pasture varies over the day due to climatic conditions. Feces containing H. contortus L3 were deposited on the soil in the middle of herbage which was initially 30 cm high. Seven days later, samples of different herbage strata (0-10, 10-20 and >20 cm), remaining feces and a layer of approximately 1 cm soil were collected. Tests were carried out in four periods: September 2006, December 2006, March 2007, and June 2007. Samples were collected at sunrise, mid-day, sunset, and mid-night. The humidity and temperature conditions observed in different months influenced larval migration from the feces to the grass. In September, December and March, it rained after fecal deposition on pasture, which favored migration of larvae from the feces to the herbage. Conversely, in June 2007, when there was no rainfall after fecal deposition and temperatures were lower, L3 were mainly recovered from feces. As regards the vertical migration of larvae, the numbers of H. contortus L3 in the forage strata remained relatively constant over the day. This indicates there is not a determined period in which sheep on pasture are at higher risk of infection. Finally, in all collection periods a considerable amount of third stage larvae was observed on the herbage top, which is the first plant part consumed by sheep. (C) 2008 Elsevier B.V. All rights reserved.

Espectro e distribuição vertical das estratégias de dispersão de diásporos do componente arbóreo em uma floresta estacional no sul do Brasil

A dispersão de diásporos é um evento de elevada importância para as espécies vegetais, que dispõem de diversas estratégias para este fim. O presente estudo teve por objetivos conhecer e caracterizar o espectro das diferentes estratégias de dispersão do componente arbóreo em uma floresta estacional de Santa Maria, Rio Grande do Sul, Brasil (próximo às coordenadas 53º54'W e 29º38'S) e, a partir desses dados, investigar sua relação com os estratos verticais da floresta. Foram amostrados todos os indivíduos com perímetro à altura do peito > 15 cm, em 100 unidades amostrais de 10×10 m. A caracterização das estratégias de dispersão foi realizada por meio de observações a campo de frutos e potenciais dispersores, e consulta à bibliografia especializada. Foram amostradas 58 espécies pertencentes a 26 famílias botânicas. Dessas espécies, 74% apresentaram estratégia de dispersão zoocórica; 24%, estratégia de dispersão anemocórica e apenas Gymnanthes concolor Spreng. apresentou a estratégia autocórica. Analisando-se a proporção das estratégias de dispersão por meio da densidade relativa, verificou-se que 80% dos indivíduos são zoocóricos, 12% anemocóricos e 8% autocóricos. Para a floresta analisada foram encontradas diferenças significativas nos padrões de distribuição vertical das espécies agrupadas de acordo com a estratégia de dispersão. A zoocoria ocorreu em espécies de todos os estratos, enquanto a autocoria ficou limitada ao sub-bosque. Já a anemocoria foi mais importante entre as espécies com indivíduos emergentes.