Influence of customized composite resin fibreglass posts on the mechanics of restored treated teeth.

AIM: To evaluate the mechanical behaviour of the dentine/cement/post interface of a maxillary central incisor using the finite element method and to compare the stresses exerted using conventional or customized post cementation techniques. METHODOLOGY: Four models of a maxillary central incisor were created using fibreglass posts cemented with several techniques: FGP1, a 1-mm-diameter conventionally cemented post; CFGP1, a 1-mm-diameter customized composite resin post; FGP2, a 2-mm-diameter conventionally cemented post; CFGP2, a 2-mm-diameter customized composite resin post. A distributed load of 1N was applied to the lingual aspect of the tooth at 45° to its long axis. Additionally, polymerization shrinkage of 1% was simulated for the resin cement. The surface of the periodontal ligament was fixed in the three axes (X =Y = Z = 0). The maximum principal stress (σ(max) ), minimum principal stress (σ(min)), equivalent von Mises stress (σ(vM) ) and shear stress (σ(shear)) were calculated for the dentine/cement/post interface using finite element software. RESULTS: The peak of σ(max) for the cement layer occurred first in CFGP1 (1.77 MPa), followed by CFGP2 (0.99), FGP2 (0.44) and FGP1 (0.2). The shrinkage stress (σ(vM) ) of the cement layer occurred as follows: FGP1 (35 MPa), FGP2 (34), CFGP1 (30.7) and CFGP2 (30.1). CONCLUSIONS: Under incisal loading, the cement layer of customized posts had higher stress concentrations. The conventional posts showed higher stress because of polymerization shrinkage.

Dynamic functional impression technique for severely resorbed alveolar ridges.

The process of bone resorption can reduce the volume of the alveolar crest, which makes may make difficult impression taking of the alveolar tissue and the subsequent fit of a new denture. This clinical report describes a fast and simple technique for impressions of edentulous ridges to replace complete dentures, using a temporary tissue conditioner material on the denture base. The existing denture must cover the whole supporting area and should be in harmony with the adjacent oral structures. This technique reduces the number of steps involved and minimizes treatment time and expenses.

Preheating impact on the degree of conversion and water sorption/solubility of selected single-bottle adhesive systems.

OBJECTIVE: This study evaluated the degree of conversion (DC) and the water sorption/solubility of preheated single-bottle adhesive systems. METHODS AND MATERIALS: Five adhesive systems were tested: Adper Easy One and Adper Single Bond 2 (3M ESPE), Excite and Tetric N-Bond (Ivoclar/Vivadent), and XP Bond (Dentsply/Caulk). After storage for two hours at 25°C or 60°C, 50 samples (n=5) were prepared for all adhesive systems and stored dry in lightproof containers at 37°C for 24 hours. Fourier transform infrared/attenuated total reflectance spectroscopy was used to evaluate the DC, and water sorption/solubility was measured by means of mass loss and gain after water storage. The data were analyzed by two-way analysis of variance followed by Tukey's test (p<0.05). RESULTS: Preheated adhesive systems showed statistically significantly higher DC than those kept at 25°C. Except for XP Bond, preheated adhesive systems presented statistically significantly lower water sorption/solubility means. CONCLUSIONS: Preheating improved the DC for all tested adhesive systems. Also, it promoted a decrease of water sorption/solubility, except for the XP Bond adhesive system.

Combate ao Desmodus rotundus rotundus (E. Geoffroy,1810) na regiäo cárstica de Cordisburgo e Curvelo, Minas Gerais / Combat of Desmodus rotundus rotundus (E. Geofroy, 1810) in the Cordisburgo and Curvelo carstic region, Minas Gerais, Brazil

Com o objetivo de avaliar em uma regiäo cárstica o tipo de refúgio, as espécies de morcegos, a populaçäo de animais domésticos, as associações interespecíficas nas coabitações com outros mamíferos silvestres suscetíveis à raiva e a eficácia da warfarina aplicada no dorso do Desmodus rotundus rotundus foi realizada uma pesquisa de maio de 1998 a março de 2000, nos municípios de Cordisburgo e Curvelo, Minas Gerais. Em 49 refúgios vistoriados, 29 naturais e 20 artificiais, localizados em 14 propriedades, encontrou-se o Desmodus rotundus rotundus em 18 abrigos naturais. Destes, 17 eram cavernas formadas pela dissoluçäo ou abatimento de rocha calcária, típica do carste, e um era túnel escavado na terra pela açäo das águas de um rio. As características geomorfológicas e de localizaçäo espacial foram registradas com base nas coordenadas geográficas, obtidas com auxílio de um sensor geográfico de posiçäo. Nesses abrigos foram capturados e identificados 1457 morcegos de 14 espécies, sendo 640 Glossophaga soricina (Pallas, 1766), 566 Desmodus rotundus (E. Geoffroy, 1810), 73 Anoura geoffroyi (Gray 1838), 58 Trachops cirrhosus (Spix, 1823), 38 Diphylla ecaudata ecaudata (Spix, 1823), 23 Platyhrrinus lineatus (E. Geoffroy, 1810), 16 Lasiurus ega (Gervais, 1856), 14 Carollia perspicillata (Linnaeus, 1758), 13 Phyllostomus hastatus hastatus (Pallas, 1767), 9 Artibeus lituratus (Olfers, 1818), 3 Mimmon bennettii (Gray, 1838), 2 Myotis nigricans (Schinz, 1821), 1 Eptesicus brasiliensis (Desmarest, 1819) e 1 Pygoderma bilabiatum (Wagner, 1843). Näo se conseguiu isolar ou detectar o vírus rábico no cérebro de 25 hematófagos selecionados e em 52 de outras espécies. A maioria desses abrigos também era usada por pacas (Agouti paca Linnaues, 1766), capivaras (Hydrochaeris hydrochaeris, Linnaues, 1766), guaxinins (Procyon cancrivorus, G. Cuvier, 1798) e raposas (Lycalopex vetulus, Lund, 1842) que säo suscetíveis à raiva. Em 546 Desmodus rotundus rotundus foi aplicada na regiäo interescapular, aproximadamente um grama de uma pasta contendo warfarina dissolvida em vaselina, na razäo de dois gramas para cada 100 gramas do produto. Observou-se reduçäo significativa na incidência de mordeduras em bovinos e eqüídeos e na presença ou vestígios recentes de Desmodus rotundus rotundus em quatro abrigos dos 18 que estavam habitados no início do trabalho. Nas vistorias pós-tratamento dos vampiros com warfarina, em todos os abrigos, näo se encontraram morcegos näo hematófagos...