ABSTRACT
O tratamento endodôntico requer modelagem eficaz para que a desinfecção dos canais seja otimizada. Esta deve ser realizada de maneira conservadora para respeitar a integridade estrutural do dente e preservar a dentina radicular saudável, determinando então o prognóstico à longo prazo. Um grande desafio para realizar a modelagem ideal é a presença de curvaturas no canal. Propondo-se comparar a modelagem de dois sistemas mecanizados, Easy ProDesign Logic (Easy Equip. Odontológicos, Belo Horizonte, Brasil) e TruNatomy (Dentsply Sirona Endodontics Ballaigues, Suiça), em canais curvos, 20 canais simulados (IM do Brasil - Tecnologia e Inovação para Odontologia, São Paulo, Brasil) foram instrumentados por um único operador. As imagens pré e pós-instrumentação foram sobrepostas e analisadas com auxílio do programa Adobe Photoshop 2021 (Adobe Systems, San Jose, CA), obtendo-se os valores de centricidade nas alturas de 1 à 9mm do canal simulado. Os dados foram analisados estatisticamente utilizando o software Bioestat 5.0 (Instituto de Desenvolvimento Sustentável Mamirauá, Belém, PA, Brasil). A relação de centricidade de preparo, nos grupos TruNatomy e Logic, foi comparada através do teste Krukal-Wallis. De acordo com os resultados observados, não foram encontradas diferenças estatisticamente significantes entre os dois sistemas em nenhuma das alturas avaliadas (p<0.05). Quanto à qualidade do preparo, os dois sistemas mostraram-se eficientes em preservar a anatomia original do canal, realizando preparos com boa centralização em todas as alturas avaliadas.
Subject(s)
Models, AnatomicABSTRACT
BACKGROUND/PURPOSE: The primeval evaluation of the properties of composite resins with different compositions that impact clinical behavior is very important in guiding use in clinical settings. The aim of this study was to evaluate color stability (ΔE) and Knoop microhardness (KHN) of composite resins containing different compositions. MATERIALS AND METHODS: Forty-five disks were made composite resins: Filtek Z350 XT/3MESPE and Beautifill II/SHOFU and divided into 3 subgroups: Control - immersed in artificial saliva; OB - brushing with Oral B 3D White; CT - brushing with Colgate Total 12. The OB and CT groups had the disks brushed daily with 120 cycles after immersion in coffee solution (10â¯min) for a period of 30 days. ΔE and KHN was obtained at baseline and after the treatments. Data were analyzed ANOVA and Tukey tests (pâ¯<â¯0.05). RESULTS: ANOVA revealed significant differences for ΔE and KHN. ΔE: the highest mean was observed in Beautifil II composite resin group, which differed significantly from Z350 group. For the Beautifil II, the treatments were significantly different from each other. For the Z350, the control group showed significant differences in relation to OB e CT groups. KHN: the highest mean was observed in Z350 group, which differed significantly from Beautifil II group. For Z350, the control group showed significant differences in relation to OB e CT groups. For Beautifil II, the treatments did not differ significantly among themselves. CONCLUSION: The composite resin containing fluoride in the composition showed higher color alteration (ΔE) and lower Knoop microhardness (KHN), thus demonstrating that composition is an important factor in the clinical performance of esthetic restorative materials.
ABSTRACT
Two major complexes form structural bridges that connect the erythrocyte membrane to its underlying spectrin-based cytoskeleton. Although the band 3-ankyrin bridge may account for most of the membrane-to-cytoskeleton interactions, the linkage between the cytoplasmic domain of band 3 (cdb3) and adducin has also been shown to be critical to membrane integrity. In the present paper, we demonstrate that adducin, a major component of the spectrin-actin junctional complex, binds primarily to residues 246-264 of cdb3, and mutation of two exposed glutamic acid residues within this sequence completely abrogates both α- and ß-adducin binding. Because these residues are located next to the ankyrin-binding site on cdb3, it seems unlikely that band 3 can bind ankyrin and adducin concurrently, reducing the chances of an association between the ankyrin and junctional complexes that would significantly compromise erythrocyte membrane integrity. We also demonstrate that adducin binds the kidney isoform of cdb3, a spliceoform that lacks the first 65 amino acids of erythrocyte cdb3, including the central strand of a large ß-pleated sheet. Because kidney cdb3 is not known to bind any of the common peripheral protein partners of erythrocyte cdb3, including ankyrin, protein 4.1, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and phosphofructokinase, retention of this affinity for adducin was unexpected.
Subject(s)
Anion Exchange Protein 1, Erythrocyte/metabolism , Calmodulin-Binding Proteins/metabolism , Cytoplasm/metabolism , Anion Exchange Protein 1, Erythrocyte/chemistry , Binding Sites , Humans , Mass SpectrometryABSTRACT
The erythrocyte membrane skeleton is the best understood cytoskeleton. Because its protein components have homologs in virtually all other cells, the membrane serves as a fundamental model of biologic membranes. Modern textbooks portray the membrane as a 2-dimensional spectrin-based membrane skeleton attached to a lipid bilayer through 2 linkages: band 3-ankyrin-beta-spectrin and glycophorin C-protein 4.1-beta-spectrin.(1-7) Although evidence supports an essential role for the first bridge in regulating membrane cohesion, rupture of the glycophorin C-protein 4.1 interaction has little effect on membrane stability.(8) We demonstrate the existence of a novel band 3-adducin-spectrin bridge that connects the spectrin/actin/protein 4.1 junctional complex to the bilayer. As rupture of this bridge leads to spontaneous membrane fragmentation, we conclude that the band 3-adducin-spectrin bridge is important to membrane stability. The required relocation of part of the band 3 population to the spectrin/actin junctional complex and its formation of a new bridge with adducin necessitates a significant revision of accepted models of the erythrocyte membrane.
