http://hdl.handle.net/2027.42/57485 Search the Channel search http://deepblue.lib.umich.edu/simple-search http://hdl.handle.net/2027.42/57488 Title: Composites: Better, Faster and Easier<br/><br/>Authors: Hamilton, James C.<br/><br/>Abstract: Two hour continuing dental education lecture presented by James C. Hamilton, DDS at Loma Linda School of Dentistry with a live demonstration on a typodont of the Custom Matrix Technique for light cured dental restorative materials. This technique utilizes a clear poly vinyl siloxane bite registration material to take a small impression without a tray and uses that impression as a die to force the unset light cured dental restorative material into the original anatomy, surface texture and occlusion that the patient had when the procedure started. Then the restorative material is cured through the clear bite registration material creating a hard smooth surface without an air inhibited, layer reducing or eliminating any finishing or polishing, and saving 5 to 10 minutes of chairtime. If the original surface is defective that defect is easily filled in with red border molding wax prior to taking the impression with a clear bite registration material. The lecture utilizes the following cases to teach the technique: Porcelain Veneer Temporization, #9 Cervical Abrasion, #3 Mesial-Occlusal, #19 Mesial-Occlusal,#13 Mesial-Occlusal, #22 Rest for Partial Denture, #6 Large Class 3, Available Products, #18 Occlusal, #10 Class 5 (Penetrating Stain), #9 Class 5 (Gross Caries), #17 and 18 Occlusal, #4 Distal-Occlusal (Sectional Matrix), #12 Distal-Occlusal, #10 Peg Lateral,and #30 Occlusal (Marginal Breakdown). The Live demonstration restores a MO on #31 and eliminates simulated gross caries on a molar prior to taking a clear impression of a surface that will be transmitted to the new restorative material. Fri, 26 Jan 2007 00:00:00 GMT http://hdl.handle.net/2027.42/55803 Title: Macroporous and nanofibrous polymer scaffolds and polymer/bone-like apatite composite scaffolds generated by sugar spheres<br/><br/>Authors: Wei, Guobao; Ma, Peter X.<br/><br/>Abstract: Scaffolds are crucial to tissue engineering/regeneration. In this work, a technique combining a unique phase-separation process with a novel sugar sphere template leaching process has been developed to produce three-dimensional scaffolds. The resulting scaffolds possess high porosities, well connected macropores, and nanofibrous pore walls. The technique advantageously controls macropore shape and size by sugar spheres, interpore opening size by assembly conditions (time and temperature of heat treatment), and pore wall morphology by phase-separation parameters. The bioactivity of a macroporous and nanofibrous poly( L -lactic acid) (PLLA) scaffold was demonstrated by the bone-like apatite deposition throughout the scaffold in a simulated body fluid (SBF). Preincorporation of nanosized hydroxyapatite eliminated the induction period and facilitated the apatite growth in the SBF. Interestingly, the apatite growth primarily occurred on the surface of the pores (internal and external) but not the interior of the nanofibrous network away from the pore surface. It was also noticed that the macropore size did not affect the apatite growth rate, while the interpore opening size did. The compressive modulus also increased substantially when a continuous apatite layer was formed on the pore walls of the scaffold. The resulting composite scaffold mimics natural bone matrix with the combination of an organic phase (a polymer such as PLLA) and an inorganic apatite phase. The demonstrated bioactivity of apatite layer, together with well-controlled macroporous and nanofibrous structures, makes the novel nanocomposite scaffolds desirable for bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006 Tue, 01 Aug 2006 00:00:00 GMT http://hdl.handle.net/2027.42/50068 Title: Temporal and spatial patterns of tenascin and laminin immunoreactivity suggest roles for extracellular matrix in development of gustatory papillae and taste buds<br/><br/>Authors: Mistretta, Charlotte M.; Haus, Linda F.<br/><br/>Abstract: Gustatory papillae are complex organs that are composed of 1) an epithelium, 2) specialized sensory cells within the epithelium (the taste buds), 3) a broad connective core, and 4) sensory innervation. During papilla development, cells in the various tissue compartments must divide, aggregate, detach, migrate, and reaggregate in relation to each other, but factors that regulate such steps are poorly understood and have not been extensively studied. All of these processes potentially require participation of the extracellular matrix. Therefore, we have studied temporal and spatial patterns of immunoreactivity for two extracellular matrix molecules, tenascin and laminin, in the developing fungiform and circumvallate papillae of fetal, perinatal, and adult sheep tongue. To determine relations of tenascin and laminin to sensory innervation, we used an antibody to growth-associated protein (GAP-43) to label growing nerves. Immunocytochemical distributions of tenascin and laminin alter during development in a manner that reflects morphogenesis rather than histologic boundaries of the taste papillae. In early fungiform papillae, tenascin immunoreactivity is very weak within the mesenchyme of the papilla core. However, there is a subsequent shift to an intense, restricted localization in the apical papilla core only—directly under taste bud-bearing regions of the papilla epithelium. In early circumvallate papillae, tenascin immunoreactivity is patchy within the papilla core and within the flanking, nongustatory papillae. Later, immunoreactivity is restricted to the perimeter of the central papilla core, under epithelium that contains developing taste buds. In fungiform and circumvallate papillae, the shift in tenascin immunolocalization is associated with periods of taste bud formation and multiplication within the papilla epithelium and with extensive branching of the sensory innervation in the papilla apex. Laminin immunoreactivity, although it is continuous throughout the basement membrane of general lingual epithelium, is interrupted in the epithelial basement membrane of early fungiform and circumvallate papillae in regions where taste buds are forming. The breaks are large in young fetuses, when taste buds first develop, and are evidenced later as punctate disruptions. Heparan sulfate proteoglycan immunoreactivity confirms that these are basement membrane discontinuities. GAP-43 label coincides with innervation of the papilla core and is most extensive in regions where tenascin immunoreactivity is weak or absent. GAP-43 immunoreactivity is also found in early taste buds: Later, it is extensive within more mature multiple taste buds, presumably in relation to synaptogenesis. We propose that tenascin has a role in promoting deadhesion of cells in the papilla epithelium during periods of taste bud formation and multiplication. Discontinuities in the epithelial basement membrane under developing taste buds, indicated with laminin and heparan sulfate proteoglycan immunoreactivity, may interact to facilitate taste bud morphogenesis and multiplication, to permit access of papilla innervation to the forming taste buds, and/or to allow epithelial/mesenchymal interactions during papilla and taste bud development. © 1996 Wiley-Liss, Inc. Mon, 15 Jan 1996 00:00:00 GMT http://hdl.handle.net/2027.42/50062 Title: Maturation of neuron types in nucleus of solitary tract associated with functional convergence during development of taste circuits<br/><br/>Authors: Mistretta, Charlotte M.; Labyak, Susan E.<br/><br/>Abstract: Late fetal through postnatal development in sheep is a period of increasing convergence of afferent taste fibers onto second-order neurons in the nucleus of the solitary tract (NST). To learn whether neuron morphology alters in concert with convergence and neurophysiological development in NST, three-dimensional neuron reconstructions were made of cells in a functionally defined region of gustatory NST from Golgi preparations of the brainstem. Elongate, multipolar, and ovoid neurons were studied in fetuses from 85 days of gestation through the perinatal period (term = 147 days of gestation), to postnatal stages. Somal size and form, and dendritic complexity and extent, increased markedly from 85 to about 110 days of gestation in both of the proposed NST projection neurons, elongate and multipolar. From 130 days of gestation to postnatal ages, growth of dendrites of elongate neurons plateaued or declined, whereas dendrites of multipolar neurons apparently continued to increase in size and extent. In addition, spine density decreased on elongate neurons but remained stable on multipolar neurons. Morphological variables of ovoid cells, proposed interneurons in NST, did not alter over this later period. The data suggest that multipolar, not elongate or ovoid, neurons are logical candidates to receive the increasing afferent fiber input onto NST cells during late gestation. Also, neural activity from taste afferent fibers is more likely to have a role in altering NST neuron morphology at later, rather than earlier, developmental periods. © 1994 Wiley-Liss, Inc. Fri, 15 Jul 1994 00:00:00 GMT