Pellicle materials

Studies on pellicle composition are hampered by the fact that only limited amounts (minute quantities) of pellicle material can be collected and recovered from human teeth in vivo for analytical investigations. It has been calculated that the pellicle layer formed per labial surface of a tooth over 2 h in vivo only contains approximately 1 xg of protein [39], Therefore, much work has been performed using in vitro models to mimic the formation of the salivary pellicle. Glandular salivary secretions or whole saliva supernatants are used to form a pellicle-like protein layer adsorbed on hydroxyapatite or tooth enamel. Although considerable insight into the selectivity and affinity characteristics of salivary proteins during adsorption onto these surfaces has been obtained from... 

The extraction and fractionation of Tulare pellicle adopted conventional bioassay-directed procedures commonly used for isolation of natural products. Sequential Soxhlet extraction of finely ground pellicle with solvents of increasing polarity gave extracted material, after evaporation of the solvent, which was suitable for testing in vitro in a similar way to the unextracted tissues. The results were unusual in that acetone, methanol, and water extracts all exhibited activity, as did the extracted pellicle material only the hexane extract lacked activity [18]. This suggested that hexane-exiractable... 

Abrasive. Dentifrices have the unique ability to remove extrinsic tooth stains, which are caused by agents such as berries, tea, smoking, antibiotics, and certain bacteria as they attach to the dental pellicle. These stains can be removed only by abrasive cleaning a toothbmsh alone is not adequately effective. It has been shown that only 4% of a test population were able to maintain thein teeth in an acceptably stain-free state without an abrasive and that 18% of the population were "heavy" stainers (2). However, colored materials found in dental plaque are removable without abrasives. 

Formation of the acquired salivary pellicle is the result of biopolymer adsorption at the tooth-saliva interface. The term acquired pellicle was first suggested in a review of the nomenclature of the enamel surface integuments by Dawes et al. [1], to describe the cuticular material formed on the enamel surface after eruption. The pellicle consists of adsorbed proteins and other macromolecules from the oral environment (saliva, crevicular fluids) and is clearly distinguished from the microbial biofilm (plaque) (fig. 1). 

Hannig M Transmission electron microscopic study of in vivo pellicle formation on dental restorative materials. Eur J Oral Sci 1997 105 422-433. 

This chapter describes the results of an ongoing study we are conducting into the nanoscale mechanical properties, chemical composition and structure of healthy enamel, carious lesions and the acquired salivary pellicle layer. A variety of material characterization techniques are being used, including nanoindentation, scanning electron microscopy (SEM), electron microprobe analysis (EMPA), scanning acoustic microscopy, atomic force microscopy (AFM) and time-of-flight secondary ion mass spectroscopy (TOF SIMS). 

Pellicle and tea-immersed pellicle were analyzed using nanoDMA (dynamic mechanical analysis) to see if the tannins had an effect on the viscoelasticity of the pellicle. NanoDMA is a technique used to study and characterize mechanical properties in viscoelastic materials. The method is an extension of nanoindentation testing [58, 59], An analysis of the nanoindentation load-depth curve gives the hardness (H) and reduced elastic modulus (E ), provided the area of contact, A, between the indenter tip and the sample is known [ 13]. By... 

Also, because of the high EUV absorptivity of solid materials, including thin polymer films, there are no materials currently demonstrated with sufficient transparency that can be used as EUV pellicles. As a result, there are no pellicles for EUV masks, which presents significant defect control challenges in EUV lithography. 

The identification of Tulare walnut pellicle as the source of antiaflatoxigenic activity greatly simplified procedures for isolation of the bioactive constituents since it made it unnecessary to extract the whole kernel, which would have introduced large quantities of extraneous material. Attention was therefore focused on the constituents of pellicle alone. 

Simple regeneration with IM HCl leads to the formation of an aqueous suspension of ZrP microcrystals consisting of few layers with respect to the parent material. Pellicles or membranes made up entirely of ZrP can be obtained by filtering the suspension this particular type of ZrP has been called pellicular zirconium phosphate (hereafter ZrP(p,). 

Recover the cytoplasm, a turbid, straw-colored fraction, which occupies about 40% of the volume, by inserting a Pasteur pipette through the lipid pellicle. Pool the material into thick-walled polycarbonate TLS 55 tubes. 

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