Int J Esthet Dent
December 2017
Several treatment options are described in the literature to solve the microdontia-related problems of maxillary anterior teeth. These options are often focused on an orthodontic rather than a restorative approach. The case presented here started with an orthodontic phase followed by a restorative one.
View Article and Find Full Text PDFClinical needs and growing patient expectations have forced modern dentistry to focus on finding ever simpler protocols and to develop materials which offer high performance in their mechanical resistance and esthetics. In recent years, the scientific community has been venturing into the world of CAD/CAM, a significant technological innovation imported from the world of engineering. This innovation has made it possible to exploit a material which has long been noted for its mechanical and mimetic qualities: zirconium oxide.
View Article and Find Full Text PDFA set of new ligands, L2H(2)-L5H(2), containing the 1,4,8,11-tetraaza-5,7-dione framework has been prepared, The ligands feature lipophilic substituents either on the carbon atom in the 6 position or on the amino groups, or on both. The solution behaviour of the ligands when included in TritonX-100 micelles has been investigated by means of potentiometric titrations and protonation and complexation constants for the Cu(2+) cation have been determined in micellar medium. Micellar assemblies containing the ligands and pyrene have been prepared, and coupled pH-metric and fluorimetric titrations allowed the determination of the response of the systems as ON-OFF fluorescent sensors for Cu(2+).
View Article and Find Full Text PDFIn the present paper we have investigated some photo-physical characteristics of different micellar-based fluorescent probes containing a fluorophore (pyrene) and a quencher unit (dodecyl-dioxo 2,3,2). The fluorescent response of the probe in the presence of Cu(II) ions was studied using different micellar substrates, and it was found that the pH at which the On-Off jump occurs is not influenced by the chemical structure of surfactant. In addition, the experimental residual fluorescence is not proportionally affected by microviscosity or by the size of the micellar aggregates.
View Article and Find Full Text PDFA new approach to the use of micelles in the fluorescent sensing of metal cations is proposed and applied to the case of Hg(2+). We demonstrate how it is possible to transform a system from an ON-OFF to an OFF-ON sensor by changing the length of the chain used to lipophilise a ligand that resides inside TritonX-100 micelles together with pyrene as the fluorophore. Three tetrathia-monoaza macrocyclic ligands have been synthesised with the same ring but functionalised on the nitrogen atom with a methyl (C1-NS4), an n-butyl (C4-NS4) or an n-dodecyl (C12-NS4) chain.
View Article and Find Full Text PDFA new series of ligands, containing one (L1H(2)-L4H(2)) or two (L5H(4)-L6H(4)) 1,4,8,11-tetraaza-5,7-dione units and functionalized with a propargyl group on the C atom between the C=O moieties, has been synthesized. Protonation constants for the ligands and formation constants of their Cu(2+) complexes have been determined in water, and the coordination geometry of the complexes existing at various pH values has been investigated by coupled pH-metric and spectrophotometric titrations. Ligands capable of simple uptake of Cu(2+) with the formation of neutral, square-planar complexes containing the -2-charged diamino-diimido donor sets and ligands containing further coordinating groups (quinoline or pyridine) capable of single and double cation translocation have been investigated.
View Article and Find Full Text PDFA micellar approach is proposed to build a series of systems featuring an "off-on-off" fluorescent window response with changes in pH. The solubilizing properties of micelles are used to self-assemble, in water, plain pyrene with lipophilized pyridine and tertiary amine moieties. Since these components are contained in the small volume of the same micelle, pyrene fluorescence is influenced by the basic moieties: protonated pyridines and free tertiary amines behave as quenchers.
View Article and Find Full Text PDFA new approach based on self-assembly inside micelles has been individuated to prepare a system behaving as a water-operating selective fluorescent sensor for Cu2+ and Ni2+.
View Article and Find Full Text PDFBackground: Several studies have shown that GTR therapy of intrabony defects results in significantly better outcomes than access flap alone. Most of the available data, however, have been produced in highly controlled research environments by a small group of investigators. Generalizability of results to different clinicians and different subject populations has not been evaluated so far.
View Article and Find Full Text PDFInt J Periodontics Restorative Dent
February 1994
The etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth. Preparation of enamel should be 0.5 mm to give minimal porcelain thickness and to avoid an overcontoured restoration.
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