fabricated and prefabricated. In the late 19th century, the “Richmond crown,” a single-piece post-retained crown with a porcelain facing, was engineered to function as a bridge retainer. Richmond crown is not post and core system but it is customized, cast able post and crown system as both are single unit and casted together. It is easier to make cast metal restorations with the aid of posts f...

the do1(18c6)fi (mwli. na. k and i 8c6=18-crown-6) complexes have been chosen as the model systems toinvestigate the nature of chemical bonds between alkali metal cations and large mffitidentaie orgmnic ligands.the b3lyp/6-3i+g(d,p) level of calculation has been used for obtaining equilibrium geernetnes and p(r)functions (electron density distributions). by the aid of fundamental physical theor...

Complexes of the anion of the secondary amine 2-phenylaminopyridine (LH) with the heavier alkali metals Na-Cs have been prepared in the presence of various macrocyclic polyether crowns [12-crown-4 (12C4), 15-crown-5 (15C5), and 18-crown-6 (18C6)], which coordinate to the metal ions in all cases. Depending on the combination of alkali metal and crown, the products include separated ion pairs [(c...

This clinical report compares the esthetic outcome of replacing the same left maxillary central incisor with 2 types of implant-supported restorations, a zirconia abutment with a Procera crown and a custom metal abutment with metal ceramic crown. There were only subtle differences noted and both restorations yielded a satisfactory result.

Phosphine is conformationally stable because of the high inversion energy barrier of the phosphorus atom, which allows the phosphorus atom to become a chiral center. Thus, enantiopure P-stereogenic 12-, 15-, 18-, and 21-membered aliphatic phosphines "diphosphacrowns" were synthesized from secondary P-stereogenic bisphosphine as a chiral building block. Their complexation behaviors with alkali m...

background and aim: metal ceramic restorations are widely used in crowns. the marginal fitness of these artificial crowns is prone to alteration during the firing cycle of porcelain. gold electroformed metal-ceramic restorations have been introduced as alternatives to conventional metal-ceramic restorations. however little is known about the relationship between procelain firing procedures and ...

AIMS The aim of the study was to evaluate and compare the oral stereognostic ability and satisfaction for fixed prosthesis in human being. MATERIALS AND METHODS The present study was carried out on 40 subjects, the purpose being to investigate the relation of oral perception to diagnostic and therapeutic procedures. Two types of cast metal crowns--one had morphology closely resembling origina...

Stability constants in 90% (v/v) DMSO /water mixture were evaluated for the complexes of Ag(I), Co(II), Cu(II), Mn(II), Ni(II), Zn(II), Pb(II), Cr(III) and Fe(III) with the macrocyclic compounds, namely, 15-crown-5, benzo-15-crown-5, 18-crown-6, dibenzo18-crown-6, dicyclohexano-18-crown-6, dibenzo-24-crown-8 and dicyclohexano-24-crown-8 by conductometric titrations. A potentiometric study of co...

Recently we reported the profound effects of second-sphere crown ether binding upon the redox energetics and intervalence spectroscopy of selected mixed-valence (Crowd metal complex associatino is driven primarily by ether oxygen/ ammine hydrogen interactions, where the H-bond-donating capability of NH3 is greatly enhanced by coordination to a transition-metal cation.) For delocalized species s...

This study investigated the effect of fiber reinforced composite resin (FRC) post lengths, ferrule, and full coverage metal crown on fracture resistance of endodontically treated teeth (ETT) using an experimental FRC post with the similar elastic modulus of dentin (11.5 GPa). ETT was restored according to 1 of 7 combinations of FRC post length (10, 5, 2.5, 0 mm), ferrule (0, 2 mm), and with/wit...