STATEMENT OF PROBLEM No study has evaluated the efficacy of auxiliary tooth preparation elements for crowns with originally reduced resistance form. PURPOSE This study evaluated the effects of different auxiliary preparation features on the resistance form of crowns with reduced axial wall and total occlusal convergence. MATERIAL AND METHODS An Ivorine tooth was prepared on a milling machin...

The various association constants, bnm and Knm, of NaCl and NaClO4 with [12]crown-4, [15]crown-5, [18]crown-6, benzo[15]crown-5, benzo[12]crown-4, dibenzo[18]crown-6 and dinaphtho[18]crown-6 have been estimated in a mixture of dioxane/water (80/20) using a sodium ion selective electrode (ISE). The constants have been estimated using 1=ðKnm1⁄2Lo n1m21Þ5 ð1 2 nP 0Þn ð1 2 mP 0Þm=P 0; where P 0, th...

OBJECTIVE The purposes of this study were to determine the accuracy of crown and root length measurements of premolars using cone-beam computed tomography (CBCT) and to generate reference CBCT-based data on incisor, canine, and premolar lengths in patients with malocclusions. METHODS Imaging was performed using a CBCT scanner with a 0.292-mm voxel size and 12-bit grayscale. The CBCT-based len...

The syntheses of two di(1,8-naphtho)-16-crown-4 compounds are described. In the X-ray structure of di(1,8-naphtho)-16-crown-4, the compound crystallizes in the orthorhombic space group Pna21 with four molecules per asymmetric unit. Alkali metal cation selectivities of the ionophores are assessed in solvent polymeric membrane electrodes.

Two new perylene bisimide (PBI) derivatives possessing crown ether receptors at the 1,7 bay-positions and solubilizing ionic imide substituents were synthesized and their self-assembly properties in the presence of different metal ions were studied, revealing highly selective barium ion templated self-assembly of 15-crown-5 functionalized PBI into H-type dimer aggregates.

Conformational restriction imposed upon Ru(bpy)32+ crown ether complexes by metal ion binding leads to enhanced luminescence.

Fabricating a crown to retrofit an existing abutment tooth for a partial removable dental prosthesis (PRDP) is one of the most time-consuming and labor-intensive clinical procedures. In particular, when the patient is concerned with esthetic aspects of restoration, the task of fabricating becomes more daunting. Many techniques for the fabrication of all-metallic or metal-ceramic crowns have bee...

Photochromic crown compounds, such as monomeric and polymeric crown compounds incorporating spirobenzopyran, spironaphthooxazine, spirobenzothiapyran, Malachite Green, and Crystal Violet moieties, were synthesized for applications in the fields of analytical and separation chemistry. The photochromic crown compounds, especially crowned spirobenzopyran derivatives, were applied to metal ion extr...

This in vitro study quantified the marginal discrepancy of the implant-to-prosthetic-crown interface on nonsubmerged dental implants restored with either a cemented or a screw-retained approach. Metal-ceramic crowns were fabricated for 20 ITI 4.1 x 10 mm solid-screw titanium implants. Ten implants received octa abutments and screw-retained crowns fabricated on premachined gold cylinders. The re...

The synthesis and spectroscopic investigation of aza-crown ethers with anthraquinoneand 1-aminoanthraquinone-functionalized side chains are described. Cation-induced shifts in the UV/VIS absorption spectra of the ligands dissolved in propylene carbonate are observed only for Li+ among the alkali metal ions and for Mg2+ among the alkaline earth metal ions as well as for Ag+ and T1+. Only hypsoch...