This article reports on the use of a natural tooth crown to repair substantial defects caused by caries. A 50 y old woman wished to have a mandibular left-side third molar extracted. Concurrently, the patient voiced concerns about the metal collar of a premolar. It was decided to extract the third molar and to use this tooth to perform an autologous tooth crown transplant at the upper second pr...

Compounds consisting of [M(1,2-disila-[3n]crown-n)] (M = Mg, Ca, Sr, Ba; n = 5, 6) and [Ba(1,2-disilabenzo[18]crown-6)] cations and different anions were obtained by equimolar reaction of the hybrid disila-crown ethers 1,2-disila[15]crown-5 (1), 1,2-disila[18]crown-6 (2) and 1,2-disila-benzo[18]crown-6 (7) with alkaline earth metal salts. Even with strongly coordinating anions such as Br or I s...

A new fluorescent ionophore for alkaline earth metal ions, 4'-(9-fluorenecarboxamido)benzo-15-crown-5 (3), was synthesized; its photochemical behavior was investigated using UV, fluorescence, (1)H NMR, and (13)C NMR spectrometry. In the absence of a metal ion, the fluorene moiety showed weak fluorescence emission (fluorescence "Off" state). However, complexation with metal ions greatly enhanced...

PURPOSE Resin to metal bond strength of two commercial and one experimental metal-resin bonding system for crown and bridge veneer composites was evaluated. MATERIALS AND METHODS All specimens were prepared and tested according to ISO 10477 Amendment 1. A high precious alloy (HPA), a Co/Cr-alloy (Co/Cr) and pure titanium (Ti) were wet-ground to a final surface finish of 800 grit and air-dried...

STATEMENT OF PROBLEM Dentin and core materials that substitute for missing dentin are dissimilar materials. A core material with a lower elastic modulus may deform more under applied stress and therefore result in reduced stress concentration at the core/dentin junction. PURPOSE This in vitro study examined the effect of core stiffness on the fracture resistance and failure characteristics of...

STATEMENT OF PROBLEM The conservation of sound tooth structure helps preserve tooth vitality and reduce postoperative sensitivity. Innovative preparation designs, like those for porcelain laminate veneers, are much less invasive than conventional complete-coverage crown preparations. However, no study has quantified the amount of tooth structure removed during these preparations. PURPOSE The ...

Tris(bipyridyl)ruthenium(II) complexes modified such that one of the bipyridines is appended with a crown ether display luminescence that is responsive to complexation with metal ions. The parent species, Ru(bpy)3(2+), is moderately luminescent, with an emission lifetime of about 1 micros in fluid solution at room temperature. The modified complexes are much less emissive, with lifetimes near 1...