Oral rehabilitation of endodontically treated roots is inherently difficult, and the functional loads result in extremely complex structural responses of the oral tissues. The objective of this study was to evaluate, by finite element analysis, stresses induced in an endodontically treated maxillary central incisor that was restored with a cast metallic post and core system and a overlying cera...

Despite enthusiasm for the educational potential of the World Wide Web, few dental educators use the new opportunities offered by this medium beyond the presentation of textual information. Based on this observation, we have decided to design our own interactive Web-based 3D crown preparation course. The course objective is to provide dental students with fundamental didactic and technical know...

Previous surveys have shown that subgingival restoration margins generally lead to significant inflammation of the marginal periodontium 6, 13, 16, 17 and, inter alai, trauma of the “biological width”. This term is defined as the area of the coronal periodontium of the limbus aleovaris, which consists of the connective tissue and epithelial attachment as well as the gingival sulcus (Figure 1a)....

The preparation of polymer membrane selective to Iron(II) ion and its application to ion-selectiveelectrode is reported here. PVC membrane contains Iron–selective N-phenylaza-15-crown-5 asionophore. The membrane electrode is highly selective to Iron(II) ion and exhibit good linearresponse over a wide concentration range of 1.0 × 10-2 to 1.0 × 10-6 M with Nernstian slope of29.2 ± 0.6 mV per deca...

Introduction: Complicated crown fractures involve enamel, dentin, and pulp and occur in 0.9 to l3% of all dental injuries. If left untreated, will always result in pulp necrosis but, if it handled correctly, prognosis of the pulp following a traumatic crown fracture can be favorable. Correspondence: Saeedeh Sadr, DMS, MS. ...

A facile procedure is described for the preparation of [14C]epicholesterol from [14C]cholesterol. Cholesterol is first converted to cholesteryl mesylate, which is treated with cesium acetate and 18-crown-6 in refluxing toluene to give epicholesteryl acetate. The latter is hydrolyzed, without isolation, with potassium hydroxide in tetrahydrofuran-methanol to give epicholesterol, which is obtaine...

BACKGROUND This paper introduces a method to digitally design a virtual model of a tooth preparation of the mandibular first molar, by using the commercial three-dimensional (3D) computer-aided design software packages Geomagic and Imageware, and using the model as an input to automatic tooth preparing system. METHODS The procedure included acquisition of 3D data from dentate casts and digita...

the preparation of polymer membrane selective to iron(ii) ion and its application to ion-selectiveelectrode is reported here. pvc membrane contains iron–selective n-phenylaza-15-crown-5 asionophore. the membrane electrode is highly selective to iron(ii) ion and exhibit good linearresponse over a wide concentration range of 1.0 × 10-2 to 1.0 × 10-6 m with nernstian slope of29.2 ± 0.6 mv per deca...

Macrocyclic compounds (crown ethers), specifically 18-crown-6 (18-C-6), benzo-15-crown-5 (B-15-C-5), di-benzo-18-crown-6 (DB-18-C-6) and di-cyclohexano-18-crown-6 (DC-18C-6), are used as extractants as well as synergists with amine-group extractants. Platinum and rhodium belong to platinum-group metals (PGMs) and have very similar ionic radii and similar properties. The separation of PGMs is mo...