Existing demographic and epidemiologic data are used to project the number of hours of operative dentistry treatment needed by all age groups in the year 2000. The findings suggest that calls to reduce the operative dentistry curriculum because of a decline in the need for single tooth restorative services may be premature, despite the recent caries decline in children and adolescents. The need for operative dentistry treatment is projected to increase until the 21st century, and the nature of this need has implications for the content of operative dentistry curricula.

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a splitting that increases with decreasing barrier width. For barrier widths below 5 nm it exceeds the thermal energy at room temperature. For a given bairier width, we find only small variations of the tunneling induced splitting demonstrating agood homogeneitywithin a molecule ensemble.The entanglement may be controlled by application of electromagnetic field. For example, using an electric field along the molecule axis we can break the entanglement. Tunneling of carriers is prevented then and emission from intra-dot and inter-dot excitons in which electron and hole are located on the same and on opposite dots, respectively, is observed. The voltage required for the entanglement breaking increases with de^ creasing barrier width reflecting the increasing 'robustness'of the entanglement for narrow barriers.

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