Implant radiography and radiology

The practitioner placing dental implants has many options with respect to pre-implant radiographic assessment of the jaws. The advantages and disadvantages of the imaging modalities currently available for pre-implant imaging are discussed in some detail. Intra-oral and extra-oral radiographs are generally low dose but the information provided is limited as the images are not three-dimensional. Tomography is three-dimensional, but the image quality is highly variable. Computed tomography (CT) has been the gold standard for many years as the information provided is three-dimensional and generally very accurate. However, CT examinations are expensive and deliver a relatively high radiation dose to the patient. The latest imaging modality introduced is cone beam volumetric tomography (CBVT) and this technology is very promising with regard to pre-implant imaging. CBVT generally delivers a lower dose to the patient than CT and provides reasonably sharp images with three-dimensional information. A comparison between CT and CBVT is provided. Magnetic resonance imaging is showing some promise, but the examinations are not readily available, generally expensive and bone is not well imaged. Magnetic resonance imaging is excellent for demonstrating soft tissues and therefore may be of great use in identifying the inferior dental nerve and vessels. All of the above technology is of little value if the information required is not obtained and so information is also provided on imaging of some of the vital structures. Of particular interest is the inferior dental canal, incisive canals of the mandible, genial foramina and canals, maxillary sinus and the incisive canal and foramen of the maxilla

It's not the economy, stupid! External effects on the supply and demand of cinema entertainment

The paper addresses whether the state of the economy impacts the supply of and demand for cinema entertainment. A literature review on the drivers of cinema supply and demand is provided, and two competing hypotheses are extracted. Economic downturns could either lead to a sober mood and drive the interest in serious genres or drive the need for distraction leading to an increased interest in feel-good or action movies. However, characteristics of the movie industry suggest that economic key factors have only limited effects on supply and demand. A time series analysis of supply and demand in three major European markets indicate that demand is unrelated to the state of the economy. In aggregate, the demand does not instruct supply. Fluctuations in individual movie quality superpose potential effects of the economic context on the aggregated demand. Simultaneously, a focus on film as art superposes potential effects of the economic context on the supply