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Background: The advantage of using a faster film for length determination in endodontic therapy is obvious. However, for such a film to be generally accepted, it must demonstrate comparable diagnostic quality to traditionally used films., Methods: The comparative accuracy of canal length determination of Ultraspeed and Ektaspeed Plus dental X-ray films was assessed in maxillary first and second molars; for different canals, for different teeth, for different exposures, and for different examiners (five general dentists and three endodontic specialists)., Results: In general, there were no significant differences between films, among examiners, or any interaction between films and exposures. That is, an assessor's ability to estimate lengths was not significantly influenced by the film type or by exposure used. There was a wide divergence in the individual assessor's ability to estimate lengths. Specialists estimated lengths more accurately than general practitioners and estimated lengths more accurately with Ektaspeed Plus film. Length determination in distobuccal and mesiobuccal canals was more accurate than in palatal canals. Most palatal canals were underestimated in length by more than 1mm. The use of file sizes larger in number than size 15 is recommended in these canals., Conclusion: For length determination, Ektaspeed Plus dental X-ray film is as effective as Ultraspeed film. Given the acceptable quality and accuracy of Ektaspeed Plus film, there seems to be no clinical reason to subject patients to greater radiation by using a slower film during endodontic therapy.

Rotational panoramic radiographs have become an invaluable tool in modern dentistry. To use the full potential of this resource the entire radiograph must be examined in a systematic way to extract the great wealth of information available. This paper provides the framework for the development of a systematic method to examine panoramic radiographs. The essential elements are that all areas of the radiograph should be examined and that there are a number of high yield areas with regard to pathology that require special attention.

Morphometrical and histochemical techniques were used to demonstrate changes to the cartilage layer of the rat temporomandibular joint condyle following chronic exposure to fluoride. An increase in thickness of the cartilage layer was noted in rats given 100 parts per million sodium fluoride in drinking water. No significant changes were observed with either control or low dose (10 parts per million) groups. The observed thickening was attributable to an increase in number and size of cells of the lower hypertrophic zone. Accumulations of glycogen were observed in these cells, which reflects the inhibitory effect of fluoride on glycolysis. Stimulation of chondrocytes by fluoride may have delayed the normal processes of capillary invasion, resulting in thickening of the cartilage layer. No changes to staining patterns of immature or mature types of collagen were observed, nor did the staining pattern of detectable glycosaminoglycans change due to fluoride.

Not all opacities observed on panoramic dental radiographs are associated with the jaws. Two thousand six hundred and twenty-eight panoramic radiographs obtained from a single dental health clinic were evaluated for the presence of opacities associated with the mandible. Opacities were observed in 4 per cent of cases. The radiographic features of these opacities are presented. The importance of including soft tissue calcifications which may be superimposed over the mandible on panoramic views in the differential diagnosis is discussed. Information on the various soft tissue calcifications which can occur in this region is presented.

A technique is presented which improves visualization of the medio-lateral aspect of the maxillary sinus using rotational panoramic radiography. The method was also assessed for accuracy of styloid process projection. Using a specially constructed Perspex stand, dried skulls of varying ages were radiographed in various reproducible positions using a panoramic unit. The best medio-lateral view of the maxillary sinus of adult skulls was achieved by: (1) raising the height of the film approximately 20 mm in relation to the subject; (2) moving the subject 15-20 mm forward of the standard position for a panoramic view for adults (10-15 mm for children); and (3) tilting the occlusal plane downwards approximately 8-10 degrees. The styloid processes were readily seen using this maxillary sinus view. The resultant image of the process was elongated by a factor of 1.24 +/- 0.02 by this technique.

The skills necessary to successfully perform radiological procedures in general dental practice are described and should be used as criteria when developing an effective undergraduate curriculum and as determinants of the contents of continuing education programmes. The present status of undergraduate curricula. continuing education, and postgraduate programmes as well as the recognition of the specialized nature of dento-maxillo-facial radiology, are discussed and recommendations for future developments are made.

Fluoride in high concentrations is known to have an adverse effect on the formation of enamel. The effect of a single injection of two concentrations of sodium fluoride on inner enamel secretory ameloblasts was investigated morphologically by electron microscopy and functionally by assessing the location and relative amount of available calcium, using the potassium pyroantimonate method. The results showed that acute doses of fluoride interfere with the normal function of secretory ameloblasts. The increase in the population of lysosome-like structures observed after fluoride administration is suggestive of defects in the synthetic pathway. Concomitant with the effect of fluoride on secretory ameloblasts is an inhibition of enamel formation, resulting in incomplete enamel rods and leaving large remnants of Tomes' processes buried in the enamel. The distribution of the calcium pyroantimonate deposits found tends to support the concept of calcium traveling between the cells to the enamel. Acute doses of fluoride also reduce the amount of calcium available for complexing with pyroantimonate in the intercellular region.

Cervicofacial emphysema is an infrequently reported sequela to dental surgery. Most cases result from the accidental introduction of air into the soft tissues during the use of air-driven, high-speed handpieces or air/water syringes. Surgical procedures, in particular removal of lower third molars, predispose to the development of an emphysema. The clinical presentation is usually a facial or cervicofacial swelling coincident with the dental treatment. The use of air instruments, immediate onset, crepitus and often a radiographically discernible enlarged facial space are the diagnostic features. Pain is not usually a feature. The possibility of mediastinal involvement should be recognized and the patient monitored appropriately. Active treatment requirements are minimal. Reassurance of the patient, antibiotic prophylaxis and analgesics, if required, are generally sufficient. This paper reviews the above features and discusses means of prevention. Early recognition and appropriate management are emphasized.

This study investigated developments in microwave energy fixation and the general applicability of microwave fixation to studies of dental pulp. Rat mandibles with incisors were dissected out and immersed in various solutions before and after exposure to microwave energy. Histological examination showed no combination with microwave fixation to be equal in quality to control tissues fixed in formalin. Inferior but satisfactory results could be achieved by immersion of tissues in formalin after microwave irradiation, a step thought to protect the microwave fixed tissue from subsequent damage caused by decalcification. Good fixation of tissues outside the pulp was achieved using microwave energy. Further investigation is required to perfect microwave fixation of pulpal tissue.