Search

Introduction: This study examines the effects of the new Medicare Benefits Schedule (MBS) operating from 1st November 2014 on the number of Medicare rebated panoramic radiography (PR) and cone beam computed tomography (CBCT) scans., Methods: Data for rebated PR and CBCT scans were extracted from Medicare Australia Statistics online for four 12-month periods: November 2011-October 2012, November 2012-October 2013, November 2013-October 2014 and December 2014-November 2015., Results: There was a reduction in the number of CBCT scans rebated across Australia under the new MBS. Nationally, December 2014-November 2015 showed a 65.3% reduction in the number of CBCT scans when compared to the peak in the previous 12 months under the old MBS. The number of rebated PR scans remained constant., Conclusion: The new MBS implemented on 1st November 2014 resulted in a reduction in the number of rebated CBCT scans, but had no effect on rebated PR scans. Overall, there has been considerable cost savings for Medicare due to the change in MBS. Additionally, the reduction in the number of rebated CBCT scans has resulted in a substantial reduction in the ionising radiation load to the Australian community as a whole, but especially the younger age groups., (© 2017 The Royal Australian and New Zealand College of Radiologists.)

Objective: The objective of this study was to examine distortion on panoramic radiographs by assessing the accuracy of angular measurements in the mandibular third molar region on panoramic radiographs using computed tomography (CT)., Methods: Images from patients referred to a radiology practice for low-dose CT scans of their lower third molars were used in this study. The angle between the long axes of the second and third molars was assessed on panoramic radiographs and the corresponding CT images. Apparent tilting of the tooth across the arch on the panoramic image and the bucco-lingual inclination on CT were also recorded and compared., Results: Eighty-eight patients had 163 mandibular third molars. The mean difference between the panoramic measurements and the CT measurements was -1.44 degrees, indicating that on the panoramic radiograph the third molar appeared less mesially inclined on average. This pattern was present in most cases, but in 64 cases the third molar appeared more mesially inclined on the panoramic radiograph. It was not possible to predict the direction of the discrepancy based on the radiographic findings. The discrepancy between the 2 measurements was greater if the third molar appeared tilted across the arch on the panoramic image, and tilted teeth showed a higher bucco-lingual inclination on reformatted CT images., Conclusions: Distortions inherent in panoramic imaging because of projection geometry produce discrepancies in the angular measurements in the mandibular third molar regions on panoramic radiographs. Interpretation of third molar angulation from panoramic radiographs is often unreliable and may not accurately reflect the true orientation of the tooth. Apparent tilting of the tooth across the arch on the panoramic radiograph exacerbates the problem and appears to correlate with the bucco-lingual inclination of the third molar as visualized on reformatted CT images., (Copyright © 2011 Mosby, Inc. All rights reserved.)

Chronic recurrent multifocal osteomyelitis (CRMO) is an aseptic inflammatory disorder of unknown cause occurring in children and adolescents. It is characterized by multifocal bone lesions with pain and swelling recurring over months to years. Lesions usually involve the metaphyses of the long bones and involvement of the jaw is rare. The clinical presentation, radiographic appearance and histology of a case of CRMO involving the mandible in an 8-year-old girl are documented. The radiographic appearance of another three cases is also described.

Fibrous dysplasia is a relatively common disorder of bone. It may affect the bones of the face and skull and, in so doing, produce a wide variety of clinical presentations. Plain film assessment of craniofacial fibrous dysplasia may be difficult because of varying appearances and complex, overlapping structures. The MRI appearances of fibrous dysplasia are often non-specific and may be confusing. Findings on CT are also variable, but more commonly lead to a specific diagnosis. This is because of the characteristic ground-glass appearance of woven bone, seen on CT in most if not all cases of craniofacial fibrous dysplasia.

Objectives: To assess narrowing of the inferior dental canal in the lower third molar regions using computed tomography (CT) and to determine the value of radiographic markers on rotational panoramic radiographs in assessing the true relationships of the inferior dental canal., Methods: Patients referred for CT assessment of impacted lower third molars were used in this study. The lower third molars were assessed using CT to determine the position and morphology of the inferior dental canal relative to the roots and the cortical plates. The radiographic markers on rotational panoramic radiographs were correlated with the CT findings when rotational panoramic radiographs were available., Results: The patients referred had 202 lower third molars. Inferior positioning of the inferior dental canal was the most common location on CT. Narrowing of the inferior dental canal was found in relation to the lower third molars in 66.8% of cases. The chance of narrowing of the inferior dental canal as shown using CT increased when at least one of the radiographic markers, superimposition, narrowing, deviation or reduction in density was present on the rotational panoramic radiograph. Deviation of the inferior dental canal on rotational panoramic radiographs was found to be the most significant predictor of narrowing of the inferior dental canal and a close relationship to the roots, as shown in CT., Conclusions: Narrowing of the inferior dental canal is a common finding when impacted lower third molars are assessed using CT. On rotational panoramic radiographs deviation of the inferior dental canal is the best predictor of narrowing of the inferior dental canal and a close relationship to the roots.

A body of published evidence suggests that a significant portion of enamel matrix protein synthesized by ameloblasts localises in the lysosomal-endosomal organelles of these enamel organ cells. Little is known regarding the lysosomal proteolytic activities during amelogenesis. The aims of this study were to detect and measure the activities of lysosomal peptidases cathepsin B (E.C. 3.4.22.1) and dipeptidyl-peptidase II (E.C. 3.4.14.2) in the enamel organ of the rat incisor and to ascertain whether rat enamel matrix proteins are degraded by these peptidases in vitro. Whole enamel organs were dissected from rat mandibular incisors. Enamel protein was also collected from the rat teeth. Analysis indicated that the rat incisor enamel organs contained specific activities of both dipeptidyl-peptidase II and cathepsin B at levels comparable with those of kidney which is rich in both these lysosomal peptidases. Gel electrophoresis and immunoblotting demonstrated that both cathepsin B and dipeptidyl-peptidase II were able to substantially degrade the rat enamel proteins in vitro. Based on these observations, we propose that lysosomal proteases have roles in amelogenesis in the intracellular degradation of amelogenins.

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.

A case of a rare odontogenic cyst arising in the lateral periodontal membrane in the mandible in a 14 year old girl is reported. This lesion appeared to be a new entity and has been named glandular odontogenic cyst (GOC) or sialo-odontogenic cyst. Histologically the lesion was lined by mucous producing cuboidal epithelium containing several areas of thickening and numerous duct-like structures. The cyst recurred with the same histology two years postoperatively.

Dipeptidyl peptidase II (DPP II), E.C. 3.4.14.2, a serine class endopeptidase, is widely used as a lysosomal marker in cytochemical studies. To date most ultrastructural studies of ameloblasts use the presence of acid phosphatase activity to identify cellular organelles to be lysosomal. Using decalcified rat mandibles, with kidney tissue as a positive control, DPP II activity, was assessed with specific substrate Lysyl-alanine-4-methoxy-2-naphthylamide in ameloblasts at an ultrastructural level. Reaction product (RP) indicative of DPP II activity was observed only within lysosome-like organelles. These RP-labelled organelles were only localized in the supra- or para-nuclear regions of the ameloblasts, which corresponds with previous studies using acid phosphatase cytochemistry. However, in contrast with these studies, RP was not detected in the distal region of the ameloblasts, viz., in the Tomes' processes of the secretory ameloblasts or near the ruffled border in the maturation ameloblasts. The transitional ameloblasts were notable for the intensity of staining of their RP-labelled organelles. We propose that DPP II may have a role in programmed cell death which is thought to occur in this transition zone. Biochemical analysis of rat incisor enamel organ homogenates, indicated tissue fixation resulted in an 82% reduction in DPP II activity, although the specific activity of DPP II was not affected.

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.

Mapping of the ghost envelope for an Orth Oralix panoramic x-ray unit (Philips Medical Systems) was carried out with a lead sphere suspended at various locations around a dry mandible. The ghost envelope is a three-dimensional zone within which an object or anatomic structure must lie to produce a ghost image on panoramic radiographs. If the three-dimensional shape of the ghost envelope for a particular panoramic unit is known, information can be gained about the clinical location of objects appearing on radiographs produced with that machine. Objects outside the envelope will not result in ghost image formation. Objects within the envelope will result in characteristic ghost images depending on their position. This article analyzes ghost image characteristics in relation to object position and discusses the limitations of the method. A series of ready reference diagrams is provided, which may aid in the localization of soft tissue calcifications and foreign objects observed on panoramic radiographs.

Female Wistar rats, 3 weeks old, were given sodium fluoride in saline solution (isotonic) by intraperitoneal injection at a dose of either 0, 10 or 20 mg per kg body weight. This treatment was given 9 times over 4.5 days. After fixation by perfusion and demineralization in neutral EDTA, hemi-mandibles were sectioned in a cryostat. Sections were stained for dipeptidyl peptidase II activity, using the specific substrate Lys-Ala-MNA and the coupler Fast Blue B for histochemical localization. Staining indicative of dipeptidyl peptidase II was found in the enamel organ of the incisor, particularly in cells of the stratum intermedium and in both secretory and maturation ameloblasts. This staining was markedly reduced in ameloblasts of rats given either 10 or 20 mg sodium fluoride per kg body weight.

This article deals with the incidence of anatomic variations in the styloid process and stylohyoid ligament as found in panoramic radiographs. Also, the accuracy was determined for measuring the length of styloid processes from panoramic radiographs, the variation in length of the styloid process with age, and the relationship of elongated styloid processes and ossified stylohyoid ligaments to symptoms of styloid-stylohyoid syndrome. Variations in styloid process and stylohyoid ligaments are not uncommon, especially segmentation of the process in young subjects. The apparent length of the styloid process was magnified approximately 1.37 times and was never diminished by panoramic radiographs. A steady increase in styloid process length was observed to age 30 years, with another slight increase starting at age 60 years. Subjects with elongated styloid processes (greater than 40 mm) had the highest incidence of discomfort on swallowing, whereas subjects with ossification of the stylohyoid ligament had the highest incidence of discomfort on turning the head from side to side.

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.

A modification of the standard bisecting-angle technique for periapical views of incisor teeth is presented. The technique involves a constant x-ray cone position, which is perpendicular to the floor for maxillary incisors and parallel to the floor for mandibular incisors. The periapical film is held between the incisor teeth as if it were an occlusal film for all anterior periapical radiographs. Tracings from lateral skull radiographs, taken of dried skulls of various ages, were used to determine the optimal angle between the periapical film and the floor to produce a dimensionally accurate periapical view of the incisors. The technique is suggested as an alternative to the standard bisecting-angle technique and the parallel technique. It is intended for anterior periapical radiographs when clinical conditions make conventional techniques difficult. For example, it can be used in very young children, patients with gagging problems, and patients with narrow lower jaws or large muscular tongues.

Various doses of sodium fluoride (NaF), salmon calcitonin (CT) and NaF combined with CT were given intravenously to rats (236 +/- 2 g). Blood plasma samples were collected at various times up to 24 hours and measured for total calcium (adjusted for variation in plasma albumin), inorganic phosphate, ionic fluoride, urea, and creatinine. Following injection of NaF alone, significant hypocalcemia and hyperphosphatemia was observed. In contrast, CT injections resulted in hypocalcemia and hypophosphatemia. NaF and CT given in combination generally resulted in the hypocalcemia being equal to or greater than that calculated from the simple addition of their individual effects. Significant increases in both plasma creatinine and plasma urea were observed following treatment with NaF alone or with CT and NaF together, whereas CT alone had negligible effect. These results suggest that NaF does not mimic the effects of CT; rather that NaF and CT interact to modify their individual effects. The influence of NaF probably occurs via an effect on kidney function.

This study assessed the effect of a single intravenous dose of sodium fluoride (20 mg/kg body wt.) on plasma ionic fluoride and on some other plasma electrolytes and metabolites in rats, rabbits, and cockerels. At any given time following sodium fluoride administration, the plasma ionic fluoride was highest in rabbits and lowest in cockerels. The rate of removal of fluoride from plasma was slower in rabbits as compared with that in the other two species. Plasma sodium, chloride, total protein, albumin, total globulins, and osmolality were not significantly altered by sodium fluoride in any of these three species. However, plasma phosphate (inorganic), urea, creatinine, and glucose were elevated, and plasma calcium was reduced in the rats and the rabbits, but none was significantly altered in the cockerels. The analyses indicated that species variability does exist in fluoride toxicity.

Calcitonin-containing cells (C cells) were identified in male Wistar white rats using an immunoperoxidase technique. They occupied a central position within the thyroid; very few were found peripherally, inferiorly, and superiorly; and none were present in the isthmus. The number of calcitonin-containing cells present per gram of body weight increased with age up to 70 days and had declined by 100 days. Determining the true total C-cell count through the entire thyroid is a very laborious procedure. However, a simple estimate of this total count can be made; the total number of C cells in every tenth section (6 microns) of thyroid was found to be highly correlated with the weight of the animal expressed as an allometric function. A better estimate can be derived from counts of just three sections: the tenth, twentieth, and thirtieth after the section of greatest cross sectional area.

Between 1978 and 1983, at least 20 children with fluoride poisoning were admitted to two major children's hospitals in Brisbane. Data on telephone calls received by Poisons Information Centres in Australia about fluoride toxicity show that Brisbane, the water supply of which is not fluoridated, received approximately twice as many calls per head of population as were received in Sydney and Melbourne. Concern is also expressed at the standard of packaging of fluoride tablets currently marketed in Australia. A treatment plan for cases of acute fluoride poisoning after oral ingestion is presented.

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.