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.

Dentomaxillofacial radiology in Australia and dentist satisfaction with radiology reports.

BACKGROUND: Dentomaxillofacial Radiology (DMFR) is comprised of the smallest cohort of specialists in Australia. A survey was undertaken to assess awareness of DMFR, radiology reporting and referring protocols as well as dental practitioners' satisfaction with their radiology reporting arrangements. METHODS: An original online survey created using Checkbox† was sent to dental practitioners. The survey was promoted on Australian-based dental Facebook forums and emailed to targeted members via Australian professional dental associations. RESULTS: A total of 399 responses were received, with over 80% of respondents aware of DMFR as a specialty. Approximately 40% of practitioners were self-reporting their imaging. There was correlation between increased satisfaction with external reporting and utilization of DMFR services and decreased satisfaction with medical radiology services. More than 90% of general dentists and greater than 85% of dental specialists prefer DMFR reports to medical radiology reports. Approximately 80% of practitioners believed that their satisfaction would change positively if they had access to a DMFR report. CONCLUSION: The research indicates a high degree of self-reporting or non-reporting by dental practitioners. There is low satisfaction with external reporting performed by Medical Radiologists primarily due to a lack of dental knowledge or detail and a preference for DMF Radiology reports.

Morphology of the greater palatine grooves of the hard palate: a cone beam computed tomography study.

BACKGROUND: There is increasing frequency of dentoalveolar and palatal implants placed in the posterior maxilla for prosthodontic and orthodontic purposes. The purpose of this study is to provide information on the location and morphology of the greater palatine grooves (GPG) in the hard palate and to promote awareness of this structure. METHODS: Eighty-nine cone beam computed tomography (CBCT) scans were analysed for the presence of a groove, crest or bridging. RESULTS: This study on the morphology of the GPG in the maxillary first and second molar regions showed three distinct appearances: (1) no palatal groove; (2) one palatal groove; (3) two palatal grooves. The detection frequency of no palatal groove in the first molar region was 60%, 34% had one groove and 6% having two grooves. The detection frequency of no palatal groove in the second molar region was 72%, 26% had one groove and 2% had two grooves. The number of crests in the first and second molar regions ranged from 0 to 3. CONCLUSIONS: The present study demonstrates a great variation in morphology of the GPG of the hard palate. Knowledge of the GPG will decrease possible complications of implant surgery, particularly palatal implant surgery and to not confuse the GPG with pathology.

Comparative adoption of cone beam computed tomography and panoramic radiography machines across Australia.

BACKGROUND: The aim of the present study was to assess the current adoption of cone beam computed tomography (CBCT) and panoramic radiography (PR) machines across Australia. METHODS: Information regarding registered CBCT and PR machines was obtained from radiation regulators across Australia. The number of X-ray machines was correlated with the population size, the number of dentists, and the gross state product (GSP) per capita, to determine the best fitting regression model(s). RESULTS: In 2014, there were 232 CBCT and 1681 PR machines registered in Australia. Based on absolute counts, Queensland had the largest number of CBCT and PR machines whereas the Northern Territory had the smallest number. However, when based on accessibility in terms of the population size and the number of dentists, the Australian Capital Territory had the most CBCT machines and Western Australia had the most PR machines. The number of X-ray machines correlated strongly with both the population size and the number of dentists, but not with the GSP per capita. CONCLUSIONS: In 2014, the ratio of PR to CBCT machines was approximately 7:1. Projected increases in either the population size or the number of dentists could positively impact on the adoption of PR and CBCT machines in Australia.

Central calcifying epithelial odontogenic tumour in the posterior maxilla: a case report.

The calcifying epithelial odontogenic tumour (CEOT), or Pindborg tumour, is a rare, benign odontogenic tumour. CEOT is usually asymptomatic and an incidental radiological finding, often presenting as a mandibular radiolucency with flecks of calcific material. We report an unusual case of CEOT in the left posterior maxilla of a 46-year-old male that was associated with an unerupted tooth. The tumour in this case caused non-specific sinus symptoms and appeared radiographically similar to an odontoma or ossifying fibroma due to its dense calcific contents. Diagnosis was confirmed histologically following surgical removal of the lesion, which showed classic CEOT histomorphology. We report this case to highlight the unusual clinico-radiologic presentation and illustrate the diagnostic difficulties that can occur with radiolucent and/or radiopaque lesions in the jaws.

The growth of Medicare rebatable cone beam computed tomography and panoramic radiography in Australia.

BACKGROUND: There is a lack of objective data documenting the growth of cone beam radiology in Australia. Medicare rebates for cone beam computed tomography (CBCT) scans have been available since 1 July 2011. The aim of this study was to examine the Medicare data on the use of CBCT in order to quantify the growth of this technology over a three-year period and to assess if the growth of CBCT was impacting upon the use of dental panoramic radiology. METHODS: The Medicare dataset was accessed, and data relating to the number and distribution of CBCTs and panoramic radiographs (PRs) were extracted. The data were broken down by state and territory, as well as by age group and gender of the patient, for the financial year periods July 2011 to June 2012, July 2012 to June 2013 and July 2013 to June 2014. Items relating to PRs were also extracted for the periods 2005-2008 and 2008-2011. RESULTS: In the period July 2011 to June 2014, a total of 226 232 CBCTs and 2 881 351 PRs were rebated through Medicare. The rate of CBCT services provided per 100 000 population increased by 42.3% over the three-year period, whereas the rate of PRs remained fairly constant. From the age group 5-14 years through to 55-64 years, females received more CBCTs and PRs than males. The total number of PRs rebated through Medicare increased slightly over each previous three-year period (2005-2008 and 2008-2011). CONCLUSIONS: There has been rapid growth of the use of CBCT over a three-year period, most marked in the State of Victoria. The higher number of CBCT examinations in females across almost all age groups, but most notably in the 15-24 years age group, raises questions about clinical decision making in the selection of cone beam imaging. There was little evidence that CBCTs were being used as a substitute for PRs, except for a small but consistent drop in the number of PRs being requested for diagnosis of surgically related dental conditions.

Effects of acute doses of sodium fluoride on the morphology and the detectable calcium associated with secretory ameloblasts in rat incisors.

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.

Effects of a single intravenous dose of sodium fluoride on plasma electrolytes and metabolites in rats, rabbits, and cockerels.

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.

The glandular odontogenic jaw cyst: report of a case.

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.

Calcitonin cell population and distribution in the thyroid gland of the rat.

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.

A histochemical study of the effects of high doses of sodium fluoride on dipeptidyl peptidase II activity in the rat incisor ameloblast.

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.

Getting the most from rotational panoramic radiographs.

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.

Visualization of the maxillary sinus and styloid processes using rotational panoramic radiography.

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.

Cervicofacial emphysema following dental procedures.

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.

Soft tissue calcifications in the differential diagnosis of opacities superimposed over the mandible by dental panoramic radiography.

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 comparison of Kodak Ultraspeed and Ektaspeed plus dental X-ray films for the detection of dental caries.

BACKGROUND: Using the fastest dental X-ray film available is an easy way of reducing exposure to ionizing radiation. However, the diagnostic ability of fast films for the detection of proximal surface caries must be demonstrated before these films will become universally accepted. METHODS: Extracted premolar and molar teeth were arranged to simulate a bitewing examination and radiographed using Ultraspeed and Ektaspeed Plus dental X-ray films. Three different exposure times were used for each film type. Six general dentists were used to determine the presence and depth of the decay in the proximal surfaces of the teeth radiographed. The actual extent of the decay in the teeth was determined by sectioning the teeth and examining them under a microscope. RESULTS: There was no significant difference between the two films for the mean correct diagnosis. However, there was a significant difference between the means for the three exposure times used for Ultraspeed film. The practitioners used were not consistent in their ability to make a correct diagnosis, or for the film for which they got the highest correct diagnosis. CONCLUSIONS: Ektaspeed Plus dental X-ray film is just as reliable as Ultraspeed dental X-ray film for the detection of proximal surface decay. The effect of underexposure was significant for Ultraspeed, but not for Ektaspeed Plus. Patient exposure can be reduced significantly with no loss of diagnostic ability by changing from Ultraspeed X-ray film to Ektaspeed Plus X-ray film.

The effect of chronic fluoride administration on rat condylar cartilage.

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.

Microwave irradiation as a form of fixation for dental pulp.

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.

A comparison of Kodak Ultraspeed and Ektaspeed Plus dental X-ray films for use in endodontics.

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.

The teaching of dento-maxillo-facial radiology in Australian dental schools.

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.