Garnet V. Packota

Role of different imaging modalities in assessment of temporomandibular joint erosions and osteophytes: a systematic review

OBJECTIVES To evaluate the ability of different diagnostic imaging techniques for diagnosing the presence of erosions and osteophytes in the temporomandibular joint (TMJ). METHODS A systematic search of PubMed, Medline, all Evidence Based Medicine (EBM) reviews, Embase, Web of Sciences and Lilacs identified nine articles that met the selection criteria: some type of TMJ diagnostic imaging, data from autopsy or dry skull TMJs as gold standard, absence of diagnosed systemic arthritis and evaluation of the presence of erosions and/or osteophytes. A hand search of the references of the selected articles was also performed. RESULTS Selected studies evaluated panoramic imaging (unenhanced and colour-enhanced digital subtraction panoramic imaging), axially corrected sagittal tomography, axially corrected frontal tomography, sagittal MRI, CT, high-resolution ultrasound and cone beam CT (CBCT). CONCLUSIONS Axially corrected sagittal tomography is currently the imaging modality of choice for diagnosing erosions and osteophytes in the TMJ. CT does not seem to add any significant information to what is obtained from axially corrected sagittal tomography. CBCT might prove to be a cost- and radiation dose-effective alternative to axially corrected sagittal tomography. Combining different radiographic techniques is likely to be more accurate in diagnosing erosions and osteophytes in the TMJ than using a single imaging modality. Diagnostic studies that simultaneously evaluate all of the available TMJ imaging technologies are needed.

Effect of object location on the density measurement and Hounsfield conversion in a NewTom 3G cone beam computed tomography unit

OBJECTIVES The purpose of this study was to determine the effect of an objects location in a cone beam CT imaging chamber (CBCT-NewTom 3G) on its apparent density and to develop a linear conversion coefficient for Hounsfield units (HU) to material density (g cm(-3)) for the NewTom 3G Scanner. METHODS Three cylindrical models of materials with different densities were constructed and scanned at five different locations in a NewTom 3G Volume Scanner. The average HU value for each model at each location was obtained using two different types of software. Next, five cylinders of different known densities were scanned at the exact centre of a NewTom 3G Scanner. The collected data were analysed using the same two types of software to determine a standard linear relationship between density and HU for each type of software. RESULTS There is no statistical significance of location of an object within the CBCT scanner on determination of its density. A linear relationship between the density of an object and the HU of a scan was rho = 0.001(HU)+1.19 with an R2 value of 0.893 (where density, rho, is measured in g cm(-3)). This equation is to be used on a range between 1.42 g cm(-3) and 0.4456 g cm(-3). CONCLUSIONS A linear relationship can be used to determine the density of materials (in the density range of bone) from the HU values of a CBCT scan. This relationship is not affected by the objects location within the scanner itself.

Large asymptomatic antrolith of the maxillary sinus. Report of a case.

A case of an unusually large antrolith of the maxillary sinus is presented. Because of the size of the mass, benign neoplasms were considered in the differential diagnosis. Surgery was the treatment of choice, and recurrence of the lesion is not expected.

Osteomyelitis of the mandible in a patient with dysosteosclerosis : report of a case

Dysosteosclerosis is a rare bone dysplasia that has radiographic, histopathologic, and clinical similarities to osteopetrosis. This article reviews the dental findings reported in patients with dysosteosclerosis and presents the first reported case of osteomyelitis of the mandible in a patient with this disease. This is also the first report that demonstrates ankylosis of impacted teeth in dysosteosclerosis.

Third-molar mineralization as a function of available retromolar space

Abstract Objective: To test in the maxilla and mandible for an association between stage of third-molar (M3) mineralization and space in the jaws for M3 eruption. Mineralization is hypothesized to be delayed not only for impacted M3s but also for M3s with eruption space less than their mesiodistal crown diameter. Material and methods: Retrospective cone beam computed tomography (CBCT) scans of 37 females and 32 males aged 17–24 years, for a total sample of 197 upper and lower M3s, were used to assess the status of M3 eruption and measure the M3 crown diameter (CD) relative to the length of the retromolar space (RS). Stage of M3 mineralization was then compared between impacted and erupting M3s as well as between two conditions of relative eruption space (RS/CD ≥ 1 versus RS/CD < 1) using Mann–Whitney U tests. Results: Impacted M3s were at significantly earlier (delayed) stages of mineralization compared to erupting M3s. Mineralization was also delayed for M3s with eruption space less than their mesiodistal crown diameter (e.g. RS/CD < 1). A moderate positive correlation between stage of M3 mineralization and space was seen in both jaws, and was stronger in the mandible. Conclusion: Our study shows for the first time that stage of M3 mineralization is associated not only with impaction but also with amount of retromolar space, and that these associations are consistent in upper and lower jaws. Present findings underscore that M3 mineralization stage may be a clinically useful predictor of M3 impaction that thus merits further investigation.

Synchrotron-radiation-based X-ray micro-computed tomography reveals dental bur debris under dental composite restorations

Dental burs are used extensively in dentistry to mechanically prepare tooth structures for restorations (fillings), yet little has been reported on the bur debris left behind in the teeth, and whether it poses potential health risks to patients. Here it is aimed to image dental bur debris under dental fillings, and allude to the potential health hazards that can be caused by this debris when left in direct contact with the biological surroundings, specifically when the debris is made of a non-biocompatible material. Non-destructive micro-computed tomography using the BioMedical Imaging & Therapy facility 05ID-2 beamline at the Canadian Light Source was pursued at 50 keV and at a pixel size of 4 µm to image dental bur fragments under a composite resin dental filling. The burs cutting edges that produced the fragment were also chemically analyzed. The technique revealed dental bur fragments of different sizes in different locations on the floor of the prepared surface of the teeth and under the filling, which places them in direct contact with the dentinal tubules and the dentinal fluid circulating within them. Dispersive X-ray spectroscopy elemental analysis of the dental bur edges revealed that the fragments are made of tungsten carbide-cobalt, which is bio-incompatible.

Canadian Residents' Corner / Coin canadien des résidents en radiologieAnswer to Case of the Month #153: Leontiasis Ossea

Figure 1. (A) Waters/occipitomental view. Enlargement of the left greater wing of the sphenoid, zygomatic arch, and facial asymmetry (white arrows). Diminutive maxillary sinus (arrowheads). Mandibular findings are seen faintly (black arrows). (B) Pantomograph. Expansile lytic lesion centered in the left mandibular angle without associated periosteal reaction or cortical breakthrough (black arrows). Left sphenoid expansion (arrowheads) is also seen. There is superior displacement of the inferior alveolar canal in the left mandible (grey arrows).

Answer to Case of the Month #153: Leontiasis Ossea

Figure 1. (A) Waters/occipitomental view. Enlargement of the left greater wing of the sphenoid, zygomatic arch, and facial asymmetry (white arrows). Diminutive maxillary sinus (arrowheads). Mandibular findings are seen faintly (black arrows). (B) Pantomograph. Expansile lytic lesion centered in the left mandibular angle without associated periosteal reaction or cortical breakthrough (black arrows). Left sphenoid expansion (arrowheads) is also seen. There is superior displacement of the inferior alveolar canal in the left mandible (grey arrows).