A day at the European Respiratory Society Congress: passive smoking influences both outdoor and indoor air quality.
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Air Pollution↗
Biomedical subjects
A Ruprecht
Publications and source records attributed to A Ruprecht.
Spontaneous regression of a large radiolucent lesion in the mandible.
This report presents a case of a large radiolucent lesion in the left posterior area of the mandible, causing displacement and resorption in the roots of a molar and enlargement of the body and ramus. Three years later, the lesion had undergone spontaneous regression without treatment. The radiological features and differential interpretation, as well as a discussion of the possible mechanism for the spontaneous regression are presented.
Adult↗
The three-dimensional microstructure of the trabecular bone in the mandible.
This study investigated the three dimensional (3D) trabecular microstructure of the alveolar and basal bone in the mandible using micro-CT and compared the morphometric values of the different sites. Ten specimens were prepared and scanned using a micro-CT system. Both the alveolar and basal trabecular bone of the premolar region in the mandible were measured for the structural analysis. Cross-sectional 1024x1024 pixel images were created. From the two-dimensional (2D) images produced, 3D structural images were reconstructed. After scanning the specimen, the volumes of interest (VOI) of the alveolar and basal bone regions were selected from the 3D reconstruction images, and the structural parameters such as bone volume fraction, bone surface density, trabecular thickness, trabecular separation, trabecular number and structural model index were analyzed. The trabecular structure showed a marked variation within the sites of the specimen, especially in the basal trabecular bone inferior to the mandibular canal. In both the alveolar and basal bone regions, a mixture of both plate-like and rod-like structures was observed. The alveolar region showed a more compact, plate-type trabecular structure than the basal regions. In parametric comparison with the basal bone, the alveolar bone generally had a higher bone volume fraction, bone trabecular thickness and trabecular number, and lower bone surface density, trabecular separation and structural model index. The alveolar bone consisted of a compact bone structure with a large amount of thick plate-type trabecular bone, which was effectively resistant to the masticatory forces. As the measurements were made closer to the basal bone, a loose structure was observed with lower bone volume and fewer, thin, rod-like trabeculae.
Adult↗
Particulate matter from tobacco versus diesel car exhaust: an educational perspective.
BACKGROUND: Air pollution is a common alibi used by adolescents taking up smoking and by smokers uncertain about quitting. However, environmental tobacco smoke (ETS) causes fine particulate matter (PM) indoor pollution exceeding outdoor limits, while new engines and fuels have reduced particulate emissions by cars. Data comparing PM emission from ETS and a recently released diesel car are presented. METHODS: A 60 m3 garage was chosen to assess PM emission from three smouldering cigarettes (lit sequentially for 30 minutes) and from a TDCi 2000cc, idling for 30 minutes. RESULTS: Particulate was measured with a portable analyser with readings every two minutes. Background PM10, PM2.5, and PM1 levels (mean (SD)) were 15 (1), 13 (0.7), and 7 (0.6) microg/m3 in the car experiment and 36 (2), 28 (1), and 14 (0.8) microg/m3 in the ETS experiment, respectively. Mean (SD) PM recorded in the first hour after starting the engine were 44 (9), 31 (5), and 13 (1) microg/m3, while mean PM in the first hour after lighting cigarettes were 343 (192), 319 (178), and 168 (92) microg/m3 for PM(10), PM2.5, and PM1, respectively (p < 0.001, background corrected). CONCLUSIONS: ETS is a major source of PM pollution, contributing to indoor PM concentrations up to 10-fold those emitted from an idling ecodiesel engine. Besides its educational usefulness, this knowledge should also be considered from an ecological perspective.
Air Pollutants↗
Transfer of particulate matter pollution from smoking to non-smoking coaches: the explanation for the smoking ban on Italian trains.
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Air Pollutants↗
3D volume rendering using multislice CT for dental implants.
OBJECTIVES: To determine the precision and accuracy of three-dimensional (3D) volume rendering spiral multislice computed tomography (CT)-based linear measurements of the mental foramen for dental implants, in vitro, and their precision, in vivo. METHODS: Five cadaver heads were imaged by multislice spiral CT (Toshiba Aquilion) with 0.5 mm thick axial slices (0.5 mm/0.5 s of table feed) at 0.5 mm interval reconstructions. The image data sets were transferred to a networked computer workstation. Using computer graphics the data were analysed with a 3D volume rendering technique using Vitrea software. Two oral and maxillofacial radiologists, independently, made electronic linear measurements from the superior border of the mental foramen to the crest of the alveolar process. The soft tissues were removed and physical measurements made using a 3 Space (Polhemus, Colchester, VT, USA) electromagnetic digitizer with a personal computer running Windows 98. The same linear measurements of 15 patients using the same imaging methodology were performed and the precision was analysed. RESULTS: The findings showed no statistically significant inter- or intra-observer differences in vitro and in vivo, or between imaging and physical measurements in vitro (P>0.05). CONCLUSIONS: 3D multislice spiral CT imaging allows highly accurate measurements for dental implant placement in proximity to the mental foramen. Computer graphics software, using volume rendering is suitable for implant planning.
Aged↗
A new device for measuring density of jaw bones.
OBJECTIVES: The purpose of this project was to develop a lightweight, simple device to evaluate alveolar process bone density using normal intraoral and extraoral imaging procedures. METHODS: A simple lightweight device was constructed using barium sulfate as the major radiopaque component. The 5 x 32 x 12 mm(3) resin block has eight segments with known densities ranging from 1.304 (g/cm(3)) to 1.982 (g/cm(3)). The device was integrated into an XCP unit for standard intraoral radiographs and placed between the jaws for computer aided tomographic imaging. The relationship between the device segment densities and the optical densities of the exposed film was plotted. RESULTS: A linear inverse relationship was found between the device segment densities and optical densities when segment densities were between 1.304 (g/cm(3)) to 1.882 (g/cm(3)). However, the relationship was non-linear for segment densities above 1.882 (g/cm(3)). CONCLUSIONS: Normal human bone density is 1.85 (g/cm(3)), and this densitometer is useful for determination of material densities from 1.304 (g/cm(3)) to 1.882 (g/cm(3)). The device may be useful for precise bone density assessment.
Absorptiometry, Photon↗
Evaluation of an ossifying fibroma using three-dimensional computed tomography.
We describe the appearance of a mandibular ossifying fibroma in spiral computed tomography-based multiplanar (MPR) and three-dimensional (3D) reconstruction using computer graphics. The usefulness of the interactive reconstructed images, especially using a vascular protocol, for qualitative and quantitative analyses is demonstrated. This technique is an important adjunct to evaluation with conventional axial CT.
Adolescent↗
Parameters of radiologic care: An official report of the American Academy of Oral and Maxillofacial Radiology.
The American Academy of Oral and Maxillofacial Radiology developed these Parameters of Care to provide national guidelines for the use of radiographs prescribed for the diagnosis of disease, treatment planning, and follow-up care of patients with abnormalities of the oral and maxillofacial region. The Parameters cover radiographic techniques, imaging of the temporomandibular joint, imaging of diseases of the jaws, and imaging of dental implant sites.
Dental Caries↗
Accuracy and precision of spiral CT in the assessment of neoplastic lesions associated with the mandible.
RATIONALE AND OBJECTIVES: The purpose of this study was to determine the accuracy (validity) and precision (reliability) of spiral computed tomographic (CT) images by using film- and computer graphics-based measurements of simulated neoplastic lesions associated with the mandible. MATERIALS AND METHODS: Four cadaver heads, each with two simulated tumors containing contrast medium positioned medial to the mandibles, were examined by using a subsecond spiral CT scanner. Data were transferred to film and to a computer workstation. With computer graphics, data were analyzed by using multiplanar reconstructed images. Linear measurements of the length, width, and depth of simulated tumors were made by two observers, twice each, on the film scans by using manual calipers and on the multiplanar reconstructed images by using computerized measurements. The soft tissues were then removed from the cadavers and the same measurements made by using the same calipers. RESULTS: No statistically significant differences between computer graphics- or film-based measurements and physical measurements (P > .05) or between inter- and intraobserver measurements (P > .05) were found. CONCLUSION: The authors found high reproducibility of measurements for all dimensions. Spiral CT allows accurate computer graphics- and film-based measurements of neoplastic lesions associated with the mandible.
Aged↗
Radiological findings in an unusual osteosarcoma in the maxilla.
An unusual case of osteosarcoma of the maxilla, which was initially diagnosed as fibrous dysplasia on the basis of the clinical CT and histopathological findings, is presented. However, panoramic and periapical radiography suggested a malignant neoplasm. After surgery, the tumor was diagnosed histopathologically as a low-grade osteosarcoma. We conclude that panoramic and periapical radiographs are important adjuncts and should be included in any investigation of the jaws where CT scanning is unable to differentiate between osteosarcoma and fibrous dysplasia.
Adult↗
The prevalence of radiographically evident mandibular tori in the University of Iowa dental patients.
OBJECTIVES: To evaluate the radiographic prevalence of mandibular tori and to determine the attributes which make tori radiographically evident. METHODS: The prevalence of mandibular tori was determined from 1600 radiographic surveys of patients attending the College of Dentistry, University of Iowa, 200 for each decade of life from the first to the eighth. Dry skulls were evaluated at the National Museum of Natural History. Mandibular tori were measured, classified and radiographed to correlate the radiographic findings with the physical characteristics. RESULTS: Overall, 16.9% of the patient population had radiographically detectable mandibular tori with some cohorts within the population as high as 33%. Lobulated tori extending 4 mm or more mediolaterally were radiographically detectable. CONCLUSIONS: This study revealed one of the higher prevalence rates of mandibular tori in the literature for a population within the United States. Radiographic threshold analysis suggests that this group of Iowans has a high percentage of medium to large discretely lobulated tori.
Adolescent↗
The validation of 3D spiral CT-based measurements of simulated maxillofacial neoplasms.
OBJECTIVE: The purpose of this study was to determine the precision and accuracy of 3-dimensional spiral computed tomography-based linear measurements of neoplasms associated with the mandible. STUDY DESIGN: Four cadaver heads, each with 2 simulated tumors made of clay, containing contrast medium, and positioned medial to the mandible, were examined by means of a subsecond spiral computed tomography unit. The computed tomography data were transferred to a computer workstation and analyzed through use of 3-dimensional reconstructed images. Linear measurements of the length, width, and depth of the simulated tumors were made by 2 observers, twice each. The soft tissues were then removed and the same measurements made by means of calipers. RESULTS: There were no statistically significant differences between the 3-dimensional computed tomography and physical measurements (P >.05). The mean difference was found to be less than 0.4 mm. CONCLUSIONS: Spiral computed tomography imaging allows for precise and accurate 3-dimensional computed tomography-based measurements for neoplastic lesions in the mandible.
Aged↗
MR imaging of the temporomandibular joint: a validation experiment in vitro.
RATIONALE AND OBJECTIVES: The authors compared magnetic resonance (MR) image quality obtained from 3- and 1-mm-thick sections in the depiction of the temporomandibular joint (TMJ) and its adjacent structures. MATERIALS AND METHODS: Eight TMJ specimens from four adult cadaver heads were depicted with MR imaging. Both 3- and 1-mm-thick sections were generated. One oral and maxillofacial radiologist, who was blinded to section thickness, evaluated the anatomic details of the images. Subsequently, the joints were surgically explored by two oral and maxillofacial surgeons, and the physical findings were recorded. RESULTS: Some statistically significant differences were found between the physical findings and the 3-mm-thick section images, while no significant differences were found with the 1-mm-thick sections. CONCLUSION: The TMJ and its adjacent structures were better depicted by thinner MR images.
Aged↗
Radiologic interpretation of bone striae: an experimental study in vitro.
OBJECTIVE: The purpose of this study was to determine whether the mandibular alveolar striae patterns seen in radiographs represent trabecular bone. STUDY DESIGN: Segments of human cadaver mandible were obtained. Two identical radiographs were made of each segment initially, after removal of trabecular bone, after slight smoothing of the endosteal surface, and after aggressive smoothing of the endosteal surface. The radiographs were projected in random pairs for each sample. Six dentists judged whether a difference in the amount of trabecular bone could be detected. RESULTS: Chi-square test analysis revealed no significant difference in the amount of trabecular bone judged initially and after removal of trabecular bone. A significant difference appeared to exist on radiographs made initially and after slight smoothing. A significant difference was judged to exist on radiographs made after slight removal of the endosteal surface and after aggressive removal of the endosteal surface. CONCLUSIONS: Mandibular radiographic striae patterns, interpreted as arising from trabecular bone, actually result from bone patterns on the endosteal surface.
Aged↗
Radiology--a dental specialty awaiting its just recognition.
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Humans↗
2-D and 3-D reconstructions of spiral computed tomography in localization of the inferior alveolar canal for dental implants.
OBJECTIVE: The purpose of this study was to compare and validate the accuracy of measurements on 2-dimensional and 3-dimensional reconstructions from spiral computed tomography in localization of the inferior alveolar canal. STUDY DESIGN: Four edentulous human cadaver heads with intact mandibles were imaged in a spiral computed tomography scanner. The data were transferred to a networked computer workstation to generate 2-dimensional orthoradially reformatted and 3-dimensional volumetric images. Linear measurements of the images were made from the superior border of the inferior alveolar canal to the alveolar crest. The specimens were then dissected at corresponding locations, and physical measurements were made. RESULTS: There were no statistically significant differences between the 2-dimensional computed tomography measurements and the physical measurements or between the 3-dimensional computed tomography measurements and the physical measurements. However, we did find a statistically significant difference between the 2-dimensional and 3-dimensional computed tomography measurements. CONCLUSIONS: 2-dimensional and 3-dimensional computed tomography images allow accurate measurements for localization of the inferior alveolar canal.
Adult↗
Accurate linear measurements in the anterior maxilla using orthoradially reformatted spiral computed tomography.
OBJECTIVES: To validate measurement accuracy in proximity to the incisive canal from two-dimensional (2D) reformatted spiral computed tomography (CT). MATERIALS AND METHODS: Eight cadaver heads were examined with spiral CT with 1 mm thick axial slices and 1 mm.s-1 table feed. The data was transferred to a networked computer workstation to generate 2D orthoradially reformatted images. The length of the incisive canal and width of the alveolar crest were measured independently by two oral and maxillofacial radiologists. The soft tissues in the region of the incisive foramen were removed and physical measurements made using an electromagnetic digitizer. RESULTS: There was no statistically significant difference between measurements on orthoradial 2DCT images and physical measurements (P > 0.05). CONCLUSIONS: Accurate measurements for dental implant placement in proximity to the incisive canal can be made from reformatted spiral CT images.
Aged↗