Allan G Farman

A new case of primary oral Kaposi's sarcoma associated with immunosuppressive therapy is presented. The literature related to oral Kaposi's sarcoma is reviewed, and the pathogenesis of this condition is briefly discussed. There is a possiblity that early lesions of Kaposi's sarcoma may be misadiagnosed clinically and histopathologically as simple pyogenic granulomas.

The Flash Dent digital intraoral radiographic system is yet to be described in the scientific literature. A Windows operating environment, a lens based optical scintillator charge-coupled device (CCD) and 'IMG' image format are the major features which distinguish this from other available systems. In this paper we describe the component of the Flash Dent system, investigate the validity of the X-ray generator specifications, determine comparative image doses and assess the performance of the intraoral sensor. Although we found Flash Dent software facilitates image processing, X-ray generator operation, sensor performance and dimensional measurements, inconsistencies between sensors and the use of a non-standard image format require further consideration for improvements on the part of the manufacturer.

Computed dental radiography is a filmless system of dental x-ray imaging. It features multiple sensors with receptive areas and image quality that approach the size and resolution of film. The system is able to match the utility of film on levels such as multiple-sized images and printing output. It approaches film in quality of image and diagnostic capacity. In features such as speed of image acquisition, reduction in radiation dose, retrieval of data, and organization and storage of images, the computed dental radiography system surpasses traditional x-ray film.

Dimensional and angular measurements from radiographs can be used in clinical dentistry to determine the inclination of impacted teeth, the relative position of roots and restorative abutments, and for implant site assessment. This study was carried out to assess the in-vitro accuracy of such measurements obtained from three rotational panoramic systems and two standardized lateral oblique projections (45 degrees and 60 degrees) using two cephalometric systems. Acrylic test models with wires positioned to represent the position and angulations of the teeth were used. Ten images were taken with Oralix Pan DC/1, Panelipse and Orthophos panoramic machines. Fourteen lateral oblique radiographs were also taken using two cephalometric units: an Orthophos and a Quint Sectograph. The models were repositioned between each exposure. Horizontal, vertical and angular dimensions of every tooth position on each radiograph were measured by three evaluators and compared using ANOVA at an a priori significance level of alpha = 0.05. Assessment of vertical dimensions was consistently more accurate on lateral oblique projections than on the panoramic radiographs. In general, the most accurate horizontal measurements could also be made with the lateral oblique projections. No differences in angular measurement accuracy were found between any of the projections. The use of statistical means and standard deviations can be misleading in ranking accuracy where a consistent conversion factor can be applied. While panoramic radiography is convenient for dimensional and angular assessments, lateral oblique radiographs taken with a standard cephalometric apparatus are an alternative when greater clinical accuracy is needed.

A series of 7748 leiomyomas of the whole body is presented. Ninety-five per cent of lesions occurrred in the female genital tract. Sixty-one of the remaining 371 were rejected because of inadequate histology or uncertainty as to exact site of origin. The 310 cases thus selected were analysed for histology, sex, race, site and age distributions. Comparisons are made between 230 skin lesions, 42 gastric lesions and 5 oral lesions. A further 43 cases of oral lesions were found in an extensive review of the world literature.

Eight new cases of the calcifying odontogenic cyst have been reported. In addition, a review of the literature produced an additional sixty-five cases. This lesion can occur in any age group, but it shows a peak incidence in the second decade. It is evenly distributed between the maxilla and the manidible and occurs with equal frequency in males and females. There does not appear to be any race predilection. The calcifying odontogenic cyst may occur in association with other pathologic entities. It is postulated that it does not in every case represent a separate pathologic entity but that it may represent a secondary phenomenon which occurs within preexisting lesions.

The purpose of this study is to compare Tuned-Aperture Computed Tomography (TACT) image sets made with linear vertical, linear horizontal, conical, and x-shaped x-ray projection arrays with regard to observer accuracy in (1) measuring the distance from the apex of a tooth root to the middle of the inferior alveolar canal (IAC), (2) measuring the shortest distance from the surface of a tooth root to the surface of the IAC, and (3) determining whether the root is buccal or lingual to the IAC. The same relationships were also examined by means of pairs of images and the buccal object rule. Two artificial mandible sections with simulated IACs were fabricated. The same human mandibular premolar root was used in both models to prevent development of learning cues to differentiate between models. The models were imaged from both sides, resulting in 4 orientations. An optical bench was designed to precisely orient different beam projection arrays for production of TACT image sets and pairs of images for use with the buccal object rule. Twelve dentists participated as observers to independently assess the relationships between the tooth root and the IAC with regard to the 4 orientations. For measuring the distance from the tooth apex to the middle of the IAC, TACT image sets made from conical and x-shaped arrays proved significantly more accurate than TACT image sets made from linear vertical or linear horizontal projections or pairs of digital images used with the buccal object rule (P <.05). For measuring the shortest distance between the tooth surface and the IAC surface, TACT image sets made from linear vertical, conical, and x-shaped projection arrays were significantly more accurate than measurements made through use of the buccal object rule or TACT image sets made through use of a linear horizontal projection array (P <.05). The following percentages of mistakes were made in determining whether the tooth root was buccal or lingual to the IAC: buccal object rule (58%), linear horizontal array (31%), linear vertical array (2%), conical array (0%), and x-shaped array (0%). For TACT, images acquired with conical and x-shaped beam projection arrays are preferred to those acquired with linear arrays for assessing the relationship between tooth roots and the IAC. TACT was found to be significantly more accurate than standard application of the buccal object rule for the relationships investigated.

An in vitro investigation was carried out to compare CCD-based intraoral radiographic systems with E-speed film for the detection of proximal enamel defects beneath orthodontic bands, with and without added niobium filtration to attenuate the x-ray beam. Twenty caries-free extracted teeth were randomly divided into five groups. Fifteen of 30 contacting proximal surfaces remained lesion free; the other 15 received a small, medium large mechanically induced enamel defect. Images were made with and without the addition of 30 microns niobium filtration, and with and without orthodontic bands. Six dentists were viewers. Receiver operating characteristic (ROC) curves were developed for each modality under each test situation. The area under the curve (Az) was used as an index of diagnostic accuracy, and the critical ratio was used for statistical comparisons. In the absence of orthodontic bands, the Az values for E-speed film and for nonenhanced RVG-S were greater than for all other modalities tested, indicating that they have the greatest diagnostic accuracy. With orthodontic bands, the RVG-S with steep gradient enhancement (X-function) had a higher Az value than all other modalities. Addition of niobium had no significant effect on defect detection. CCD-based devices hold no diagnostic advantage over conventional film for detecting changes in the density of enamel not covered by orthodontic bands. Contrast enhancement of digital images (RVG-S X-function) holds promise for the detection of such changes beneath orthodontic bands.

Mamoru WAKOH, DDS, Ph.D., Allan G. FARMAN, BDS, Ph.D., William C. SCARFE, BDS, MS, Michael S.'KELLY, MS* and Kinya KUROYANAGI, DDS, Ph.D.** ... Division of Radiology and Imaging Sciences, School of Dentistry, University of Louisville, Kentucky, USA *Office ...

The impact of digital imaging on dental practice depends upon the degree of planning conducted before implementation. Digital technologies have the potential to improve diagnosis; facilitate patient treatment procedures; and streamline storage, transfer and retrieval. These technologies also provide for secure backup of patients' image data, critical to re-establishing the practice should fire, flood or earthquake occur. The decision to invest in digital radiographic equipment should be a simple one for dental practitioners. Although digital x-ray sensors have long equaled analog film for diagnostic tasks, they have several advantages over film radiography, including immediate image production with solid-state devices; interactive display on a monitor with the ability to enhance image features and make direct measurements; integrated storage with access to images through practice management software systems; security of available backup and off-site archiving; perfect radiographic duplicates to accompany referrals; security mechanisms to identify original images and differentiate them from altered images; the ability to tag information such as a patient identifier, date of exposure and other relevant details; and interoperability of the Digital Imaging and Communications in Medicine file format. Most clinicians should contemplate integrating, at a minimum, intraoral digital x-ray sensors and a digital panoramic system into their practices.

In a previous paper (Farmari 1976) the prevalence ol atrophic glossitis was re-ported to be particularly high among Cape Colored diabetic outpatients, resident in the Cape Peninsula and environs. Additionally, it was found that two-thirds of the detected lesions were centrally ...

Tomograms of the temporomandibular joint were digitized in three different formats using a PC-based system. The image resolution for various projections was determined at different camera-film distances. Three series of images were transmitted by telephone, and transmission times were measured. The original radiographs, the digitized images, the transmitted images and the transmitted-and-printed images were presented to 10 observers, who were asked to rate image quality. No difference in image quality was found between the initial digitized and the transmitted images. However, transmitted and transmitted-and-printed images were of significantly lower quality than the original radiographs or the digitized images viewed on a computer monitor. Transmission time was reduced significantly (50%) by cropping the images before transmission. The image quality of individual radiographs was better than radiographs formatted as a series.

A survey of North American dental schools revealed that processing quality control and routine maintenance checks on x-ray generators are, in most instances, being carried out in a timely manner. Available methods for reducing patient exposure to ionizing radiation are, however, not being fully implemented. Furthermore, in some instances, dental students are still being exposed to x-rays primarily for teaching purposes.

It is also possible that your web browser is not configured or not able to display style sheets. In this case, although the visual presentation will be degraded, the site should continue to be functional. We recommend using the latest version of Microsoft or Mozilla web browser to ...

This clinical study compares the diagnostic value of interactive 3-dimensional tuned-aperture computed tomography (TACT) with conventional dentoalveolar radiographic examinations of impacted maxillary incisors. TACT was compared variously with conventional intraoral, occlusal, rotational panoramic, and lateral cephalographic examinations. Sixteen dentists independently evaluated the clarity of anatomic structures of impacted anterior maxillary teeth and surrounding tissues. Estimation of confidence in clinical assessment of the patient was made together with a determination of the diagnostic potential of the studied modalities for altering treatment plans. TACT was found to significantly improve depiction of the buccal/palatal position of the impacted tooth and its relationship with adjacent teeth (P < .0001) irrespective of the availability of lateral cephalograms. Subjective assessments for clinical decision making approximated a 10% increase in confidence ratings with TACT. The added diagnostic value with TACT varied from case to case. The interactive 3-dimensional TACT display was perceived to be more informative for assessing impacted teeth and their relation to surrounding tissues than conventional methods in some cases but not in others. TACT altered treatment-option selection in some instances.

The objective of this study was to compare the diagnostic efficacy of tuned-aperture computed tomography (TACT) and conventional film for the detection of simulated periodontal defects. Periodontal defects were created in 15 premolar-molar interproximal sites selected from 8 cadaver jaw segments. Ten observers viewed 45 image pairs (baseline and follow up) in 4 TACT modalities and film to assess the presence of defect. The TACT modalities were 1st and 2nd generation prototype systems (TACT-1 and TACT-2) with circular (C) and random (R) distribution patterns of source projection (TACT-1C, TACT-1R, TACT-2C, TACT-2R). Observer performance and related factors were analyzed by using receiver operating characteristic and analysis of variance. Mean A(z) values were 0.64 for film, 0.74 for TACT-1C, 0.82 for TACT-1R, 0.64 for TACT-2C, and 0.69 for TACT-2R. TACT-1R was significantly better than film (P < .001), TACT-2C (P < .001) and TACT-2R (P = .007). TACT-1R provided the best diagnostic performance in the detection of simulated periodontal defects among the 5 modalities compared in this study.

The objective of this study was to evaluate the perceived clinical efficacy of a charge-coupled device (CCD) detector for panoramic radiography by comparing the images produced to conventional film/screen radiographs using the same machine and patient population. For clinical evaluation, 18 criteria were selected. These included overall assessment of the area of coverage, clarity of dental structures, clarity of bony outlines, specific anatomic details such as the maxillary sinus floor, mandibular canal and mandibular condyle, and region-by-region assessment of the dentition. Observers acted independently using identical optimal viewing conditions. Film and digital radiographs were evaluated separately. A five interval Likert rating scale was used. Digital images were rated superior to the conventional film radiographs for 14 criteria. Film radiographs marginally outperformed digital images for three criteria. For one criterion (periodontal bone status) the two modalities showed no difference in terms of the means ratings. It was concluded that digital images are clinically equivalent to conventional film/screen images for panoramic dental radiography.

We sought to compare observer measurement error and subjective ratings for International Standards Organization D-, E-, and F-speed direct exposure dental x-ray films used to determine endodontic working lengths. Radiographs were exposed to achieve a standard background density of approximately 2.0. Three human maxillary posterior teeth for which No. 10 K-files had been placed at various lengths within 4 canals were studied in a cadaver section. A total of 30 radiographs were used (10 from each film type). Five licensed dentists excluding all authors viewed the radiographs independently and in random sequence. Distances from the file tips to the radiographic apices were measured and were compared with known lengths for error determination. The observing dentists also subjectively rated the images as desirable or undesirable. Statistical methods included a 3-factor ANOVA with Tukey honestly significant difference post hoc analysis to compare objective measurements and chi-square with respect to subjective ratings. No significant differences were attributable to film speed grouping or observers (P > .05); however, there was a specimen effect in that a significant difference was found in measurement accuracy among the 4 canals (P < .05). Differences in subjective ratings for the 3 film types were not statistically significant (P > .05). All 3 film types were similar in objective and subjective ratings. This being the case, the faster film is preferred to minimize the radiation dose to the patient.

To maximise the benefit from radiographs for the patient, the dentist or dental specialist should be familiar with the whole of the image produced. For cephalograms, this usually includes the cervical spine. Minor variations in the anatomy of the cervical vertebrae include ...

The purpose of this study was to describe the Orthopantomograph OP 100 Digipan modification and to determine the image-layer and dosimetric characteristics of this system. Image-layer contours for the Digipan were determined at resolution limits of 4.0, 3.0, and 1.5 line pairs (Ip) mm(-1) using a resolution grid positioned at intervals along the beam projection paths. A hexagonal test device was placed above the grid to determine the magnification factors at the selected resolution limits. For dosimetry, a 30 mm2 ionization chamber was placed at the beam entry points while imaging the molar, premolar, and anterior teeth using both the Digipan and conventional film receptors. The maximum resolution exceeded 4.0 Ip mm(-1)in the center of the image layer. Using a 1.5 Ip mm(-1) resolution limit, the focal trough width was 14 mm at 0-degree horizontal angulation, 20 mm at 37 degrees, and 36 mm at 83 degrees. At 1.5 Ip mm(-1), the horizontal magnification was -21% facial and +42% lingual to the center of the image layer in the incisor region; -25% facial and +19% lingual to the center of the image layer at a horizontal angulation of 83 degrees. At 4.0 Ip mm(-1), horizontal magnifications in the incisor region were -2.0% facially and +0.5% lingually; at 83 degrees they were -3.9% facially and +1.1% lingually. The neck entrance dose for imaging the anterior and premolar regions averaged 89.5 (+/-5.6) microGy. The cheek entrance doses for imaging the molar region averaged 220.6 (+/-8.0)microGy with the Digipan. With film the average entrance doses were 297.9 (+/-8.6) microGy (anterior and premolar regions) and 682.1 (+/-16.9) microGy (molar region). The Digipan image layer is similar, but slightly narrower than that previously reported for the Orthopantomograph OP 100 using standard film-screen combinations. The resolution at the center of the image layer exceeded 4.0 Ip mm(-1). The Digipan produced images with an entry dose savings of approximately 70% when compared with photo-timed exposures using conventional film with the Orthopantomograph OP 100.

The purpose of this study was to compare dimensions on charge-coupled device-acquired images under various enhancements with dimensions on film radiographs and in vivo dimensions with respect to the linear measurement of periradicular radiolucent lesions. The dimensions of 25 lesions imaged by means of a charge-coupled device-based digital receptor and Ektaspeed Plus radiographic film were measured and compared with dimensions as actually measured on impressions of the lesions taken during surgery. Digital images were displayed in unenhanced, equalized, and equalized/color-coded modes. The color-coding protocol was repeated to determine the method error, and each image treatment was also remeasured to determine intrarater reliability. Differences were compared through use of a Friedman 2-way analysis of variance with a follow-up Wilcoxon signed rank test (alpha = 0.01). Actual lesion dimensions were larger than dimension estimates obtained with digital images (range, 23% to 35%) and film radiographs (range, 29% to 43%). Color-coded images were significantly less accurate than equalized images and unenhanced images. Images equalized through use of the measurement algorithm of the resident software provided estimates that were more accurate than estimates made with film radiographs and a standard millimeter rule. Intrarater variability was low. The application of color coding was found to be unreliable. When applied to intraoral images, color-coded image processing of digital images had limited value in the estimation of periradicular lesional dimensions.

Various models have been used to study the accuracy of imaging systems for detection of dental caries. This study compares the ability of dentists to detect mechanically created defects versus natural dental caries cavitations on the proximal surfaces of extracted teeth with ...

To compare the in vitro reliability and accuracy of linear measurements between cephalometric landmarks on cone beam computed tomography (CBCT) 3D volumetric images with varying basis projection images to direct measurements on human skulls. Sixteen linear dimensions between 24 anatomic sites marked on 19 human skulls were directly measured. The skulls were imaged with CBCT (i-CAT, Imaging Sciences International, Hatfield, Pa) at three settings: (a) 153 projections, (b) 306 projections, and (c) 612 projections. The mean absolute error and modality mean (+/- SD) of linear measurements between landmarks on volumetric renderings were compared to the anatomic truth using repeated measures general linear model (P < or = .05). No difference in mean absolute error between the scan settings was found for almost all measurements. The average skull absolute error between marked reference points was less than the distances between unmarked reference sites. CBCT resulted in lower measurements for nine dimensions (mean difference range: 3.1 mm +/- 0.12 mm to 0.56 mm +/- 0.07 mm) and a greater measurement for one dimension (mean difference 3.3 mm +/- 0.12 mm). No differences were detected between CBCT scan sequences. CBCT measurements were consistent between scan sequences and for direct measurements between marked reference points. Reducing the number of projections for 3D reconstruction did not lead to reduced dimensional accuracy and potentially provides reduced patient radiation exposure. Because the fiducial landmarks on the skulls were not radio-opaque, the inaccuracies found in measurement could be due to the methods applied rather than to innate inaccuracies in the CBCT scan reconstructions or 3D software employed.

To report the imaging features of osteomyelitis of the mandible in various two-dimensional multiplanar and three-dimensional reformations using cone beam computed tomography (CBCT). The images were 12-bit DICOM files acquired with a 10cm field of view and voxel resolution of 0.4mm. Two-dimensional multiplanar reformatted reconstructions included coronal, "panoramic" (variable thickness), and serial cross-sections. Three-dimensional reconstructions included surface renderings. Images were presented to referring oral and maxillofacial surgeons in "real time" immediately after acquisition. The features of mandibular osteomyelitis seen on CBCT included: a peripheral sclerotic rim, cortical layering (involucrum), central loss of trabecular pattern with internal round radiolucent resorptive tracts, minimal jaw expansion, and reduction of the alveolar cortex. Sequestra were occasionally evident. The history and presentation of each case on CBCT were consistent with osteomyelitis of the mandible; however, the clinical differential diagnosis in each case had included malignancy. The definitive diagnosis was confirmed by histological examination of biopsy specimens. Two of the three cases were patients who had been treated with bisphosphonates. CBCT facilitated comprehensive and dynamic imaging of the jaws based on surgical consultation, rather than inflexible imaging protocols. CBCT images guided operative planning.