Results 1 - 10 of 2051
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[en] The authors observed 2 cases of fibrous dysplasia on the cranial and maxillofacial bones in 31.28 aged sisters, who had come to the Infirmary of Dental College, Yonsei University. The serial roentgenograms and clinical findings had been taken and the results established as polyostotic fibrous dysplasia according to the findings in their images. To author have obtained the results as follows: 1. Bony expansion of the mandible occurred at 18 years of age and the facial asymmetry appeared due to development of the lesions. 2. The traumatic history were not noted but weak tendency of familial history noted. 3. Endocrine disturbances, hyperpigmentation on the skin and premature puberty in the infancy were not noted. 4. We have concluded these diseases as polyostotic fibrous dysplasia on the cranial and maxillofacial bones with weak familial tendency according to the findings.
[en] The aims of the present survey were to determine whether differences existed between male and female dentists in Saudi Arabia in career development, positions occupied within their employment, and to analyze the effect of different variables on their career development in some of the provinces in Saudi Arabia. A self-conducted questionnaire was distributed among male and female dentists, general practitioners as well as specialists, working at several governmental hospitals in Saudi Arabia. The questionnaires consisted of 40 questions in the format of multiple choices and yes/no answer. Data were analyzed by gender with the significant difference level set at (P < 0.05). The response rate was 40.8% of which 51.9% were females and 48.1% males with 70% of them below 45 years of age. No significant difference was found between males and females in having higher education or additional degrees. The specialty that was highly reported among females was pedodontics and in males, orthodontics. Males were more likely to hold authorized administrative positions (63%), while females held administrative positions which were internally arranged by their departments (57%). Eighty-three percent of female respondents thought that there was favouritism towards males in appointment to administrative positions, while only 5.5% of male respondents reported that there was favouritism to females in occupying the same positions. There was no significant difference between male and female dentists in Saudi Arabia with respect to job opportunities, working hours and relationships with their colleagues. In addition, there is evidence of an intensifying determination of female dentists in Saudi Arabia, to pursue their chosen career while coping with the diverse demands of being a professional, a wife and mother. (author)
[en] Radiographs are a well-accepted tool in diagnosing periodontal bone lesions and making an accurate evaluation of the treatment. However, the assessment of bone is hampered by the complicated and as it were unpredictable pattern of bone structure. Therefore, and to compensate for the bias always present in human observations, a computer aided procedure was developed to detect and describe periodontal bone lesions. This paper describes a comparison of the performance by human observers and of the computer program. Two series of artificial periodontal bone lesions served as material for the assessments. This study shows that the automated lesion detection program enables an assessment of periodontal bone lesions, which is at least comparable with the results of a group of experienced observers and probably better. It is considerably better than the results of observers individually, and decreases the time-dependent variability appearing in repeated assessments of a single observer. The computer aided detection of periodontal lesions can be considered as a useful and reliable tool in periodontal diagnosis. 9 ref.; 2 figs
[en] The purpose of this study was to evaluate the optimal distance and angle of observers by modulation transfer functions (MTFs) and receiver operating characteristics (ROCs). Digital periapical radiograms were taken from 43 patients who have dental diseases (19 patients : dental caries, 12 patients : periapical lesions, 12 patients : periodontal diseases). Segmental images (4 X 4 cm) were evaluated by 4 MTFs and ROC analysis. The optimal distance (magnification) using MTF by Mannos and Sakrison was 12.97, and those by Nill, Ngan and Rao were 8.39, 4.78, 5.84 respectively. The optimal distance obtained from 4 radiologists by ROC analysis was 32 cm (Az value : 0.89), and it was 40 cm (Az value : 0.78) from 4 non-radiologists. There were significant differences of Az values between 4 radiologists and 4 non-radiologists at 24, 32 and 40 cm (p<0.05). No significant differences of optimal distances were observed using 4 MTFs among +20, +10, 0, -10, -20 degrees (p>0.05). The optimal angle obtained from 4 radiologists by ROC analysis was +20 degrees (Az value : 0.91), and no significant differences of Az values were observed among +20, +10, 0, -10 and 20 degrees (p>0.05). The optimal angle obtained from 4 non-radiologists by ROC analysis was 0 degree(Az value : 0.81), and no significant differences of Az values were observed among +20, +10, 0, -10 and 20 degrees (p>0.05). And there was significant difference of Az value between 4 radiologists and 4 non-radiologists at +20 degree (p<0.05), but no significant differences of Az values were observed among +10, 0, -10 and -20 degrees (p>0.05).
[en] This study was undertaken to investigate the relationships film and processing solution at different processing temperature. Three kinds of periapical film were used for this study. They included EP-21 film, DF-58, and A film EAch film was processed by automatic film processor with RD-III, X-dol 90, and A processing solutions at 68 degree, 74 degree, 80 degree, 86 degree, and 92 degree F. Film density was measured with the densitometer, and base plus fog density, film relative speed, film contrast, and subject contrast were evaluated. The following results were obtained: 1. As the processing temperature was increased, base plus density was increased. Inadequate base plus fog densities were obtained with three films in combination with three processing solutions at 92 degree F. 2. Lowest base plus fog densities were obtained with A film, followed in ascending order by EP-21, and DF-58 film i n combination with A or RD-III processing solutions. The sequence of base plus fog densities was in ascending order by EP-21, A, and DF-58 film in combination with X-dol 90 processing solution. 3. The sequence of film relative speed values was in ascending order of EP-21, A, and DF-58 film in combination with A and RD-III processing solutions, respectively.
[en] The purpose of this study was to compare the qualities of the four different processing chemicals (solutions). With EP 21 films (Ektaspeed plus film, Kodak Co., USA), nine unexposed and nine exposed films of a step wedge were processed utilizing automatic film processor (XR 24, Durr Co., Germany) for 5 days. During 5 days, the total number of processed films including out-patient's intraoral films were about 400-500 for each brand. Base plus fog density, film density, contrast of processed films were measured with densitometer (model 07-443 digital densitometer, Victoreen Co., USA). These measurements were analyzed for comparison. The results were as follows,1. For the base plus fog density, there was significant difference among the four chemicals (p<0.05). The sequence of the base plus fog densities was in ascending order by Kodak, X-dol 90, Agfa and Konica. 2. For the film density, all chemicals showed useful range of photographic densities (0.25-2.5). The sequence of the film densities was in ascending order by Kodak, X-dol 90, Konica and Agfa. But there was no statistically significant difference of film density between X-dol and Kodak (p<0.05). 3. The sequence of the contrasts was in ascending order by Konica, X-dol 90, Kodak and Agfa. But there was no statistically significant difference of contrast between X-dol and Konica (p<0.05). These results indicated that the four processing chemicals had the clinically useful film density and contrast, but only Kodak processing chemical had useful base plus fog density.
[en] We have tested value of the product of kerma in air and surface (kerma area product (KAP)) on 31 intra-oral X-ray units at different locations in the Republic of Serbia, in order to optimize the dose for patients. As image receptors are used films of class D, E and F, phosphor plate systems (storage phosphor plate (SPP)) and digital sensors (charged-couple-device (CCD)). The exposure time for each image receptors is given in accordance with the diagnostic requirements for incisors, canines and molars, upper and lower jaw. The measured values for the median molars of the upper jaw, the tested doses ranging from 22.4 to 116.2 mGy cm2. The tested values for film class D, are different compared to other receptors E, F, CCD and SPP, from 5 to 9 times, which is consistent with studies of similar character.(author).
[en] In the course of life the periodontum is subject to changes which may be physiological or pathological. Intraoral radiographs give insight into the hard structures of the dentomaxillar region and provides information on lesions in the bone of the periodontum in that they show radiopacities and radiolucencies caused by such lesions. In this thesis the relation is investigated between the true shape and dimensions of periodontal bone lesions and their radiographic images. A method is developed and tested of making standardized and reproducible radiographs suitable for longitudinal studies of periodontal lesions. Also the possibility is demonstrated of an objective and reproducible interpretation of radiographic characteristics of periodontal bone lesions. (Auth.)
[en] Radiation and radioactivity were discovered more than 100 years ago. Since then, radiation has become important in cancer treatment. Approximately one million people will develop invasive cancer each year. Of these, 40% will receive curative benefit from surgery, radiation, chemotherapy, or a combination modality. Normal body tissues vary in their response to radiation. As with tumors, normal tissues in which cells are quickly dividing may be affected. This causes some of the side effects of radiation treatment. Since radiation is a local treatment, side effects depend on the area of the body being treated. The early effects of radiation may be seen a few days or weeks after treatments have started and may go on for several weeks after treatments have ended. Other effects may not show up until months, or even years, later. As radiotherapy is a viable treatment modality for head and neck cancer, however a wide range of potentially debilitating dental complications may accompany this treatment. The orofacial tissues of dental significance that may be affected by head and neck radiotherapy are the salivary glands, mucous membranes, taste buds, bone and teeth. (author)