23 research outputs found
Modeling Disease Vector Occurrence when Detection Is Imperfect: Infestation of Amazonian Palm Trees by Triatomine Bugs at Three Spatial Scales
Blood-sucking bugs of the genus Rhodnius are major vectors of Chagas disease. Control and surveillance of Chagas disease transmission critically depend on ascertaining whether households and nearby ecotopes (such as palm trees) are infested by these vectors. However, no bug detection technique works perfectly. Because more sensitive methods are more costly, vector searches face a trade-off between technical prowess and sample size. We compromise by using relatively inexpensive sampling techniques that can be applied multiple times to a large number of palms. With these replicated results, we estimate the probability of failing to detect bugs in a palm that is actually infested. We incorporate this information into our analyses to derive an unbiased estimate of palm infestation, and find it to be about 50% â twice the observed proportion of infested palms. We are then able to model the effects of regional, landscape, and local environmental variables on palm infestation. Individual palm attributes contribute overwhelmingly more than landscape or regional covariates to explaining infestation, suggesting that palm tree management can help mitigate risk locally. Our results illustrate how explicitly accounting for vector, pathogen, or host detection failures can substantially improve epidemiological parameter estimation when perfect detection techniques are unavailable
Analysis of magnetic resonance imaging characteristics and pain in temporomandibular joints with and without degenerative changes of the condyle
The aim of this study was to investigate temporomandibular joint (TMJ) pain and magnetic resonance imaging characteristics in 104 TMJs with and 58 without degenerative changes of the condyle, such as osteophytes, erosion, avascular necrosis, subcondral cyst and intra-articular loose bodies. TMJ images were also assessed for flattening, retropositioning and hypomobility of condyle and disc displacement. Comparison of the TMJ side-related data showed a significant relationship between disc displacement without reduction (DDwoR) and the presence of degenerative bony changes (p = 0.00). Flattening, retropositioning and hypomobility of condyle showed no significant difference in relation to the presence or absence of degenerative bony changes. Retropositioning of the condyle was significantly associated to disc displacement with reduction (DDwR) (p = 0.00), while condylar hypomobility was significantly more frequent in TMJ with DDwoR (p < 0.05). Independent of the presence or type of DD, TMJ pain was more frequent in the presence of degenerative bony changes. When considering only DDwR, TMJ pain was significantly associated to a degenerative condition (p = 0.03). When there were no degenerative bony changes, TMJ pain was significantly more frequent in DDwoR (p = 0.04). Despite the present findings, the absence of symptoms in some patients with condylar bony changes suggests that the diagnosis of osteoarthritis should be established by evaluation of magnetic resonance images in association with clinical examination.37652953
Accuracy of enhancement filters in measuring in vitro peri-implant bone level
Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES)Objectives To identify the accuracy of enhancement filters of an intraoral phosphor-plate system for measuring the simulated peri-implant bone level. Materials and methods A total of 20 titanium implants (Titamax((R))) were placed into six fragments of bovine ribs and defects simulating bone loss were created. Periapical radiographs were taken with a phosphor-plate system (Vista Scan((R))) according to the paralleling standard technique, and nine enhancement filters were applied: fine, caries 1, caries 2, perio, endo, noise reduction, invert, emboss, and sculpture. The Friedman test compared the radiographic measurements of the defects to those obtained on the bovine ribs with a digital caliper. Intra- and interobserver agreement was calculated with the intra-class correlation coefficient (ICC). Results The ICC values showed excellent intra- and interobserver agreement. The caries1, caries2, endo, and perio filters resulted on measurements statistically different from both the original images and the measurements of the digital caliper (P<0.05). The other filters did not show statistically significant differences from the original images nor from the measurements of the digital caliper. Conclusion In addition to the original images, the fine and emboss filters resulted on the most precise measures. The caries1, caries2, endo, and perio filters were the less accurate for measuring the peri-implant bone level.241010741077Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES
Influence of cone-beam computed tomography milliamperage settings on image quality of the mandibular third molar region
To assess the image quality of the mandibular third molar region using different milliamperage (mA) settings of cone-beam computed tomography. Twelve dry mandibles with impacted third molars were scanned with a Kodak 9000 unit (Kodak Dental Systems, Carestream Health, Rochester, NY, USA) using different mA settings (2, 4, 6.3, 8, 10, 12, and 15 mA). Two oral radiologists evaluated the images. They classified the tooth root, periodontal space, lamina dura, trabecular bone, mandibular canal, and overall image quality as excellent, good, poor, or inadequate for diagnosis. Statistical analyses were performed by one-way ANOVA with a post hoc Tukey test to investigate the influence of the mA settings in the image quality of the structures analyzed. The significance level was set at 5 %. The 15 and 12 mA settings provided the highest mean values for all the evaluated criteria, with significant differences from the values for the other mA settings. The 10, 8, and 6.3 mA settings showed no significant differences in relation to tooth root and periodontal space. For the other evaluated criteria, no significant differences were observed for the 10 and 8 mA settings. The 4 and 2 mA settings gave the lowest mean values. The best low-dose protocol with good image quality was the 10 mA setting. Lower dose protocols with 8 and 6.3 mA settings can also be used for these purposes, but caution is necessary because of increased image noise.301273
Enhancement cone beam computed tomography filters improve in vitro periimplant dehiscence detection
Objective. To investigate whether cone beam computed tomography filters would improve periimplant dehiscence detection. Study design. A hundred titanium implants were placed in bovine ribs in which defects simulating periimplant dehiscence had previously been created. After images acquisition, three oral radiologists assessed them with and without the following filters: Angio Sharpen high 5 x 5, Shadow, Sharpen 3 x 3, Sharpen Mild, and Smooth. The McNemar test verified the disagreement between all images versus the reference standard and original images versus images with filters; P < .05 was considered statistically significant. Results. Dehiscence detection using the original images and the Shadow filter disagreed from the reference standard (P < .05), as well as when using the filters instead of the original images (P < .05). Conclusion. All the filters tested, with the exception of the Shadow, improved periimplant dehiscence detection. The Sharpen 3 x 3 filter was considered best for this task.116563363
Influence of scan mode (180 degrees/360 degrees) of the cone beam computed tomography for preoperative dental implant measurements
ObjectiveThe aim of this study was to evaluate the effect of scan mode of the cone beam computed tomography (CBCT) in the preoperative dental implant measurements. Material and methodsCompletely edentulous mandibles with entirely resorbed alveolar processes were selected for this study. Five regions were selected (incisor, canine, premolar, first molar, and second molar). The mandibles were scanned with Next Generation i-CAT CBCT unit (Imaging Sciences International, Inc, Hatfield, PA, USA) with half (180 degrees) and full (360 degrees) mode. Two oral radiologists performed vertical measurements in all selected regions; the measurements of half of the sample were repeated within an interval of 30days. The mandibles were sectioned using an electrical saw in all evaluated regions to obtain the gold standard. The intraclass correlation coefficient was calculated for the intra- and interobserver agreement. Descriptive statistics were calculated as mean, median, and standard deviation. Wilcoxon signed rank test was used to determine the correlation between the measurements obtained in different scan mode with the gold standard. The significance level was 5%. ResultsThe values of intra- and interobserver reproducibility indicated a strong agreement. In the dental implant measurements, except the bone height of the second molar region in full scan mode (P=0.02), the Wilcoxon signed rank test did not show statistical significant difference with the gold standard (P>0.05). ConclusionsBoth modes provided real measures, necessary when performing implant planning; however, half scan mode uses smaller doses, following the principle of effectiveness. We believe that this method should be used because of the best dose-effect relationship and offer less risk to the patient.252E155E15
Effect of alternative photostimulable phosphor plates erasing times on subjective digital image quality
Objective: To evaluate the influence of alternative erasing times of DenOptix (R) (Dentsply/Gendex, Chicargo, IL) digital plates oil subjective image quality and the probability of double exposure image not Occurring. Methods: Human teeth were X-rayed with phosphor plates using tell different erasing times. Two observers evaluated the images for subjective Image quality (sharpness, brightness, contrast, enamel definition, dentin definition and dentin-enamal Junction definition) and for the presence or absence of double exposure image. Spearman's correlation analysis and ANOVA was performed to verify the existence ora linear association between the subjective image quality parameters and the alternative erasing times. A contingency table was constructed to evaluate the agreement among the observers, and a binominal logistic regression was performed to verify the correlation between the erasing time and the probability of double exposure image not occurring. Results: All 6 parameters or image quality were rated high by the examiners for the erasing times between 25 s and 130 s. The same erasing time range, from 25 to 130 s, was considered a safe erasing time interval, with no probability of a double exposure image Occurring. Conclusions: The alternative erasing times from 25 s to 130 s showed high quality and no probability of double image Occurrence. Thus, it is possible to reduce the operating time or the DenOptix (R) digital system Without jeopardizing the diagnostic task. Dentomaxillofacial Radiology (2010) 39, 23-27. doi: 10.1259/dmfr/49065239.o TEXTO COMPLETO DESTE ARTIGO, ESTARĂ DISPONĂVEL Ă PARTIR DE AGOSTO DE 2015.391232
Evaluation of panoramic radiomorphometric indices related to low bone density in sickle cell disease
In sickle cell disease, erythroid hyperplasia causes trabecular destruction leading to low bone density. This condition could be suspected by the radiomorphometric indices and your diagnosis becomes relevant in a multidisciplinary context of health care for sickle cell subjects, providing prognostics and contributing to determine adequate therapeutic and preventive actions. The aim of this study was to assess the risk of low bone density in subjects with sickle cell disease (SCD) through analysis of panoramic radiographic exams by radiomorphometric indices. Seventy-eight Brazilian subjects with SCD took part in this study and were subdivided into four groups: (I) 31 SCD subjects aged under 40 years; (II) 13 SCD subjects aged 40 years or more; (III) 12 normal subjects aged under 40 years; and (IV) 22 normal subjects aged 40 years or more. In the panoramic radiographs, the mandibular cortical index (MCI) classification, increased spacing of the trabecular bone, panoramic mandibular index (PMI), and mental index (MI) were evaluated. Exact Fisher's test was used to compare age between the different groups. Descriptive analysis of the data was performed to evaluate the simple visual estimation of low bone density (increased bone trabecular space and MCI), and a one-way analysis of variance (Bonferroni criteria) was used to compare the means of the quantitative indices (PMI and MI). The significance level was p < 0.05. In the MCI classification, C2 was more prevalent, especially in groups I and IV. Increased spacing of the trabecular bone was more frequent in groups I and II. MI did not show a statistically significant difference among the groups. PMI showed a statistically significant difference only between groups III and IV. The radiomorphometric indices applied in the present study can be used on panoramic radiographs to detect the presence of low bone density in SCD subjects.23720372042FAPESB (Bahia Research Support Foundation
Effectiveness of computed tomography to evaluate central giant cell lesion
Central giant cell lesion (CGCL) is a benign disease involving the mandible (70%) more than the maxilla; it tends to be more common in women. Clinically, the lesion may be associated with pain, tooth displacement, facial asymmetry, paraesthesia and ulceration of the mucosa. The radiographic aspect of CGCL is highly variable since it may appear as a unilocular or multilocular radiolucent area with expansion and perforation of the cortical bone. Few previous reports have dealt with the usefulness of CT in the evaluation of this lesion. The purpose of this study is to report the clinical and imaging features of a case, including CT, treated by a conservative method.o TEXTO COMPLETO DESTE ARTIGO, ESTARĂ DISPONĂVEL Ă PARTIR DE AGOSTO DE 2015.36852252