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Positioning services based on GNSS (Global Navigation Satellite Systems) have been using MEO satellites designed to guarantee Earth global coverage for decades. This satellite distribution is sometimes complemented with satellites in Inclined Geosynchronous (IGSO) and Geostationary (GEO) Orbits to improve satellite visibility in particular service areas. During recent years, with the advancements and reduction in costs in the deployment of LEO (Low Earth Orbit) constellations, the opportunity of using LEO satellites for PNT (Positioning, Navigation, and Timing) solutions is being studied. This concept opens the possibility to provide high accuracy positioning overcoming the typical drawbacks of RTK (Real-Time Kinematics) or PPP (Precise Point Positioning), such as the need for ground infrastructure or long convergence times. The high velocity dynamics of the low orbits can help to cancel the effect of the ionosphere in the signals to be processed at the user level. Therefore, the introduction of LEO satellites together with the classical MEO GNSS constellations could be a solution to reduce the dependency on dense station networks. The size of the LEO constellations and the design of their orbits are key factors to improve the PPP solution. Moreover, both the accuracy and the convergence time of the PPP solution depend also on the quality of the on-board equipment of the satellite, especially on the quality of the atomic clock in terms of stability and noise, and on the quality of the orbit and clock corrections sent to the PPP users. GMV has decades of experience in both GNSS and LEO precise orbit determination (POD) fields and in high-accuracy GNSS applications for different market domains. With this experience, several analyses have been carried out to assess the achievable performance when introducing the processing of LEO signals for high accuracy positioning solutions, contributing to the overall GNSS community. The objective of this paper is to describe the analysis run by GMV with the use of synthetic data simulating GNSS and LEO signals, showing results and the associated assessment of the achievable performance. [ABSTRACT FROM AUTHOR]

Objective: To establish the diagnostic validity of panoramic X-rays (PRx) in temporomandibular osteoarthrosis (OA) using the clinical and imaging criteria (magnetic resonance imaging, MRI) of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) as gold standards. Methods: Eighty-four patients with full clinical records (RDC/TMD), PRx, and MRI scans were selected. Two stomatologists evaluated the PRx for OA. The MRI findings were derived from the radiologist report. Intra/inter-examiner concordance was established. The diagnostic concordance between clinical signs and MRI was determined. Both were used as gold standards to calculate the validity of PRx in OA. Results: The diagnostic validity of PRx with MRI as gold standard was sensitivity = 69·0% and specificity = 67·9%. The diagnostic validity of PRx with clinical criteria as gold standard was sensitivity = 61·6% and specificity = 57·9%. Discussion: Panoramic X-rays have scant diagnostic validity in temporomandibular osteoarthrosis when taking MRI or clinical criteria of RDC/TMD as gold standards. [ABSTRACT FROM AUTHOR]

Objective: To establish the diagnostic validity of panoramic X-rays (PRx) in temporomandibular osteoarthrosis (OA) using the clinical and imaging criteria (magnetic resonance imaging, MRI) of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) as gold standards., Methods: Eighty-four patients with full clinical records (RDC/TMD), PRx, and MRI scans were selected. Two stomatologists evaluated the PRx for OA. The MRI findings were derived from the radiologist report. Intra/inter-examiner concordance was established. The diagnostic concordance between clinical signs and MRI was determined. Both were used as gold standards to calculate the validity of PRx in OA., Results: The diagnostic validity of PRx with MRI as gold standard was sensitivity=69.0% and specificity=67.9%. The diagnostic validity of PRx with clinical criteria as gold standard was sensitivity=61.6% and specificity=57.9%., Discussion: Panoramic X-rays have scant diagnostic validity in temporomandibular osteoarthrosis when taking MRI or clinical criteria of RDC/TMD as gold standards.

Objective: To compare the risk factors and clinical manifestations of patients with temporomandibular disorders (TMDs) diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) (axis I) versus an age and gender matched control group., Study Design: A total of 162 patients explored according to the RDC/TMD (mean age 40.6±18.8 years, range 7-90; 11.1% males and 88.9% females) were compared with 119 controls, measuring differences in TMD risk factors (sleep disturbances, stress, psychoactive medication, parafunctions, loss of posterior support, ligament hyperlaxity) and clinical variables (joint sounds, painful muscle and joint palpation, maximum aperture)., Results: Myofascial pain (MFP) (single or multiple diagnoses) was the most frequent diagnosis (42%). The most common diagnostic combination was MFP plus arthralgia (16.0%). Statistically significant differences were observed in clenching (OR 2.3; 95%CI: 1.4-3.8) and in maximum active aperture (MAA) on comparing the two groups both globally (TMD vs. controls) (patients 36.7±8.6 mm, controls 43.1±5.8 mm; F=45.41, p=0.000) and on comparing according to diagnostic categories. MFP explained most of the observed differences in the risk factors: stress perception (OR=1.98;I.C.:1.01-3.89), psychoactive medication (OR=2.21; I.C.:1.12-4.37), parafunctions (OR=2.14;I.C.:1.12-4.11), and ligament laxity (OR=2.6;I.C.:1.01-6.68). Joint sounds were more frequent in patients with MFP (39.7% vs. 24.0%; χ²=4.66; p=0.03), and painful joint palpation was more common in patients with disc displacement with reduction (DDWR)(15.9% vs. 5.0%; χ²= 5.2; p=0.02) and osteoarthrosis (20.8% vs. 5.0%; χ²=7.0; p=0.008)., Conclusions: There is a high prevalence of signs and symptoms of TMDs in the general population. Significant differences are observed in clenching and MAA between patients and controls considered both globally and for each diagnostic category individually. The analyzed risk factors (except loss of posterior support) show a statistically significant OR for the diagnosis of MFP.

Aims: We analyze the possible clinical differences between bone jaw exposed areas in ONJ (osteonecrosis of the jaws) and ORN (osteoradionecrosis)., Patients and Method: Group 1 was composed with 53 ONJ cases and group 2 with 20 ORN cases. In both groups we analyzed, the major size of the exposed bone areas, the number of exposed areas, the location on the jaws and the presence of others associated and severe complications, such as skin fistulas and jaw fractures. We also investigated the possible local aetiology or trigger factor of the lesions., Results: The major size of the bone exposed areas was 2.29+/-2.02(mean +/- std.dev) in group 1 and 2.7+/-2.9 (mean +/- std.dev) in group 2 (p>0.05). The number of exposed areas was 1.8+/-1.34 (mean +/- std.dev) in group 1 and 1.2+/-0.55 (mean +/- std.dev) in group 2 (p>0.05). There were more fractures in the second group (20%) (p<0.05), and skin fistulas (35%) (p<0.05). We found more patients in group 1 in which the dental extraction was the local aetiology of the bone necrosis (35 cases, 66.03%), while in group 2 there were 8 (40%) (p<0.05)., Conclusions: In our study with ONJ there were not differences in the major size of the bone exposed areas, but there were more lesions per patient than in group with ORN. The severity of the complications, such as jaw fractures and skin fistulas were higher in ORN, and in this group it was more frequent the spontaneous lesions than in the ONJ where it is more frequent following dental extractions.

Lichen sclerosus or lichen sclerosus et atrophicus is a chronic inflammatory disease predominantly affecting the genital mucosa and skin. Clinically, it is characterized by white atrophic plaques in the anogenital region. The lesions are generally asymptomatic, but may cause discomfort with itching and pain. Extragenital mucosal involvement is very unusual, and lesions limited to the oral mucosa are even less frequent. Knowledge of such lesions is important in order to establish a differential diagnosis with other white oral lesions, and histological confirmation is required. We present the case of a 31-year-old woman with a well delimited, pearly white lesion located in the upper gingival mucosa, lip mucosa and adjacent skin. The lesion had led to loss of periodontal attachment of the affected tooth, causing pain in response to tooth brushing. The biopsy confirmed lichen sclerosus, and treatment was provided in the form of intralesional corticoid injections, followed by improvement of the mucosal lesion, though without recovery of the periodontal loss.

In patients at risk because of heart disease, bacteremias induced by invasive dental treatments have been reported as a cause of bacterial endocarditis (BE) - a serious disorder that continues to involve a high mortality. As a result, different scientific societies have supported recommendations for the administration of antibiotics prior to invasive dental treatments, in order to neutralize bacteremia. In this context, the recommendations of the American Heart Association (AHA) are the most widely used in our setting. Advances in our knowledge of the etiopathogenesis of bacterial endocarditis have placed increasingly less importance on invasive dental treatments as a causal factor (the AHA again reduced the number of cases in which antibiotic prophylaxis is recommended, on occasion of its latest guidelines update in 2007) - with increasingly greater importance being placed on factors associated with hygiene and oral health. The present study offers a critical review of the relationship between dental treatment, bacteremia and bacterial endocarditis.

Unlabelled: A study is made of the experience gained with the Child Oral Care Program (Plan de Atención Dental Infantil, PADI) in the Service of Stomatology of Valencia University General Hospital (Valencia, Spain) after four years in operation (July 2003 - July 2007)., Study Design: The sample comprised 2626 children between 5-14 years of age, pertaining to department 9 of the Valencian public health system. A clinical history was compiled in each case, a radiological study was made, and a treatment plan was elaborated including fillings, extractions, and control visits., Results: Of the 2626 designated children, 2369 visited our Service - mostly referred from the Preventive Dental Care Units. A total of 5784 fillings were carried out (93.3% with silver amalgam, 5.6% with composites and the rest as provisional fillings). The permanent first molars were the teeth with the largest number of fillings (70.2% of the total). These were followed in order of frequency by the second molars (19.1%). As regards composite resin fillings, most involved the upper central incisors, followed by the upper lateral incisors. A total of 644 extractions were performed, corresponding to 110 permanent teeth and 534 temporary teeth. In the case of the permanent dentition, the first molars were the most commonly removed teeth. In the temporary dentition, the most frequently removed teeth were the second molars., Conclusions: The response of the population to this program has been very good, and reinforces the preventive measures already in place, with the provision of restorative treatments to improve the oral and dental health of the pediatric population, and yielding good results in terms of the program quality indicators. The Service of Stomatology (Valencia University General Hospital) is able to address the demand and offers the public health network integrated and continuous patient care.

Objectives: To analyze the frequency and type of the most common benign tumors of the oral mucosa found at the Hospital Stomatology Service, and to study the clinical characteristics and possible etiological factors., Material and Methods: This is a retrospective study of 300 patients with histologically diagnosed benign tumors of the oral mucosa. Data was compiled for each case, documenting information relating to age, gender, medication, habits (smoking, oral hygiene), anamnesis (reason for consultation, symptomatology, evolution), and the characteristics of the lesion (site, color, size, surface, consistency, and base)., Results: Of all the tumors studied, 53% were histologically diagnosed as fibroma. In the study of prevalence of benign tumors of the oral mucosa, no differences were found for age; however there were differences according to gender, finding a greater prevalence of fibromas, pyogenic granulomas, and giant cell granulomas in women, at a ratio of 2:1. The group of tumors studied showed a significantly asymptomatic behaviour, and self-limiting and slow growth. With respect to the possible etiologic agents, we found no statistically significant differences between them., Conclusions: Following the study of 300 patients histologically diagnosed with benign tumor of the oral mucosa, we can state that with regard to prevalence, we found significant differences with respect to gender, being more frequent in women. The fibroma is the most frequent benign tumor of the oral cavity.