ABSTRACT
Multiphase flow imaging is a very challenging and critical topic in industrial process tomography. In this article, simulation and experimental results of reconstructing the permittivity profile of multiphase material from data collected in electrical capacitance tomography (ECT) are presented. A multiphase narrowband level set algorithm is developed to reconstruct the interfaces between three- or four-phase permittivity values. The level set algorithm is capable of imaging multiphase permittivity by using one set of ECT measurement data, so-called absolute value ECT reconstruction, and this is tested with high-contrast and low-contrast multiphase data. Simulation and experimental results showed the superiority of this algorithm over classical pixel-based image reconstruction methods. The multiphase level set algorithm and absolute ECT reconstruction are presented for the first time, to the best of our knowledge, in this paper and critically evaluated. This article is part of the themed issue 'Supersensing through industrial process tomography'.
ABSTRACT
A total of 1340 5-year-old children were examined as part of the first national survey of the oral health of children in the United Arab Emirates. The objective was to determine dental caries status and compare variations in caries experience in all 9 medical districts. Sampling and examination for caries was done following World Health Organization guidelines and criteria. Only 17% of the children were caries-free. The mean decayed/missing/filled teeth (dmft) index was 5.1, ranging from 3.8 in Ajman to 6.6 in Dubai. More than half (52%) had > 4 dmf teeth. Overall, caries is highly prevalent in the primary dentition of 5-year-old children and mostly untreated.
Subject(s)
DMF Index , Dental Caries/epidemiology , Tooth, Deciduous , Child , Child, Preschool , Dental Caries/diagnosis , Dental Caries/therapy , Dental Health Surveys , Dental Restoration, Permanent/statistics & numerical data , Female , Humans , Male , Oral Health , Prevalence , Residence Characteristics , Sex Distribution , United Arab Emirates/epidemiologyABSTRACT
A total of 1340 5-year-old children were examined as part of the first national survey of the oral health of children in the United Arab Emirates. The objective was to determine dental caries status and compare variations in caries experience in all 9 medical districts. Sampling and examination for caries was done following World Health Organization guidelines and criteria. Only 17% of the children were caries-free. The mean decayed/missing/filled teeth [dmft] index was 5.1, ranging from 3.8 in Ajman to 6.6 in Dubai. More than half [52%] had > 4 dmf teeth. Overall, caries is highly prevalent in the primary dentition of 5-year-old children and mostly untreated
Subject(s)
Dental Health Surveys , Dental Caries , DMF Index , Oral HealthABSTRACT
Children aged 2, 4 and 5 years were examined for dental caries using WHO criteria, in the Emirate of Abu Dhabi, UAE, in 1996. The children were from the three administrative regions of Abu Dhabi, Al Ain and Western Region. Sampling of health centres and kindergartens was stratified by urban or rural location. Parents completed a questionnaire, and children were classified into high, middle or low groups on the basis of their parents' education and income. All 20 kindergartens and 22 health centres sampled agreed to participate. The participation rate of sampled children was high and complete data were available for 640 children--217 aged 2 years, 204 aged 4 years, and 219 aged 5 years. Similar numbers of boys and girls were included. The prevalence of dental caries was very high--36% to 47% at age 2 years, 71% to 86% at age 4 years and 82% to 94% at age 5 years. The mean dmft at age 5 years was 8.4 in Abu Dhabi, 8.6 in Al Ain and 5.7 in Western Region. Few teeth had been filled. Apart from age, the parents' education and income were found to be statistically significantly related to caries experience (P<0.05), while gender, ethnicity (UAE or non-UAE), region, and urban or rural living, were not related to dental caries experience (P>0.3). While high parental educational attainment was related to lower caries experience, conversely, high parental income was related to higher caries experience. Caries experience was higher than that recorded approximately 6 years previously and is a cause of concern.
