3 resultados para RADIOLOGIA E FOTOBIOLOGIA

em Universidade Federal do Rio Grande do Norte(UFRN)


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The people of Ceará state are descended from miscegenation between the Portuguese colonizers and the native population, resulting in a different facial pattern from other populations. It is important that this pattern be thoroughly understood, along with its minimum and maximum values so that they can be assessed and respected, allowing professionals who deal with the craniofacial complex to work more efficiently and scientifically. Aim: To characterize the morphological pattern of individuals from Ceará state, whose father and grandfather are also native from Ceará, in the 10-12 year age group, not submitted to previous orthodontic treatment, in order to determine: 1) the prevalence of occlusal pattern; 2) the prevalence of dental anomalies (DA) and, 3) the skeletal and dental cephalometric characteristics of individuals that present with normal occlusion and harmonious facial pattern. Methodology: A list of 10-12 year-olds was obtained from 515 schools containing 162,713 students (Education Secretariat of Ceará State), from which 234 individuals were examined (107 boys and 157 girls). The assessment criteria adopted were: 1) Angle s Classification System to determine occlusal pattern. The occlusal characteristics were measured through overbite, overjet, crowding and interincisal diastema. 2) DA are anomalies of number, shape, size, eruption and structure and, 3) in the group that presented with normal occlusion, we used cephalometric analysis measures proposed by Downs, Steiner, Tweed, Holdaway, Jacobson and McNamara. Results: 1) 25.8% of the schoolchildren had normal occlusion, 47.5% class I malocclusion, 22.3% class II malocclusion and 4.2% class III malocclusion. No statistically significant difference was found between the age group studied and sex. Thirty percent of the individuals had normal overbite, while 36.7% and 19.7% had increased and reduced overbite, respectively. Normal overjet was found in 33.7% of the individuals, increased overjet in 50% and reduced in 16.3%. Dental crowding was observed in 62.5% of the individuals and the presence of interincisal diastema in 14.8%. 2) The prevalence of DA was 56.1%, 6.8% in the number, 10.8% in shape, 4.1% in size, 34.5% in eruption, 26.4% in structure and 17.4% had more than one DA. No association was found between DA and sex, but DA was significantly associated to malocclusion (p<0.05); 3) there was no association between sex or facial type between the measures of nasal-labial angle, position and effective maxillary length, effective mandibular length and the sagittal relationship between the molars, overjet and overbite, position of upper incisors, lower incisors and between the incisors themselves. There was a difference between sex, on the VERT index and in lower anterior facial height, upper incisor inclination and line-H, between facial types for the occlusal plane angles, mandibular plane, facial axis, lower incisor inclination, mandibular position, upper incisor position, lower anterior facial height, ANB and line-H. It was concluded that: 1) the most prevalent occlusal type was class I malocclusion, with no distinction for sex or age group, and the assessment of occlusal characteristics showed that excessive overbite and overjet were the most predominant findings, along with a high occurrence of tooth crowding; 2) a high prevalence of DA was found, particularly eruption anomalies, not influenced by sex but significantly associated to malocclusion and 3) individuals from Ceará are predominantly brachyfacial, exhibiting a number of similarities inherent to their facial pattern, such as a convex profile, retracted jaw, reduced lower third and protruded lower incisors. This study was multidisciplinary, involving researchers from the areas of epidemiology, radiology and dentistry, thereby meeting the multidisciplinarity requirements of the Postgraduate Program in Health Sciences

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Since Demirjian's system of estimating dental maturity was first described, many researchers from different countries have tested its accuracy among diverse populations. Some of these studies have pointed out a need to determine population-specific standards. In Brazil, the Northeast region is the one that most suffers the negative impact of exodus, specially related to the increase of abandoned children in the cities. The aim of this study was to test the accuracy of Demirjian's system for assessing the dental maturity of northeastern Brazilian children, so as to present a scale for maturity score conversion into dental age developed specifically for this population. This could be used for forensic, anthropological and legal matters, and also as a model for other countries attempting to formulate their own conversion scales. Panoramic radiographs of 1,491 children (821 females and 670 males), aged 7 to 13 years, from Ceará state, northeast Brazil, were assessed by a single observer to determine dental age (DA) according to Demirjian's system. The mean percentage of intra-observer agreement was 86.6%, with a mean Cohen's Kappa coefficient of 0.67 (substantial agreement). The DA was compared by paired t-test to subjects' chronological age (CA). The differences between CA and DA in all age groups were statistically significant (p<0.0001), demonstrating a great advancement in DA among Brazilians. Scatter plots were drawn for both genders, and the data were fitted to a growth curve, y = 100/ (1 + e-a(x b)). Graphs corresponding to the 50th percentile curves were produced. A table with new values for the conversion of maturity score into dental age for northeastern Brazilian children is presented. The great advancement in DA, as obtained by Demirjian's system in this population, justified the determination of specific scores for dental maturity assessment

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Cephalometric analysis is the mensuration of linear and angular measures through demarcation points as distances and lines on teleradiography, and is considered of fundamental importance for diagnosis and orthodontic planning. In this manner, the objective of this research was to compare cephalometric measurements obtained by dentists and radiologists from the analysis of the same radiograph, in a computerized cephalometric analysis program. All research participants marked 18 cephalometric points on a 14-inch notebook computer, as directed by the program itself (Radiocef 2®). From there, they generated 14 cephalometric parameters including skeletal, dental-skeletal, dental and soft tissue. In order to verify the intra-examiner agreement, 10 professionals from each group repeated the marking of the points with a minimum interval of eight days between the two markings. The intra-group variability was calculated based on the coefficients of variation (CV). The comparison between groups was performed using the Student t-test for normally distributed variables, and using the Mann-Whitney test for those with non-normal distribution. In the group of orthodontists, the measurements of Pog and 1-NB, SL, S-Ls Line, S-Li Line and 1.NB showed high internal variability. In the group of radiologists, the same occurred with the values of Pog and 1-NB, S-Ls Line, S-Li Line and 1.NA. In the comparison between groups, all the analyzed linear values and two angular values showed statistically significant differences between radiologists and dentists (p <0.05). According to the results, the interexaminer error in cephalometric analysis requires more attention, but does not come from a specific class of specialists, being either dentists or radiologists.