Dental Environment Stress: Findings among Lusophone Dental Students

Objective: To perform cross-cultural adaptation of the Dental Environment Stress (DES), to test its construct validity and reliability, and to identify the sources of stress among Brazilian dental students. Material and Methods: The DES was transculturally adapted to Portuguese using translation/back-translation, review by an expert bilingual committee and consensus building. The first version was tested in a sample of 42 dental students to check the understanding level of the alternatives. The final version was applied to all the students enrolled in a Brazilian Public Dental School. Construct validity was assessed through factor analysis, performed by principal components analysis and Varimax rotation and reliability by internal Cronbach's alpha coefficient (95% CI). Wilcoxon rank sum was conducted to test for gender and Kruskall-Wallis for year comparison. Multivariate analysis relied on ordinal logistic regression modeling. Results: Factor analysis revealed five factors that possessed eigenvalues greater than 1.5 and together explained 46.88% of the total variance. Internal consistency of each factor was adequate, with Cronbach's alpha ranging from 0.65 to 0.84. 'Examinations and grades' (82.80%) was the highest scored item. Females presented higher rates, as well as second's and fifth's years students. The entering students were generally concerned with factors related to "Academic Performance", whereas clinical year students with "Insecurity Concerning their Professional Future". Conclusion: The Portuguese version of the DES presented good results, thus it could be a valid instrument to assess the factors of perceived stress in Lusophone countries, subsidizing the development of strategies to minimize the stress and optimize school performance.

Influence of different water types on the physical and mechanical properties of gypsum

Abstract Aim: To evaluate if gypsum mixed with different water types, with their different compositions influence the dimensional change, surface roughness and compressive strength of type IV and V gypsum specimens. Methods: Sixty specimens were fabricated from metal matrices and divided into six groups (n=10) according to the used type of gypsum and water: G1, G2 and G3 - type IV gypsum and tap, mineral and distilled water, respectively; G4, G5 and G6 - type V gypsum and tap, mineral and distilled water, respectively. Water/powder ratio followed the manufacturer's recommendations (19 mL/100 g) in all groups. The same specimens were used for all tests. A micrometer dial evaluated the dimensional change. The surface roughness of three random points was determined with a rugosimeter; a universal testing machine performed the compressive strength test. The data were subjected to analysis of variance (ANOVA). Results: There was no statistically significant difference (p>0.05) between the three types of water in the studied variables. There was statistically significant difference (p<0.05) between the gypsum mixes for the dimensional change variable. Conclusions: The different water types, with their different compositions, did not influence the analyzed physical and mechanical properties.

Importance of periodontal ligament thickness

This study evaluated whether periodontal ligament (PL) thickness varied with root size and examined the possible influence of this variation on orthodontic mechanics. Measurements were taken of the maxillary left first molar in 54 male Wistar rats. Mean mesial and distal PL thicknesses were compared between the intermediate buccal and mesiobuccal roots using paired Student's t-tests with a 5% significance level. Mean values differed significantly between roots (p < 2.2 × 10-16). PL thickness in rats is directly proportional to root dimensions.

Afecções neurológicas associadas ao retardo mental em alunos de uma instituição especializada de Londrina, Estado do Paraná / Neural affections associated with mental retardation in students from Londrina, Paraná State, Brazil

Retardo mental (RM) é um estado de desenvolvimento intelectual alterado que dificulta a integração social do indivíduo. Nosso objetivo foi estudar 147 portadores de RM, alunos da APAE de Londrina, Estado do Paraná, matriculados de 1989 a 2003. Através de um estudo descritivo, avaliamos a prevalência de neuropatologias em relação ao sexo, ao tipo de parto a que o afetado foi submetido, à idade materna ao nascimento e ao histórico de RM nas famílias. As patologias encontradas foram: RM ? casos isolados, 34,8%; síndrome de Down (SD), 19,7%; paralisia cerebral (PC), 19,7%; outras síndromes, 15,6%; dislexia, 6,8%, e distúrbio comportamental, 3,4%. Dentre as variáveis que apresentaram maior diferença destacam-se: sexo, na diplegia-PC, 3 homens:1 mulher; tipo de parto, na hemiplegia-PC, 10 normais: 1 cesariana; e história familiar de RM entre os portadores de SD, 24,1%. Entre os portadores de RM filhos de mãe com idade avançada (>41 anos), a SD apresentou maior prevalência (50%).

Mental Retardation (MR) is an altered state of intellectual development that makes the social integration of individuals difficult. The objective was to study 147 MR individuals, registered students of APAE, from the city of Londrina, Paraná State, Brazil, from 1989 to 2003. Through a descriptive approach, we were able to assess the prevalence of neural pathologies in relation to gender, the kind of birth delivery the individuals have undergone, the age of their mothers at their birth, and the MR family history. The following diseases were found: MR ? isolated cases, 34.8%; Down Syndrome (DS), 19.7%; cerebral palsy (CP), 19.7%; other syndromes, 15.6%; dyslexia, 6.8%; and behavior disturbance, 3.4%. Among the variables that showed large differences were: the gender, in diplegia-CP, 3male:1female; kind of birth delivery, in hemiplegia-CP, 10normal:1cesarean; family history of MR among DS individuals, 24.1%. Among the MR individuals from elder mothers (>41 years old), DS was more frequent (50%).