Analysis of Roughness and Surface Hardness of a Dental Composite Using Atomic Force Microscopy and Microhardness Testing

The objective of this study was to evaluate the influence of a cola soft drink (CSD) and coffee on the microhardness and surface roughness of composite resin. Fifty cavities were prepared on the vestibular surface of bovine incisors and restored with nanoparticulate resin. The teeth were divided into five groups (n = 10): group A (control), immersion in artificial saliva (AS) for 14 days; group B, immersion in coffee for 15 min (3x/day) for 7 days followed by immersion in AS for another 7 days; group C, immersion in CSD for 15 min (3x/day) for 7 days followed by immersion in AS for another 7 days; group D, immersion in AS for 7 days, immersion in coffee for 15 min (3x/day) for 7 days; group E, immersion in AS for 7 days, immersion in CSD for 15 min (3x/day) for 7 days. After the immersion periods the specimens were analyzed for their microhardness and surface roughness. The data were subjected to analysis of variance (ANOVA) followed by t-test with 5% significance. Group A presented the highest average microhardness and lowest surface roughness, so it was possible to conclude that the consumption of CSD and coffee alters the microhardness and surface roughness of new restorations.o TEXTO COMPLETO DESTE ARTIGO, ESTARÁ DISPONÍVEL À PARTIR DE AGOSTO DE 2015.173446451Brazilian institutions Fundacao de Amparo a Pesquisa do Estado de Alagoa

Transverse effect of Haas and Hyrax appliances on the upper dental arch in patients with unilateral complete cleft lip and palate: A comparative study

Objective: The aim of the present study was to evaluate the transverse effect of rapid maxillary expansion in patients with unilateral complete cleft lip and palate while comparing the Haas and Hyrax appliances. Methods: The sample consisted of 48 patients divided into two groups: Group I - 25 patients treated with modified Haas appliance (mean age: 10 years 8 months); and Group II - 23 patients treated with Hyrax appliance (mean age: 10 years 6 months). Casts were taken during pre-expansion and after removal of the appliance at the end of the retention period. The models were scanned with the aid of the 3 Shape R700 3D scanner. Initial and final transverse distances were measured at cusp tips and cervical-palatal points of maxillary teeth by using the Ortho Analyzer(tm) 3D software. Results: The mean expansion obtained between cusp tips and cervical-palatal points for inter-canine width was 4.80 mm and 4.35 mm with the Haas appliance and 5.91 mm and 5.91 mm with the Hyrax appliance. As for first premolars or first deciduous molars, the values obtained were 6.46 mm and 5.90 mm in the Haas group and 7.11 mm and 6.65 mm in the Hyrax group. With regard to first molars, values were 6.11 mm and 5.24 mm in the Haas group and 7.55 mm and 6.31 mm in the Hyrax group. Conclusion: Rapid maxillary expansion significantly increased the transverse dimensions of the upper dental arch in patients with cleft palate, with no significant differences between the Hass and Hyrax expanders

Restinga forests of the Brazilian coast: richness and abundance of tree species on different soils

The aim of this study was to determine changes in composition, abundance and richness of species along a forest gradient with varying soils and flood regimes. The forests are located on the left bank of the lower Jucu River, in Jacarenema Natural Municipal Park, Espírito Santo. A survey of shrub/tree species was done in 80 plots, 5x25 m, equally distributed among the forests studied. We included in the sampling all individuals with >3.2 cm diameter at breast height (1.30 m). Soil samples were collected from the surface layer (0-10 cm) in each plot for chemical and physical analysis. The results indicate that a significant pedological gradient occurs, which is influenced by varying seasonal groundwater levels. Restinga forest formations showed significant differences in species richness, except for Non-flooded Forest and Non-flooded Forest Transition. The Canonical Correlation Analysis (CCA) showed that some species are distributed along the gradient under the combined influence of drainage, nutrient concentration and physical characteristics of the soil. Regarding the variables tested, flooding seems to be a more limiting factor for the establishment of plant species in Restinga forests than basic soil fertility attributes.O objetivo deste estudo foi o de determinar as mudanças na composição, abundância e riqueza de espécies ao longo de um gradiente de floresta com variações de solo e inundações. As florestas localizam-se na margem esquerda do Rio Jucu, no Parque Natural Municipal de Jacarenema, Espírito Santo. O levantamento das espécies arbustivo/arbóreas foi realizado em 80 parcelas de 5x25m, distribuídas equitativamente entre as florestas estudadas. Foram incluídos na amostragem todos os indivíduos com >3,2 cm diâmetro à altura do solo (1,30 m). Foram coletadas amostras de solo superficial (0-10 cm) em cada parcela para análise química e física. Os resultados mostraram a existência de gradiente pedológico significativo, que é influenciado pelas variações sazonais do lençol freático. As formações florestais da Restinga apresentaram diferenças significativas na riqueza de espécies, com exceção da Floresta Não Inundável em relação a Floresta Não Inundável de Transição. A Análise de Correlação Canônica (CCA) mostrou que algumas espécies apresentam sua distribuição ao longo do gradiente sob influência da drenagem, das concentrações de nutrientes e das características físicas dos solos. Entre as variáveis testadas, a inundação parece ser o fator mais limitante para o estabelecimento de espécies vegetais nas florestas de Restinga do que os atributos básicos de fertilidade do solo