Avaliação cefalométrica das alterações verticais e anteroposteriores associadas ao uso do expansor maxilar com cobertura oclusal

INTRODUÇÃO: os aparelhos expansores maxilares com cobertura oclusal têm sido sugeridos para controlar o aumento na dimensão vertical da face após a expansão rápida da maxila, porém ainda não há um consenso na literatura sobre seus reais efeitos. OBJETIVO: o objetivo deste trabalho foi avaliar as alterações cefalométricas verticais e anteroposteriores associadas à expansão da maxila realizada com o aparelho expansor com cobertura oclusal. MÉTODOS: a amostra foi composta por 25 crianças, de ambos os gêneros, com idades entre 6 e 10 anos, portadoras de mordida cruzada posterior esquelética. Após a expansão maxilar, o próprio aparelho expansor foi utilizado como contenção fixa. Foram analisadas telerradiografias em norma lateral tomadas antes do início do tratamento e após a remoção do aparelho expansor. CONCLUSÃO: com base nos resultados, pôde-se concluir que o uso do aparelho expansor com cobertura oclusal não alterou significativamente as medidas cefalométricas verticais e anteroposteriores das crianças.

Skeletal alterations associated with the use of bonded rapid maxillary expansion appliance

Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.

Comparative study of chemical and mechanical retentive systems for bonding of indirect composite resin to commercially pure titanium

This study evaluated the effect of chemical and mechanical surface treatments for cast metal alloys on the bond strength of an indirect composite resin (Artglass) to commercially pure titanium (cpTi). Thirty cylindrical metal rods (3 mm diameter x 60 mm long) were cast in grade-1 cpTi and randomly assigned to 6 groups (n=5) according to the received surface treatment: sandblasting; chemical treatment; mechanical treatment - 0.4 mm beads; mechanical treatment - 0.6 mm beads; chemical/mechanical treatment - 0.4 mm; and chemical/mechanical treatment - 0.6 mm beads. Artglass rings (6.0 mm diameter x 2.0 mm thick) were light cured around the cpTi rods, according manufacturer's specifications. The specimens were invested in hard gypsum and their bond strength (in MPa) to the rods was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 500 kgf load cell. Data were analyzed statistically by one-way ANOVA and Tukey test (a=5%). The surface treatments differed significantly from each other (p<0.05) regarding the recorded bond strengths. Chemical retention and sandblasting showed statistically similar results to each other (p=0.139) and both had significantly lower bond strengths (p<0.05) than the other treatments. In conclusion, mechanical retention, either associated or not to chemical treatment, provided higher bond strength of the indirect composite resin to cpTi.

Comparative study of two commercially pure titanium casting methods

The interest in using titanium to fabricate removable partial denture (RPD) frameworks has increased, but there are few studies evaluating the effects of casting methods on clasp behavior. OBJECTIVE: This study compared the occurrence of porosities and the retentive force of commercially pure titanium (CP Ti) and cobalt-chromium (Co-Cr) removable partial denture circumferential clasps cast by induction/centrifugation and plasma/vacuum-pressure. MATERIAL AND METHODS: 72 frameworks were cast from CP Ti (n=36) and Co-Cr alloy (n=36; control group). For each material, 18 frameworks were casted by electromagnetic induction and injected by centrifugation, whereas the other 18 were casted by plasma and injected by vacuum-pressure. For each casting method, three subgroups (n=6) were formed: 0.25 mm, 0.50 mm, and 0.75 mm undercuts. The specimens were radiographed and subjected to an insertion/removal test simulating 5 years of framework use. Data were analyzed by ANOVA and Tukey's to compare materials and cast methods (α=0.05). RESULTS: Three of 18 specimens of the induction/centrifugation group and 9 of 18 specimens of plasma/vacuum-pressure cast presented porosities, but only 1 and 7 specimens, respectively, were rejected for simulation test. For Co-Cr alloy, no defects were found. Comparing the casting methods, statistically significant differences (p<0.05) were observed only for the Co-Cr alloy with 0.25 mm and 0.50 mm undercuts. Significant differences were found for the 0.25 mm and 0.75 mm undercuts dependent on the material used. For the 0.50 mm undercut, significant differences were found when the materials were induction casted. CONCLUSION: Although both casting methods produced satisfactory CP Ti RPD frameworks, the occurrence of porosities was greater in the plasma/vacuum-pressure than in the induction/centrifugation method, the latter resulting in higher clasp rigidity, generating higher retention force values.

Influence of intracanal post on apical periodontitis identified by cone-beam computed tomography

The determination of the success of endodontic treatment has been often discussed based on outcome obtained by periapical radiography. The aim of this study was to verify the influence of intracanal post on apical periodontitis detected by cone-beam computed tomography (CBCT). A consecutive sample of 1020 images (periapical radiographs and CBCT scans) taken from 619 patients (245 men; mean age, 50.1 years) between February 2008 and September 2009 were used in this study. Presence and intracanal post length (short, medium and long) were associated with apical periodontitis (AP). Chi-square test was used for statistical analyses. Significance level was set at p<0.01. The kappa value was used to assess examiner variability. From a total of 591 intracanal posts, AP was observed in 15.06%, 18.78% and 7.95% using periapical radiographs, into the different lengths, short, medium and long, respectively (p=0.466). Considering the same posts length it was verified AP in 24.20%, 26.40% and 11.84% observed by CBCT scans, respectively (p=0.154). From a total of 1,020 teeth used in this study, AP was detected in 397 (38.92%) by periapical radiography and in 614 (60.19%) by CBCT scans (p<0.001). The distribution of intracanal posts in different dental groups showed higher prevalence in maxillary anterior teeth (54.79%). Intracanal posts lengths did not influenced AP. AP was detected more frequently when CBCT method was used.

Do the origins of primary teeth affect the bond strength of a self-etching adhesive system to dentin?

The aim of this in vitro study was to evaluate the tensile bond strength of a self-etching adhesive system to three different dentinal substrates. Primary molar teeth that had been recently exfoliated (RE), with unknown time of exfoliation (UT), and extracted due to prolonged retention (PR) were used for this investigation. Ten primary molar teeth of each group were cut in the middle following the mesio-distal direction, creating a total of twenty specimens per group. The specimens were included in acrylic resin and had a flat dentin surface exposed. The self-etching adhesive system was applied to this surface and a 3-millimeter high cone with diameter of 2 mm in the adhesion area was constructed using composite resin. The specimens were stored in distilled water at 37ºC for 24 hours. Fifteen specimens of each substrate were used for the tensile bond test (n = 15) and 5 had the interface analyzed by scanning electron microscopy (SEM). The data was examined by one-way ANOVA and presented no significant differences between groups (p = 0.5787). The mean values obtained for RE, UT and PR were 18.39 ± 9.70, 19.41 ± 7.80, and 23.30 ± 9.37 MPa, respectively. Any dentinal substrates of primary teeth studied are safe for tensile bond strength tests with adhesive systems.

Nd:YAG laser irradiation effect on apical intracanal dentin - a microleakage and SEM evaluation

The purpose of this in vitro study was to evaluate the effect of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation on intracanal dentin surface by SEM analysis and its interference in the apical seal of filled canals. After endodontic treatment procedures, 34 maxillary human incisors were randomly assigned to 2 groups. In the negative control group (n=17), no additional treatment was performed and teeth were filled with vertically condensed gutta-percha; in the laser-treated group (n=17), the root canals were irradiated with Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) before filling as described for the control group. Two specimens of each group were prepared for SEM analysis to evaluate the presence and extent of morphological changes and removal of debris; the other specimens were immersed in 0.5% methylene blue dye (pH 7.2) for 24 h for evaluation of the linear dye leakage at the apical third. SEM analysis of the laser-treated group showed dentin fusion and resolidification without smear layer or debris. The Student’s t-test showed that the laser-treated group had significantly less leakage in apical third than the control group. Within the limitations of this study, it may be concluded that the morphological changes on the apical intraradicular dentin surface caused by Nd:YAG laser resulted in less linear dye apical leakage.

Desempenho, qualidade dos ovos e balanço de nitrogênio de poedeiras comerciais alimentadas com rações contendo diferentes níveis de proteína bruta e lisina

O experimento foi conduzido para avaliar os efeitos de rações com diferentes níveis de proteína bruta (PB) e lisina sobre as características de desempenho, a qualidade interna dos ovos e o balanço/retenção do nitrogênio. Foram utilizadas 160 poedeiras Hisex White com 48 semanas de idade, alojadas individualmente em delineamento inteiramente casualizado em esquema fatorial 4 × 2, com quatro níveis de PB (12, 14, 16 e 18%) e dois de lisina (0,85 e 1,00%), totalizando oito rações com cinco repetições de quatro aves. O consumo de proteína bruta, o peso dos ovos, a massa de ovos e a porcentagem de albúmen apresentam resposta linear crescente aos níveis de PB na dieta. O balanço de nitrogênio não é alterado pelos níveis de proteína das rações.

Experimento didático sobre cromatografia gasosa: uma abordagem analítica e ambiental

This paper describes an experiment to teach the principles of gas chromatography exploring the boiling points and polarities to explain the elution order of a series of alcohols, benzene and n-propanone, as well as to teach the response factor concept and the internal standard addition method. Retention times and response factors are used for qualitative identification and quantitative analysis of a hypothetical contamination source in a simulated water sample. The internal standard n-propanol is further used for quantification of benzene and n-butanol in the water sample. This experiment has been taught in the instrumental analysis course offered to chemistry and oceanography students.

Estudo da mobilização de metais e elementos traços em ambientes aquáticos do semi-árido brasileiro aplicando análises de componentes principais

The spatial and temporal retention of metals has been studied in water and sediments of the Gavião River, Anagé and Tremedal Reservoirs, located in the semi-arid region, Bahia - Brazil, in order to identify trends in the fluxes of metals from the sediments to the water column. The determination of metals was made by ICP OES and ET AAS. The application of statistical methods showed that this aquatic system presents suitable conditions to move Cd2+ and Pb2+ from the water column to the sediment.

Nutritional aspects of the prevention and treatment of osteoporosis

Osteoporosis is a global health problem characterized by low bone mass and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture. Nutrition plays a critical role in reducing the risk of osteoporosis through its effect on all of these fragility factors, especially on the development and maintenance of bone mass. An adequate calcium, vitamin D and protein intake resulted in reduced bone remodeling, better calcium retention, reduced age-related bone loss, and reduced fracture risk. Recent evidence indicates that a healthy dietary pattern including dairy products (mainly fat free), fruit and vegetables and adequate amounts of meat, fish and poultry is positively related to bone health. Furthermore, mineral and vitamin supplementation should be closely monitored by health professionals since it could have adverse effects and be insufficient to ensure optimal protection of bone health.

Influência do consumo alimentar na gestação sobre a retenção de peso pós-parto

OBJETIVO: Avaliar a influência da alimentação durante a gestação sobre a retenção de peso pós-parto. MÉTODOS: Foram acompanhadas 82 gestantes adultas e saudáveis que iniciaram o pré-natal em serviço público de saúde no Município de São Paulo, SP, entre abril e junho de 2005. As medidas de peso e estatura foram aferidas na primeira entrevista (até 16 semanas de gestação) e a medida de peso foi repetida em visita domiciliar 15 dias após o parto. O Recordatório de 24 horas foi usado para avaliar o consumo alimentar e foi aplicado nos três trimestres da gestação. Foi calculado o consumo médio de gordura saturada, fibras, açúcar adicionado, refrigerantes, alimentos processados, frutas, verduras e legumes, e a densidade energética da dieta. A retenção de peso foi obtida pela diferença entre a medida de peso pós-parto e a primeira medida realizada. A influência da alimentação sobre a retenção de peso pós-parto foi avaliada por meio de análise de regressão linear múltipla e foi realizado o teste para tendência linear. As variáveis utilizadas para ajuste do modelo foram: índice de massa corporal no início da gestação, estatura, renda familiar per capita, tabagismo, idade e escolaridade. RESULTADOS: O índice de massa corporal inicial médio foi de 24 kg/m² e a retenção média de peso foi de 1,9 kg. O aumento do consumo de gordura saturada (p = 0,005) e alimentos processados (p = 0,014) elevou de forma significativa a retenção de peso pós-parto, após ajuste pelas variáveis de controle. As demais variáveis de consumo alimentar não apresentaram relação significativa com a variável desfecho. CONCLUSÕES: O maior consumo de alimentos não saudáveis, como alimentos processados, e de gordura saturada influencia a elevação da retenção de peso pós-parto.

Apparent digestibility of diets with different concentrations of lysine and energy in piglets with different body weights and post-weaning age

The effects of body weight or age and dietary digestible lysine and metabolizable energy on apparent digestibility of energy and dry matter were evaluated in piglets after weaning. The animals were weaned at 21 days of age and distributed in two groups: 8.68 ± 0.76 kg at 28 days of age (weaned 7 days earlier); and 12.73 ± 0.99 kg at 35 days of age (weaned 14 days earlier). The pigs were allotted in digestibility cages in a completely randomized block design with the following factorial arrangements: 2 × 4 composed of two weight categories and four levels of digestible lysine (1.222; 1.305; 1.390 and 1.497%); and 2 × 3 composed of two weight categories and three levels of metabolizable energy (3,510; 3,700 and 3,830 kcal/kg rations). Digestible lysine was evaluated in six replications and metabolizable energy in eight replications and each animal constituted an experimental unit. Piglets with higher body weight and age were more efficient in nitrogen retention and energetic balance, compared to lighter and younger piglets, particularly those given lower concentration of lysine in the diet. The energy increase favored nitrogen retention by the heavier and older piglets. However, coefficients of dry matter and energy apparent digestibility did not differ among weight categories. Older and heavier piglets were more efficient in nitrogen retention, although this efficacy depended on concentration of the energy in the diet. This better use of protein and energy suggest differences on nutritional requirements.

Energy and amino acid content in phase 1 nursery diet: piglet performance and body chemical composition

It was evaluated the effects of metabolizable energy (ME) and digestible lysine (dLYS) densities on performance and body composition of weaned piglets. The study used 114 piglets weaned at 7.4 ± 0.80 kg, out of which 108 were allotted in the nursery and 6 were slaughtered on the weaning day to determine comparative data of body chemical composition. Six nutrients densities were stipulated from a previous study based on the highest nitrogen retention, maintaining the following ME:LYS relationship in the experimental diets: 3,390:1.291; 3,450:1.409; 3,650:1.411; 3,780:1.461; 3,940:1.507; and 4,109 kcal/kg ME:1.564% dLYS. The experimental diets were offered for 13 days when the piglets reached 12.986 ± 1.449 kg of body weight. The probable residual effects of nutritional density on the subsequent performance of the piglets were evaluated. At the end of initial phase 1, six piglets from each density were slaughtered to determine their chemical composition in body fractions and empty body. There was no significant influence of nutritional levels on the performance of the piglets at the end of the evaluation. The results of food conversion and body composition confirm the level indicated in the previous study, 4 g dLYS/Mcal of ME. The increase of energy and lysine densities confirms the need for a correct relationship among both of them to assure better performance of the piglets at the beginning of the growing phase.

Lisina digestível e zinco quelado para frangos de corte machos: desempenho e retenção de nitrogênio na fase pré-inicial

Em dois ensaios experimentais, avaliaram-se níveis de lisina digestível (0,90; 1,00; 1,10; 1,20 e 1,40%) combinados a zinco quelado (43 e 253 ppm) para frangos de corte machos. Os períodos considerados foram: 1 a 11 dias de idade (desempenho) e 1 a 7 dias de idade (balanço de nitrogênio). O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5 × 2. No ensaio de desempenho, utilizaram-se 7 repetições e 15 aves por unidade experimental e, no ensaio de digestibilidade, 6 repetições e 6 aves por unidade experimental. As dietas continham 2.960 de EM/kg e 21% de proteína bruta. Na fase de 1 a 11 dias de idade, não houve efeito de interação lisina digestível × zinco quelado no desempenho, mas verificou-se efeito quadrático dos níveis de lisina digestível sobre o peso final, o ganho de peso e o ganho de peso relativo e efeito linear crescente no consumo de ração. A conversão alimentar não diferiu com as variações dos níveis de lisina digestível e zinco na dieta. Nas condições de avaliação do desempenho, o nível ótimo de lisina digestível para frangos de corte machos mantidos em piso de concreto é de 1,19%. Na fase de 1 a 7 dias de idade, não houve influência da relação entre níveis de lisina digestível e zinco quelado no balanço de nitrogênio. A retenção de nitrogênio aumentou de forma linear crescente com o aumento da concentração de lisina digestível na dieta, o que está de acordo com o aumento linear do ganho de peso e da eficiência alimentar. A exigência de lisina digestível para frangos de corte machos de 1 a 7 dias de idade é igual ou superior a 1,40%.