Influence of substances with acid pH on composite resins microhardness

Resin composites are aesthetic restorative materials widely used in Dentistry and changes in pH can promote amendments in composite surface, compromising their initial characteristics. The aim of this study was to evaluate, in vitro, the effect of low pH beverages on two commercially available materials, the composite resins ICE (SDI) and Durafill VS (Heraeus Kulzer). The materials were evaluated for surface microhardness obtained by Vickers microhardness testing. Fifteen samples were prepared with 11 mm diameter and 2 mm thick, each restorative material. The samples were kept in storage conditions of the following substances: Gatorade ® (pH 2,9); Coca- Cola ® (pH 2,2) and distilled water (pH 6,0; control group) under temperature of 37 ° C, and the environment of immersing exchanged every 24 hours. Five samples of each material were immersed in the beverages tested and monitored for periods of 24 hours, 7, 14 and 21 days. The results were submitted to multifactorial analysis of variance and Tukey test. There were statistically significant differences (p 0.05) for factors environment, material and time, and for the interaction between them. The distilled water resulted in higher values of microhardness, followed by Coca-Cola® and Gatorade®. The highest values of microhardness were obtained at baseline, followed by 7, 14 and 21 days. There was no statistically significant difference (p 0,05) between the times of 14 and 21 days. It was concluded that the nanocomposite better results and that the acidic pH associated with progressive immersion time significantly alter the microhardness of the composites evaluated

Panoramic Radiography in the Diagnosis of Carotid Artery Atheromas and the Associated Risk Factors

Atherosclerosis is a serious chronic disease, responsible for thousands of deaths worldwide and is characterized by thickening and loss of elasticity of the arterial walls, associated with the presence of atheromatous plaques. Various risk factors act directly on predisposition to the disease, among which the following are pointed out: diabetes mellitus, arterial hypertension and inadequate diet and eating habits. More recent researches have elucidated new risk factors acting in the development of this disease, such as, for example: periodontitis, chronic renal disease and menopause. The panoramic radiograph, commonly used in dental practice, makes it possible to see calcified atherosclerotic plaques that are eventually deposited in the carotid arteries. The aim of this review article was to emphasize the dentist’s important role in the detection of carotid artery atheromas in panoramic radiographs and the immediate referral of patients affected by these calcifications to doctors. In addition, the study intended to guide the dentist, especially the dental radiologist, with regard to differential diagnosis, which should be made taking into consideration particularly the triticeal cartilage when it is calcified

FATOR DE RESPOSTA PRODUTIVA DE MOMBAÇA E MARANDU AO DÉFICIT HÍDRICO

O objetivo com este estudo foi compreender o efeito da disponibilidade hídrica sobre a produtividade no capim-mombaça [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] e capim-marandu [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster], determinando o coeficiente de resposta ao déficit hídrico (ky). O experimento foi avaliado em delineamento de blocos ao acaso, com duas forragens e três repetições. O período experimental correspondeu a doze ciclos de crescimento com intervalos fixos de colheita (28 dias para a estação chuvosa e 42 dias para a estação seca). Os ky foram determinados com base nos dados de produção real e potencial das forrageiras, bem como nos dados de evapotranspiração real e máxima. Para ambas as forragens, o acúmulo de forragem (AF) foi maior no outono e menor no inverno (5310 e 626 kg de matéria seca ha-1, respectivamente). Na média das quatro estações, o AF para capim-marandu foi 21,3% maior que o capim-mombaça (3344 vs. 2756 kg matéria seca ha-1, respectivamente). Para o capim-mombaça, o ky foi de 1,05, indicando sensibilidade média a alta ao déficit hídrico. No entanto, o ky foi de 0,63 para o capim-marandu, o que representa baixa sensibilidade ao déficit de água do solo.Palavras-chave: Brachiaria; coeficiente de sensibilidade; Megathyrsus; tolerância a seca. YIELD RESPONSE FACTOR OF MOMBAÇA GUINEA GRASS AND MARANDU PALISADE GRASS TO WATER DEFICIT ABSTRACT: The objective with this research was to understand the effect of water availability on Mombaça guinea grass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] and Marandu palisade grass [Brachiaria brizantha (Hochst. ex A. Rich.) R. D. Webster] productivity, determining the yield response factor to water deficit (ky). The experiment was evaluated in a randomized block design with two forages and three replicates. The experimental period corresponded to twelve growth cycles with fixed harvest intervals (28 days for the rainy season and 42 days for the dry season). The ky were determinate based on the data of real and potential yield of grasses, as well as the data of real and maximum evapotranspiration. To both grasses, herbage accumulation (HA) was greatest in the autumn and leats in the winter (5310 and 626 kg dry matter ha-1, respectively). On average of the four seasons, the HA for Marandu palisade grass was 21.3% higher than Mombaça guinea grass (3344 vs 2756 kg dry matter ha-1, respectively). For Mombaça guinea grass, ky was 1.05, indicating medium to high sensitivity to water deficit. However, the ky was 0.63 for Marandu palisade grass, which represents low sensitivity to soil water deficit.Keywords: Brachiaria; drought tolerance; Megathyrsus; sensitivity coefficient