Objective:The aim of this study was to evaluate the effect of the alcohol consumption on the periodontal bone support (PBS) in experimental periodontitis in rats.Materials and Methods:Sixty-three male rats were divided into seven groups: G1 (control); G2 (10% ethanol); G3 (nutritional control of G2); G4 (20% ethanol); G5 (nutritional control of G4); G6 (30% ethanol) and G7 (nutritional control of G6). The groups G3, G5 and G7 received controlled diets with equivalent caloric amounts to those consumed in G2, G4 and G6 respectively, with the ethanol replaced by sucrose. After anesthesia, ligatures were installed around the mandibular first molar, leaving the contralateral teeth unligated. After 8 weeks, the rats were killed and their mandibles were radiographed to measure the percentage of PBS on the distal aspect.Results:The intragroup analyses showed that presence of ligatures induced periodontitis (p<0.05). Unligated groups did not show significant differences among the percentages of PBS (p=0.1969). However, in ligated groups the rats that received alcohol (G2:48.71%±3.88; G4:47.66%±2.54; G6:47.32%±3.24) and the nutritional control group associated with a high concentration of ethanol (G7:47.40%±3.24) presented a significantly lower percentage of PBS than the other groups (G1:52.40%±2.75; G3:52.83%±2.41; G5:50.85%±4.14).Conclusions:These results demonstrated that alcohol consumption in rats may result in a direct effect on alveolar bone loss and increased development of periodontitis. In addition, they suggest that heavy caloric consumption of ethanol may also present an indirect effect on periodontal tissue as a consequence of malnutrition.
Bisphosphonates are currently used in the treatment of many diseases involving increased bone resorption such as osteoporosis. Statins have been widely used for the treatment of hypercholesterolemia and recent studies have shown that these drugs are also capable of stimulating bone formation. The purpose of this study was to evaluate the influence of an estrogen deficient state and the effects of simvastatin and sodium alendronate therapies on alveolar bone in female rats. Fifty-four rats were either ovariectomized (OVX) or sham operated. A month later, the animals began to receive a daily dose of simvastatin (SIN - 25 mg/kg), sodium alendronate (ALN - 2 mg/kg) or water (control) orally. Thirty-five days after the beginning of the treatment, the rats were sacrificed and their left hemimandibles were removed and radiographed using digital X-ray equipment. The alveolar radiographic density under the first molar was determined with gray-level scaling and the values were submitted to analysis of variance (alpha = 5%). Ovariectomized rats gained more weight (mean +/- standard deviation: 20.06 +/- 6.68%) than did the sham operated animals (12.13 +/- 5.63%). Alveolar radiographic density values, expressed as gray levels, were lowest in the OVX-water group (183.49 +/- 6.47), and differed significantly from those observed for the groups receiving alendronate (sham-ALN: 193.85 +/- 3.81; OVX-ALN: 196.06 +/- 5.11) and from those of the sham-water group (193.66 +/- 4.36). Other comparisons between groups did not show significant differences. It was concluded that the ovariectomy reduced alveolar bone density and that alendronate was efficient for the treatment of this condition.
ObjectiveThe present study evaluated morphometrically bone loss percentages in experimental periodontitis in rats, comparing different locations (lingual mandible, palatal maxilla and buccal maxilla) and two evaluation methods (distance and area methods).Material and MethodsLigatures were placed around the maxillary right second molar and around the mandibular right first molar in 14 female Wistar rats. The contralateral molars served as intragroup controls. After 4 weeks, the rats were sacrificed and their mandible and maxilla were removed. The specimens were dissected and stained with methylene blue dye. Bone loss was evaluated by two different methods on the surfaces of the defleshed jaw. In the first method, the distance from the cementoenamel junction (CEJ) to the alveolar bone crest was measured in the roots of teeth associated with ligature. In the second method, the area of bone loss was determined using the alveolar tissue bone, CEJ and the proximal region of roots associated with the ligature as reference. The data were converted to bone loss percentages caused by ligature: (ligated – unligated) x 100/ligated.ResultsWhen comparing the distance and area methods, no statistically significant difference was observed (p>0.05). Both methodologies indicated that the maxilla presented greater bone loss than the mandible and it was more accentuated on the buccal side than on the palatal side (p<0.05).ConclusionThe findings of this study show that both the area and the distance methods can be used to evaluate bone loss caused by ligature placement in rats, and suggest applying the morphometric methodology to the maxilla on the buccal side.
Técnicas tradicionais de classificação de imagens multiespectrais têm sido a ferramenta usual para o mapeamento temático da cobertura da terra. Tais técnicas foram projetadas para tratar fenômenos que apresentam limites bem definidos e que podem ser facilmente discretizados. Contudo, existem regiões de incertezas e imprecisões a serem mapeadas, as quais demandam técnicas alternativas, como classificações baseadas em abordagem fuzzy. Nesse contexto, este trabalho tem o objetivo de apresentar e analisar comparativamente os resultados obtidos a partir da aplicação da técnica de Máxima Verossimilhança e de dois classificadores baseados em abordagem fuzzy (relativo bayesiano e Distância da Média fuzzy). Para tanto, foi adquirida uma imagem ETM+/Landsat de uma área teste previamente selecionada; realizado o treinamento dos classificadores; e definidas as classes de cobertura da terra. Os resultados obtidos com a aplicação das técnicas de Máxima Verossimilhança, relativa bayesiana e Distância da Média mostraram que classificações relativas são mais adequadas às situações onde ocorre confusão entre as classes, ou seja, quando estas apresentam comportamento inerentemente fuzzy e respostas espectrais similares, dificultando a separação das mesmas. Além disso, as classificações fuzzy fornecem informações relacionadas com a incerteza na atribuição dos pixels às classes, que podem ser úteis e tornar os mapas temáticos gerados mais confiáveis.
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