Hyaluronan does not improve bone healing in critical size calvarial defects in rats: a radiographic evaluation

Aim: This study evaluated radiographically the effects of 1% hyaluronan in bone healing using a critical size rat-calvaria defect model. Methods: Thirty adult male Wistar rats were used in this study. Two 6-mm-diameter critical-size defects were created and the treatments were randomly distributed as follows: 1) 1% hyaluronan; 2) 1% hyaluronan soak loaded onto an absorbable collagen sponge (ACS) carrier; 3) saline; and 4) ACS alone. The animals were sacrificed at 4 and 8 weeks when biopsies were collected and radiographs obtained using a direct digital radiograph system and a standardized protocol. A blind examiner evaluated the radiographic density of the images twice and an intra class correlation was performed to evaluate examiner reproducibility (R2=0.99, p<0.001). Comparisons between 4 and 8 weeks of treatment were performed by Student’s t test and comparisons between treatments and time by two-way A NOVA at 5% significance level. Results: There were no noteworthy differences between 4 or 8 weeks within each treatment group (p>0.05). When treatments were compared no significant differences between groups were found (p>0.05). Conclusions: Within the limits of this study, it can be concluded that 1% hyaluronan gel alone or its association with a carrier does not improve bone healing.

Dieta hiperlipídica e sua influência na evolução da doença periodontal experimental em ratos: resultados preliminares / Hiperlipidic diet and its influence on the evolution of experimental periodontal disease in rats: preliminary results

O presente estudou avaliou, histometricamente, a influência da dieta hiperlipídica sobre a evolução da doença periodontal experimental em ratos. Foram utilizados 32 ratos que foram aleatoriamente divididos em dois grupos: grupos 1 (ração para animais de laboratório) e grupo 2 (tacão hiperlipídica). Uma ligadura de fio de algodão foi colocada ao redor do primeiro molar inferior esquerdo e o dente contra-lateral serviu como controle. Os animais foram sacrificados nos intervalos de 7, 14, 21 e 28 dias após a colocação da ligadura para avaliarmos a doença periodontal experimental. Análise histométrica foi realizada para quantificar a perda óssea na região da bifurcação. Os dados foram analisados com os testes ANOVA e de Tukey ao nível de significância de 5%. Os animais não apresentaram alteração de peso corpóreo significante em relação ao início do experimento, diferenças também não foram encontradas entre os dois grupos (p>0.,05). Os dentes com ligadura apresentaram maior área de perda óssea (APO) que os dentes controle (p<0,0001). No entanto, não foram observadas diferenças estatisticamente significantes entre a evolução da doença periodontal e entre as diferentes dietas (p>0,05). Desta maneira, dentro dos limites deste estudo, podemos concluir que o consumo de uma dieta hiperlipídica não exerce influência sobre a perda óssea resultantes da periodontite induzida em ratos.

Obesity and periodontal disease: why suggest such relationship? An overview

Obesity is a chronic condition that has social and economic implications for public health. It can be associated with periodontal disease since the metabolic alterations observed in that condition could have some influence in immunity. The elevated levels of lipid and glucose can be associated with periodontal disease, contributing to an exacerbated host inflammatory response, alterations in neutrophil function, and with the inhibition of macrophage growth factors, reducing tissuehealing capacity. In this way, obese individuals could have higher chances of undergoing tissue destruction in the presence of periodontal infection. On the other hand, periodontitis may be involved in alterations of lipid metabolism, since gram-negative bacteria could promote a rise in cholesterol and triglyceride levels due to chronic exposure to low levels of LPS in circulating blood, leading to the production of cytokines, which could initiate the production of lipoproteins by the liver. The objective was to review the literature about obesity and periodontal disease and provide a better understanding of their relationship.