Influence of High-Fat Diet on Bone Tissue: An Experimental Study in Growing Rats.

BACKGROUND: The relationship between obesity and bone tissue remains contradictory, especially when the effect of high-fat diet is assessed in experimental models. The aim of this study was to evaluate the effects of high-fat diet on bone metabolism of growing rats. METHODS: Twenty weaned female Wistar rats were equally divided into two groups: SD (standard diet) and HFD (high-fat diet with 60 % of energy as fat). After five weeks of the two diets, the rats were euthanized, and the liver, blood and bones extracted. The liver was analysed for malondialdehyde (MDA) and reduced glutathione (GSH) concentrations. Blood was analysed by the ELISA method for osteoprotegerin (OPG) and tumour necrosis factor ligand superfamily member 11 (TNFSF11/RANKL). The bone tissue was analysed by dual-energy X-ray absorptiometry (DXA), mechanical tests, computed microtomography, histological quantitative analysis and scanning electron microscopy. The gene expressions of PPAR-γ Runx-2, RANKL and Cathepsin-K were also evaluated. RESULTS: HFD caused an increase in the MDA concentration, indicating oxidative stress. It also increased the expression of PPAR-γ, which is the gene that is related to adipocyte differentiation. There was an increase in BMD of the tibia of animals fed with the HFD, but other microstructural and mechanical properties were maintained unaltered. In addition, there were no changes in the gene expressions related to the differentiation of osteoblasts and osteoclasts, as well as no changes to the biochemical markers of bone formation and bone resorption. CONCLUSION: Liver and gene parameters are changed in response to the HFD. However, although there was an increase in BMD, the microstructure and function of the bone did not change after a 5-week HFD.

Emerging therapy in arthritis: Modulation of markers of the inflammatory process.

The induction of tolerance has been proposed as a therapeutic strategy for arthritis aiming to decrease progression of the pathology, probably by promoting suppressor mechanisms of the autoimmune response. This work aimed to confirm whether the treatment with vitamin D3 could synergize oral tolerance induced by hydrolyzed collagen peptides, in our experimental model of antigen induced arthritis in New Zealand rabbits. Clinical observation of the phenomenon indicates that simultaneous treatment with hydrolyzed collagen peptides and vitamin D3 was beneficial when compared with no treatment, for arthritic animals, and for arthritic animals that received treatment with only hydrolyzed collagen peptides or vitamin D3. Treatment with hydrolyzed collagen peptides caused diminished proinflammatory cytokine levels, an effect synergized significantly by the simultaneous treatment with vitamin D3. The anatomical-pathological studies of the animals that received both treatments simultaneously showed synovial tissues without lymphocytic and plasma cell infiltrates, and without vascular proliferation. Some of the synovial tissue of the animals of these groups showed a slight decrease in Galectin-3 expression. We propose that simultaneous oral treatment with vitamin D3 and hydrolyzed collagen peptides could increase the immunoregulatory effect on the process of previously triggered arthritis. We used articular cartilage hydrolysate and not collagen II because peptides best expose antigenic determinants that could induce oral tolerance. Oral tolerance may be considered in the design of novel alternative therapies for autoimmune disease and we have herein presented novel evidence that the simultaneous treatment with vitamin D3 may synergize this beneficial effect.

Anatomical variations of the mandibular nerve and its branches correlated to clinical situations.

AIM: The mandibular division of the trigeminal nerve is the largest of the three major divisions of the trigeminal nerve (fifth cranial nerve). In this way, many health professionals belonged to different fields are commonly evaluating patients suffering with orofacial pain and stomatognatic dysfunction associated to this structure. But, in the most cases, it is difficult to establish a correct diagnosis due to the anatomical complexity of the head and neck surfaces, especially when the focus is the trigeminal nerve. Thus, the objective of this research was to present the anatomical variations of the mandibular nerve and its branches correlated to more common clinical situations. METHODS: For this purpose, 20 human heads were anatomically dissected, so to study their structures, an external, medial and endocranial view. RESULTS: No significant variations related to ophthalmic and maxillary nerves were observed. Anatomical variations were observed in 20% of the total human heads dissected, all related to mandibular nerve and its branches: masseter, temporal, auriculotemporal and lingual. Variations in three to seven, on the number of the following nerves ramus, masseter and temporal were described. CONCLUSIONS: According to the present data using the described methodology, it was possible to conclude that anatomical variations are present in many subjects and they can explain many clinical situations that involve the stomatognathic structures.

Morphodigital evaluation of the trabecular bone pattern in the mandible using digitized panoramic and periapical radiographs.

AIM: Information about the agreement between periapical and panoramic radiographs is limited. A comparative morphologic and radiographic study of the trabecular bone pattern in the mandible was made. METHODS: To assess the agreement between the two different radiographic techniques, periapical and panoramic radiographs of 50 adult patients, from the documentation files of the Radiology Course at the Faculty of Dentistry of Ribeirão Preto, University of São Paulo, were digitized. Regions of interest in the bone trabeculae were selected in both techniques, being the lower canine surroundings in the mandible body (basal bone) the preferred region of selection. Images of interest were processed by the NIH Image software to convert bitmaps into skeletonizations, a mathematical morphology operation, and check bone trabecular pattern so as to evaluate the occurrence of different results when using either radiographic techniques. RESULTS: This study showed that the morpho-radiographical comparison of the trabecular bone pattern in the mandible, using digitized images of panoramic and periapical radiographs, presented significantly different results between both techniques (P<0.05). Limitations in image quality inherent to panoramic radiology contribute to a reduced diagnostic accuracy. CONCLUSIONS: Clinical interpretation of intraoral and panoramic radiographic images regarding bone quality should be taken carefully. Research is also indicated to further develop such selection criteria.

DNA Checkerboard method for bacterial detection of microbiota from teeth and tongue biofilms. A preliminary study.

AIM: The aim of this study was to determine the prevalence of 13 bacterial species in the dorsum tongue biofilm and compare its microbiota to that of subgingival samples in healthy adult subjects using DNA Checkerboard hybridization. METHODS: A total of 40 samples, from subgingival and tongue biofilm, were enrolled into the study. All the samples were harvested and analyzed by DNA Checkerboard method for their content of 13 species of bacteria. Bacterial scores from each subject and location were averaged and the results of both sites were compared using the Wilcoxon signed ranks test. RESULTS: All the microorganisms evaluated were detected in both tongue and subgingival samples, without significant differences in their prevalence. CONCLUSIONS: The dorsum of the tongue was colonized by various microorganisms with similar prevalence as found in the subgingival biofilm of healthy individuals, suggesting that the tongue could be a potential microbial reservoir and may play a role in the recolonization of teeth surfaces.

Adhesive bond strength between a ceramic system and composite resin bonded by resinous cement submitted or not to thermocycling process.

AIM: The success of ceramic restorations is influenced by biocompatibility and resistance provided after bonding with an adhesive system. The aim of this in vitro study was to evaluate the adhesive bond strength between ceramic (IPS Classic V, Ivoclar Vivadent) and composite resin (Z-250, 3M), submitted or not to thermocycling treatment. METHODS: Forty ceramic cylinders were obtained with the following dimensions: 2 mm diameter and 3 mm high. The bond surface was polished with polishing paper (#600), conditioned with 10% hydrofluoric acid and silanized, according to manufacturer's recommendations. Later, the ceramic cylinders were bonded, with resinous cement (Rely X, 3M) to composite resin cylinders (Z-250, 3M) with the same dimensions, under 1 kg load. The assemblies were divided into two groups submitted to the following treatments: Group 1 (control): immersed in distilled water at 37 degrees C for 3 days, and Group 2: thermocycled (500 cycles) into two baths (5 degrees C and 55 degrees C), with 1 min of storing time each. In order to evaluate the adhesive resistance, the assemblies were tractioned in a universal testing machine (EMIC MEM 2000) with a crosshead speed of 0.5 mm/min. Obtained data were submitted to statistical analysis (ANOVA and Tukey's test). RESULTS: The means (MPa) and standard deviation obtained for Groups 1 and 2 were, respectively, 29.64+/-9.48 and 17.55+/-4.78. Group 1 presented significantly higher values than Group 2 (P<0.05). CONCLUSION: The results obtained in this study showed that the thermocycling procedure decreased the adhesive resistance between the materials studied.

Analysis of the diametral compressive bond strength between composite resin and amalgam in different stages of oxidation.

AIM: Amalcomp is a technique that combines composite resin to amalgam in restorative procedures to improve esthetics and minimize the negative effects of polymerization on dental tissues. The objective of this in vitro study was to measure the diametral compressive bond strength between Fill Magic composite (Vigodent) versus Permite (DFL) or Velvalloy (SS White) amalgams in different oxidation stages. METHODS: Twenty-four cylinders of each amalgam brand were fabricated using a Teflon matrix and divided into 3 groups according to the immersion period in artificial saliva for oxidation: A (1 day), B (7 days) and C (30 days). After immersion, the amalgam cylinders were bonded to the composite specimens using the Scotch Bond Multi Use Plus (3M) bonding system. Diametral compression assays were then carried out in an EMIC-MEM 2000 universal testing machine set to 0.5 mm/min. Statistical analysis was performed using ANOVA and Tukey's test. RESULTS: The mean recorded strength (MPa) for each oxidation group was: A=9.71, B=8.21 and C=6.98 (A>B = C; P<0.01). Permite (7.24) provided significantly less adhesion to the composite than Velvalloy (9.36; P<0.05). There was no interaction between the factors alloy, resin and time. CONCLUSIONS: Under the conditions of this study, the less oxidized amalgam showed the greatest diametral compressive strength values.