Biomedical subjects

R Mongiorgi

Publications and source records attributed to R Mongiorgi.

61 records · Page 4Linked to original sources

PubMedDate not supplied

[Scanning electron microscopy (SEM) and microanalysis (EDS) applied to the study of biomaterials for dental use. 6].

The study considers the use of scanning electron microscopy (SEM) and EDS microanalysis applied to the study of numerous mineral-based biomaterials of common use in odontostomatology. The products studied are the following: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non rabsorbable fine Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2, Osprogel, Bio-Oss, Biostite, Ospro-vit, Merck Hydroxyapatite. By means of SEM it was possible to study the morphology and the microchemistry of the various biomaterials so as to have information about their physical and chemical characteristics, such as the crystalline form, the crystalline aggregations, the space dimensional distribution of the pores and check the possibilities of composition variability. All of these factors are fundamental to evaluate the functional biocompatibility of a biomaterial, once that its performance in a biological environment is known.

Biocompatible Materials↗

PubMedDate not supplied

[The specific characteristics determined by nonbiological tests of mineral-based biomaterials used in dentistry. 7].

In this work we relate about the results coming from crystallographic, physical and mineral tests taken on following biomaterials used in odontostomatology: reabsorbable Dac Blu, non reabsorbable Dac Blu, not reabsorbable atomized Dac Blu, not reabsorbable thin Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2, Osprogel, Bio-Oss, Biostite, Osprovit, Merck Hydroxiapatite. The data were obtained using the following tests: XRF, XRD, FTIR, TG, DTG, DTA, SEM. The results, although taken on few samples, showed that these biomaterials present a variability in some features, which can define the structural functionality.

Biocompatible Materials↗

PubMedDate not supplied

Electromagnetic fields in the treatment of postmenopausal osteoporosis: an experimental study conducted by densitometric, dry ash weight and metabolic analysis of bone tissue.

The authors conducted an experimental study on 32 female rats which had been castrated at 10 months of age in order to verify the ability of pulsating electromagnetic fields to prevent osteoporosis induced by surgical menopause. Two different values of intensity of PEMFs were used: 30 G and 70 G. After 4 months of treatment the following testing was done: monophotonic bone densitometry of the lumbar spine, quantitative measurement of the dry ash weight of the femurs, and hematochemical tests to evaluate bone metabolism. The experimental study showed that the PEMFs supplied at 30 Gauss were capable of slowing down the loss of bone mass, while the PEMFs supplied at 70 Gauss obstructed bone decay, providing values for Bone Mineral Density and dry ash weight which were very similar to those observed in the non-castrated control group. Hematochemical tests did not reveal significant variations between the two groups.

Animals↗

PubMedDate not supplied

Experimental surgical model in osteoporosis study.

To induce osteoporosis in animals many different experimental models are suggested. Experimental animal models play an important role in improving the knowledge of the aetiology, pathophysiology, diagnosis, and preventive and therapeutical techniques regarding osteoporosis. These experimental models permit thorough and standardized data that would be difficult to obtain by experimental clinical studies because of the difficulty of evaluating the differences that exist among patients. The choice of an in vivo experimental model is conditioned by a lot of factors: the reliability, the reproducibility, the feasibility and often some factors linked to equipment and costs which are also very important. In the present study some experimental models are examined and discussed, and in particular an experimental surgical model, that was performed in the Department of Experimental Surgery of the Rizzoli Orthopaedic Institute, is described. Female Sprague-Dawley rats, 40 or 50 weeks old, 350 +/- 20 g b.w., underwent bilateral oophorectomy in order to obtain an oestrogen deficiency. During the postoperative period the animals were maintained at the same housing conditions and diet. Fourteen days after oophorectomy it was possible to observe an osteopenia, that became progressively more pronounced up to 100 days. Till now this model permitted the comparative evaluation of different therapeutical treatments in such a diffuse and still debated pathology. Many are the experimental models adopted for comparative experimental studies of osteoporosis. Our model can induce a constant decrease of bone mass both in 50 and in 40 week old rats.

Animals↗

PubMedDate not supplied

Evaluation of an experimental model of osteoporosis induced in the female rat through ovariectomy.

The present paper intends to check the possibility of improving convenience of the osteoporosis model from ovariectomy in the rat by anticipating the operation to the 40th week rather than the 52nd week of age, thought by some authors to be the optimum model. To this end two parameters have been examined: 1. the bone mass variation determined with the vertebral photon densitometer and weighing of the femur ashes; 2. the chemico-crystallographic characteristics of the bone determined through chemical analysis and X-ray diffractometry. The results obtained induce us to believe that ovariectomy carried out on rats of 40 or 52 weeks of age determine bone mass losses that are statistically comparable. The variations in the dry bone weight/ash bone weight ratio are superposable and the structural chemical characteristics, due to the increase in bone turnover are testified by the increase in osteocalcin. Moreover, it was observed that the most reliable evaluation of bone mass loss can be obtained with the vertebral photon densitometry. Thus, it is thought that the model which foresees ovariectomy of rats 40 weeks after birth compared with those operated 52 weeks after birth, represents a good model of osteoporosis from estrogen deficiency which, due to the evident practical advantages deriving from the use of younger animals it associates a decrease in the use of laboratory animals with statistically reliable results.

Absorptiometry, Photon↗

PubMedDate not supplied

Effects of pulsed magnetic fields in the therapy of osteoporosis induced by ovariectomy in the rat.

This paper presents preliminary results on the effects of pulsed electromagnetic fields (EMF) in the therapy of post menopausal osteoporosis induced by ovariectomy in female rats aged ten months. In particular, the effects of the intensity of pulsed EMF applied at constant frequency has been studied. Magnetic fields pulsed at 50 Hz were used having a positive sinusoidal wave form with a maximum intensity of 30 and 70 Gauss. Treatment lasting one hour per day for 4 months showed that the pulsed EMF with 30 Gauss of maximum intensity are able to slow down the bone mass loss, keeping it within some 10%; with pulsed EMF with 70 Gauss of maximum intensity, instead, no significant bone mass loss was observed.

Animals↗

PubMedDate not supplied

Resin-infiltrated dentin layer formation of new bonding systems.

The purpose of this study was to evaluate the resin-dentin interfacial morphology and shear bond strength of several new and experimental dentin bonding systems classified as single-bottle/total etch, multi-step/total etch, and self-etching. Class 1 and 5 cavities were prepared from freshly extracted permanent molars and restored with composite resin. Each bonded sample was cross sectioned and one-half was completely demineralized and deproteinized, while the other half was polished along the cut surface to permit measurement of the thickness of resin-infiltrated dentin layer (RIDL) within intertubular dentin (iRIDL) and around the peritubular walls (pRIDL) of resin tags by SEM. Shear bond strength was measured for all the systems 2 minutes after photocuring. SEM showed iRIDL and resin tags of different morphology depending on material and dentin location. The iRIDL was thinner in superficial dentin and thicker in deep dentin. Peritubular RIDL (pRIDL) was thinner than intertubular RIDL. Bond strength measurements varied from 12 to 21 MPa, depending on the materials used. Self-etching primer systems exhibited the highest bond strength, although one of the one-step/total etch systems also yielded very high values. The contribution of pRIDL to adhesion onto superficial dentin is limited by the small number of tubules. Single-component bonding agents produced SEM morphology and bond strengths similar to those of multi-step systems. Self-etching systems, despite their limited RIDL thickness, produced the highest immediate bond strengths. Bond strength did not correlate well with the thickness and morphology of RIDL.

Adult↗