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Biomedical subjects

P Menghini

Publications and source records attributed to P Menghini.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Elastomeric chains in orthodontics. An in vitro evaluation of ten different types].

BACKGROUND: This study is an evaluation and a comparison assessment of ten different types of orthodontics elastomeric chains in an in vitro situation simulating the clinical therapy for the canine tooth distalisation. METHODS: We designed and produced two custom made systems in order to simulate the clinical movement and to measure the elastic recovery. The first device was suitable to activate the elastomeric chains up to 100% of its extension and successively to reduce this extension through the time, as it happens during the clinical practice. Simultaneously with the activation of the chains, it was possible to submit the device to two different termocycling procedures. The measuring system was a linear guide skid-mounted on a balance which provided two grasps in the order to achieve the activation rate and to measure it. The force showed by the elastic recovery was relieved at the starting of the experience and after 1, 7, 14, 21 days. RESULTS: We relieved that the elastomeric chains decreased their elastic recovery to the 50-70% of the starting rate during the first day of activation, after which the force holded fairly uniform and after three weeks it was the 20-40% of the value corresponding to the starting activation. CONCLUSIONS: The tested elastomeric chains provide forces reliable to produce the tooth movement for a maximum of a three/four weeks period; than they have to be changed since the induced movement is nullifying its efficacy. At the comparative analysis the diaphanous type shows a lower decrease of the elastic force than the gray type, and the Short& e X-Short shapes show the same behaviour and generate forces much more performing than Long shapes.

Elastomers↗
PubMedDate not supplied

[Measurement technics].

Aim of the research has been the evaluation of an image processing technique suggested for measuring procedures in the field of dental materials and devices studies. An analysis of measurement systems and largest employment's equipments in the biotechnologies field has been performed. Particularly, digital and image processing technologies have been considered and, between them, an evaluation of "Image Tool" software, made by UTHSCSA and available freeware on Internet has been carried out. The "Image Tool" software showed to be easy in handling and reliable on this results. Since it is based on image processing, the measuring precision is related to subject to be evaluated dimensions and always in the 1/1000 tolerance. This software also allow the direct surfaces measuring and comparing. The process accuracy is at the same level of mechanical regulation's measuring instruments (calipers, micrometres, surface probes) but it is not comparable to the laser controlled equipments, like CAD-CAM systems, micrometres and surface explores, precision which are much more sophisticated and expensives.

Biotechnology↗
PubMedDate not supplied

Morphometric computerized analysis on the dentinal tubules and the collagen fibers in the dentine of human permanent teeth.

A morphometric analysis has been performed on important components of human dentine using an image computerized analyzer. The dentinal tubule diameter and their area percentage were calculated. Moreover the area percentage of the collagen fibers in the dentinal matrix was measured. These parameters have been evaluated in different areas of the coronal and the radicular dentine in permanent teeth. Measurements have been performed on undecalcified and decalcified teeth and on teeth treated with enzymatic digestion to remove the organic non collagen matrix and to evidentiate the collagen fiber network. The values obtained in different areas of the tooth and in samples submitted to different treatments were evaluated by statistical analysis. Dentinal tubule diameter and area percentage significatively decrease from the inner to the peripheral dentine both in the undecalcified teeth as in the decalcified ones and in the samples undergone to enzymatic digestion. The collagen fiber percentage in the organic matrix is significatively lower in the mantle dentine.

Adult↗
PubMedDate not supplied

[Light and electron microscopy observations on different tissues of a complex odontoma].

Several aggregates of dental tissues constitute the complex odontoma. They are almost completely covered by a layer of prismatic enamel. By the observations at transmission and scanning electron microscope enamel present the characteristics of a not fully developed tissue. The organic component is still abundant and the enamel surface is covered by a cellular layer having the morphological features of the mature ameloblasts. Therefore this enamel results to be yet actively engaged in the maturation phase although the tissues of the odontoma have generally a limited developing time.

Adolescent↗
PubMedDate not supplied

Lymphatic vessels in inflamed human dental pulp.

Investigation has been performed on both the light and electron microscopic characteristics of the lymphatic vessels present in the dental pulp of human teeth which have been affected by serious carious lesions. These conditions provoke a severe inflammatory response resulting in structural and functional modifications of the tissue; increase of the tissue pressure is followed by the need for a more intensive lymphatic drainage. In the inflamed pulps, dilated lymphatic vessels with distended walls and "open junctions" between endothelial cells are detectable. On the other hand they lack certain endothelial structures which characterize the morphology of these vessels under normal conditions. In the pulpal regions affected by fibrotic proliferation shrunken vessels with irregular profiles are present. From these observations it is possible to obtain other information on the mechanisms regulating the lymphatic drainage in different structural and functional conditions of the interstitium.

Dental Pulp↗