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Biomedical subjects

C Prati

Publications and source records attributed to C Prati.

90 records · Page 5Linked to original sources
PubMed1985

DR and non-DR Ia allotypes are associated with susceptibility to coeliac disease.

We have studied the frequency of HLA-DR, -MT, and -MB antigens in adult patients with coeliac disease and in a group of healthy controls, evaluating the strength of the observed associations by measuring the aetiologic fractions. Among the antigens significantly associated with coeliac disease, MB2 (DQw2) showed an aetiologic fraction higher than those of DR3 and DR7. Our results suggest that MB2, as associated more frequently than other specificities with a hypothetical disease predisposing gene, may play a role in the pathogenesis of coeliac disease. The significant association of DR3 and DR7 with coeliac disease may be ascribed to linkage disequilibrium of these antigens with MB2.

Adolescent↗
PubMedDate not supplied

Internal jugular phlebectasia in children.

Phlebectasia is an abnormal dilatation of an isolated vein, may affect any vein, and is usually asymptomatic. When the internal jugular vein is involved, it presents as a cervical swelling that can mimic the signs of either pharyngocele or a laryngocele and, because of its rarity, is frequently misdiagnosed. We describe 2 cases of phlebectasia of internal jugular vein in children with voice change in one of them. No treatment is necessary for this benign, self-limiting condition. Clinical features, diagnosis, treatment options, and a review of the literature about this rare venous lesion are presented.

Child↗
PubMedDate not supplied

Thickness and morphology of resin-infiltrated dentin layer in young, old, and sclerotic dentin.

The purpose of the present study was to evaluate the morphology of the resin tags and the resin-infiltrated dentin layer (RIDL) of several bonding systems in superficial vs deep young, old, and sclerotic human dentin. Dentin was obtained after the removal of occlusal enamel from extracted molars. Phosphoric acid gels (35-37%) were used to etch dentin before the application of bonding systems (OptiBond FL; Prime & Bond 2.0; Scotchbond Multi-Purpose Plus and Scotchbond 1; One Step). Each bonded specimen was then sectioned into two halves. One half was polished using a standard procedure to evaluate RIDL thickness and morphology by SEM. The other half was demineralized and deproteinized to evaluate the presence and the morphology of resin tags. RIDL was thinner in superficial dentin than in deeper dentin for all the materials tested regardless of the type of dentin. Sclerotic and old dentin showed thinner RIDL, with short resin tags, and fewer lateral branches than normal dentin.

Acid Etching, Dental↗
PubMedDate not supplied

Marginal hybrid layer in Class V restorations.

The aim of this study was to evaluate the morphology of the hybrid layer (identified as marginal hybrid layer) along the cervical margins of Class V restorations using several bonding systems. Class V restorations were prepared in vitro at the CEJ in extracted third molars. Three different bonding systems were selected: Scotchbond 1 (Single Bond), Scotchbond MP, and Clearfil Liner Bond 2V. After finishing each restoration with disks, each margin was polished for one minute with polishing paste. The margins of half of the restorations were then treated with 10% phosphoric acid for five seconds, washed in deionized water, and then stored in water for 24 hours before SEM analysis. The margins of the other half of the restorations were treated with 10% phosphoric acid for five seconds, then with 1.5% NaOCl gel for two minutes to remove noninfiltrated collagen, then washed and stored in water for 24 hours. Each sample was gold coated and observed under SEM. A one-way ANOVA was performed to determine if there were any statistically significant differences in hybrid layer thicknesses. The thickness of the marginal hybrid layer measured under SEM was 1.5-2.5 microns thick in Scotchbond MP and Scotchbond 1 but varied from 0.0 to 12.0 microns in Clearfil Liner Bond 2V when observed after NaOCl postpolishing procedures. Far more porosities were seen in the marginal hybrid layer of Clearfil Liner Bond 2V. Enamel margins were free from a hybrid layer in both groups. This study demonstrated that collagen fibrils are not completely infiltrated by adhesive resin at the CEJ level along the cavorsurface margin of the restorations. The presence of noninfiltrated collagen along the external margins may reduce the sealing capability of bonding systems, leaving many open spaces and gaps, which may jeopardize the durability of the bond over time.

Acid Etching, Dental↗
PubMedDate not supplied

[Esthetic restoration of the posterior sector. State of the art].

Patient's aesthetic requirements have increased in the past few years. The limited resistance of composites to wear has delayed their universal adoption for restoration of Class I and II cavity preparations in adult teeth. Although the potential use for posterior composite resin appears promising, the point at which such materials may be regarded as ideal, reliable, routine alternatives to silver amalgam has not been reached for materials of previous generation. To resolve some of the problems associated with the posterior composite resin, new materials (photo-cured GIC, multi step bonding agent, improved composite resins as P-50, Heliomolar Radiopaque, Ray Post) and new techniques have been introduced. In this paper the problems and questions raised with the use of posterior composites have been discussed.

Adhesives↗
PubMedDate not supplied

[The characteristics and properties of calcium phosphates in biomaterial formulations used in dentistry. 1].

In this work we present the features and the properties of natural and synthetic apatites, which we use in an experimental study of various commercial products composed by calcium phosphate. After having considered the general concepts of biomaterials and biocompatibility, we describe non biological tests used for the characterization of these products. Biomaterials used in this study are: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non reabsorbable thin Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2 Osprogel, Bio-oss, Biostite, Osprovit, Merck Hydroxiapatite. Tests used are: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and thermodifferential analysis (TG, DTG, DTA), scanner-ing electron microscopy (SEM) morphological analysis. Last but not least, we underline the particular features of these tests whose interpretation allows a more precise definition of the bioactivity of a biocompatible material.

Biocompatible Materials↗
PubMedDate not supplied

[The characterization by Fourier-transform infrared vibration spectroscopy of mineral-based biomaterials commonly used in dentistry. 4].

In this study the following biomaterials were analysed by means of Fourier transform infrared vibrational spectroscopy (FTIR); they are: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non reabsorbable fine Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2 Osprogel, Bio-Oss, Biostite, Osprovit, Merck Hydroxyapatite. The analysis was performed with a Jasco 5300-FTIR. At 64 readings for spectrum with a 2 cm-1 resolution. By means of this method it has been possible to perform a structural study at a molecular level of the commercial products mentioned before. The analysis showed which of the samples examined had lost the apatite OH- group during production. It also allowed the identification of some of the hydroxyapatites examined as carbonate apatites. Finally, it allowed the identification and quantification of the organic substances in the examined products.

Biocompatible Materials↗
PubMedDate not supplied

[The marginal leakage of amalgam and Vitrebond restorations after an occlusal load test].

The use of adhesive liners in amalgam fillings and restorations is a recent form of conservative dentistry. The aim of our study was to assess marginal microleakage in amalgam and Vitrebond restorations after occlusal load test. Using extracted teeth, we prepared 16 class II amalgam restorations, (Valiant ICQ, Caulk). Adhesive liner, (Vitrebond, 3M USA), was used in half of these. The samples then had first a cyclic load test, (27 kg per 7,000 cycles), followed by a microleakage test, (sample immersed in 2% erythrosin solution for 24 hours). The results showed that, in samples with adhesive liner, color penetrated to a statistically lesser extent than in the control group without Vitrebond.

Dental Amalgam↗
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↗