Biomedical subjects

G Montanari

Publications and source records attributed to G Montanari.

At least 55 records · Page 3Linked to original sources

PubMed1991

Hydrostatic intrapulpal pressure and bond strength of bonding systems.

The purpose of this study was to evaluate the effect of intra-pulpal pressure on shear bond strength of three light-cured glass-ionomer cements (GC lining cement, Vitrabond, and Zionomer) and four dentin bonding agents [Gluma/Scotchbond, Scotchbond 2, MBL, and Clearfil Photo Bond]. Buccal dentin surfaces were prepared just below the DEJ by means of a diamond bur. Dentin treatments were made for Zionomer (Zionomer conditioner), Scotchbond 2 (Scotchprep), MBL (10-3 solution), Clearfil PB (H3PO4), GC lining cement (Polyacrylic acid), and Gluma/Scotchbond (EDTA). Resin composites were inserted into tubes, positioned on dentin, cured, tested after five min or 24 h, and compared with samples bonded and stored under an intra-pulpal pressure of 36 cm of saline. After 24 h in superficial dentin, intrapulpal pressure reduced the bond strength only in MBL, Scotchbond 2, and Zionomer. Clearfil PB bond strength was increased, while Vitrabond, GC lining cement, and Gluma/Scotchbond were unaffected by the presence of pulpal pressure. However, in deep dentin, Scotchbond 2 and Clearfil PB shear bond strengths were significantly reduced by storage in the presence of 36-cm H2O pulpal pressure. Only Vitrabond remained unaffected by pulpal pressure in deep dentin.

Composite Resins↗

PubMed1991

Results of the multicentric Italian experience on the Gamma nail: a report on 648 cases.

In a multicentric study, the data of 628 trochanteric fractures, two non-unions, and 18 pathologic or impending fractures treated by Gamma nail in 13 Italian traumatology services were collected and analyzed. In 70% of the patients weight bearing was allowed in the first postoperative week and 78% of the controlled patients returned to their pretrauma walking ability. Complications included intraoperative (1.4%) and postoperative (1.2%) shaft fractures, "cut out" of the lag screw (2.6%), and nail failure (0.5%). There were no cases of infection. An analysis of complications showed that most of them were due to technical mistakes. The safest procedure is 2 mm diaphyseal overreaming, introduction of the nail without hammering, and distal locking; the lag screw should be placed in the lower part of the head of the femur.

Aged↗

PubMed1991

[Echography in the diagnosis of breast cancer].

Fifty-one patients with clinically palpable breast cancer were examined using small-parts echotomography. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of overall diagnosis were assessed in the two groups of patients: T1 (diameter less than 2 cm) and T2-T3-T4 (diameter greater than 2 cm). The frequency of the main echographic signs associated with breast cancer was also investigated. Diagnostic accuracy was found to be high in the T2-T3-T4 group (93%), but very low in the T1 group (71%). The study confirms the importance of ultrasound as an additional test in the study of breast cancer. However, this method becomes increasingly less sensitive and specific as the size of the tumour decreases.

Breast Neoplasms↗

PubMed1990

Early marginal leakage and shear bond strength of adhesive restorative systems.

The aims of this study were to assess in vitro the early marginal seal effectiveness in Class V restorations at the cemento-enamel junction, and the early shear bond strength of several composite and dentin bonding system combinations. The seal effectiveness was studied by evaluating the dye penetrations: (a) along the superficial margin of restorations (width of surface microleakage); (b) along the dentin cavity walls (length of microleakage); and (c) toward the pulp (depth of microleakage). Good correlations were demonstrated among the seal evaluations, but no relationships were apparent between these and shear bond strength. Our study suggests that the marginal seal is influenced by composite properties more than by bonding agents. The shear bond analysis indicates only the adhesive potential of the materials without considering the composite shrinkage effects on marginal gap after the photocuring setting reactions.

Composite Resins↗

PubMed1990

Chlorpromazine disposition in relation to age in children.

The pharmacokinetics of chlorpromazine after intravenous infusion were studied in 25 children. The pharmacokinetic parameters studied are markedly different from those reported for adults. A clear relationship was demonstrated between age, serum terminal half-life (r = 0.75) and systemic clearance (r = -0.43). It appears that the pharmacokinetics of chlorpromazine are more rapid in children than in adults.

Adolescent↗

PubMed1990

Shear bond strength and SEM evaluation of dentinal bonding systems.

Shear bond strength of seven dentin bonding systems (DBS) was evaluated. After shear bond testing, the specimens were analyzed under scanning electron microscope (SEM). Buccal dentin just below the dentin-enamel junction of erupted third molars of young subjects were used. A statistical difference was observed among the material bond values. SEM examination of both sides of the sheared bonds frequently showed an adhesive failure between dentin and bonding agents in the specimens where resin penetrated into the opened dentinal tubules. A complex cohesive fracture of both resin and dentin was observed for bonding agents that required the treatment of the smear layer, while a cohesive fracture in the smear layer thickness was noted when dentin was not altered by primer solutions. The study demonstrated that the DBS that require the removal of the smear layer showed a significantly higher shear bond strength and that the bond value reflects the mode of material fracture and the presence of smear layer.

Composite Resins↗

PubMed1990

Metabolic effects induced by L-carnitine and propionyl-L-carnitine in human hypoxic muscle tissue during exercise.

An experimental model was developed to investigate some metabolic effects of strenuous exercise in hypoxic muscle tissue of human volunteers. The incidence of carnitine supplementation was studied, assuming as marker the thiobarbituric acid reaction products analysed in plasma samples collected during the course of the protocol programme. Propionyl-L-carnitine appears to antagonize in a significant degree the damaging effects of muscle fatigue combined with hypoxic status. Under these conditions the detoxifying role played by propionyl-L-carnitine, previously reported in various tissues and in other pathological conditions, appears to be relevant, although further studies are needed to elucidate the pharmacodynamics of this molecule.

Carnitine↗

PubMed1990

[Glass ionomer cements and dentinal pretreatments: the evaluation of their adhesion to the dentin].

The aim of the present study was to evaluate the shear bond strength test of two glass-ionomer cements (G C cement and Ketac Bond) after different chemical pretreatments of dentine surface. The following dentine pretreatments were used: sodium hypochlorite, polyacrylic acid, tannic acid, H3PO4, FeCl3, Fe ossalate, Tubulicid, H2O2 and aqueous solution as control. Flat dentine surface of human extracted teeth was treated with the chemical agents, washed and dried. Cylindrical specimens of glass-ionomer cement were applied on dentine surface. After 24 hours in humidifier the specimens were tested in a universal testing machine. A significant higher bond was obtained only from polyacrylic acid and sodium hypochlorite treatments. The present results suggest that dentine pretreatment represent an essential step in composite resin/glass-ionomer cement restorations.

Adhesiveness↗

PubMed1989

[Gigantic liposarcoma of the retroperitoneum].

A case of giant liposarcoma of the retroperitoneum (7.5 kg, diam. 39 x 30 x 18 cm) is reported. The most frequent sites of onset are discussed and stress is laid on the most useful diagnostic investigations. Surgical treatment, the only possibility of treatment for such large tumors, is often not radical and the recurrence rate is high.

Female↗

PubMed1989

[Class V cavities for composites. New preparation principles].

The aim of this study is to establish with the help of a computer a new type of Class V cavity that would ensure minimal marginal gap of restoration work using restorative resins. Comparison of computer graphics has shown that the ideal Class V cavity for restorative resins is cone-like with the apex or smaller base pointing towards the pulp and the walls slightly convex towards the free surface of the cavity. To prepare this sort of cavity new specular-type burrs are required.

Composite Resins↗

PubMed1989

[Dentin adhesives and the traction test. Comparative evaluation].

This study evaluated the shear bond strength of six dentinal bonding agents and one unfilled enamel bond in association with a microfilled composite resin. Eight specimens were prepared for each product. All the bonded samples were stored at 37 degrees C for 24 hours in a humidifier. Bond strength was measured with a universal testing machine. A statistically significant difference was found between the various products. The new dentinal bonding agents gave the highest bond value.

Composite Resins↗

PubMed1989

[Early marginal infiltration and Class II cavities].

The purpose of the present study was to evaluate the early marginal microleakage in 20 Class II MOD restorations made in association with conventional and sandwich technique. Human extracted third molars were used in the study. Multi-incremental technique was used in all restorations. After finishing, the teeth were stored in dye solution for 12 hours, transversally sectioned at three levels and evaluated under optical stereomicroscope. Cervical sections showed the highest marginal leakage. Sandwich technique in association with glass-ionomer cements have showed a significant lower early microleakage with respect to the conventional technique.

Composite Resins↗

PubMed1989

[A new lining material, B-tricalcium phosphate MG substitute].

Powder of not-sintered beta-tricalcium phosphate granules was used as capping material in deep cavities of monkey and human teeth. The authors have demonstrated by SEM with E-DAX the dispersion of beta-TCP in the dentinal tubules and in predentin. Histological sections didn't show any inflammation or degeneration of the pulp.

Animals↗

PubMed1989

[Surface polishing of posterior composites].

In this research we have valued at SEM the smoothness degree of the surface obtained in vitro on three kinds of composite resins for posterior restoration (P-30, P-50, Clearfil Photo Posterior); then we have compared it with the result obtained in vitro with an alloy not gamma-2 (Dispersalloy). The surfaces of the composite restorations show at SEM irregularities more or less accentuated for the presence of particles of filling got in comparison with the matrix. The surface of alloy restorations results on the contrary perfectly polished and completely comparable with the enamel surface.

Bicuspid↗

PubMed1989

[Surface polishing of anterior composites].

In this research it has been valued at SEM the smoothness degree of the surface obtained in vitro on three kinds of composite resins for anterior restorations (Lumifor, Silux, Pekalux). The surface has been polished and finished with abrasive disks (Sof Lex Pop On XT). The composite resin Lumifor presents at SEM a good finished surface. Far better results have been obtained with the microfilled composite resins Silux and Pekalux, which show at SEM surfaces perfectly polished and homogeneous.

Composite Resins↗

PubMed1989

Effects of acid and cleansing agents on shear bond strength and marginal microleakage of glass-ionomer cements.

The aims of the present study were to evaluate the effects of various dentin chemical pretreatments (a) on the shear bond strength of five glass-ionomer cements (GICs) and (b) on marginal microleakage of the five GICs used in association with resin composites in Class V restorations. The dentin treatments were: three acid agents (polyacrylic acid, tannic acid, orthophosphoric acid), three cleansing agents (Tubulicid blue solution, hydrogen peroxide, and sodium hypochlorite), and an aqueous solution as control. After dentin treatment, the test specimens were stored in water at 37 degrees C for 24 hr. Shear bond strength was determined with a universal testing machine at a cross-head speed of 0.5 cm/min. Sodium hypochlorite and polyacrylic acid significantly improved the adhesion of GICs to a different degree in the various materials. Regarding microleakage tests, 320 non-retentive cavities were prepared at the cementum-enamel junction in freshly extracted human teeth. The teeth were thermocycled, immersed in dye solution, and serial-sectioned longitudinally at three sites. Treatment with sodium hypochlorite was the most effective in reducing marginal leakage. The present results suggest that dentin treatment is an important step in all resin composite/GIC restorations.

Acid Etching, Dental↗

PubMed1989

Lipid effects of celiprolol, a new cardioselective beta-blocker, versus propranolol.

The metabolic effects of celiprolol, a new beta-adrenoceptor blocking agent with intrinsic sympathomimetic activity and alpha 2-blocking properties, were evaluated in a series of patients with hypertension, both with and without hyperlipidemia. Propranolol was tested as the reference drug in a randomized double-blind trial. Of the 35 patients of both sexes who completed the study, 17 were hyperlipidemic (low-density lipoprotein cholesterol greater than or equal to 170 mg/dl) and 18 were normolipidemic. Both drugs exerted a similar hypotensive effect after gradual dose adjustment; however, propranolol reduced heart rate to a higher extent (-20.5%) than celiprolol (-7.7%). Propranolol determined a significant rise of total and very low-density lipoprotein (VLDL) associated triglyceridemia, whereas high-density lipoprotein cholesterol (HDL cholesterol) levels and the total cholesterol/HDL cholesterol ratios were significantly depressed, particularly in hyperlipidemic patients. Celiprolol, in contrast, slightly decreased triglyceridemia (significantly in the hyperlipidemic group at week 12) and caused a 5% increase of the HDL cholesterol levels. The total cholesterol/HDL cholesterol ratio was reduced by celiprolol at week 16 in both hyperlipidemic and normolipidemic patients. The effects of the two beta-adrenoceptor blockers on HDL cholesterol and triglyceride levels differed significantly after 12 and 16 weeks of treatment, which confirm the divergent metabolic effects of the two agents.

Adrenergic beta-Antagonists↗

PubMed1989

[Dentinal adhesives and glass ionomer cements: which are the best?].

The aim of this study was to examine the degree of marginal infiltration in vitro of some different dentinal bonding agents and glass ionomer cements in class V cavities prepared at cementum-enamel junction. A microfilled composite resin was used in all the cavities. Two-hundred and fifty thermocycle tests were performed after the samples had been in water for 24 hours. After evaluation under optical stereomicroscope, statistically significant differences between the various bonding systems were revealed. It would appear that the new generation of dentinal bonding systems, e.g. Scotchbond 2, Gluma Bond and Superbond, offer significant better in vitro results.

Dental Cavity Preparation↗