Long-term use of dentine adhesive as an interfacial sealer under Class II amalgam restorations

An in vitro study was carried out to evaluate the long-term sealing properties of a light-cured dentine adhesive in Class II amalgam restorations. The restorations were subjected to repeated vertical occlusal loads and a number of thermocycling procedures. The results demonstrated significant advantages of using a dentine adhesive as an interfacial sealer in order to reduce microleakage, compared to a conventional Copal varnish.     

The effect of posterior composite restorations on the resistance of cavity walls to vertically applied occlusal loads

The resistance of the cavity walls of non-vital premolars to vertically applied occlusal forces was studied. Standardized MOD cavities were prepared, restored, and vertical forces were applied to each of the cuspal tips by the Instron machine. Results suggest that bevelled etched-enamel margins and dentine-bonded posterior composite resin restorations significantly improved (by 33%) the resistance of the remaining cavity walls compared to amalgam restorations. In a control group, in which no restorations were carried out in the prepared cavities, the resistance of the walls was significantly smaller than in both restored groups.     

HUMAN GROWTH HORMONE (hGH) STIMULATION TESTS: THE SEQUENTIAL EXERCISE AND l-DOPA PROCEDURE

Forty-eight normal volunteers, thirteen subjects with short stature without apparent cause and thirty-one patients with delayed growth clinically highly suggestive of growth hormone deficiency (GHD), with chronological ages of 11.4 +/- 0.4 years (mean +/- SEM), 14.0 +/- 0.7 years and 12.8 +/- 0.8 years; height age of 11.0 +/- 0.4 years, 8.9 +/- 0.7 years and 6.3 +/- 0.4 years and bone age of 10.7 +/- 0.7 years, 9.9 +/- 0.8 years and 7.5 +/- 0.7 years respectively, were tested with provocative tests of human growth hormone (hGH) release-insulin-induced hypoglycaemia, arginine infusion, L-DOPA, exercise and sequential exercise and L-DOPA--in order to identify growth hormone deficiency. In the 'normal' subjects (control plus short stature) the sequential exercise and L-DOPA test induced the greatest peak and integrated secretion rates of plasma hGH (16.5 +- 1.2 ng/ml and 679 +/- 70 ng/ml/120 min respectively) when compared to other tests. This combined stumulus was the only one to which all 'normal' subjects responded: a similar degree of responsiveness has not been earlier described for other hGH-stimuli. The responses observed with all stimuli were significantly lower (P less than 0.001) in GHD group compared to the 'normal subjects'. Emphasis was given to the sequential exercise and L-DOPA test as an innocuous, sensitive and simplified procedure in the evaluation of children with growth retardation.     

The Occurrence of Genital Mycoplasmas in Babies with and without Respiratory Distress

ABSTRACT. Vreaplasma urealyticum organisms (ureaplasmas) were isolated from throat swabs and/or gastric aspirates taken from 22.5 % of babies with respiratory distress in a special care unit. -The organisms were isolated most frequently (33%) from a small number of babies with severe distress. However, they were recovered only a little less often (26%) from babies without respiratory distress in the unit, and from 19 % of healthy babies, all of the aforementioned babies having been delivered vaginally. The numbers of organisms isolated from babies in the various groups were similar. There was, therefore, no clear evidence that ureaplasmas, nor M. hominis which was isolated from two babies only, were associated with respiratory distress. This finding was supported by the isolation of ureaplasmas from only one of 16 babies born by caesarian section, seven of whom developed respiratory distress but were ureaplasma-negative.     

Monocytes/macrophages infected with Toxoplasma gondii do not increase co‐stimulatory molecules while maintaining their migratory ability

Toxoplasma gondii is an obligate intracellular parasite that is able to disseminate into deep tissues and cross biological barriers, reaching immunoprivileged sites such as the brain and retina. The parasite is able to infect macrophages and dendritic cells and use them for dispersal throughout the body, but the activation state of those cells is unknown. We investigated the ability of human and murine cells from monocytic/macrophage lineages that had not previously been exposed to inflammatory cytokines to up‐regulate co‐stimulatory and adhesion molecules upon infection. Toxoplasma gondii‐infected human monocytes (freshly isolated and THP1 lineage) were unable to up‐regulate CD86, CD83, CD40 or CD1a. CD80 expression increased in infected cells but expression of l ‐selectin and β2 integrin was unaltered. We evaluated the ability of infected macrophages from wild type C57/BL/6 or CD14^?/? mice to migrate in 8 μm transwells. Infected cells from CD14^?/? mice were more likely to de‐adhere than infected cells from wild type mice but they did not show any increase in migratory ability. The non‐stimulatory profile of these infected cells may contribute to parasite spread throughout the lymphatic circulation in the initial phases of infection.     

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

Objective

The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)₂] from root canals.

Material and Methods

Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)₂-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)₂ removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)₂ was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)₂ (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)₂ were evaluated in the middle and apical thirds using a 5-score system.

Results

None of the techniques completely removed the Ca(OH)₂ dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)₂ in the middle (P=0.11) and the apical (P=0.23) thirds.

Conclusion

The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)₂ from mandibular incisor root canals.     

Surface texture evaluation of glass ionomer restorative materials polished utilizing poly(acrylic acid) gel

This study evaluated the surface texture of three different glass ionomer restorative materials and a composite resin, polished by a new method using poly (acrylic acid) gel. Conventional polishing methods and finishing agents were compared to the proposed new procedure. Evaluations were carried out employing three techniques: profilometry, scanning electron microscopy and microhardness testing. The use of a poly(acrylic acid) gel with polishing discs gave significantly better results, and is therefore recommended for clinical applications.     

Analysis and Characterization of the Interleukin 2 Receptor α and β Chain Expression inCD4−CD8− Cells

The differential effects that the binding of interleukin 2 (IL-2) to its beta or alpha beta receptors might induce in two different CD4-CD8- T-cell lines were analysed. While LD1.T3b, a double-negative T cell derived from MRL/lpr mice, constitutively expressed high levels of the IL-2R beta chain, YAC-1, a Moloney sarcoma virus-transformed CD4-CD8- T cell, expressed (as an activated T cell) the beta and alpha chains. The presence of IL-2 in the culture medium was lethal for LD1.T3b cells, while it had no effect on the growth of YAC-1 cells. IL-2 increased the expression of the beta chain and, to a lesser extent, of the alpha chain in YAC-1 cells. In addition, other markers such as CD4 and CD5 were induced by IL-2 in this cell line.