Résumé
ABSTRACT Objective The study aimed to evaluate effects of air abrasion with alumina or glass beads on bond strengths of resin cements to CAD/CAM composite materials. Material and Methods CAD/CAM composite block materials [Cerasmart (CS) and Block HC (BHC)] were pretreated as follows: (a) no treatment (None), (b) application of a ceramic primer (CP), (c) alumina-blasting at 0.2 MPa (AB), (d) AB followed by CP (AB+CP), and (e) glass-beads blasting at 0.4 MPa (GBB) followed by CP (GBB+CP). The composite specimens were bonded to resin composite disks using resin cements [G-CEM Cerasmart (GCCS) and ResiCem (RC)]. The bond strengths after 24 h (TC 0) and after thermal cycling (TC 10,000 at 4–60°C) were measured by shear tests. Three-way ANOVA and the Tukey compromise post hoc tests were used to analyze statistically significant differences between groups (α=0.05). Results For both CAD/CAM composite materials, the None group exhibited a significant decrease in bond strength after TC 10,000 (p<0.05). AB showed significantly higher bond strength after TC 10,000 than the None group, while CP did not (p<0.05). GBB exhibited smaller surface defects than did AB; however, their surface roughnesses were not significantly different (p>0.05). The AB+CP group showed a significantly higher bond strength after TC 10,000 than did the AB group for RC (p<0.05), but not for GCCS. The GBB+CP group showed the highest bond strength for both thermal cyclings (p<0.05). Conclusions Air abrasion with glass beads was more effective in increasing bond durability between the resin cements and CAD/CAM composite materials than was using an alumina powder and a CP.
Sujets)
Air abrasion/méthodes , Oxyde d'aluminium/composition chimique , Résines composites/composition chimique , Conception assistée par ordinateur , Verre/composition chimique , Céments résine/composition chimique , Analyse de variance , Cimentation/méthodes , Céramiques/composition chimique , Test de matériaux , Microscopie électronique à balayage , Reproductibilité des résultats , Résistance au cisaillement , Propriétés de surface , Facteurs tempsRésumé
We determined the release of β-endorphin and prolactin into the blood, before and after 60-minute exercise of acute cycle ergometer in five healthy students and three athletes. This exercise induced an increase in circulating mean β-endorphin level [basal to after exercise level, 14.9±0.7 (mean±SE) pg/m<I>l</I>→57.1±17.0 pg/m<I>l</I> : p<0.05] and mean prolactin level [9.4±0.7 ng/m<I>l</I>→9.1±3.1 ng/m<I>l</I> : p<0.01] . There was a significant correlation between β-endorphin and prolactin values in all samples (r=0.892: p<0.01 : n=32) . Athletes tended to release greater amounts of β-endorphin and prolactin into the blood than students after acute exercise.<BR>We find that acute exercise stimulates release of β-endorphin and prolactin in parallel and athletes have increased plasma β-endorphin and prolactin after acute exercise.
Résumé
We determined the release of β-endorphin and prolactin into the blood, before and after 60-minute exercise of acute cycle ergometer in five healthy students and three athletes. This exercise induced an increase in circulating mean β-endorphin level [basal to after exercise level, 14.9±0.7 (mean±SE) pg/m<I>l</I>→57.1±17.0 pg/m<I>l</I> : p<0.05] and mean prolactin level [9.4±0.7 ng/m<I>l</I>→9.1±3.1 ng/m<I>l</I> : p<0.01] . There was a significant correlation between β-endorphin and prolactin values in all samples (r=0.892: p<0.01 : n=32) . Athletes tended to release greater amounts of β-endorphin and prolactin into the blood than students after acute exercise.<BR>We find that acute exercise stimulates release of β-endorphin and prolactin in parallel and athletes have increased plasma β-endorphin and prolactin after acute exercise.
Résumé
Thirteen female swimmers (ranging in age from 15 to 18 years) were selected as subjects and divided into two groups; group A (subjects of experiment) consisted of six subjects in whom low pressure was loaded and group B (subjects of control) consisted of seven in whom low pressure was not given.<BR>During training, circuit weight training was performed in a low pressure environment and it was combined with conventional swimming training. We studied the effect of these types of training on their red-cell 2, 3-diphosphoglycerate, salivary cortisol, and plasma testosterone.<BR>(1) The 2, 3-DPG level showed a greater increase after loading exercise than at the time of resting in both groups A and B. The increase was highly significant in group A. Additionally, 10 days after the removal of the loading, hemoglobin and hematocrit levels were significantly decreased in groups A and B, and a significant increase in 2, 3-DPG was observed in group A.<BR>(2) Only after loading low pressure was the cortisol level higher in group A than in group B. However, there was no significant difference between the two groups in the amount of exercise loading when heart rate was used as the index.<BR>(3) Testosterone tended to show a greater increase after exercise loading than on the first day of the experiment. However, neither an effect of exposure to low pressure on testosterone nor a significant difference between the two groups was observed.<BR>According to the results, in swimming, an endurance contest, physical changes during training are almost the same in group A and B, but it is considered that a concurrent severe hypoxic condition as a result of low pressure loading brings about homeostasis in the living body and the homeostasis leads to an attempt to increase oxygen uptake by the tissues, yeilding increased staying power.