Effect of Enterococcus faecalis on apoptosis rate and the release of matrix metalloproteinase-8 of polymorphonuclear leukocytes / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the release of matrix metalloproteinase-8 (MMP-8) and apoptosis rate of polymorphonuclear leukocytes (PMNs) after PMNs was triggered by Enterococcus faecalis (E. faecalis) in vitro.</p><p><b>METHODS</b>The activated E. faecalis suspension was prepared and added to PMNs suspension as experiment group. As a positive control, phorbol myristate acetate (PMA) was used. As negative control, PMNs suspension was incubated with PBS. The release of MMP-8 was measured at 0, 20, 60, 120 min by ELISA method. E. faecalis lysate acted on PMNs as experiment group, PMNs suspension was incubated with PBS as negative control, samples in two groups were incubated at 37 degrees C for 2, 5, 10, 15 h. The apoptosis rate of PMNs was tested by Flow Cytometry.</p><p><b>RESULTS</b>At 0 min, there was no significant difference of MMP-8 release in the experiment group and positive control (P>0.01); whereas at 60, 120 min, E. faecalis induced a significant lower MMP-8 release compared with the positive control (P<0.01). The apoptosis rate of PMNs in both groups increased along with time, and apoptotic rate in experiment group was higher than that in the control group at 2, 5, 10, 15 h (P<0.01).</p><p><b>CONCLUSION</b>After E. faecalis act on PMNs, no significant release of MMP-8 from PMNs was observed. E. faecalis don't induce PMNs apoptosis delay.</p>

Effect of different decalcification condition on tooth-clearing technique / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate shrinkage range of cleared teeth caused by nitric acid with different temperature and concentration.</p><p><b>METHODS</b>48 human teeth were root canal-prepared and filled, then randomly and averagely divided into six groups on the basis of temperature and density of nitric acid and the condition of whether or not added the oscillate. Group A was 20 degrees C with 6% nitric acid, group B was 20 degrees C with 6% nitric acid and oscillate, group C was 20 degrees C with 3% nitric acid, group D was 20 degrees C with 3% nitric acid and oscillate, group E was 30 degrees C with 6% nitric acid and oscillate, group F was 30 degrees C with 3% nitric acid and oscillate. After achieving the standard of the decalcification, all the specimens were gradually dehydrated, and then cleared and conserved using methyl salicylate. Time-consumed and shrinkage range of all the specimens were recorded and analyzed.</p><p><b>RESULTS</b>The time of decalcification in group E was the fastest, then was group F, group B. Group C was the last one. The anastole of the specimens was group E > group B > group A, group F > group D > group C, group B > group D, group E > group D, there was significant difference (P < 0.05). Group C had significant difference with other groups (P < 0.05). The anastole rate of the specimens had no significant difference between group A and group B, group C and group D, group B and group F, group D and group F.</p><p><b>CONCLUSION</b>In 20 degrees C, 3% nitric acid with oscillate to carry out the decalcification can use less time and get less anastole. The result of the tooth-clearing technique is the best.</p>