In vitro evaluation of the antibacterial effectiveness of sodium hypochlorite on Enterococcus faecalis within root canals / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate in vitro the antibacterial effectiveness of sodium hypochlorite on Enterococcus faecalis (E. faecalis) within root canals.</p><p><b>METHODS</b>Roots inoculated with E. faecalis were divided into six groups, which underwent different root canal irrigation and treatment: Group 1: 5.25% NaOCl, Group 2: 2.5% NaOCl, Group 3: 0.9% NaCl, Group 4: root canal preparation + 5.25% NaOCl, Group 5: root canal preparation + 2.5% NaOCl, Group 6: root canal preparation + 0.9% NaCl. Microbiological samples were collected from root canals at three time points (before irrigation, immediately after irrigation and three days after irrigation).</p><p><b>RESULTS</b>The numbers of E. faecalis in root canal in each of the six groups were effectively reduced. Group 1 and 2 were statistically more effective than Group 3. Group 4 was statistically more effective than Group 5 and 6. Group 5 was statistically more effective than Group 6. Bacterial survival was observed in all canals of each group after a 3-day-incubation.</p><p><b>CONCLUSIONS</b>2.5% NaOCl was highly effective for root canal irrigation. However residual bacteria remained in the root canals after chemical irrigation by NaOCl and mechanical preparation.</p>

A pathological study on the influence of bleaching technique on vital tooth pulp / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of bleaching technique on vital tooth pulp.</p><p><b>METHODS</b>A total of 40 vital teeth extracted for orthodontics were selected, of which, 10 teeth without any treatment served as control, 15 teeth were extracted instantly after bleaching and 15 teeth were extracted 7 days after bleaching. Slides were made from all these three groups and subject to pathological examination under microscope.</p><p><b>RESULTS</b>No clinical symptoms were found in all the teeth before and after bleaching. All teeth in the three groups showed normal pulp on pathological examination.</p><p><b>CONCLUSIONS</b>Bleaching did not affect vital tooth pulp and is a safe technique.</p>