Effects of three different zinc oxide incorporation on the antibacterial activity against Streptococcus mutans of composite resin / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of incorporating three different zinc oxide (ZnO) on the antibacterial activity of composite resin.</p><p><b>METHODS</b>The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of nano-ZnO, tetrapod-like zinc oxide whiskers (T-ZnOw), micro-ZnO against Streptococcus mutans were examined by the broth dilution test. Then the three different ZnO were added to the powder of one kind of bicomponent self-cured composite resin at 5% respectively, and the antibacterial activities of the resin specimens were evaluated using the membrane covering method before and after 3-month accelerating aging.</p><p><b>RESULTS</b>The MIC values of the three different ZnO against Streptococcus mutans were 78.13, 312.50 and 1 250.00 microg/mL respectively and the MBC values were 156.25, 625.00, 1,250.00 microg/mL respectively. The antibacterial ratios of the resin specimens incorporating with 5% of the three different ZnO were (93.58+/-5.95)%, (89.42+/-4.11)% and (78.97+/-3.90)% respectively, while after 3-month accelerating aging those were (89.01+/-7.91)%, (84.63+/-4.72)% and (72.27+/-3.89)%.</p><p><b>CONCLUSION</b>The three different ZnO could improve the antibacterial activity of the composite resin. The nano-ZnO exhibit the strongest antibacterial activity, while the micro-ZnO weakest. The T-ZnOw presents comparatively strong antibacterial activity although with smaller specific surface area.</p>

Effects of tetrapod-like zinc oxide whiskers incorporation on antibacterial activity of composite resin / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate effects of incorporating tetrapod-like zinc oxide whisker (T-ZnOw) antibacterial agent on the antibacterial activity of composite resin, compared with that of the silver-based inorganic antibacterial agent.</p><p><b>METHODS</b>The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the two different antibacterial agents against Streptococcus mutans were investigated using the broth dilution test. Then the antibacterial activities of the self-cured composite resin specimens with different incorporating concentrations of the two antibacterial agents were evaluated using direct contact test. And the antibacterial activities of the resin specimens were examined again after 3 months of accelerating aging.</p><p><b>RESULTS</b>The MIC (MBC) of the T-ZnOw antibacterial agent and silver-based inorganic antibacterial agent were 0.15625 (0.3125) g/L and 0.15625 (0.15625) g/L. When the concentrations of T-ZnOw added to composite resin were 3%, 5%, and 10% (w/w), the antibacterial ratios of the resin specimens were (84.85+/-5.16)%, (94.22+/-3.73)%, and (99.43+/-0.48)% respectively. When the concentrations of the silver-based antibacterial agent added to composite resin were 1%, 3%, and 5%, the antibacterial ratios were (71.01+/-7.67)%, (90.76+/-5.91)%, and (97.19+/-4.10)% respectively. The antibacterial ratios of the resin specimens containing 5% of both antibacterial agents were (89.89+/-5.55)% and (78.79+/-7.81)% respectively after 3 months of accelerating aging.</p><p><b>CONCLUSIONS</b>Incorporation of the T-ZnOw antibacterial agent in composite resin can improve the antibacterial performance of the resin, and the resin exhibits better antibacterial performance than that incorporating silver-based inorganic antibacterial agent after 3 months of aging.</p>

Effect of Candida albicans growth on silicone elastomer containing nano-TiO2 / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the antibacterial effect against Candida albicans of the A-2186 silicone elastomer containing nano-TiO2 in vitro.</p><p><b>METHODS</b>Antibacterial agent of nano-TiO2 was added into A-2186 silicone elastomer with incorporating percentages of 0.5%, 1.0%, 1.5%, and 2.0% (W/W). There was no nano-TiO2 in the control group. The antibacterial effect of the A-2186 silicone elastomer was determined using the film contact method with lighting and without lighting.</p><p><b>RESULTS</b>Either with lighting or without lighting, there were significances between the experiment groups and the control group (P < 0.05). When the incorporating percent was 2.0%, the inhibitory effect was the best among the experiment groups. Without lighting, the inhibitory rate was 53.7% and with lighting, the inhibitory rate was 85.9%.</p><p><b>CONCLUSIONS</b>The A-2186 silicone elastomer containing nano-TiO2 has antibacterial properties against Candida albicans, which enhances with increases of nano-TiO2 percent in the material. With the same incorporating percentage, the antibacterial effect with lighting is better than that without lighting.</p>

CLONING AND SEQUENCING ANALYSIS OF GINGIPAIN K OF PORPHYROMONAS GINGIVALIS / 微生物学通报

The desired DNA product of KGPcd and KGP-hag was obtained from the total DNA of Porphyromonas gingivalis by PCR with two pairs of gene specific primers. The segment of KGPcd and KGP-hag (about 1.5kb and 1.6kb) was inserted into pGEM-T easy Vector. The double-stranded DNA of the postitive clone was analyzed by restriction endonuclease mapping and DNA sequenceing. The sequences of KGPcd and KGP-hag were consistent with those of the references appeared. The proteins of KGPcd and KGP-hag will be obtained for further study.