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Objective To understand the present condition of preclinical dental undergraduate in-terns' AIDS-related knowledge. Methods The questionnaire was designed referring to domestic and foreign relevant questionnaires. The cluster sampling method was used to conduct the questionnaire survey among the undergraduates who started their clinical internship in July 2016 in three domestic colleges, using SPSS 14.0 statistical software to analyze it. Results In this survey, 144 questionnaires were distributed, and 144 ones were filled out and sent back. The survey results suggested that 97.22％ (140) of interns held a posi-tive attitude towards aiding HIV-infected patients despite that 96.53％ (139) of interns knew that dental medical staff was considered to be highly susceptible with HIV. In spite of the fact that most interns knew AIDS-related knowledge and protection measures, 40.28％ (58) of interns were not clear about incubation period of AIDS, and the average awareness of children's AIDS and methods to disinfect HIV-infected dental instruments was less than half in the interns. Meanwhile it was found that 86.81％ (125) of interns didn't perform well in terms of complying with the principles of confidentiality in AIDS prevention and treatment. Conclusion Dental clinical interns' attitudes towards AIDS-infected patients should be praised. Further-more, they should accept education about infection control to have a deeper understanding about AIDS-related clinical manifestations and legal knowledge in order to reduce the probability of nosocomial infec-tion of AIDS.
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Objective@#To evaluate a nano-hydroxyapatite (nano-HA) desensitizing paste application on the bond strength of three self-etch adhesives.@*Methods@#Three dentin specimens of about 1 mm thick were cut from two teeth. Scanning electron microscope (SEM) was used to evaluate the dentin surfaces without treatment, after citric acid treatment and after nano-HA treatment. Thirty-six intact third molars extracted for surgical reasons were cut to remove the occlusal enamel with isomet, and then were etched with 1% citric acid for 20 s to simulate the sensitive dentin and divided into two groups randomly using a table of random numbers (n=18): the control group (no treatment) and the HA treated group (with nano-HA paste treatment). Each group was divided into three subgroups randomly using a table of random numbers (n=6). Subgroup A, B and C was bonded with G-Bond, Clearfil S3 Bond and FL-Bond Ⅱ according to the manufacture's instruction separately. At 24 h after bonding procedure, and after water storage for 6 months, microtensile bond strength of the specimens was tested and the failure mode was analyzed.@*Results@#SEM obeservation showed that citric acid could open the dentin tubules to set up the sensitive dentin model, and the nano-HA could occlude the dentin tubules effectively. For subgroup A, bonding strength of specimens treated with nano-HA ([41.14±8.91] MPa) was significantly high than that of the control group ([34.27±6.16] MPa) at 24 h after bonding procedure (P<0.05). However, after 6 month water ageing, the bonding strength of the control group and the HA treated group showed no significant difference (P>0.05). For subgroup B, specimens with nano-HA application showed lower bonding strength ([30.87±6.41] MPa) than that of the control group ([36.73±5.82] MPa) at 24 h after bonding procedure (P<0.05), and after 6 month water ageing, the bond strength of nano-HA application ([25.73±6.99] MPa) was also lower than that of the control group ([32.33±5.08] MPa) (P<0.05). For subgroup C, the bond strength of the control group and the HA treated group have no significant difference either before or after 6 month water ageing (P>0.05). Failure mode analysis showed that more than half of the samples in all groups were adhesive failure.@*Conclusions@#Nano-HA treatment decreased the bond strength of subgroup B, while had no adverse effect on subgroup A and subgroup C.
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Objective To observe the morphology of ethanol-wet dentin surfaces and detect their nano-scale adhesion force (Fad) by atomic force microscopy (AFM) in order to explore the potential mechanism of ethanol-wet bonding in improving clinical dentin bonding effectiveness.Methods Dentin slices from human premolar roots were prepared into flat ones, polished, and then randomly divided into five groups.All the specimens were acid-etched, rinsed, and left moist.They were then treated with 100％ ethanol for 0s (control group), 20s, 60s, 3×60s, or stepwise ethanol application.Afterwards, each group was scanned for the morphology in air and the Fad was probed by AFM.One-way ANOVA followed by Tukey`s test was employed for multiple comparisons using SPSS16.0.Results Compared with control group, ethanol-wet dentine produced a less undulating and relatively smooth surface topography.Ethanol-wet protocol significantly decreased the value of Fad in the experimental groups (P0.05).Conclusion When using AFM in air, ethanol-wet protocol with longer time can produce a less undulating and relatively smooth surface topography and decrease the Fad, whichindicates that the water saturated in dentin matrix was replaced more thoroughly by longer ethanol application time.This will benefit hydrophobicity of the dentin bonding interface.
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<p><b>OBJECTIVE</b>To evaluate the effect of an arginine-containing antihypersensitivity polishing paste on Streptococcus mutans (S. mutans) adhesion to treated dentin.</p><p><b>METHODS</b>Dentin discs were treated with acid to expose dentin tubules, and then polished with either pumice or a polishing paste containing arginine. The surface roughness of the treated dentin was measured. The effects of dentin treatment on S. mutans adhesion and glucosyltransferase (GTFs) gene expression were also evaluated.</p><p><b>RESULTS</b>The surface roughness decreased after polishing with both pumice and arginine-containing polishing paste. Moreover, the polishing paste affected gtfB and gtfC expressions.</p><p><b>CONCLUSION</b>The arginine-containing polishing paste affects S. mutans adhesion, as well as gtfB and gtfC expressions. The polishing paste may be used to prevent caries in exposed dentin areas.</p>