OBJECTIVETo evaluate the influence of different surface treatments on porcelain surface topography.

METHODSMetal ceramic prostheses in 6 groups were treated according to the different surface treatment methods, and the surface topography was observed through scanning electron microscope (SEM). Group A was the control one (untreated), group B was etched by 9.6% hydrofluoric acid(HF), group C was deglazed by grinding and then etched by 9.6% HF, group D was treated with Nd: YAG laser irradiation(0.75 W) and HF etching, group E was treated with Nd: YAG laser irradiation (1.05 W) and HF etching, and group F was treated with laser irradiation (1.45 W) and HF etching.

RESULTSSurface topography was different in different groups. A lot of inerratic cracks with the shapes of rhombuses and grid, and crater with a shape of circle were observed on the ceramic surface after treatment with energy parameters of 1.05 W Nd: YAG laser irradiation and 9.6% HF etching (group E). Surface topography showed a lot of concaves on the inner wall of the cracks, and the concaves with diameter of 1-5 microm could be observed on the inner wall of the holes, which had a diameter of 20 microm under SEM.

CONCLUSIONThe use of Nd: YAG laser irradiation with the energy parameters of 1.05 W and the HF with a concentration of 9.6% can evenly coarsen the porcelain surface, that is an effective surface treatment method.

Ceramics ; Dental Bonding ; Dental Porcelain ; Hydrofluoric Acid ; Lasers, Solid-State ; Shear Strength ; Surface Properties

OBJECTIVE To investigate and analysis of hearing status and characteristics of China civil aviation air traffic controllers(ATC). METHODS With cluster random sampling, air conduction threshold data of 1498 ATC, who had finished the class Ⅲa medical assessment this year in a certain area were studied. The subjects were tested by pure tone audiometry, the prevalence rate of speech and high frequency hearing loss between gender groups were compared; After age correction, the threshold of different frequencies were compared between age groups. RESULTS The prevalence rate of hearing loss at speech frequency was 6.68％ in male and 1.97％ in female. The result of high frequency was 7.87％ and 1.23％ respectively. Both the threshold and prevalence rate of hearing loss of every frequency were higher in male(P<0.05); The threshold of 3000 Hz

AIM: To prepare radix scutellariae microemulsion gel and investigate its therapeutic effect on chronic eczema based on the previous research of radix scutellariae self microemulsion. METHODS: The gel matrix and humectant were optimized by single factor method and response surface method to obtain the formula and preparation technique of the gel. The Franz diffusion cell method was used to evaluate the transdermal properties of microemulsion and microemulsion gel in vitro. By establishing a chronic eczema model in the mouse ear, the swelling degree, swelling inhibition rate, pathological changes and tumor necrosis factor α (TNF-α), Interleukin-1β (IL-1β) and interleukin - 6 (IL-6) of radix scutellariae microemulsion gel were measured, to investigate the therapeutic effect on chronic eczema in mice. RESULTS: The physical and chemical properties of radix scutellariae microemulsion gel were stable. Compared with microemulsion, the microemulsion gel had better transdermal performance. The cumulative transdermal amount of baicalein and wogonin, the main components of microemulsion gel, was 1.85 times and 2.77 times of that of microemulsion respectively. Moreover, the steady flow rate and permeability coefficient of microemulsion gel significantly increased, and the lag time significantly shortened. Pharmacodynamic study showed that compared with the model group, the radix scutellariae microemulsion gel could significantly reduce the ear swelling of mice (P<0.05), and the serum inflammatory factor TNF - α, IL-1β and IL-6 reduced content by over 37%. Compared with the radix scutellaria aqueous extract and aqueous extract gel, the treatment of chronic eczema was better. CONCLUSION: The preparation process of radix scutellaria microemulsion gel is feasible, with strong transdermal property, and a significant therapeutic effect on chronic eczema.