ABSTRACT
Objective To evaluate the influence of different surface roughness on final surface texture of glazed ceramic. Methods Sixty porcelain discs were fabricated and randomly divided into five groups (n=12), which were sequentially grounded with water-cooled sandpapers of decreasing abrasiveness (220# , 400# , 600# , 800# and 1200# grit), and then all the specimens were glazed. Before and after glazing, the surface roughness (Ra) μm of the same specimens were evaluated quantitatively with profilometer and qualitatively using scanning electron microscopy (SEM). Results The smoothest surfaces were obtained with 1 200# sandpapers griting prior to overglazing (Ra =0. 19 μm),and 220# sandpapers griting prior to overglazing displayed the roughest surfaces (Ra =0. 55 μm) ; each group displayed significant difference before and after glazing (P < 0. 05). The images obtained through SEM were consistent with the profilometer readings. Conclusions The results suggest that decreasing the surface roughness of dental ceramic prior to glazing is of great importance in order to obtain the smoothest surface after glazing.
ABSTRACT
Objective To investigate the significance of calcification in thyroid node for diagnosis of thyroid carcinoma.Method Retrospective analysis of 107 thyroid nodules' pre-operative ultrasonic and postoperative pathologic results.Results Total ultrasonic thyroid calcification ratio was 27.1%(29/107),which in benign samples was lower than Ihat in malignant samples(17.2%vs 70.0%,P＜0.01).Micro-calci-fication ratio in benign samples Was lower than thai:in malignanl samples(8.0%vs 50.0%,P＜0.01).Conclusion The ralio of thyroid carcinoma with calcification is higher,so the detection of thyroid carcinoma,especially micro-single-calcification should be significant.