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BACKGROUND:Nano-hydroxyapatite as a surface modification material that is bonded to the surface of the zirconia ceramics upon sintering at high temperature can improve bone-inducing activity and bone bonding strength of the zirconia ceramics. Moreover, the sintering temperature is crucial for performance and bonding of the composite. OBJECTIVE:To detect the shear strength of nano-hydroxyapatite ceramics coating bonded to zirconia ceramics at different sintering temperatures. METHODS:Nano-hydroxyapatite slurry was prepared using sol/gel technology. Thereafter, 20 zirconium green bodies were coated with nano-hydroxyapatite slurry and randomly divided into four groups. Then, the specimens were put into non-pressure sintering furnace and sintered at 1 300, 1 400, 1 500, and 1 550℃, respectively. At last, we measured the shear strength of al the specimens after sintering by universal testing machine, and analyze the type of fractures. RESULTS AND CONCLUSION: With the rising of sintering temperature, the shear strength of the specimens was gradualy increased, and there were significant differences between the four groups [(4.04±1.19), (6.60±0.95), (16.51±1.93), (80.47±19.31) MPa,P < 0.05]. Within the scope of 1 550℃, the sintering temperature was positively relative to the shear strength of specimens. These findings indicate that in the certain temperature range, the higher the sintering temperature, the greater the shear strength of the bonding interface between zirconia and nano-hydroxyapatite. When the sintering temperature is 1 550℃, the shear strength of the bonding interface is the highest.
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This study was aimed to investigate the theoretical basis of Jian-Shen Li-Shui (JSLS) formula. Knowledge of acute phase of cerebral hemorrhage in ancient Chinese medicine literature, modern pathophysiology theories, experimental researches and clinical results were studied, in order to discuss theoretical basis of JSLS formula. The results showed that JSLS formula embodied basic theories of traditional Chinese medicine (TCM) and experiences of physicians from different generations. It also reflected modern pharmacology research results. It was supported by animal experiments and clinical research results. It was concluded that JSLS formula was in accordance with essence of TCM syndrome differentiation. There were enough evidences for the formation of the formula. It was worthy of further study.
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<p><b>OBJECTIVE</b>This study aimed to improve students' ability in practical and theoretical courses of oral health education and to promote students' learning interest and initiative.</p><p><b>METHODS</b>Fourth-year students of the oral medical profession from 2006 to 2008 at Weifang Medical University were chosen as research objects for oral health education to explore the experimental teaching reform. The students were divided into test and control groups, with the test group using the "speak out" way of teaching and the control group using the traditional teaching method. Results of after-class evaluation of the test group, as well as final examination and practice examination of the two groups, were analyzed and compared.</p><p><b>RESULTS</b>After-class evaluation results of the test group showed that the "speak out" teaching method was recognized by the students and improved students' ability to understand oral health education. The final examination and practice examination results showed that the score of the test group was higher than that of the control group (P < 0.01).</p><p><b>CONCLUSION</b>"Speak out" teaching methods can improve students' ability for oral health education, in accordance with the trend of teaching reform.</p>
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Humans , Health Education , Oral Health , StudentsABSTRACT
Objective To determine the prevalence of symmetry of C shaped root canal system in mandibular second molars.MethodsA total of 70 madibular second molars with C shaped root canal system to be considered as needing root canal therapy were included in this study,of which 68 contralateral X ray apical films were obtained.The symmetry of the root and the root canal system was analyzed using magnifying glass.ResultsOf the 68 mandibular second molars with C shaped root canal system diagnosed clinically,62 cases with C shaped root canal system bilaterally,with the prevalence 91.18%.ConclusionThe anatomic feature of mandibular molars with C shaped root canal system is complicated,and the prevalence of symmetry is very high,which is in favor of estimating the anatomic feature from contralateral tooth.