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Objective@#To compare the efficacies of two training protocols, i.e. the multimedia instruction and the conventional method, in periodontal surgery teaching for undergraduate students.@*Methods@#One hundred and twenty-three dental undergraduates in their pre-clinical training course were recruited and divided into two groups according to the learning grade matching principle: the experimental group (multimedia instruction, 60 students) and the control group (conventional method, 63 students). The teaching aim was to train the students gingivectomy and periodontal flap surgery by using the pig jaws. The conventional teaching method of teacher-demonstrating and student-practicing was used in the control group, and the practice time of the students′ for each surgery was 45 minutes. A standardized teaching video combined with the teachers′ explanations of the key steps was used in the experimental group. The students′ practice time for each surgery was 60 minutes. The efficacy of teaching protocol was evaluated by the teachers according to the scoring criteria set by the teaching group.@*Results@#In gingivectomy training, accuracy of fixed points, angle of postoperative gingival margin and morphology of gingiva of the experimental group were better than those of the control group. The experimental group also had more complete and continuous excised gingivae and more thorough adjacent gingival removal. The total scores of the experimental group were significantly higher than those of the control group (92.8±2.6 vs. 89.9±3.7, P<0.05). In periodontal flap surgery training, the experimental group operated the blade around the shape of the tooth better in internal bevel incision than the control group. Additionally, the incision position of internal bevel incision, periosteal integrity after flapping and flap depth of the experimental group were better than those of the control group. Besides, the experimental group had smoother flap edge and more thorough debridement. The total scores of the experimental group were significantly higher than those of the control group (92.2±4.1 vs. 89.2±4.4, P<0.05).@*Conclusions@#The teaching efficacy of multimedia instruction was better than that of the conventional method. Its value needs to be further tested in future teaching practice.
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Objective:To isolate P-cadherin positive and negative oral gingival epithelial cells , and to compare the biological characteristics with junctional epithelial cells .Methods:Human oral gingival epi-thelial cells and junctional epithelial cells were cultured .P-cadherin positive and negative cells were iso-lated from oral gingival epithelial cells .The cellular adhesion , proliferation and migration were measured and compared .Results:The P-cadherin positive cells accounted for 20%of oral gingival epithelial cells . Compared with juctional epithelial cells , P-cadherin positive oral gingival epithelial cells showed similar properties of adhesion and migration , and stronger proliferation ability (0.72 ±0.06 vs.0.60 ±0.05, P<0.05).P-cadherin negative oral gingival epithelial cells showed weaker ability of adhesion (48%± 6%vs.87%±11%, P<0.05), proliferation (0.36 ±0.04 vs.0.60 ±0.05, P<0.05) and migration (10.3 ±2.7 vs.23.4 ±4.8, P<0.05).Conclusion: P-cadherin positive oral gingival epithelial cells showed some similar but different biological characteristics , compared with juctional epithelial cells , which suggested that during the process of transforming oral gingival epithelial cells into juctional epithelial cells, complex gene and protein changes were involved instead of simply cellular migration .
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0.05).The distances from furcation entrance to alveolar crest,to bottom of bone pocket,and to the deepest site of horizontal bone defect measured by CBCT were less than those probed directly(P