Objective:To study the fracture resistance of nanofilled composite resin restoration for the treatment of incisally fractured in-cisors. Methods:30 extracted permanent maxillary central incisors were randomly divided into A, B and C groups (n=10). In group A and B, the teeth were cut obliquely from the mesial incisal angle. Labial reduction of 0. 5 mm for veneer and dovetails in the lingual surfaces were prepared. In group A, additional 2mm of the incisal edge were cut horizontally. The teeth were restored with nanofilled com-posite resin. The samples in group C were unprepared as the controls. The specimens were stored in artificial saliva and underwent 2 000 cycles of thermal cycling test. Fracture resistance of the teeth was measured by a test machine and the fracture mode was observed. Re-sults:The mean fracture load(N) of group A, B and C was 466.93 ±171.68, 444.5 ±173.00 and 474.77 ±97.55 respectively(P>0. 05). All fractures in the 2 test groups but 1 in the control group were in a favorable way. Conclusion:Incisally fractured incisors restored with nanofilled composite resins can achieve the fracture resistance similar to that of intact natural tooth. Failure modes of the restored teeth are in favorable way. Additional cut of 2 mm of the incisal edge dose not affect the fracture resistance of the restored teeth.

Objective: To study the expressien and heterogeneity of epidenmoid growth factor receptor(EGFR) in human mucoepidermoid carcinoma MEC 1 cells. Methods: EGFR1 McAb (MaH) immunofluorescent stain and flowcytometer (FCM) were used to detect the positive percentage and heterogeneity of EGFR expression in MEC 1 cells. Results: Positive expression of EGFR was found in 100% of MEC 1 cells. Average peak channel of relative fluorescent intensity was 8.006?4.410. Double peaks of MEC 1 cells from single parameter histogram was observed with FCM. Conclusion: All MEC 1 cells express EGFR and there are heterogeneous cell populations of EGFR expression in MEC 1 cell line.

From the view of medical ethics,the importance of the communication between intern and patient are illustrated.The author holds that the intern should develop the communication consciousness,realize the patient's expectation,and satisfy the patient's desire with humanism consciousness and role-switch consciousness.

OBJECTIVETo study the clinical effects of demineralized dentin matrix (DDM) as a apexificating agent.

METHODSHuman teeth were crushed into fragments and were deflated, demineralized, lyophilized to produce DDM. The DDM was used as an apexificating agent to treat 57 teeth compared with calcium hydroxide. X-ray film and clinical observation were undertaken after half a year, one year and two years.

RESULTSOne year later, a barrier in the tooth apex was found in the X-rays film. Then permanent filling material was used. After two years, DDM group had a healing rate of 92.86%, was higher than that of 91.30% in calcium hydroxide group, but there were no statistical significance.

CONCLUSIONThe findings suggest that DDM can be used as a new apexificating agent. One year after the apexification is the best opportunity to change the apexificating agent to a permanent root canal filling material.

Adolescent ; Adult ; Child ; Dental Materials ; therapeutic use ; Dental Pulp Necrosis ; therapy ; Dentin ; Humans ; Root Canal Filling Materials ; therapeutic use ; Root Canal Therapy ; methods ; Tooth Apex ; drug effects ; Tooth Root ; growth & development