This study evaluated the feasibility of using three-dimensional printing (3DP) to fabricate porous titanium implants. Titanium powder was blended with a water-soluble binder material. Green, porous, titanium implants fabricated by 3DP were sintered under protective argon atmosphere at 1,200, 1,300, or 1,400°C. Sintered implant prototypes had uniform shrinkage and no obvious shape distortion after sintering. Evaluation of their mechanical properties revealed that titanium prototypes sintered at different temperatures had elastic modulus of 5.9-34.8 GPa, porosity of 41.06-65.01%, hardness of 115.2-182.8 VHN, and compressive strength of 81.3-218.6 MPa. There were significant differences in each type of these data among the different sintering temperatures (p<0.01). Results of this study confirmed the feasibility of fabricating porous titanium implants by 3DP: pore size and pore interconnectivity were conducive to bone cell ingrowth for implant stabilization, and the mechanical properties matched well with those of the human bone.

Background: Numerous novel teaching methods have been developed in recent times for use in medical education. Of these methods, problem-based learning (PBL) and case-based learning (CBL) have attracted the most attention. We evaluated and compared the efficiency of these two teaching methods in dental education and discussed the importance of teachers to these courses. This study aims to evaluate the efficiency of PBL and CBL in dental education, and discuss the importance of teachers to the courses.Methods: In this study, 28 students enrolled in a seven-year program at the College of Stomatology at Shanghai Jiao Tong University were chosen as participants. In the fourth year, PBL combined with independent learning was used to teach students the theory of oral mucosal diseases. During the internship, CBL was used to present specific cases. Both methods were carried out with group discussion. After the PBL course, teachers assessed its effect by the students' class performance, their ability to collect data, and group cooperation. After the CBL course, its effect was assessed by the students' ability in history-taking, diagnosis and antidiastole, and case analysis. In addition, the teachers' roles in both methods were assessed by both the students and the teachers themselves. Data was collected by questionnaire survey and statistically analyzed with SPSS Statistics 20.Results: PBL significantly improved students' self-learning abilities in the theory course. CBL helped students make diagnoses and develop treatment plans for actual cases in the internship. Both students and teachers thought that teachers were indispensable to both PBL and CBL. There was no difference between student and teacher views.Conclusions: Although PBL and CBL have different focuses, their combination may enhance teaching effectiveness in dental education. Additionally, teachers play an important role in the application of both these teaching methods.

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