Participants
The participants are from two sessions of fourth-year undergraduates of stomatology, one of which is PBL group and the other is MBL group. The inclusion criteria: being a fourth-year undergraduate dental students in Xiangya School of Stomatology, Central South University, and consent to participate the program. The exclusion criteria: foreign students who were unable to use Chinese fluently can participate in this project but not included in the statistics. A total of 56 fourth-year undergraduate dental students were eventually enrolled in the study, with 28 (13 males, 15 females, aged 22 ± 0.64) in the MBL group and 28 (14 males, 14 females, aged 22 ± 0.67) in the PBL group. All participants were randomly divided into 4 subgroups, each subgroup including 7 students.