Design and setting
The dental material science practical session took place in the faculty simulation laboratory. Students were divided into three batches and each session lasted around two hours. The session began with the teacher giving a short briefing using a PowerPoint slide presentation on commonly used dental materials in clinical settings. This is followed by a short manual demonstration on the manipulation of the materials performed by the teacher. The session included mixing and manipulating dental composite resin, glass ionomer cement, zinc oxide eugenol cement, calcium hydroxide cement, alginate impression material and zinc oxide eugenol impression paste. The content of the practical session was discussed and validated among the faculty members of the department to ensure that the learning activities were in line with the course learning outcomes, which was further approved by the department head. Next, students in the feedback sandwich and ATA groups were given the opportunity to mix and manipulate the different materials by themselves at their respective stations. A total of six stations were set up for them to manipulate the six different types of materials and the students were given 10 min at each station. During the session, teachers closely monitored each student’s performance at the respective station and provided feedback accordingly. This included evaluating the students’ skills in mixing the materials step-by-step and manipulating the materials within the manufacturers’ recommended setting time.Prior to the session, two teachers (feedback providers), who were also faculty lecturers with post-graduate dental qualifications, read, familiarised, and practised by themselves with characteristics of effective feedback in the dental education context. They discussed various interpretations to align themselves with the timing and language style while delivering the feedback. For the feedback sandwich group, the first teacher adopted feedback sandwich model proposed by Schwenk and Whitman in 1987 [