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Abstract
Even though the traditional live demonstration method is commonly used in teaching laboratory techniques to dental students, it has many drawbacks. The aim of this study was to assess the acquisition of knowledge, practical skills, and perceptions of dental students who had a live demonstration versus procedural video on arranging artificial teeth. All 79 third-year dental students at a dental school in Sri Lanka, who had no previous experience in arrangement of teeth, were randomly divided into two groups in 2016. Students in group 1 had a live demonstration, while students in group 2 had a video demonstration. A pretest and posttest were conducted to assess the students’ knowledge about arrangement of teeth. After one week, students in both groups were requested to arrange teeth, and a practical skills score was given. Following this, a questionnaire was used to assess the students’ perceptions regarding their method of learning. Three students in group 1 did not attend the live demonstration, so the results were based on 76 participants: group 1 n=36, group 2 n=40. The results showed no significant difference between the two group’s mean pretest scores (p=0.460). However, group 2 showed a statistically significant increase in mean posttest score over its pretest score (p=0.002). This difference was not seen in group 1. There was no significant difference in the mean skills test score for the two groups (p=0.588). These results suggest the procedural video was as good as the live demonstration in teaching the specific task selected for this study. However, when the perceptions of the two groups were compared, the students considered the video as a better teaching tool except when clarification was needed.
- dental education
- prosthodontics
- preclinical skills
- computer-assisted instruction
- educational methodology
- educational technology
The predoctoral dental curriculum generally focuses on development of psychomotor skills of students in their early clinical years. This concept is especially applicable in prosthetic dentistry in which laboratory practical skills play an important role. Students are thus exposed to the technical aspect of skills in order to improve the outcome of clinical procedures. Courses that aim at the development of dental laboratory skills are typically conducted in the preclinical years, since that helps prepare students in clinical prosthetic dentistry.
Dental schools around the world traditionally have used a live demonstration method in teaching laboratory skills. A live demonstration to a small group has been shown to be useful in teaching dental laboratory technology: it increased students’ confidence, improved communication skills, and provided better understanding of procedures than did didactic teaching.1,2 However, studies have shown that the live demonstration technique carries many drawbacks such as students’ reliance on the instructor, difficulty in visualization of the procedure, and slight variation of the procedure among different instructors.1–4 Moreover, the effectiveness of demonstrations depends on the number of students assigned to each instructor and the amount of time spent on the demonstration. Additionally, although the demonstrations are performed only once, many students may need to follow the same procedure repeatedly to grasp the essential skills. One study also found that traditional teaching methods caused significant psychological distress that may influence the degree of depression, anxiety, and burnout among students.1
Due to these drawbacks of traditional teaching methods, educators are considering new methods for teaching laboratory skills. Among these, video demonstrations or procedural videos may be integrated into preclinical laboratory dental teaching. Procedural video combines teaching with visualization of laboratory steps. It also offers media-rich audio and visual stimulation covering a wide spectrum of learning styles or preferences, which allows students to revise technical procedures before, during, and after the laboratory sessions.5 It also provides uniformity and similar learning experiences to the entire group of students.2
Teaching dental laboratory technology for undergraduate dental students at the University of Peradeniya, Sri Lanka, takes place during the third year of the five-year curriculum. The students are taught the construction of primary casts, fabrication of custom trays, construction of working casts, construction of record blocks, mounting on an articulator, arranging teeth on an articulator, and processing of dentures and are expected to acquire the practical laboratory skills involved in each of these steps. The knowledge component is taught via lectures and small-group discussions led by the academic staff, whereas live demonstrations for teaching laboratory skills are conducted during the laboratory sessions by the technical officers attached to the department. Demonstration for each procedure is carried out once for each group of students.
Even though this system has been practiced for many years, it appears to have drawbacks. The students are under tremendous stress, especially when carrying out difficult procedures such as arranging artificial teeth. With increasing workload in the laboratory, the use of support from technical officers for teaching purpose is becoming difficult. These difficulties led us in 2015 to develop a video series based on the laboratory procedures in complete denture fabrication. The series consisted of seven videos, one of which was on “Arranging Artificial Teeth on the Articulator.” The aim of this study was to assess the acquisition of knowledge, practical skills, and perceptions of dental students who had a live demonstration versus procedural video on arranging artificial teeth.
Methods
The study was granted approval by the ethics review committee of the Faculty of Dental Sciences, University of Peradeniya, Sri Lanka (ERC/FDS/UOP/I/2016/31). All 79 third-year dental students in 2016 at the Faculty of Dental Sciences, University of Peradeniya, Sri Lanka, were invited to participate in the study. Although lectures and discussions had already been conducted on the subject, these students had not been given demonstrations on arranging teeth. Written informed consent was obtained from participants prior to the study. All students were identified by a reference number throughout the study period. This study was carried out in four stages.
Stage 1: Assessment Before Training
All participants were given a pretest with the aim of assessing the recall knowledge acquired during the lectures and small-group discussions on arranging teeth. The questionnaire included ten multiple-choice questions (MCQs) that tested the basic knowledge of the students on arranging denture teeth. The questionnaire was developed by a panel of prosthodontists and was pretested with 15 dental undergraduates. Characteristics of the participants such as gender, ethnicity, and use of computers and e-learning facilities were also gathered.
Stage 2: Teaching Sessions
Students were divided into two groups using a simple random sampling method. Group 1 students had live demonstrations on arranging teeth and were provided with a printed study guide at the same time. Group 2 students had a video-based demonstration of the procedure and were provided with a printed study guide at the same time. The medium of instruction was English for both live and video-based demonstrations.
As three students in group 1 did not attend the live demonstration session, they were excluded from the study. Thus, group 1 consisted of 36 students, and group 2 consisted of 40 students. Teaching and practice sessions as well as the skill test for both groups were conducted in the student dental laboratory setting.
Participants of group 1 were subdivided into groups of eight or ten each (8, 8, 10, 10). Each group was assigned to one technical officer. All the technical officers had previous experience in conducting demonstrations on arranging teeth for dental students. Maximum effort was taken to standardize the procedure by adopting the following. Guidelines on arranging artificial teeth were developed by a panel of prosthodontists. The script and the story board of the video were written based on these guidelines. All the technical officers were instructed to strictly adhere to these guidelines when carrying out the live demonstrations. They were given the instructional video prior to the exercise and were instructed to conduct the live demonstration in an identical manner to the procedure shown in the video. At the end of the session, the students were given a written guide on arranging teeth.
Each participant in group 2 was given a work station with a personal computer, a compact disc of the video on arranging teeth, and the materials necessary for the procedure. The 20-minute video covered all the steps in arrangement of teeth on standard edentulous casts mounted in a plane line articulator. The participants were given the opportunity to watch the video as many times as they wanted. They were also given the opportunity to carry out the procedure while watching the video. The students were not allowed to take the video home, considering the possibility of sharing learning materials among the student groups. However, the video was made available to the group 2 students in the laboratory for viewing during their free time. These students were also provided with the written study guide.
Stage 3: Knowledge Assessment
Immediately after the teaching session, the students in both groups were given a posttest, which included ten MCQs that assessed their recall knowledge and certain practical clues that were supposed to be acquired only during the practical session. They were also asked to complete a ten-item questionnaire with responses on a five-point Likert scale (1=strongly disagree to 5=strongly agree). The items addressed their stress, confidence, and perceptions regarding the teaching method they had experienced.
After completing the questionnaires, the students in both groups were given one week to practice the skills they had learned. The students in group 1 had access to the instructor to ask questions and seek clarification, whereas the students in group 2 had access to the video for one week.
Stage 4: Skill Assessment
At the end of the week, the students in both groups were asked to arrange maxillary and mandibular anterior denture teeth on standard edentulous casts mounted in a plane line articulator within 90 minutes. The skill of arranging artificial anterior teeth was assessed by two blinded examiners independently using a checklist, and an average score was given to each participant. The scores on this test were used to assess the effectiveness of the two demonstration methods on the students’ skill development. The scores obtained by the students were used only for the purpose of this study and not for assessment in the course.
Once all the data were collected, the procedural video was made freely available for all the students through Dental Moodle, the e-learning program used in this institution. The students in group 2 were given live demonstrations in a similar setting. At the end of the study, all the students were given a questionnaire with ten five-point Likert-scale items to assess their perceptions of each teaching method and to compare the two methods.
Statistical analysis was performed to address the aims of the study. A paired t-test was used to determine any significance difference between the pre- and posttest results of each group. Whenever the underlying assumption in parametric test was violated, an equivalent nonparametric test was used to test the significance. For example, when the normality assumption of the data is not held for a two-sample t-test, the Wilcoxon signed rank test or the Wilcoxon rank sum test was used. Significance among more than two groups was studied using one-way analysis of variance and Kruskal-Wallis test. The hypothesis tests were evaluated at 0.05 significance. Furthermore, the uniformity of the distribution of responses for the Likert scale was tested by using the chi-square goodness of fit test.
Results
A total of 76 students participated in the study: group 1 n=36, and group 2 n=40. The majority of the participants were female and Sinhalese (Table 1).
Demographic characteristics of dental students who participated in the study (N=76)
Regarding the use of and access to e-learning materials, it was evident that the students used more than one device to access the Internet. The majority stated that they used laptop computers to access the e-learning materials, and 62% accessed the Internet using a mobile broadband service. All the students stated they had used e-learning materials at least once for their studies, but 45.5% said they only used them occasionally.
Knowledge Assessment
The two-sample t-test found no significant difference in the mean pretest scores for the two groups (p=0.460). Since the number of observations in each group was large (>30), we assumed normality of the difference between the pre- and posttest scores. Therefore, a paired t-test was used. The analysis found no significant difference between the mean pre- and posttest scores for group 1 (p=0.102). However, there was a significant difference between the mean pre- and posttest scores for group 2 (p=0.002). Furthermore, the 95% confidence interval for the mean difference (pre-post) for group 2 was (−18.80, −4.70), which indicated an improvement in the mean posttest score. The students who received video demonstrations thus showed a statistically significant increase in their knowledge from pretest to posttest when compared with the students who received live demonstrations.
Additionally, we investigated the effect of the two demonstration methods in relation to gender and ethnicity. There was no statistically significant difference in mean pretest and posttest scores between the two genders or between different ethnic groups in groups 1 or 2 (Table 2). Therefore, we concluded that the differences in demonstration method did not have a different effect on the knowledge of the different gender and ethnic groups.
Assessment of knowledge: mean change of results from pretest to posttest
Skill Assessment
A two-sample t-test found no significant difference in the mean skill test scores between the two groups (p=0.588). Thus, we concluded that the difference in demonstration method did not have an effect on the skill development of the students.
Similar to the knowledge assessment, we intended to assess any difference in the effect of the demonstration methods on the skill development of the gender and ethnic groups. There was no statistically significant difference in the mean skill test score of the two gender groups or the three ethnic groups in group 1 or group 2 (Table 3). Consequently, we concluded that the two demonstration methods did not affect the skill development in different gender or ethnic groups.
Assessment of skill: effect of different teaching methods on gender and ethnic groups
Students’ Perceptions
Finally, two questionnaires were used to assess students’ perceptions of the two demonstration methods. The first questionnaire was given soon after the skill test in which students in each group were exposed to only one demonstration method. By the time the second questionnaire was distributed, all of the students had received both demonstration methods.
On the first questionnaire, the two groups showed somewhat similar results when modes (highest number) of responses were compared. A majority in both groups disagreed that they still felt stress during the teeth-setting procedure after the demonstration, and a majority in both groups agreed with statements 2 through 10 (Table 4). Students in both groups also agreed that each of the demonstration methods needed further improvement.
Comparison between the two groups of students’ perceptions of their experience with the training method
Because of the nature of the data (ordinal and not normally distributed), the hypothesis test (Wilcoxon rank-sum) was performed on each statement to check whether there was a difference in the median response for two groups. The calculated p-values showed no difference in the median responses for each statement between the two groups (Table 4).
On the second questionnaire, since all students had received both types of demonstrations, they were asked to compare the two methods. Again, due to the nature of the data, the hypothesis test (Wilcoxon signed-rank) was performed on statements to check whether the median response for video was greater than live demonstration. The test found a statistically significant difference between the live and video demonstrations in the understanding of contacts and relationship of different teeth with each other (p<0.001).
A statistically significant difference was also found between the video and live demonstrations with regard to understanding the overall procedure (p=0.001), good visibility (p<0.001), and understanding of instructions (p=0.042). As the median score for the video demonstration was higher in each of these instances, we concluded that the students perceived the video demonstration gave them a better understanding of teeth contacts, better clarity, better visibility, and better understanding of language compared to the live demonstration.
A statistically significant difference between the live and video demonstration (p=0.001) with a higher median score for the video demonstration showed that the students were more comfortable in learning with the video demonstration. When asked if this method improved students’ confidence to perform denture teeth setting procedure and if it helped them recall facts in giving answers on the MCQs, a statistically significant difference was found between the video and live demonstrations (p=0.042 and p<0.001). The median score for video demonstration was higher in both instances. Thus, we concluded that the students perceived the video demonstration was better at giving them confidence to perform arranging denture teeth as well as for recalling facts.
Overall, the responses to seven out of ten statements on the questionnaire favored the video demonstration. However, the calculated p-values (at 0.05 significance level) indicated that there was inadequate evidence to conclude that the median response for video demonstration was greater than the live demonstration when students were asked if all the details were provided and if they were able to ask questions and seek clarifications from their friends and faculty during the demonstration (p=0.05).
The Wilcoxon signed-rank test was performed for the statement “clarification of doubts was easy” based on the hypothesis that mean score for video demonstration would be less than that for live demonstration. The p-values showed that there was a statistically significant difference between video demonstration and live demonstration (p<0.001). The median for video was less than live. This finding indicated that the students considered that the live demonstration was better with regards to answering student questions.
Discussion
New technology has broadened the teaching tools available for students. Several studies that tested the use of procedural videos to educate dental students in their preclinical laboratory work have found them to be as effective as live demonstrations.6–9 Thus, we conducted our study to assess the efficacy of a newly developed procedural video in the development of knowledge and skill in arranging teeth in complete denture fabrication. Furthermore, we wanted to assess the students’ perceptions of the two teaching methods.
The evaluation of the knowledge component showed no significant difference between the pretest scores in both groups, which indicated a similar level of understanding at baseline. When the pretest and posttest scores were compared in group 1 and group 2, a statistically significant difference was found only in group 2, indicating an improvement in their knowledge. Therefore, we concluded that reinforcing and recalling facts were better in the group that received video demonstration. A previous study also found that instructional media was associated with improved knowledge in dental courses.10
When we assessed the students’ performance in arranging denture teeth, we found no significant difference in the skill test scores between the two groups. Similar findings have been reported in other studies with dental and nursing students. Alqahtani et al. in 2015 concluded that a carefully designed and developed procedural video was equally effective as a live demonstration when a comparison was made in teaching skills for fabrication of an Adam’s clasp.2 Maria et al. concluded that video-assisted teaching and a self-instructional module were equally effective in improving the practices of nurses regarding care of patients on a ventilator.11 Kaur et al. found that live demonstration and video-assisted teaching methods were equally effective in the skill development of nursing students on nasogastric tube feeding.12
However, contrasting findings were reported in another study in which students in the traditional learning group performed significantly better than the test group in terms of anterior denture teeth setting.13 In that study, the test group performed significantly better than the control group in primary impression-taking and primary cast fabrication. There was no statistically significant difference in master impression taking, master cast fabrication, record block fabrication, and posterior teeth setting.
When we assessed our students’ perceptions of the teaching methods, we found that they rated video demonstration as a better method than the live demonstration on seven out of ten statements. This was in agreement with the study done by Alqahtani et al., who found a higher mean response for procedural video group than live demonstration group with regard to clarity and ease of understanding of the steps.2 In Aragon and Zibrowski’s study, the students preferred video, claiming they were able to see better and the procedure could be reviewed at any time.14
Inability to allow the students to take the video home, enabling them to view it as many times as needed, can be considered as a limitation of our study. In addition, even though maximum effort was taken to standardize the procedure, individual variation of the instructor may have affected the live demonstration. Also, since the study took place at only one dental school, its results may not be generalizable to students in other programs.
Even though there is evidence that video-based learning is a preferred method of learning by students, some studies have shown contrasting findings with regard to students’ attitudes towards video-based learning. In their study, Smith et al. found no difference between medical students’ attitudes towards the method of instruction.15 A preference for live teaching was found in a study by Bazyk and Jeziorowski, who compared the use of videotaped and live demonstrations to teach occupational therapists.16 Their students rated the learning experience of both methods as good, but expressed a preference for the live demonstration. Those students also believed that the live demonstration allowed them the opportunity to ask questions and interact with the instructor, which we also found in our study. Another study found that even though the students preferred video demonstration, they were reluctant to replace live demonstrations with it.2
Conclusion
This study found a statistically significant difference in terms of improvement of knowledge in the group that used the procedural video. However, there was no statistically significant difference between the groups using the videotaped demonstration and the live demonstration in terms of skill in arranging teeth for complete denture fabrication. A well-designed videotaped demonstration was as good as a live demonstration in teaching the specific task selected for this study. However, the students considered video demonstrations to be a better teaching tool except for the disadvantage of not being able to ask questions and get clarification instantly from an instructor. Thus, we recommend that while incorporating video-based learning to teach dental laboratory technology to dental students, some element of interaction between the student and the teacher should be encouraged for a better learning experience.
Acknowledgments
The authors wish to acknowledge the 2012–13 dental students and the technical officers attached to the Department of Prosthetic Dentistry, Faculty of Dental Sciences, University of Peradeniya for their cooperation in this study.
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