Main

There is a need for change in dental education; information overload in dental curricula from the advances made in basic, medical and dental sciences along with the increasing complexity of treating an ageing population and the changing patterns of dental disease and treatment needs means that the education of undergraduates, postgraduates and dental practitioners must adapt to meet these challenges.

Dental curricula designers must be selective, not only in planning what is clinically appropriate and relevant in producing practitioners for the twenty-first century, but also in helping to develop the necessary skills for students to become critical thinkers and life-long learners so as to maintain an up-to-date, appropriate knowledge-base throughout their careers.

In light of the deficiencies of a traditional dental education (Table 1) recommendations have been made for curriculum reform by adopting modern learning approaches such as problem- based learning.1

Table 1 Table 1
Full size table

What is PBL?

Problem-based learning (PBL) is a relatively recent educational strategy that uses complex, real-world problems or situations that small groups of learners discuss and investigate to create possible solutions or hypotheses in response to the problem situation. Issues derived from the problem by students that are not understood become learning objectives that the learners independently or collaboratively research and report back on in context to the original problem. Such problems are ideally of a biomedical, clinical and social nature that help integrate many areas of knowledge into one learning experience. Such a learning approach is said to have many desirable outcomes (Table 2).

Table 2 Table 2
Full size table

Components of PBL

The key components of a PBL learning environment include:

  • Small-group learning

  • Problem-based

  • Student-centred activity

  • Self-directed learning

  • Tutor facilitated.

While the use of small-group and case-based learning are a common feature in a dental curriculum, the components of student-centred activity, self-directed learning and tutor facilitation are alien concepts in a traditional curriculum. Student-centred activity means that it is the students and not the tutors who are at the centre of the learning process. It is the students and not the staff who are responsible for determining learning issues, and it is the students and not the staff who discuss and investigate the problem and impart knowledge in relation to the original situation. Students work collaboratively to achieve this and in the process learn important group interaction and communication skills. The self-directed learning means that students are responsible for defining their own learning objectives, learning needs, learning resources and learning progress. These features of self-directed learning are important for building skills in self-assessment and critical thinking. The role of tutor changes from that of an authoritative information giver to that of an active listener, questioner, resource guide, and consultant.

One of the first institutions to implement PBL in a clinical setting was the University of McMasters, Canada, in the late 1960s. Since that time PBL has become a buzz-word in the health sciences for both innovation and controversy in medical education. The use of PBL and its variants in medical schools around the world has grown at a phenomenal rate. However, in dental education the adoption of this new learning approach has been considerably slower. This relative slowness in adoption of PBL in dentistry may be related to the fact that no universal ratified model exists for PBL in dentistry. There is also difficulty in integrating PBL into the teaching of clinical skills and usually inertia to change to any new system or innovation.

With many institutions worldwide implementing PBL, variations of pure PBL have evolved because of financial, logistical, and political reasons restricting its implementation in an 'ideal' form. Barrows describes PBL as a genus with a taxonomic structure having many species and subspecies and how they fit in with the educational objectives possible with PBL.2

The need to change?

The fourth year Bridge course at the Prince Philip Dental Hospital, Hong Kong, has traditionally existed as a staff-directed course based on lectures, seminars and operative techniques' procedures. Despite student feedback of an apparently successful 1996-97 Bridge Course, it was evident that many students had poor information recall and unsatisfactory ability to transfer information from lectures and seminars to the clinical environment. It was also very apparent that students were passive learners both in seminars and lectures. Students rarely challenged information presented and were slow in using prior knowledge in working out solutions to problems. This was in spite of a questioning based approach to seminars and small group-work in lectures to increase student activity. The apparent lack of genuine activity and interest in seminars may have been reflected in the fact that the questions were not voluntary or in clinical context, and therefore not considered stimulating. Because of these issues it was decided to use a PBL approach in this clinical subject to address these aspects.

Rationale for a PBL approach

The use of a clinical problem was at the centre of this change, it was intended that it would be the problem that would direct the learning. The use of contextual or a real-life problem is said to be a significant factor for promoting retrieval of information and learning. Information recall is said to be enhanced when the situation in which it is learnt closely resembles the situation in which it needs to be applied.3 This is supported by Anderson who elaborates further on the educational rationale for PBL using the 'information processing approach' to learning.4 Schmidt discusses three important conditions that apply to the acquisition of new information to optimise learning.5 These are: the activation or recall of relevant prior knowledge; learning in a contextual situation that resembles the future need in which it will be required; and the elaboration of ideas or hypotheses.

Introduction of the PBL course

After the University of McMasters introduced PBL many other medical schools soon followed. However, with each institution that implements PBL, modifications are often necessary to allow PBL to be introduced into the local environment. These alterations may have been governed by time, resources or even politics. Such modifications have caused controversy as to what is 'pure' PBL.

This PBL learning approach was embedded alongside a conventional lecture and directed seminar clinical and para-clinical curriculum. At this time in the curriculum students did not have any time-tabled self study sessions. For these reasons the modifications required to allow implementation were primarily related to the constraints of curriculum time.

PBL takes more time than conventional teaching. The seminar discussion and report-back, the self-directed learning and the time taken for student evaluation means more time is required by students and curriculum planners in comparison with a conventional courses.6

However, this apparent disadvantage of taking more time to learn subject content is offset by other advantages. Woods discusses two issues to counter this 'disadvantage' based on the additional skills that are learnt through PBL and that students want to learn more.7 Students learning through PBL not only learn subject material but also develop problem solving skills, critical thinking skills and skills for life-long self-directed learning; these are not usually developed from didactic teaching. Also, as students find PBL more stimulating and enjoyable than conventional tutor-centred teaching8 there is often a desire to learn more than is required at that time by the students. Also, knowledge can still be re-applied later on to different problems in the course.7

Because of the time limitations two aspects of the PBL model were changed to allow implementation of a PBL approach. A file of key references and journals were allocated to groups as a learning resource and during the seminar process, tutors would be directive in guiding students to the learning objectives when necessary.

The embedded PBL course

The seminar and practical sessions for the course were originally time-tabled over 8 weeks during one semester with an additional 2 weeks planned for assessments and/or 'catch-up' time. It was anticipated that the seminars would take around 1 hour and the remaining 2 hours would be used for instructional teaching and assessment of the technical and practical aspects of bridge preparation.

Seven lectures were scheduled that involved small group, student-centred activity as well as tutor-led presentations and discussions on key issues. The learning rationale for small group work in the class meetings had similar aims as those for PBL including: contextual learning, activation of prior knowledge and elaboration of this knowledge in light of the problem scenario.

Three problems were planned for the course and each problem was planned to last three sessions, allowing between 1 and 2 weeks for students' preparation. The problems were presented in the form of written text with a series of short paragraphs that explained a particular patient-problem scenario. The first session involved discussion of the problem and identification of the learning objectives and the remaining two sessions for student report-back of findings and discussion.

PBL has different educational objectives compared with didactic curricula. For this reason different assessment procedures should be used to reflect this. In this course a continuous assessment was used in all seminars to evaluate students' participation, and emphasise the importance of student interaction in the discussion process of the problems and feed-back sessions. A mid-semester exam was planned with the aim of testing students' ability to apply knowledge and involved questions based on clinical slides, treatment planning, multiple choice and short answer questions.

Seminar process

At the first seminar it was apparent that students were uncomfortable and unsure of what was expected; questions from the tutor were usually needed to direct the student discussion and enquiry process. The tutor or students would record on the white-board important issues, definitions and learning objectives that later would be researched.

While it was the intent for students to take responsibility for recording information on the white-board and allocation of learning objectives, lack of time and the need to direct students to the problems' learning objectives meant that tutor intervention was often required. Small groups of students were allocated different learning objectives to research, often with a journal article to review. At the follow-up seminars the intent was to have an interactive discussion between the students. However, the standard presentation became a 'mini-lecture', with students reading from notes with little interchange occurring between the students.

The first session of the problem discussion over-ran slightly. However, the report-back session usually over-ran by between 10-25 minutes of the anticipated 60 minutes; by the end of the course teaching time additional sessions were needed to finish the problems.

Facilitator observations

The use of 'mini-lectures' by students appeared to have several problems. The one-way delivery of the report-back prevented good group discussion. Students were usually not proficient in their level of comprehension of subject matter or ability to transfer this information to colleagues in a way that would be stimulating and easily understood. Also, students waiting to present may be highly focused on their topic and would therefore make a poor audience until their presentation was finished.

Perhaps the most significant reason for the lack of group interaction was related to students having limited knowledge on the topics discussed (having only researched one of the learning objectives). This would then make it difficult for students to effectively comment, challenge or question fellow students on subjects other than their own.

Student assessment

An anonymous course evaluation asking questions based on a one to five point scale (5 = strongly agree, 3 = neutral, 1 = strongly disagree) and personal comments section was given to the students to assess this new course. Forty-nine questionnaires were sent to students who were asked to complete the form and return. Thirty-six questionnaires were returned. The lack of total compliance may be because of some individuals not completing the form and handing them back immediately, which during a busy working day may ultimately be forgotten.

Even though the intent was to give students as much time as possible during the course, students still reported the work-load as 'heavy' (3.9) and the pace of the course 'too fast' (3.56).

The use of problems for learning appeared well valued and did address one of the original aims of preparing students for clinical situations (Table 3).

Table 3 Table 3
Full size table

However, these ratings were not as high as hoped for which may be related to many factors; the problems were only written text and perhaps not as stimulating as a case with radiographs, study models or clinical photographs. Such a simulated problem may have helped in making the problem more real life and therefore interesting.

The somewhat neutral response regarding the enjoyment of learning through problems may have been related to different issues. Student journal diaries have shown that there are stressful stages of adaptation to a new teaching approach. These range from anxiety, fear and frustration to excitement and enthusiasm.9,10 Such feelings of stress are undoubtedly related to the experience of change from a familiar department-controlled, tutor directed curriculum to a new learning strategy such as PBL. The increased responsibility associated with self-directed learning and student presentation of information adds to the levels of stress and so may diminish enjoyment. The anxiety and stress-associated self-directed learning, and not knowing the range and depth of knowledge required, may be seen by students preferring to have had directive and instructional approach to lectures rather than the interactive small group activities and questioning style that was used (3.78).

Other factors may also have affected students enjoyment related to confusion from using journal articles with conflicting results, and the style and content of student presentations. While students did report a file of references for each group as useful (3.81), students were neutral in finding learning from journals interesting (3.19) or effective (2.89). Comments were made that a more limited number of key journals would be useful. In regard to student presentations, students gave a neutral response (3.08) on being able to understand material presented at the end of the seminar. In addition seven students made additional comments on their concern on the content and quality of student presentations. This was second only in number to comments on the heavy workload.

Conclusion

The undertaking of PBL into a teaching programme requires considerable thought as to what the desired educational objectives are. Pure PBL requires significant resources and time to implement and maintain for it to be effective. During a busy traditional didactic curriculum it is difficult if not impossible to instigate effectively an educationally rewarding pure PBL programme for a single-based clinical subject. If time or the physical and human resources are not available then other teaching strategies may be more effective.

Even though there was small group activity, predominantly self-directed learning and there was a problem directing the learning, this was not effective PBL. Several important aspects of the PBL format were changed to allow the introduction of this course (that were primarily related to time constraints). The main changes involved tutor control and direction in the seminar process, the provision of reference material and the additional workload on the students in a busy curriculum. These factors may have taken the ownership and enjoyment out of students directing their own learning and having the reward of finding their own relevant learning material. However, there were other issues that may have contributed to students' ambivalence as to their satisfaction and enjoyment of this course (Table 4).

Table 4 Table 4
Full size table

Overall students valued learning through the use of problems and they did feel that this would prepare them well for the clinical environment. They also felt that this style of PBL did allow more participation, expression, discussion and the opportunity to ask questions (Table 5).

Table 5 Table 5
Full size table

Recommendations

From this experience of an embedded PBL style programme, the following suggestions can be made if a PBL teaching strategy is to be used in a clinical subject:

  • This student-centred PBL learning is very time-consuming. When insufficient time is available in a busy curriculum consideration should be made of using alternative teaching strategies.

  • In the seminar report-back, students should have the same learning objectives so that group participation and discussion in relation to the problem can occur. The use of mini-lectures should not be allowed to occur.

  • The use of simulated real-life cases or clinical problems with study models, radiographs and photographs may be more stimulating and enjoyable than 'paper' problems.

  • The use of a PBL approach for learning in a single clinical subject does not mimic real life problems where basic science and multidisciplinary clinical subjects are invariably involved. Therefore to fully integrate learning and allow more realistic contextual learning, clinical problems should have relevant interdisciplinary subjects incorporated to the learning. This may facilitate better transferability of knowledge to new clinical scenarios.

The author would like to thank Drs Alex Chan, Tak Chow and Hasten Liu for their participation and enthusiasm in this programme, and to the BDS 4 1997-98 class of students.