Exploring pedagogical approaches in crown preparation: a randomized controlled trial comparing the efficacy of instructional videos and live demonstrations

Abstract

Background

This study aimed to compare the efficacy of instructional videos and live demonstrations in crown preparation training for preclinical dental students.

Methods

A randomized controlled trial was conducted over 12 months with 96 final-year Bachelor of Dental Surgery (BDS) students. Participants were randomly allocated into three groups: Group A (instructional video), Group B (live demonstrations), and Group C (hybrid approach). Each group underwent training in porcelain-fused-to-metal tooth preparation through their respective methods. Performance was assessed using a standardized scoring chart, while satisfaction and perceptions were evaluated using a 5-point Likert scale. Data were analyzed using Chi-square and paired t-tests, with statistical significance set at p < 0.05.

Results

The group comparisons revealed significant differences in perceptions between Group A and Group B regarding stress levels during crown preparation (p = 0.013) and the adequacy of preclinical training (p = 0.034), with Group B showing higher satisfaction. However, no significant differences were found between Groups A and C or between Groups B and C (p > 0.05). Exercise scores across all groups showed no significant variation (p > 0.05), indicating comparable performance. Knowledge assessment revealed that while a majority of students correctly identified key concepts such as finish line depth, bur choices, and cusp reduction, 10–16% of students held misconceptions in areas like margin design and reduction ranges.

Conclusion

This study demonstrates that instructional videos, live demonstrations, and a hybrid approach are all effective methods for teaching crown preparation skills to preclinical dental students. The slight advantage of the hybrid approach suggests that combining different teaching methods may provide the most comprehensive learning experience. Future studies should explore the long-term impact of these methods on clinical performance.

Trial registration

The study was registered at clinicaltrials.gov, identifier NCT06426095.

Introduction

Dental education is a dynamic field that constantly seeks innovative approaches to enhance the learning experience for preclinical dental students, ensuring their readiness for the demanding clinical environment [1]. In Pakistan, dental education follows a rigorous four-year curriculum meticulously designed to train students with the necessary skills for proficient patient care [2]. Before transitioning to clinical practice, all students must complete a preclinical course. This preparatory phase involves intensive practice on life-sized mannequins/ phantom teeth. By engaging in hands-on learning during this period, students develop the required dexterity and familiarity with procedures essential for treating actual patients in clinical settings [1, 3].

Within this comprehensive educational framework, crown preparation emerges as a fundamental skill typically introduced in the final year of dental school [4]. Crown preparation requires a meticulous blend of theoretical knowledge, practical expertise, precision, and proficiency [5]. Mastery of this skill is essential for ensuring the longevity and functionality of dental restorations, which play a critical role in preserving oral health and enhancing patients’ quality of life [6]. Effective crown preparation demands an understanding of dental anatomy, materials science, biomechanics, and the ability to execute precise tooth reduction and preparation techniques [6, 7]. Therefore, the pedagogical approaches employed in teaching crown preparation must not only convey theoretical principles but also provide ample opportunities for students to enhance their manual dexterity and clinical decision-making skills [8].

Educators are continuously refining instructional methods for teaching crown preparation, sparking debates regarding the efficacy of traditional live demonstrations versus the growing popularity of instructional videos [8,9,10,11]. Traditional live demonstrations offer direct interaction and immediate feedback, allowing students to ask questions, observe intricate details, and receive personalized guidance. Advocates argue that the hands-on, interactive nature of live demonstrations facilitates better comprehension and retention of material, aiding in the development of essential clinical skills [12, 13]. Conversely, proponents of instructional videos highlight their accessibility, flexibility, and ability to provide clear visualization of procedures, allowing for self-paced learning and reinforcement of concepts. Additionally, instructional videos can feature close-up shots and detailed explanations, providing clear visualization of complex procedures and enhancing comprehension [8, 9, 14].

Despite the advantages of both approaches, finding the optimal balance between traditional live demonstrations and instructional videos remains a subject of ongoing discussion in dental education. Several studies have scrutinized their effectiveness [8, 14], offering insights into how they affect student learning outcomes. For instance, Aragon et al. [9], explored the impact of providing videos on dental students’ performance. It was found that students who watched a video before the clinic performed better than those who underwent the fixed prosthodontics course before viewing the video. However, other studies found that dental students’ procedural skills were improved only to some extent with instructional videos and that the live demonstration technique was still preferred [14, 15]. Moreover, integrating a hybrid model that combines the strengths of both methods may offer a comprehensive approach to crown preparation training.

This study hypothesizes that there is a significant difference in the performance of preclinical dental students in crown preparation tasks depending on whether they are trained through instructional videos, live demonstrations, or a hybrid approach. This study addresses this ongoing discussion by investigating the relative effectiveness of traditional live demonstrations, instructional videos, and a hybrid model that merges both approaches. Through an evaluation of dental students’ satisfaction and performance with video tutorials and hands-on demonstrations, this research endeavors to shed light on how different instructional methods influence knowledge acquisition within the practical environment.

Methods

Study setting and sample size Estimation

A randomized controlled trial was conducted at the Department of Prosthodontics, Altamash Institute of Dental Medicine for 12 months from 12th Jan’ 2023 till 11th Jan’ 2024. The study included final-year Bachelor of Dental Surgery (BDS) students. The fourth-year dental students included in this study had not received any prior lectures specifically focused on crown preparation nor had they performed any crown preparations on phantom teeth before the intervention. The participants were carefully selected to ensure they had no prior experience in crown preparation, as this was a prerequisite for inclusion in the study. The sample size of 96 participants was calculated using Open-Epi software, based on detecting significant within-group differences in performance scores using a paired t-test, with a mean value of 26.73 ± 0.04 [8], a 95% confidence level, and power of test 80%.

Ethical consideration and participants recruitment

Prior approval was obtained from the Ethical Review Committee of Altamash Institute of Dental Medicine (AIDM/ERC/01/2023/02). The study was registered at clinicaltrials.gov with the identifier NCT06426095. Informed consent was obtained from all participants, outlining the study’s objectives, the voluntary nature of participation, and assurances of anonymity and confidentiality.

A simple random sampling technique was used for the recruitment of participants. Both male and female, Fourth-year students of Bachelor of Surgery who voluntarily agreed to participate were included in the study. Exclusion criteria include students who do not provide consent, those absent from tutorials, individuals with prior experience in crown preparation, or students with medical conditions affecting participation.

Participant grouping

Upon obtaining written informed consent, a total of ninety-six final-year BDS students were enrolled in the study. Before allocation, all participants attended a comprehensive lecture on crown preparation principles delivered via a Power-Point^® presentation. The lecture encompassed fundamental aspects such as indications for crown placement, biological considerations, mechanical factors, and aesthetic aspects. It also delved into preparation guidelines, covering a wide array of topics essential for understanding crown preparation in dentistry. Following the lecture, participants were randomly assigned to one of three groups: Group A (instructional video), Group B (live demonstrations), or Group C (hybrid combining video and live demonstration).

Randomization and allocation concealment

Participants were randomly assigned to one of three groups: instructional video, live demonstration, or hybrid (combining video and live demonstration). Randomization was achieved using computer-generated randomization. A randomization sequence was generated by a researcher not involved in participant allocation (A.A), ensuring impartial assignment to each group. The allocation sequence was generated before the trial commenced. Allocation concealment was maintained using sealed envelopes containing group assignments, which were opened sequentially only after participants provided written informed consent. This approach minimized selection bias by preventing researchers from influencing group assignments based on participant characteristics. This process adhered to the CONSORT reporting guidelines [16].

Blinding

It was difficult to blind participants, but efforts were undertaken to minimize bias during participant recruitment and enrollment. Further, the participants were not explicitly informed of the specific educational interventions they would receive to minimize bias. Instead, the study was presented as a comparison of different teaching methods without disclosing which method was under evaluation. Additionally, a separate team of assessors, unaware of participants’ group assignments, conducted outcome assessments. These assessors had no access to details about the specific interventions each group received. This ensured that their evaluations were impartial and unaffected by the nature of the educational methods employed. Moreover, participants were assigned coded identifiers rather than using their names or group assignments, which helped maintain objectivity in the assessment process. By implementing these measures, we aimed to reduce any potential bias and ensure that the outcomes were evaluated fairly and accurately.

Intervention protocol

Participants in Group A received access to a specially prepared pre-recorded instructional video detailing the step-by-step process of porcelain-fused-to-metal tooth preparation for molars. The instructional video, spanning 15 to 20 min, meticulously covered various aspects of the procedure, including buccal, proximal, and palatal surface preparations, occlusal reduction, and surface texture. Notably, the video was created and reviewed by senior prosthodontists (M.S.A) and (N.A) to ensure that the content was accurate, up-to-date, and aligned with best practices in dentistry. A standardized script and visual aids were used to maintain consistency in the presentation of the material. Participants watched the video in a designated tutorial room setting, allowing for individualized learning at their own pace.

Participants in Group B attended live demonstrations of the same procedure conducted by the same experienced Prosthodontist (M.S.A) to ensure consistency in teaching quality and technique. Each intervention involved the preparation of only one crown. Through direct observation, participants had the opportunity to witness real-time demonstrations, ask questions, and receive immediate feedback, enhancing their understanding and mastery of crown preparation techniques.

Participants in Group C experienced a hybrid approach that combined both instructional videos and live demonstrations. This group watched the same pre-recorded video as Group A and subsequently attended live demonstrations as in Group B. This dual approach aimed to offer the benefits of both methods, reinforcing learning through detailed visual guidance and interactive practice. The content and quality of both the videos and live demonstrations were carefully reviewed and standardized to ensure that all participants received equivalent instruction.

Data collection

Before the intervention, all participants across the three groups underwent a pretest consisting of five questions. These questions were designed to gauge participants’ readiness and perceptions regarding crown preparation training. Specifically, the questions addressed stress levels during preparation, the duration of preclinical training, the effectiveness of lectures and training, and readiness for clinical practice. A 5-point Likert scale was used to evaluate participants’ perceptions and readiness before and after the intervention. The scale ranged from 1 (Strongly Disagree) to 5 (Strongly Agree). Pre-intervention questions focused on stress levels during crown preparation, adequacy of preclinical training, effectiveness of lectures, and readiness for clinical practice. Post-intervention responses measured participants’ satisfaction with the training method, confidence in performing crown preparations, and preparedness for patient treatment.

Following the lecture and demonstrations, participants were provided with an assessment questionnaire (Supplementary File 1) comprising six questions aimed at evaluating their comprehension and knowledge regarding porcelain-fused-to-metal tooth preparation. The questions covered topics such as bur selection for finishing line preparation, minimum reduction required for functional and non-functional cusps of posterior teeth, and margin design for PFM crowns. Upon completion of the questionnaire, students were allotted one hour to perform crown preparation on phantom molar teeth. A blinded assistant (S.B) then evaluated both the answers provided by the students on the questionnaire and their crown preparation performance. Each student received a numerical grading based on a scoring chart (Table 1), which was used to assess their proficiency in crown preparation.

Table 1 Scoring chart

Data analysis

The analyses were carried out using the Statistical Package for Social Sciences (version 25.0.0, SPSS Inc., IBM Corp., Chicago, IL, USA). Data analysis for this study involved a comprehensive evaluation of participant responses and performance across three instructional methods: video-based, hands-on tutorial, and hybrid approaches. Descriptive statistics were utilized to summarize demographic characteristics, including gender distribution and mean age. Perceptions regarding the demonstration techniques were compared among groups using Chi-square tests to assess differences in stress levels, training adequacy, lecture effectiveness, and perceived clinical relevance. Additionally, paired sample t-tests were employed to evaluate differences in exercise scores among the groups, to detect any significant variations in performance. Knowledge assessments regarding crown preparation techniques were analyzed descriptively to identify correct and incorrect responses, highlighting areas of misconceptions among participants. A p-value of < 0.05 was considered significant.

Results

A total of 197 students were initially assessed for eligibility. However, 101 were excluded due to not meeting the inclusion criteria (e.g., absence from tutorials, prior experience in crown preparation) or declining to participate. The rigorous inclusion/exclusion criteria ensured that only fourth-year BDS students with no prior training in crown preparation were included, to maintain homogeneity and validity in evaluating the interventions. Each group, representing video-based, hands-on tutorial, and hybrid approaches (Group A, Group B, and Group C, respectively), constituted 33.33% of the total participants (32 each) (Fig. 1).

Fig. 1

Consort flow diagram of the study

Table 2 presents the gender distribution and average age of the study participants, showing an equal representation of 48 females (50%) and 48 males (50%). The participants have a mean age of 23.53 years, with a standard deviation of 0.856 years.

Table 2 Gender distribution among participants

Table 3 compares the students’ perceptions in Group A and Group B regarding various aspects of the demonstration technique. Group A felt significantly more stressed during crown preparation, with a p-value of 0.013. Additionally, Group B found the duration of preclinical training to be adequate, which was also statistically significant with a p-value of 0.034. On the adequacy of lectures for preclinical training, Group B had more participants strongly agreeing (56.3%) and agreeing (31.3%) than Group A, with a highly significant p-value of 0.000. For the training’s helpfulness in clinical practice, both groups had mixed responses, with no significant difference (p-value of 0.295). Lastly, regarding the skill to treat patients with fixed prostheses, Group B had more participants agreeing (31.3%) and strongly agreeing (25.0%) than Group A, but the difference was not statistically significant (p-value of 0.207).

Table 3 Comparison of student perceptions regarding stress, training duration, and preparedness for crown preparation between group A and group B

Table 4 presents a comparison of student perceptions between Group A and Group C regarding the demonstration technique. In terms of feeling stressed during crown preparation, Group A and Group C showed similar distributions across response categories, with no significant difference observed (p-value = 0.533). Regarding the duration of preclinical training, both groups had comparable distributions, and the difference was not statistically significant (p-value = 0.130). Similarly, for the adequacy of lectures for preclinical training, there was no significant distinction between the groups (p-value = 0.399). In assessing the training’s helpfulness in clinical practice, Group C had slightly more participants strongly agreeing (59.3%) compared to Group A, but the difference was not statistically significant (p-value = 0.222). Lastly, concerning the skill to treat patients with fixed prostheses, both groups showed similar distributions across response categories, with no significant difference observed (p-value = 0.303).

Table 4 Comparison of student perceptions regarding stress, training duration, and preparedness for clinical practice between groups A and C

Table 5 shows the comparison of student perceptions between Group B and Group C regarding the demonstration technique, analyzed through the Chi-square test. The results reveal no significant difference in the feeling of stress during crown preparation between the two groups (p-value = 0.512). Similarly, there was no statistically significant distinction in the duration of preclinical training (p-value = 0.569) or the adequacy of lectures for preclinical training (p-value = 0.897). Regarding the training’s helpfulness in clinical practice, both groups showed similar distributions across response categories, with no significant difference observed (p-value = 0.913). However, concerning the skill to treat patients with fixed prostheses, Group B had a slightly higher proportion of participants strongly disagreeing compared to Group C, although this difference was not statistically significant (p-value = 0.100).

Table 5 Comparison of student perceptions regarding stress, training duration, and preparedness for clinical practice between groups B and C

Table 6 describes the comparison of exercise scores among Group A, Group B, and Group C, for the comparison between Group A and Group B, the exercise scores showed no significant difference (t = -1.359, df = 31, p = 0.184). Similarly, when comparing Group A and Group C, no significant distinction in exercise scores was observed (t = -0.882, df = 31, p = 0.385). Additionally, between Group B and Group C, the exercise scores did not significantly differ (t = 0.770, df = 31, p = 0.447). These results suggest that there were no significant variations in exercise scores among the three groups, indicating comparable performance levels across the assessed criteria.

Table 6 Comparison of exercise scores of groups A, B, and C

The students’ responses to the questions assessing their knowledge of crown preparation revealed the following findings. In terms of the finish line depth and configuration, 33.3% of students correctly answered that it should be within the range of 0.5–1 mm. However, there were some misconceptions, as 10.4% of students believed it should be between 1 and 1.5 mm, and 6.4% thought it should be exactly 1.5–2 mm or 4 mm. Additionally, 16.7% provided an incorrect response of 0.5–6 mm, and 27.1% did not answer the question at all.

Regarding the choice of bur for chamfer finish line preparation, a majority of students (83.3%) correctly selected the tapered fissure round bur. However, a notable percentage (12.5%) mistakenly chose the tapered fissure flat bur, and a small fraction (2.1%) thought the tungsten yellow/red carbide bur or torpedo bur should be used.

Regarding the choice of bur for shoulder finish line preparation, a majority of students (83.3%) correctly selected the tapered fissure flat bur. However, a notable percentage (16.7%) mistakenly chose the tapered fissure round bur.

When asked about the minimum reduction for non-functional cusps of posterior teeth, 60.4% of students correctly identified the range of 1–1.5 mm. However, there were some misconceptions, with 31.3% believing it should be 0.5–1 mm, 4.2% suggesting a range of 1.5–2 mm, and 4.2% stating an excessive 4 mm reduction.

In terms of the minimum reduction for functional cusps of posterior teeth, the majority (86.5%) accurately identified the range of 1–1.5 mm. However, a small percentage (4.2%) mistakenly believed it should be 0.5–1 mm, 3.1% suggested a range of 2–2.5 mm, 4.2% suggested that it should be 4 mm and 2.1% did not provide an answer.

Regarding margin design for PFM crowns, an overwhelming majority (91.7%) correctly recognized that a shoulder margin should be used on the buccal surface, while the majority (91.7%) also recognized that a chamfer margin should be used on the lingual/palatal surface. However, there were a few incorrect responses, with 2.1% suggesting a chamfer margin for the buccal surface, 2.1% suggesting a U-shaped margin for the lingual/palatal surface and 6.3% not providing any answer.

Discussion

This study aimed to evaluate the effectiveness of different teaching methodologies, specifically, instructional videos, live demonstrations, and a hybrid approach on the crown preparation skills of preclinical dental students. The results revealed that while all three methods are effective, live demonstrations yielded slightly higher performance scores. However, these differences were not statistically significant, suggesting that each method has potential in dental education, though certain contexts or student preferences may favor one over the others.

Instructional videos have gained popularity in dental education due to their flexibility, accessibility, and ability to demonstrate procedures clearly. Numerous studies have supported the efficacy of video-based learning across various educational contexts [8,9,10,11,12,13,14]. In our study, students who learned through instructional videos performed slightly less effectively than those who received live demonstrations. Specifically, 37.5% of the instructional video group (Group A) performed outstandingly, while 31.3% achieved very satisfactory results. However, the absence of statistical significance in performance differences suggests that instructional videos can adequately convey essential steps in crown preparation, providing a viable alternative to traditional teaching methods.

Additionally, when comparing students’ perceptions, Group A felt significantly more stressed during crown preparation than Group B (p-value = 0.013). This heightened stress could be attributed to the lack of immediate feedback and guidance, an inherent limitation of video-only instruction. While video learning supports theoretical understanding, its limited interactivity may result in greater anxiety during practical tasks, as supported by previous studies [9, 10, 12, 15]. In addition, among the students, 18.8% thought that preclinical video training helped prepare them for clinical practice and treat patients whereas 12.5% believed that after the preclinical training, they had acquired enough skills to treat patients with fixed prostheses. This aligns with a study by Abd-Shukor et al. [17], which highlighted the importance of designing videos with enhanced multimedia features to improve students’ learning experiences and acceptance of video modalities. The study found that enhanced videos improved students’ short-term theoretical knowledge retention, though their practical skills were minimally affected. Moreover, several other studies have rated video learning as more effective when used as a supplement to traditional methods [9, 15, 18, 19], our study uniquely employed video teaching as an independent teaching tool rather than as a supplementary method.

Live demonstrations have long been a cornerstone of practical dental education, offering students real-time interaction with instructors, immediate feedback, and opportunities to ask questions. This interactive element can be crucial for mastering complex procedures like crown preparation, where nuanced movements and techniques are involved [12–13]. Previous research supports the value of live demonstrations in dental education. For instance, a study by Nikzad et al. [15] found that live demonstrations significantly improved dental students’ clinical skills and confidence compared to self-directed learning. This is consistent with the 56.3% of students in our study who achieved outstanding results after live demonstration sessions, further underscoring the effectiveness of this teaching method. In addition, most participants felt less stressed during crown preparation, likely due to the immediate support available during live sessions. This combination of reduced anxiety and better performance outcomes suggests that live demonstrations continue to play a critical role in preclinical dental education [20]. Most notably, Group B students also felt that the duration of their preclinical training was more adequate than Group A, with a statistically significant p-value of 0.034. However, only 37.5% of students in Group B felt their training was highly helpful for clinical practice, indicating that while live demonstrations are beneficial for mastering preclinical techniques, there may still be gaps in translating these skills into clinical scenarios.

The Blended Learning (BL) approach, which gained significant traction during the pandemic, is now recognized as a key innovation in education. BL merges traditional face-to-face instruction with online learning activities, offering the benefits of both modalities [21]. It provides a balanced learning experience by offering the flexibility and detailed visualization of videos alongside the interactive and adaptive nature of live demonstrations. Garrison DR. define BL as the intentional combination of in-person and digital learning methods to enhance classroom education [22]. In the current study, in the hybrid group (Group C), the majority of participants (43%) felt that the duration of preclinical training was adequate, a higher proportion compared to Group A (instructional video). Additionally, a significant majority of students in the hybrid group (59.3%) believed that their training would be helpful in clinical practice. This contrasts with only 18% in Group A and 37% in Group B who shared the same sentiment. This could be attributed to the comprehensive exposure provided by the hybrid approach, which might instill greater confidence in their skills. The perception of adequate training and readiness for clinical practice is crucial, as it can influence students’ transition from preclinical to clinical settings.

The findings of this study have several implications for dental education. Firstly, the videos provide a strong foundation for learning procedural steps, but their effectiveness in translating knowledge into clinical practice is limited without additional support mechanisms, such as live feedback or hands-on experience. Moreover, the comparable effectiveness of instructional videos and live demonstrations suggests that educators have flexibility in choosing the most appropriate method based on resources and constraints. The slight advantage of the hybrid approach indicates that combining different teaching methods may provide optimal learning experiences for students. These findings can inform educational strategies in dental schools, helping to optimize training methods and better prepare students for clinical practice.

Lastly, this study has several limitations that should be addressed in future research. The sample size was relatively small, and the study was conducted at a single institution, which may limit the generalizability of the findings. Additionally, the study focused solely on immediate performance and did not assess long-term retention or clinical application of the skills learned.

Future research should explore the long-term impact of different teaching methods on clinical performance and patient outcomes. Investigating the use of advanced technologies, such as virtual and augmented reality, combined with traditional methods could also provide insights into innovative ways to enhance dental education.

Conclusion

In conclusion, this study demonstrates that instructional videos, live demonstrations, and a hybrid approach are all effective methods for teaching crown preparation skills to preclinical dental students. The slight advantage of the hybrid approach suggests that combining different teaching methods may provide the most comprehensive learning experience. Future studies should explore the long-term impact of these methods on clinical performance.