Prospective Randomized Controlled Study to Evaluate Combining Video Feedback Teaching with Virtual Simulation for Ceramic Veneer Tooth Preparation

Summary

This randomized controlled study evaluated a teaching protocol combining video feedback and virtual simulation for 40 dental students learning ceramic veneer preparation, demonstrating improved practical skills and student satisfaction compared to traditional methods alone.

Abstract

This study aims to analyze the impact of video feedback teaching combined with virtual simulation for ceramic veneer tooth preparation. A total of 40 prospective dental students who were about to start clinical internship in Jiangsu Medical College between April 2024 and July 2024 were randomly divided by convenience sampling into a control group and a study group. The teaching effect was compared at 1, 2 and 3 months after teaching. After the training, the scores of the two groups of tooth preparations were significantly improved compared with those before training, and the scores of the operating positions were significantly reduced compared with those before training. In addition, the operating position scores of the study group (14.9 ± 2.07) were significantly lower than those of the control group (17.1 ± 1.66; p < 0.05). The study group also achieved significantly higher virtual simulation accuracy scores (89.5 ± 4.2) by the end of the training period. There was a statistically significant difference (p < 0.05) in the effectiveness of the two sets of tooth preparations. Questionnaire results indicated significantly higher satisfaction and engagement scores in the study group than in the control group (all p < 0.05). Compared with traditional teaching methods, the application of video feedback teaching combined with virtual simulation technology in the preparation of ceramic veneered teeth has a better practical training effect, as supported by both objective performance metrics and subjective learner feedback.

Introduction

Prosthodontics is an interdisciplinary field that integrates theoretical knowledge with practical application¹. With the continuous improvement in living standards, there has been a growing emphasis on aesthetic restoration technology in oral medicine. The clinical success of ceramic veneers, a mainstay of minimally invasive aesthetic dentistry, is highly dependent on the precision of the tooth preparation and the subsequent quality of the restoration’s fit and bond^2,3,4. Recent evidence underscores that optimal clinical performance and longevity of veneers are directly linked to meticulous preparation geometry and the use of advanced digital fabrication and bonding protocols^5,6. Dental education and practice are dynamic areas that often necessitate curriculum adjustments. Although preparing teeth for fixed prostheses is a routine clinical process, achieving predictable outcomes can be challenging, particularly for dental students and postgraduate residents. Dental students often struggle with achieving consistent precision in tooth preparation for fixed prostheses, especially ceramic veneers. Challenges include mastering tooth reduction, margin design, and contouring, along with the lack of immediate feedback during traditional teaching. These difficulties underscore the need for improved training methods^7,8,9.

Ceramic veneer restoration technology is of major importance in oral aesthetic restoration, and mastering this technique serves as a crucial indicator of a practitioner’s skill level in the future. Standardized practical training for dental students before they enter clinical work is essential to ensure both practitioner and patient well-being^2,3. The undergraduate education of stomatology in China adopts the 5 + 3 standardized system, with 5-year undergraduate and 3-year standardized training. In the first 4 years, the students study basic medicine, oral theory, and imitation head mold operation, and in the 5^th year, they enter clinical practice². After graduation, they participate in the standardized training of residents to practice. The teaching intervention of this study is aimed at the 3^rd-year junior college students, aiming to optimize their skill reserve before entering clinical practice. Compared with the international common 4- or 6-year system, China emphasizes the pre-standard operation training, and the virtual simulation platform is the official requirement of the necessary teaching resources. To enhance dental students’ skills in ceramic veneer preparation, a variety of teaching methods are used in dental education. The traditional teaching method is generally explained and demonstrated by the teaching instructor, with students practicing and submitting the prepared dental model to the teaching instructor for evaluation, guidance, and correction. Students continue to train repeatedly, based on feedback¹⁰. However, it is often difficult for a teacher to achieve one-on-one teaching, and the teacher cannot observe and guide the entire process of student operation, resulting in a focus only on evaluating the training results and an inability to correct and guide students in a timely manner during the operation process. Video feedback teaching addresses this by allowing students to review recordings of their work, promoting self-assessment and skill refinement through repeated analysis. Video feedback teaching – an interactive feedback teaching method – focuses on self-feedback and self-evaluation. By recording the entire process of student operations through videos, it is possible to repeatedly review, analyze, and provide feedback on the recorded videos to improve the training effect of practical operations^{11,12,13,14,15,16,17}. According to domestic and international studies, this video feedback teaching method has been applied in medical teaching, and it has achieved positive results in improving students’ cognitive ability and clinical skills¹⁸.

Although the benefits of video feedback and virtual simulation in medical education have been widely recognized¹⁹, their combined use in preclinical dental training, especially in high-precision operations such as ceramic veneer preparation, still needs to be further explored. This study focuses on systematically integrating video feedback teaching and virtual simulation technology into the same teaching framework, focusing on improving dental students' operational technical accuracy and ergonomic abilities before entering clinical practice. At the same time, by enabling iterative self-assessment, real-time error correction, and standardized skill acquisition in a risk-free environment, the collaborative use of video feedback and virtual simulation is expected to achieve more ideal results than traditional teaching alone. Specifically, this study aims to evaluate the following aspects: (1) the impact of this combined teaching method on students' ceramic veneer preparation quality (measured by standardized morphological standards); (2) its impact on students' ergonomic posture during simulated clinical processes; (3) students' perceptions of this teaching method in terms of engagement, feedback effectiveness, and learning satisfaction. Through an in-depth examination of these dimensions, this study hopes to provide empirical evidence for an innovative, technology-enabled training model to help dental students better adapt to the requirements of clinical practice.

Protocol

The experimental research study was conducted at the Oral Medicine Training Center of Jiangsu Vocational College of Medicine between April 2024 and July 2024. This study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of Yancheng Stomatological Hospital (Approval Number: Yancheng Dental Ethics Review [2024]09). We have post-registered the study (Clinical registration number: NCT07398794). Informed consent was obtained from all participants for this study.

Participants and groups
Sample size calculation was performed using PASS software based on preliminary test results from a pilot study involving 10 students (not included in the main trial). In the pilot, the mean ± standard deviation operating position score was 18.5 ± 2.1 in the traditional teaching group and 15.8 ± 2.4 in the combined teaching group, yielding an expected mean difference of 2.7 points. With a significance level (α) of 0.05, test power (1 − β) of 80%, and a 1:1 allocation ratio between groups, the calculated minimum sample size was 17 participants per group. To account for a potential attrition rate of approximately 15%, 20 participants were enrolled in each group, resulting in a total sample size of 40.

Participants were recruited from a single cohort of students who had completed their fourth semester at Jiangsu Medical College and were about to enter the third-year internship stage using a convenience sampling method. All eligible students in the cohort were invited to participate during a scheduled academic orientation session. The allocation process was performed by an independent researcher who was not involved in teaching or assessment. A computer-generated random number sequence was used for 1:1 assignment to either the control group (traditional teaching) or the study group (video feedback combined with virtual simulation). To ensure allocation concealment, group assignments were placed in sequentially numbered, opaque, sealed envelopes. A teaching assistant opened the envelopes at the time of enrolment to reveal group allocation. The assessors remained blinded to group assignment throughout the trial.

Using a convenience sampling method, 40 prospective dental students from Jiangsu Medical College who were about to start clinical internships (junior) were included in the study; they comprised 22 men and 18 women aged 17–21 years (mean age: 18.65 ± 1.8 years), and there was no significant difference in gender or age between the two groups (all p > 0.05). The inclusion criteria were as follows: All students had completed theoretical and practical coursework in the dental profession and were about to undergo pre-service training for clinical placements; all participants who initially enrolled in the study completed the entire training and assessment process.

Research methods
In this study, all students used the Prosthodontics textbook (4^th edition)²⁰. The teaching staff comprised an experienced associate professor who conducted both traditional and video feedback-based teaching sessions. The teaching methodologies for the control group (traditional teaching) and the study group (video feedback combined with virtual simulation) were distinct and are detailed below.

Control group (traditional teaching method): In the control group, the 20 min theoretical instruction on the 1^st day covered the foundational knowledge of ceramic veneers. This included topics such as the definition and uses of ceramic veneers, indications and contraindications, tooth preparation techniques (e.g., preparation depth and margin design), ergonomics during the procedure, and the tools used. This theoretical content was aimed at providing the students with the necessary background before moving on to clinical demonstrations and hands-on practice; clinical demonstration and practice–after the theoretical introduction, the instructor demonstrated the ceramic veneer preparation technique (20 minutes), providing a live example for students to observe and model; guided practice–following the demonstration, students engaged in hands-on practice (100 min), during which the instructor provided immediate feedback to correct mistakes and offer improvement guidance; continued practice – on the 2^nd day, students participated in another practice session (100 min), allowing for additional skill refinement with instructor support.

Study group (video feedback with virtual simulation): The study group’s curriculum integrated video feedback teaching with virtual simulation technology, following instructional approaches referenced from relevant literature²¹; theoretical and virtual simulation instruction – on the 1^st day, students received a 20 min theoretical instruction session similar to that of the control group. Following this, they completed the Virtual Simulation Experiment Course for Anterior Veneer Restoration available on the national virtual simulation open sharing platform²². This course was an interactive three-dimensional (3D) simulation module, not a passive video demonstration. Using a standard computer interface, students performed virtual tooth preparation on a 3D digital tooth model. The software provided real-time visual feedback on preparation depth, angulation, and margin geometry against pre-set ideal parameters. It included features such as a virtual high-speed handpiece, depth guides visualized through color-coded mapping (e.g., indicating areas of under- or over-reduction), and automated scoring based on accuracy. The module required active, step-by-step manipulation of the virtual tool to complete the preparation task. All students were required to achieve ≥80 points in the virtual simulation module (20 min) before proceeding; clinical demonstration and video recording – after the theoretical and virtual simulation sessions, the instructor demonstrated the veneer preparation technique live (20 min). During the demonstration, two students recorded the instructor’s demonstration from both front and side perspectives using mobile phones, creating videos for reference, peer critique, and video feedback. The students were then divided into pairs. Each student alternated between performing the tooth preparation and recording their partner’s practice using a mobile phone. After each practice, students reviewed their videos together, critiquing each other’s work with guidance from the instructor; video review and comparative analysis – the instructor randomly selected one student’s video to review with the entire group, providing a critique based on both the video demonstration and the final preparation product (20 min). The instructor summarized key points for improvement, encouraging students to analyze their technique in comparison with the demonstration; independent practice and group discussion – following the video review, students engaged in self-guided analysis, comparing their recorded performances against the standard. They participated in group discussions to exchange feedback and insights. On the 2^nd day, students resumed practice in groups (100 min), with the instructor offering real-time feedback and answering questions; virtual simulation data collection – performance data from the virtual simulation platform were automatically recorded for each student in the study group. This included final task accuracy score (%), time taken to complete the simulation (min), number of attempts to achieve the passing score (≥80), and detailed feedback on specific error types (e.g., over-reduction, uneven margin). These metrics provide objective, real-time measures of skill acquisition in a risk-free environment.

Evaluation indicators
Students’ ceramic veneer preparation skills were assessed at multiple time points: before the start of training and at three subsequent intervals after training (1, 2, and 3 months). The following components were part of the assessment process:

The students in both the control and study groups performed ceramic veneer preparations within a time limit of 15 min. All students’ assessments were completed by an associate professor and an associate chief physician with extensive clinical experience, and associate professors and associate chief physicians scored the same student at the same time, taking their average score as the final assessment score (professors and associate chief physicians did not know the grouping). To enhance the precision and fairness of the evaluation, the students’ prepared teeth were digitally scanned using a digital impression system (Figure 1, Figure 2, Figure 3, and Figure 4). The digital images allowed for clear visualization of the tooth preparation, which aided in accurate scoring by the evaluators.

The assessment consisted of two primary components (primary outcomes). First, the students’ ergonomic posture during the ceramic veneer preparation was evaluated using the Modified Dental Operator Posture Assessment Instrument (M-DOPAI)²³, which includes 12 scoring items related to six key body parts (back, hands, shoulders, neck, head, and feet). The scores ranged from 12 to 32, with lower scores indicating better ergonomic positioning. The intraclass correlation coefficient (ICC) for absolute agreement was 0.89 (95% confidence interval [CI]: 0.82–0.94), indicating excellent reliability. This instrument was selected due to its proven reliability and validity in assessing dental professionals’ posture. Second, the quality of the tooth preparation was assessed based on five criteria (Tooth Preparation Morphology Score)¹⁴: amount of tooth preparation (e.g., neck and shoulder preparation), positioning of the neck and shoulder, smoothness and continuity of the shoulder, finishing and polishing of the preparation, and damage to the gum or adjacent teeth. Each criterion was scored out of 20 points, with a total possible score of 100. Higher scores indicated better quality of tooth preparation, and the ICC was 0.92 (95% CI: 0.87–0.96), also indicating excellent reliability.

In this study, the quality of the tooth preparation was assessed based on five criteria, and each criterion was scored on a scale of 0–20 points according to a standardized rubric adapted from established prosthodontic teaching guidelines and previous validation studies^14,24. The detailed scoring criteria were as follows: amount of tooth reduction (0–20 points) – evaluated based on the depth and uniformity of reduction. A score of 20 indicated uniform reduction within 0.5–0.8 mm for the facial surface and 0.3–0.5 mm for the incisal edge, with no over-reduction or under-reduction. Scores were reduced for under-reduction (>1.0 mm deviation from ideal, 0–5 points), uneven reduction with visible grooves or ledges (6–10 points) or localized over-reduction leading to pulp exposure risk (11–15 points); finish line (cervico-shoulder) positioning (0–20 points) – assessed for clear, continuous margin placement at the gingival third. A score of 20 indicated a well-defined, smooth shoulder or chamfer finish line placed 0.5 mm subgingivally or equigingivally without steps or irregularities. Points were deducted for finish lines placed >1 mm subgingivally (0–5 points), uneven or poorly defined margins (6–10 points) or finish lines positioned supragingivally where indicated (11–15 points); smoothness and continuity of the shoulder (0–20 points) – judged by the absence of irregularities, grooves or sharp line angles along the entire shoulder. A score of 20 represented a smooth, continuous shoulder with no detectable irregularities under 10x magnification. Scores of 6–10 were given for minor irregularities (<0.2 mm depth), 11–15 for obvious grooves or discontinuities (0.2–0.5 mm) and 0–5 for severe irregularities or breaks (>0.5 mm); finishing and polishing of the preparation (0–20 points) – rated based on surface smoothness and absence of scratches or rough areas. A score of 20 indicated a uniformly smooth, polished surface without visible scratches under 10x magnification. Deductions were made for mild surface roughness (16–19 points), moderate scratches or roughness (11–15 points), or grossly unfinished surfaces with deep scratches (0–10 points); damage to gingiva or adjacent teeth (0–20 points) – assessed by checking for iatrogenic injury to soft tissue or neighboring teeth. A score of 20 meant no visible damage to the gingiva or adjacent tooth surfaces. Points were subtracted for minor gingival abrasion (16–19 points), noticeable adjacent tooth damage (enamel scratches, 11–15 points), or severe gingival laceration or adjacent tooth fracture (0–10 points).

After the training period, an anonymous questionnaire was administered to students in both the study group and the control group to gather feedback on the effectiveness of their respective teaching methods. The questionnaire aimed to evaluate students’ perceptions of the learning experience across various aspects, capturing both qualitative and quantitative data on the method’s effectiveness and engagement. The questionnaire was developed specifically for this study based on the teaching objectives and relevant literature on technology-enhanced learning^11,20. To assess content validity, the initial items were reviewed by three experienced dental educators for clarity, relevance, and coverage of key learning domains. Their feedback was used to refine the wording and structure of the final instrument. It consisted of six statements designed to assess key components of the learning process. Students rated each statement using a 5-point Likert scale, where 1 indicated completely disagree, 3 indicated neutral, and 5 indicated completely agree. Higher scores indicated more favorable evaluations of the teaching method. The six statements were (1) enhanced teacher–student communication, (2) increased class enthusiasm and engagement, (3) ability to identify and correct mistakes in real-time, (4) increased interest in learning, (5) improved retention of key procedures and concepts, and (6) willingness to use the combined method in future practical courses. In the current sample, the questionnaire demonstrated good internal consistency (Cronbach’s α = 0.87). The results were analyzed based on the mean score for each item, with higher scores reflecting more positive feedback on the method’s effectiveness in improving the learning experience (Table 1). This questionnaire provided valuable insights into students’ attitudes towards this innovative teaching approach.

Comparative questionnaire analysis – to enable a direct comparison of teaching method perceptions, a modified version of the satisfaction questionnaire was also administered to the control group after their training. The questionnaire assessed the same six domains: teacher–student communication, class engagement, real-time error correction, learning interest, retention of key concepts, and willingness to use the method in future courses. This allowed for a between-group analysis of subjective learning experiences.

Student feedback questionnaire (secondary outcomes) – a 5-point Likert scale questionnaire (1 = completely disagree, 5 = completely agree) was administered to both groups after training to compare perceptions of the teaching method. It assessed six domains: (1) enhanced teacher–student communication, (2) increased class engagement, (3) ability to identify/correct mistakes in real-time, (4) increased interest in learning, (5) improved retention of key concepts and (6) willingness to use the method in future courses. The questionnaire showed good internal consistency (Cronbach’s α = 0.87).

Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics. Continuous variables were tested for normality using the Shapiro–Wilk test (p > 0.05). Normally distributed data were expressed as mean ± standard deviation (x̄ ± s) with 95% CIs, and non-normally distributed data were presented as median (interquartile range). Between-group comparisons were conducted using independent samples t-tests (with homogeneity of variance confirmed by Levene’s test, p > 0.05) or the Mann–Whitney U test, as appropriate. For significant between-group comparisons, effect sizes were calculated using Cohen’s d (interpretation: small ≥0.2, medium ≥0.5, large ≥0.8), and 95% CIs were reported for mean differences. Repeated-measures analysis of variance (ANOVA) was employed for longitudinal data analysis, with sphericity verified by Mauchly’s test (p > 0.05); the Greenhouse–Geisser correction was applied if sphericity was violated. For the primary outcomes, a two-way (mixed) repeated measures ANOVA was used with one between-participants factor (group: study vs control) and one within-participants factor (time: baseline, 1, 2, 3 months). For significant effects in the repeated‑measures ANOVA, partial eta‑squared (η_p²) was reported as the effect size (interpretation: small ≥0.01, medium ≥0.06, large ≥0.14), along with 95% CIs for estimated marginal means. If a significant group × time interaction was found, simple effect analyses (tests of within-participants contrasts and between-participants effects at each time point) were performed with a Bonferroni adjustment for multiple comparisons. To test the robustness of the repeated‑measures findings given the sample size, a sensitivity analysis was performed using the non-parametric Friedman test for within-group changes over time. Categorical data were summarized as frequencies (%) and analyzed using χ² tests or Fisher’s exact test. Inter-rater reliability for assessment scores was evaluated using the ICC with a two-way random-effects model for absolute agreement. All tests were two-tailed, and statistical significance was set at p < 0.05.

Results

The results showed that there were 20 participants in the study group, comprising 10 men and 10 women, with an average age of 18.19 ± 1.82 years. There were 20 participants in the control group, comprising 12 men and 8 women, with an average age of 18.43 ± 2.10 years, and there were no significant differences in gender, age, or dominant hands between the two groups, as shown in Table 2.

A two-way repeated measures ANOVA (mixed ANOVA) was used to explore the effects of teaching...

Discussion

Dental preparation is an essential technique in prosthodontics, and the quality of the preparation determines the final restoration effect. This is particularly critical for ceramic veneers, where sub-millimeter inaccuracies in preparation depth, margin geometry, or surface smoothness can compromise the marginal fit, aesthetic outcome, and long-term bond integrity of the definitive restoration^11,25,26. Due to the irreversibility...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
IBM SPSS Statistics	IBM Corp., Armonk, NY, USA	Version 26	Used for statistical analysis including Shapiro-Wilk test and repeated-measures ANOVA.
PASS software	NCSS, LLC., Kaysville, UT, USA	Version 22	Used for sample size calculation with α=0.05 and test power=80%.