# Training in anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses: design and educational outcomes

Sophie Gosselin, Samuel Morice, Stephane Le-Goff, Elisa Caussin, Sarah

Abdel-Gawad, Philippe Boitelle, Elisabeth Dursun, Maria-Antonietta

d'Agostino, Helene Gouze, Jean-Pierre Attal, et al.

► To cite this version:

Sophie Gosselin, Samuel Morice, Stephane Le-Goff, Elisa Caussin, Sarah Abdel-Gawad, et al. Training in anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses: design and educational outcomes. BMC Medical Education, 2026, 10.1186/s12909-026-08670-5. doi:10.1186/s12909-026-08670-5

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# Training in anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses: design and educational outcomes

Received: 14 August 2025

Accepted: 20 January 2026

Published online: 26 January 2026

Cite this article as: Gosselin S., Morice S., Le-Goff S. *et al*. Training in anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses: design and educational outcomes. *BMC Med Educ* (2026). https://doi.org/10.1186/s12909-026-08670-5

Sophie Gosselin, Samuel Morice, Stephane Le-Goff, Elisa Caussin, Sarah Abdel-Gawad, Philippe Boitelle, Elisabeth Dursun, Maria-Antonietta D'Agostino, Helene Gouze, Jean-Pierre Attal & Philippe Francois

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

If this paper is publishing under a Transparent Peer Review model then Peer Review reports will publish with the final article.
# Training in anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses: Design and educational outcomes

## AUTHOR NAMES

Sophie Gosselin¹²; Samuel Morice, MDT¹²; Stephane Le-Goff, MSc¹²; Elisa Caussin, DDS, MSc²³; Sarah Abdel-Gawad, MSc¹²; Philippe Boitelle, DDS, MSc, PhD²⁴⁵; Elisabeth Dursun, DDS, MSc, PhD²⁶; Maria-Antonietta D'Agostino, DDS, MSc, PhD⁷; Helene Gouze, MD, MSc, PhD⁷⁸; Jean-Pierre Attal, DDS, MSc, PhD¹²; Philippe Francois, DDS, MSc, PhD¹²⁷

## AFFILIATIONS

¹Department of Dental Materials, Faculty of Dental Surgery, Université Paris Cité, Paris, France

²UMR1333 Santé Orale, Faculty of Dental Surgery, Université Paris Cité, Montrouge, France

³Department of Restorative Dentistry and Endodontics, Faculty of Dental Surgery, Université Paris Cité, Paris, France

⁴Department of Prosthodontics, Faculty of Dental Surgery, University of Lille, Lille, France

⁵Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland.

⁶Department of Pediatric Dentistry, Faculty of Dental Surgery, Université Paris Cité, Paris, France

⁷Department of Rheumatology, Catholic University of Sacred Health, Foundation Policlinico Universitario Agostino Gemelli IRCSS, Rome, Italy.

⁸CESP-INSERM, University of Paris Saclay, Paris, France
## CORRESPONDING AUTHOR

Philippe François, DDS, MSc, PhD

Department of Dental Materials, Faculty of Dental Surgery, Université Paris Cité, Paris,
France

Phone: +33 158076725

Email: philippe.francois@parisdescartes.fr

## ABSTRACT

**Background:** Resin-bonded fixed dental prostheses, particularly zirconia-based single-retainer cantilever designs, offer a minimally invasive option for the replacement of anterior and, more recently, posterior teeth. This study aimed to develop a cost-effective reusable simulator and evaluate a one-day, simulation-based continuing education program grounded in current evidence for anterior cantilever (AC) and posterior cantilever (PC) zirconia resin-bonded fixed dental prostheses (RBFDPs).

**Methods:** Twenty-six volunteer general dental practitioners attended two sessions that blended lectures with two hands-on exercises using custom 3D printed modified typodonts. Self-perceived knowledge, confidence, and satisfaction were captured before, immediately after, and four months postcourse with questionnaires based on the Likert scale. Descriptive statistics (means and standard deviations) were calculated, and repeated items were analysed using non-parametric Kruskal-Wallis tests (R software, version 4.5.1).

**Results:** The baseline responses indicated modest experience with AC-RBFDPs (mean 3.54 ± 1.84) and PC-RBFDPs (2.27 ± 1.76) but high demand for theoretical training. Immediate satisfaction reached a very high level (overall 5.00 ± 0.00), and all individual items evaluating the education program exceeded 4.5. At four months, satisfaction remained high (4.63 ± 0.50), and confidence in zirconia bonding improved significantly (3.04 ± 1.04 to 4.00
± 0.89; p < 0.05), although reported implementations of AC-RBFDPs (3.06 ± 1.18) and PC-RBFDPs (3.00 ± 1.26) in clinical practice remained limited.

**Conclusions:** A single-day, simulation-based course using an affordable, recyclable simulator markedly enhanced perceived competence and maintained high satisfaction at four months, while it translated only partially into practice change among general dentists. Given the small sample size and the exclusive use of self-reported outcomes, these findings should be generalised with caution. Future work should rely on larger, longitudinal multimodal strategies and include objective performance and patient-centred outcomes.

**Trial Registration:**

Not applicable

**Clinical trial number:**

Not applicable

**KEYWORDS:** Biomaterials, Continuing professional development, Education, Practical training, Resin-bonded fixed dental prostheses

# 1 BACKGROUND

Clinical and therapeutic innovations often require considerable time before being routinely adopted in everyday practice. On average, it takes 17 years for only a small fraction of these innovations to be integrated into standard clinical care [1, 2]. Translational research refers to the continuum of processes by which scientific discoveries originating from basic research are transformed into tangible applications in human health. Positioned at the intersection of science and medicine, this field is traditionally divided into two distinct yet complementary
phases. The first phase, particularly in the context of therapeutic innovation, involves translating fundamental scientific knowledge into initial clinical applications through prospective or retrospective clinical trials. The second phase focuses on the systematic integration of these clinically validated interventions into routine clinical practice [3, 4].

Anterior cantilever resin-bonded fixed dental prostheses (AC-RBFDPs) have been proposed for decades, with various proposals being made over time [5, 6]. However, in their current, scientifically validated form, namely, all-ceramic restorations with a single retainer, they were first proposed in 1997 [7], subsequently validated through long-term clinical trials when made with zirconia [8-10] and mentioned in clinical guidelines [11]. With the translational research phases now complete, AC-RBFDPs are now at a stage where many practitioners are using them on a daily basis or are deciding to start using them, hence the high demand for training. The emergence of posterior cantilever resin-bonded fixed dental prostheses (PC-RBFDPs) has been much more recent, with the first prospective and retrospective studies appearing in 2022 [12-15] and the first clinical guidelines published only recently [16]. Translational research is therefore not yet complete for PC-RBFDPs and important aspects, such as the optimal design and extent of tooth preparation for the retainer, are still the subject of ongoing discussion and debate [12-15]. This therapy is in the very early stages of being disseminated to private practitioners. There is, therefore, a real need for training and assessment of the relevance of these two topics, covering both theoretical and practical aspects.

This study aimed to develop a cost-effective simulator and evaluate a one-day theoretical and simulation-based training program for general dental practitioners on AC-RBFDPs and PC-RBFDPs in response to the growing demand for continuing education in these areas. The training was grounded in the latest scientific evidence from both biomaterials research and clinical studies. It incorporated the use of physical simulation models for hands-
on learning and emphasized the importance of effective communication with the dental laboratory technician in the successful implementation of these treatment strategies. We hypothesised that this course would elicit high satisfaction, increase self-perceived knowledge and confidence regarding AC- and PC-RBFDPs, and lead to moderate short-term changes in reported clinical practice.

## 2 METHODS

### 2.1 Study Design

A total of 26 licensed dental practitioners voluntarily participated in this study. Two continuing education sessions, which focused on both theoretical and practical aspects of implementing AC-RBFDPs and PC-RBFDPs, were organized in September 2024 and February 2025. Participants were general dental practitioners working exclusively in private practice who voluntarily enrolled in the continuing education program after learning about it through announcements in professional journals or training organizations. Because this was an exploratory educational study embedded in routine continuing education activities, no a priori power calculation was performed. The target sample size corresponded to the maximum number of general dental practitioners that could be accommodated in two course sessions (n = 26). The course was promoted as an introductory, evidence-based program specifically focused on AC- and PC-RBFDPs, and no minimum number of previously completed cases was required for participation.

All participants were first asked to complete a questionnaire assessing their clinical experience and self-perceived knowledge regarding the themes of AC-RBFDPs and PC-RBFDPs. Following the one-day theoretical and practical training, the participants were asked to complete a second questionnaire evaluating the training content and format. Finally,
a follow-up survey (responded to by 16 out of 26 practitioners) was conducted four months
later to assess changes in clinical practice, the perceived long-term relevance of the training,
and the extent to which participants had been able to apply the acquired knowledge.

**2.2 Ethical Considerations**

This study adhered to the principles outlined in the Declaration of Helsinki and received
ethical approval from the AP-HP CER Institutional Review Board (# IRB: IORG0010044).

All participants provided written informed consent before the continuing education program
to complete three questionnaires anonymously.

**2.3 Educational Objectives**

The primary aim of this continuing education program is to equip general dental practitioners
with the theoretical knowledge and practical skills necessary to safely and effectively indicate
conditions for AC-RBFDPs and PC-RBFDPs, plan treatment, prepare tooth abutments, and
bond to patients' AC- and PC-RBFDPs.

The educational objectives are grouped into four core domains:

- Clinical Decision-Making and Indications

- Identify appropriate clinical indications and contraindications for AC-
  and PC-RBFDPs.

- Evaluate patient-specific factors (e.g., edentulous span, occlusion, parafunctions, periodontal health) to determine the eligibility for AC- and PC-RBFDPs.

- Compare AC- and PC-RBFDPs with alternative treatments (implants, removable partial dentures, conventional fixed prostheses) in terms of invasiveness, cost, and biological preservation
* Understand the influence of occlusal dynamics and biomechanics on the long-term success of AC- and PC-RBFDPs.

- Biomaterials and Adhesion Science

* Recognize the different generations and mechanical properties of zirconia.

* Understand the limitations of lithium disilicate for these indications, although it is possible to use it for AC-RBFDP.

* Master the principles of adhesion to enamel, dentin, and zirconia using evidence-based bonding protocols.

* Understand the chemical and mechanical surface treatments required for zirconia (e.g., sandblasting, 10-MDP-containing primer).

- Technical and Procedural Skills

* Perform standardized tooth preparations for AC and PC-RBFDPs as follows: enamel-preserving and juxtagingival (i.e., with the finishing line located at the gingival margin), designed to optimize the connector geometry (height, width) and adapted to anterior and posterior clinical scenarios.

* Use custom typodonts and simulation models to practice: tooth preparation on incisors, premolars, and molars; intraoral scanning and impression strategies; clinical bonding procedures under rubber dam isolation; and occlusal adjustment and polishing of the final restoration.

* Evaluate common design errors through digital viewer exercises and learn to validate prosthetic files before fabrication.

- Interprofessional Communication and Clinical Integration
* Develop structured communication protocols with dental laboratory technicians to optimize prosthesis design and strength (e.g., connector dimension, embrasure form, ceramic layering).

* Interpret CAD design proposals from laboratories and provide feedback when modifications are needed

* Understand the clinical importance of a repositioning key to ensure precise positioning during adhesive cementation.

* Apply decision-making algorithms for temporization, soft tissue management (e.g., ovate pontic design, ridge ovalization), and long-term maintenance.

* Anticipate and manage possible complications (debonding, fracture, adaptation issues).

## 2.4 Chosen Educational Format

The one-day training program combined theoretical instruction and hands-on practice:

- Morning session: Introduction with a clinical case presenting over 15 years of follow-up of an AC-RBFDP, followed by a step-by-step clinical and scientific overview of AC-RBFDPs. This included indications, preparation design, temporization, material selection, bonding protocols, communication with laboratory technicians with digital viewers, occlusal adjustment, and postoperative care. A first practical hands-on process then allowed participants to perform tooth preparation and adhesive luting of an AC-RBFDP on simulation models with a repositioning key.

- Afternoon session: Core concepts of PC-RBFDPs were introduced through comparisons with anterior cases, followed by a step-by-step clinical approach
highlighting the specificities of posterior sites, especially with respect to
biomechanical considerations. A second practical hands-on session focused on
premolar- and molar-supported preparations and adhesive luting of PC-
RBFDPs.

## 2.5 *Creation of the Custom Typodont Model and Progression of the Two Hands-on Sessions*

To ensure that the training presented can be applied by as many people as possible, a cost-effective and reusable simulator was developed.

To do this, typodonts mounted on an occluder compatible with ANA-4 attachments (Frasaco, Tettnang, Germany) were ordered from an e-commerce site (AliExpress, Hanghzou, China), and silicone gingiva with edentulous areas compatible with the realization of an AC-RBFDP on the incisor abutment and two PC-RBFDPs with premolar and molar abutments were purchased to replace those of the initial typodont (ANA-4 TWOKV 101/ANA-4 TWUKV 201, Frasaco). Figure 1 illustrates the maxillary and mandibular models created for the training, along with the occlusal integration quality assessed articulating paper in the occluder.

To provide a clinical step-by-step visual reference as a preparatory overview for the training, all tooth preparations for both AC- and PC-RBFDPs were performed and documented photographically at each stage. Figure 2 illustrates this sequential procedure using the example of a premolar-supported PC-RBFDP.

The prepared teeth and their corresponding preparations (including the internal threads used to fix the tooth on the typodont) were subsequently scanned using a high-depth-of-field intraoral scanner (CEREC Primescan, Dentsply Sirona, Germany). This served two main purposes.
From a pedagogical standpoint, the scans were used to design the AC and PC-RBFDPs, which participants could later visualize and assess in real time using a digital viewer accessible on their personal smartphones (Exocad Webview, Align Tech, Darmstadt, Germany). This facilitated interactive discussion and evaluation of prosthetic designs during the training to improve communication with laboratory technicians. These scans were also used to illustrate to participants the various provisionalization options for such edentulous spaces, using prosthetic restorations fabricated in advance by a dental technician. Figure 3 shows these possible temporizations that practitioners can see directly on their typodont if they have any questions.

In addition, the different types of zirconia bridges were manufactured upon request, ranging from monolithic stained restorations made with multilayered 3Y-TZP/5Y-PSZ zirconia to layered restorations on a 3Y-TZP framework, so that participants could appreciate the range of possible aesthetic outcomes offered by these different technical approaches.

From an organizational perspective, scanning the prepared teeth allowed each participant to practice the preparation on a sound tooth and subsequently replace it with a standardized preprepared tooth replica. This approach enabled self-assessment of their preparation quality and ensured that all participants could proceed to the bonding step using the same prosthetic piece on the same tooth abutment, which is essential for logistical consistency. The replicas of the prepared teeth were printed using a dental model resin (Precision Model, Formlabs, USA) on an LCD printer (Form 4B, Formlabs), whereas the posterior cantilever resin-bonded bridge analogs were fabricated using a more realistic, although costlier, resin (Premium Teeth B1, Formlabs). The repositioning keys were also designed and printed using a rigid transparent resin (Dental LT Comfort, Formlabs). Figure 4 shows the maxillary typodont with the prepared tooth analogs mounted in place under a rubber dam. Figure 5 shows the designs of the three RBFDPs.
The participants then proceeded with bonding the various prosthetic components, followed by occlusal adjustment. The step-by-step protocol was presented in advance, both as a demonstration and as guidance prior to their individual hands-on practice. Figure 6 shows an example of the step-by-step explanation provided to practitioners prior to their manipulation.

## 2.6 Assessment Questionnaires

The participants were asked to complete three separate questionnaires at different time points to assess their perceptions of knowledge about AC- and PC-RBFDP procedures and their satisfaction related to the course and implementation in their clinical practice. These questionnaires were adapted from tools previously used and validated in peer-reviewed dental education studies to evaluate perceived knowledge, confidence and satisfaction in simulation-based or hands-on training [17-19]. Their content was refined through an expert-consensus process involving clinical specialists in anterior and posterior cantilevered RBFDPs, dental biomaterials experts, an education researcher and a methodologist, ensuring content relevance and alignment with the course objectives prior to their implementation. Each questionnaire included a series of items rated using a 5-point Likert scale, allowing for a nuanced evaluation of individual perceptions. For each item, the participants could choose one of five response options: strongly disagree (1), disagree (2), neither agree nor disagree (3), agree (4), or strongly agree (5). The midpoint value of 3 corresponded to a neutral response. The use of a Likert scale made it possible to capture degrees of agreement or satisfaction, offering greater granularity than binary or open-ended questions do. At baseline, the questionnaire covered four main domains: previous clinical experience with AC- and PC-RBFDPs (items 1-2), perceived need for further theoretical input (items 5-6), perceived confidence regarding material selection and zirconia bonding (items 3-4 and 7-10), and understanding and use of
digital tools in communication with the dental technician (items 11–12). The immediate postcourse questionnaire (Table 2) focused on perceived course relevance and overall satisfaction, whereas the four-month questionnaire (Table 3) reassessed selected items on apprehension, zirconia bonding confidence, use of digital tools and satisfaction, and added items on self-reported changes in clinical practice. Responses were anonymized using unique participant codes and securely stored in a password-protected spreadsheet.

<table><caption>**Table 1.** Baseline Likert-scale questionnaire assessing prior clinical experience, perceived knowledge, confidence in key clinical steps, and use of digital tools related to AC- and PC-RBFDPs (n = 26).</caption><thead><tr><th>ITEMS (answered by n=26 practitioners)</th><th>Mean score (and standard deviation)</th></tr></thead><tbody><tr><td>1) I have already performed one or more AC-RBFDPs (to replace a maxillary or mandibular incisor)</td><td>3.54 (±1.84)</td></tr><tr><td>2) I have already performed one or more PC-RBFDPs (to replace a canine, premolar, or molar)</td><td>2.27 (±1.76)</td></tr><tr><td>3) I feel apprehensive about performing an AC-RBFDP</td><td>3.42 (±1.30)</td></tr><tr><td>4) I feel apprehensive about performing a PC-RBFDP</td><td>4.00 (±1.33)</td></tr><tr><td>5) I feel a clinical need for in-depth training on key theoretical concepts of AC-RBFDP</td><td>4.42 (±0.95)</td></tr><tr><td>6) I feel a clinical need for in-depth training on key theoretical concepts of PC-RBFDP</td><td>4.58 (±0.86)</td></tr><tr><td>7) I already feel comfortable choosing a prosthetic material for performing an AC-RBFDP</td><td>3.04 (±1.25)</td></tr><tr><td>8) I already feel comfortable choosing a prosthetic material for performing a PC-RBFDP</td><td>2.38 (±1.10)</td></tr><tr><td>9) I feel comfortable with the zirconia bonding procedure</td><td>3.04 (±1.04)</td></tr><tr><td>10) I feel comfortable choosing between monolithic and layered zirconia according to mechanical or esthetic requirements.</td><td>2.54 (±1.14)</td></tr><tr><td>11) I believe I understand the laboratory work performed by the dental technician when fabricating AC-RBFDP or PC-RBFDP</td><td>2.38 (±1.13)</td></tr><tr><td>12) I believe I fully utilize digital tools in communication with my dental technician</td><td>2.69 (±1.29)</td></tr></tbody></table>

<table><caption>**Table 2.** Immediate posttraining Likert-scale questionnaire evaluating perceived relevance of the course, usefulness of the practical session, and overall participant satisfaction (n = 26).</caption><thead><tr><th>ITEMS (answered by n=26 practitioners)</th><th>Mean score (and standard deviation)</th></tr></thead><tbody><tr><td>1) The duration of the training (theoretical and practical) was appropriate to fully address the topic of AC-RBFDPs and PC-RBFDPs</td><td>4.85 (±0.37)</td></tr><tr><td>2) The AC-RBFDP now appears to me as a credible alternative to implant therapy for replacing a missing tooth</td><td>4.96 (±0.20)</td></tr></tbody></table>
<table><tr><td>3) The PC-RBFDP now appears to me as a credible alternative to implant therapy for replacing a missing tooth</td><td>4.54 (±0.71)</td></tr><tr><td>4) The hands-on session was essential for a better clinical understanding of the indication and fabrication of AC-RBFDPs and PC-RBFDPs</td><td>4.77 (±0.51)</td></tr><tr><td>5) The diversity of clinical cases addressed during the practical session was sufficient to gain a good understanding of AC-RBFDPs and PC-RBFDPs</td><td>4.73 (±0.45)</td></tr><tr><td>6) The explanation of clinical cases presented at the beginning of the course effectively complemented the practical part of the training</td><td>4.77 (±0.43)</td></tr><tr><td>7) As a result of this training, I will take new clinical parameters into account when considering the use of AC-RBFDPs or PC-RBFDPs</td><td>4.92 (±0.27)</td></tr><tr><td>8) It now seems easier to apply the concepts addressed in the hands-on session to real clinical practice</td><td>4.85 (±0.37)</td></tr><tr><td>9) Overall, I am satisfied with this training course</td><td>5 (±0.00)</td></tr></table>

The third questionnaire (Table 3), distributed online four months postcourse, aimed to assess whether participants' satisfaction or clinical implementation had evolved over time.

Several items from the first two questionnaires were repeated in the third, enabling comparative statistical analysis across time points.

<table><caption>**Table 3.** Four-month posttraining Likert scale questionnaire assessing changes in clinical practice and practitioner satisfaction (n=16).</caption><thead><tr><th>ITEMS (answered by n=16 practitioners)</th><th>Mean score (and standard deviation)</th></tr></thead><tbody><tr><td>1) Since the training, I have started performing, or increased the number of AC-RBFDPs realized</td><td>3.06 (±1.18)</td></tr><tr><td>2) Since the training, I have started performing, or increased the number of PC-RBFDPs realized</td><td>3.00 (±1.26)</td></tr><tr><td>3) I feel apprehensive about performing an AC-RBFDP (Statistically compared to Q3 Table 1)</td><td>2.69 (±1.20)</td></tr><tr><td>4) I feel apprehensive about performing a PC-RBFDP (Statistically compared to Q4 Table 1)</td><td>3.38 (±1.26)</td></tr><tr><td>5) I feel comfortable with the zirconia bonding protocol (Statistically compared to Q9 Table 1)</td><td>4.00* (±0.89)</td></tr><tr><td>6) I believe I fully utilize digital tools in communication with my dental technician (Statistically compared to Q12 Table 1)</td><td>3.50 (±1.41)</td></tr><tr><td>7) Overall, I am satisfied with the training course taken four months ago (Statistically compared to Q9 Table 2)</td><td>4.63* (±0.50)</td></tr><tr><td>8) My clinical practice has changed since the training conducted four months ago</td><td>3.44 (±1.21)</td></tr><tr><td>9) I would recommend this training course to a colleague</td><td>4.50 (±0.52)</td></tr></tbody><tfoot><tr><td colspan="2">Mean values marked with an asterisk differ significantly from those recorded on the day of the course (as shown in Tables 1 and 2) with p &lt; 0.05.</td></tr></tfoot></table>

## 2.7 Statistical Analysis

Among the participants in the two training sessions, 26 provided informed consent and agreed to participate in the study. Complete and legible precourse and immediate postcourse questionnaires were collected from all 26 participants. Sixteen of the 26 participants initially
included completed the follow-up questionnaire administered four months after the training.

Descriptive statistics (means and standard deviations) were calculated for each questionnaire.

To compare responses to identical items between the precourse and four-month questionnaires (Tables 1 and 3) and between the immediate postcourse and four-month satisfaction item (Tables 2 and 3), the nonparametric Kruskal-Wallis test was used, as the assumptions of normality and homogeneity of variances were not satisfied. Because each comparison involved only two time points, no post-hoc procedure was required. No statistical comparisons were performed between the precourse and immediate postcourse questionnaires. All statistical analyses were performed using R software (version 4.5.1; R Foundation for Statistical Computing), with the significance threshold set at p < 0.05.

## 3 RESULTS

Twenty-six general dental practitioners (GDPs) completed the baseline and immediate postcourse questionnaires, and 16 (62%) responded to the 4-month follow-up survey, corresponding to 38% loss to follow-up.

The baseline responses revealed limited previous use of resin-bonded fixed dental prostheses (RBFDPs) and strong training needs: only modest experience with anterior (mean ± SD = 3.54 ± 1.84) and posterior (2.27 ± 1.76) cantilever RBFDPs was reported, whereas the perceived need for deeper theoretical knowledge scored highly for both anterior (4.42 ± 0.95) and posterior (4.58 ± 0.86) procedures. The confidence in key clinical skills was correspondingly low, with moderate comfort with zirconia bonding (3.04 ± 1.04) and comfort in selecting monolithic or layered zirconia (2.54 ± 1.14).

Immediately after the one-day course, participant satisfaction was very high: overall satisfaction reached the maximum score (5.00 ± 0.00), and all other items exceeded 4.5, including perception of adequate course duration (4.85 ± 0.37) and recognition of AC- and
PC-RBFDPs as credible alternatives to implant therapy (4.96 ± 0.20 and 4.54 ± 0.71, respectively). The participants also reported that the hands-on session was essential to clinical understanding (4.77 ± 0.51) and that they would integrate new clinical parameters into treatment planning (4.92 ± 0.27).

Four months later, practitioners reported limited clinical uptake of the techniques, as reflected by scores close to the neutral value for the initiation or increase in the number of AC-RBFDPs (3.06 ± 1.18) and PC-RBFDPs (3.00 ± 1.26). Satisfaction remained high (4.63 ± 0.50), although it was significantly lower than the score immediately after the one-day course (5.00 ± 0.00). A decrease in perceived apprehension was observed for both AC-RBFDPs (from 3.42 ± 1.30 to 2.69 ± 1.20) and PC-RBFDPs (from 4.00 ± 1.33 to 3.38 ± 1.26), alongside a slight increase in the use of digital tools for communication with laboratory technicians (from 2.69 ± 1.29 to 3.50 ± 1.41). However, these changes were not statistically significant. The self-reported mastery of zirconia bonding improved significantly (3.04 ± 1.04 to 4.00 ± 0.89).

## 4 DISCUSSION

To our knowledge, this is the first published study to combine theoretical instruction with hands-on simulation for the teaching of single-retainer anterior and posterior zirconia cantilevered resin-bonded fixed dental prostheses. In addition, the course uniquely incorporates structured communication with the dental laboratory technician through the use of digital viewers, allowing participants to engage directly with prosthetic design parameters. Accordingly, we implemented baseline questionnaires assessing perceived knowledge and clinical experience (Table 1) and repeated selected perception items four months after the course (Table 3) to evaluate the impact of the training over time. In parallel, immediate post-course satisfaction questionnaires were used to capture participants’ reactions to the training,
an essential component in CPD, as positive learner engagement is often a prerequisite for facilitating subsequent changes in clinical practice [20].

Several factors have been identified as key to the clinical success of AC- and PC-RBFDPs [8-10,16,21,22]. Many are common for both indications such as the use of a single, enamel-bonded retainer to reduce shear stress at the adhesive interface, preservation of a rigid enamel shell to limit abutment flexure, establishment of tight proximal contacts to help distribute occlusal forces, and the use of zirconia frameworks combined with reliable contemporary bonding protocols (air abrasion and MDP-containing primers) [16, 21]. In addition, specific biomechanical considerations appear particularly important for posterior cantilever designs, including maximizing connector height and ensuring a sufficient connector cross-section, minimizing the occlusal gap between retainer and pontic, selecting canines, premolars or molars as abutments, and avoiding pontic spans that exceed the mesiodistal width of the abutment tooth [16,21]. When these principles are respected, 3Y-TZP or multilayer zirconia (with the connector positioned within the high-strength layer) can provide a mechanically reliable framework for AC- and PC-RBFDPs [16,21,23]. Anterior cantilevered RBFDPs now demonstrate excellent long-term outcomes, with survival rates extending beyond 10-15 years and predictable clinical performance, making them a well-established first-line option for single anterior tooth replacement [8-10]. Posterior cantilevered RBFDPs show promising medium-term results, with recent prospective and retrospective studies reporting high survival and very low complication rates, although the available evidence remains more limited [12-15]. Nevertheless, despite the encouraging medium-term clinical data now available, PC-RBFDPs cannot yet be considered as well-established or codified as their anterior counterparts. Their indication should therefore be approached with caution and restricted to carefully selected single-tooth replacements, particularly in situations where implant therapy is contraindicated [16]. This reinforces the
relevance of training general practitioners in these emerging but clinically valuable options so they can apply them safely and appropriately in daily practice.

This study demonstrated that a single-day, simulation-based continuing education course can elicit very high levels of both immediate and delayed satisfaction among general dental practitioners while producing measurable improvements in self-perceived competencies. These findings are broadly consistent with our initial hypothesis, showing high satisfaction, increased self-perceived competence, and moderate short-term behavioral changes. These outcomes were achieved with limited material costs through the use of a reusable typodont-based simulator. In general, the purpose of a simulator, whether physical or virtual, is to create an immersive environment that enables learners to develop clinical skills in conditions that closely replicate real-life practice [24]. In this simulation-based training, the integration of 3D printing technologies for organizational purposes enabled the development of a cost-effective program that achieved exceptionally high participant satisfaction owing to VAT polymerization technologies and the large amount of available resins [25, 26]. As shown in Table 2, no item in the immediate posttraining evaluation received a score below 4.73 ± 0.52, and the overall satisfaction rating reached 5.00 ± 0.00, reflecting unanimous approval from all participants. This was made possible not only by the high quality of the simulators and the practical organization but also by the right mix of theoretical training incorporating the key concepts of AC- and PC-RBFDPs. Owing to the low manufacturing costs and reusability of the simulators, this training program could be easily replicated to support the teaching and dissemination of knowledge on AC- and PC-RBFDPs. These therapies represent, respectively, a cornerstone of current clinical practice and a promising treatment modality for the future [7-10, 12, 13, 16].

However, despite these positive outcomes, the intervention alone appears insufficient to induce sustained changes in clinical practice once practitioners return to their routine
professional environment, whether for AC-RBFDPs or PC-RBFDPs, despite the fact that these two procedures are at different stages of translational research. New therapeutic options are regularly introduced in the medical field, and remaining informed about them is essential for adapting to clinical practice accordingly. This is the principle underlying the concept of continuing professional development (CPD), which is defined as “the systematic maintenance, improvement, continuous acquisition and/or reinforcement of life-long knowledge, skills and competencies of health professionals” [27]. In this study, we aimed not only to improve practitioners’ theoretical and clinical knowledge but also to observe what impact this would have on changing their practice. It can be evaluated by the four-level Kirkpatrick model, which evaluates training outcomes along an ascending continuum [28]. Level 1 (“Reaction”) gauges how much participants liked the course and found it relevant. Level 2 (“Learning”) checks what new facts, skills or attitudes they picked up, usually with pre/posttests or self-ratings. Level 3 (“Behavior”) asks whether those skills show up chairside once the dentists are back in practice. Level 4 (“Results”) looks for wider benefits such as better patient outcomes, fewer complications, and lower society costs linked directly to the training. Because Levels 3 and 4 depend on real-world follow-up, many dental CPD studies stop at Levels 1 or 2, and Level 3 and 4 evidence remains scarce [29]. In our study, participant satisfaction reached a ceiling immediately after the course (Level 1), and self-reported knowledge and confidence in zirconia bonding remained significantly higher four months later (Level 2). Behavioral transfer (Level 3) was present but moderate: the four-month item “My clinical practice has changed since the training was conducted four months ago” averaged 3.44 ± 1.21 on a five-point Likert scale, sitting just above the neutral midpoint of 3. Because we did not track patient-centered or economic outcomes, Level 4 could not be evaluated. Studies conducted in other areas of dentistry with similar designs have reported comparable outcomes [29, 30].
It is widely acknowledged that a single didactic lecture is insufficient to induce lasting changes in clinical practice [20]. To achieve deeper and more sustainable transformations, continuing education must incorporate complementary pedagogical strategies, including experiential learning approaches such as simulation-based training (as implemented in our study) or other interactive formats such as collaborative or gamified activities. These methods not only enhance engagement but also promote the transfer of knowledge into routine clinical behavior. To enhance the long-term retention and impact of our training, a valuable strategy could be to complement it with additional educational formats. These might include asynchronous resources such as on-demand podcasts or e-learning modules [31, 32], as well as active learning approaches like problem-based learning (PBL), which fosters critical thinking through engagement with authentic clinical scenarios [33], and team-based learning (TBL), which strengthens collaborative and decision-making skills in structured group settings [16]. PBL and TBL have been widely reported to enhance knowledge acquisition, clinical reasoning, learner engagement and teamwork in medical education [34,35]. These learner-centred strategies therefore complement simulation-based training and help support the transfer of newly acquired competencies into clinical behaviour when combined with feedback and spaced reinforcement.

Finally, serious games represent a promising avenue, immersing learners in interactive, game-based environments that simulate clinical situations and promote critical thinking, problem-solving, and decision-making abilities [17, 18]. Achieving a profound shift in clinical practice and, more specifically, integrating new therapies into everyday care requires a series of repeated, multimodal educational interventions delivered over time. This transformation is inherently gradual and can be further hindered by the material or organizational constraints practitioners encounter once they return to their own clinics [31, 36].
Several limitations must be acknowledged in this study. First, all outcomes were self-reported with a 61.5% follow-up response rate: the realized questionnaires captured only practitioners' perceptions of their knowledge, confidence, and satisfaction, without any objective measurement of clinical performance. Consequently, the results are vulnerable to cognitive biases, most notably the tendency to overestimate one's own competence or the impact of a learning experience [37]. The four-month response rate observed in this study is consistent with several questionnaire-based investigations conducted among general dental practitioners, which typically report response rates in the 50-70% range for CPD and practice-based survey [38]. Nevertheless, the possibility of non-response bias cannot be excluded, and the four-month findings should therefore be interpreted with appropriate caution.

A further concern is social desirability bias because participants knew that their responses were being analyzed for research; they may have provided answers that they believed were more acceptable or favorable to the investigators rather than fully candid assessments. These biases, for instance, the perfect satisfaction rating of 5.00 ± 0.00 for the training, could inflate both the perceived effectiveness of the course and the magnitude of the reported behavioral change. [39]. Finally, although the questionnaires and overall evaluation framework were developed through expert consensus and adapted from instruments previously used in peer-reviewed dental education research [17,19], they were neither pilot-tested nor subjected to formal psychometric validation. In addition, they were administered to a limited number of practitioners with heterogeneous backgrounds and variable prior experience with AC- and PC-RBFDPs. As a result, the reliability and generalizability of the findings should be interpreted with caution. Nevertheless, this heterogeneity also reflects the reality of general dental practice and provides an authentic picture of how such CPD activities may perform in real-world conditions of routine clinical implementation [34,40].
## 5 CONCLUSIONS

This investigation demonstrated that a one-day, simulation-based continuing education intervention can achieve very high immediate and delayed participant satisfaction and significantly improve self-perceived competence in evidence-based AC- and PC-RBFDP procedures. However, the limited change in clinical adoption observed four months later indicates that a single training session is not sufficient to support long-term behavioral change. Embedding iterative and multimodal learning strategies in the future, such as digital microlearning, problem-based clinical scenarios or structured team-based reinforcement, may enhance skill retention and promote integration into routine clinical workflows.

## LIST OF ABBREVIATIONS

AC-RBFDP: anterior cantilever resin-bonded fixed dental prosthesis ; CAD: computer-aided design ; CPD: continuing professional development ; GDP: general dental practitioner ; LCD: liquid crystal display (3D printer type) ; 10-MDP: 10-methacryloyloxydecyl dihydrogen phosphate ; PC-RBFDP: posterior cantilever resin-bonded fixed dental prosthesis ; STL: stereolithography file format ; VAT: vat photopolymerization

## DECLARATIONS

### *Ethics Approval and Consent to Participate*

This study adhered to the principles outlined in the Declaration of Helsinki and received ethical approval from the AP-HP CER Institutional Review Board (# IRB: IORG0010044).
All participants provided written informed consent prior to the continuing education program to participate in this study.

### Consent for Publication

Not applicable.

### Availability of Data and Materials

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

### Competing Interests

The authors declare that they have no competing interests.

### Funding

Not applicable.

### Authors' Contributions

Concept and design: SG, JPA, PF.

Acquisition, analysis, and interpretation of data: SG, JPA, PF.

Writing: original draft preparation: SG, PF.

Writing: review and editing: SG, SM, SLG, EC, SAG, PB, ED, MADA, HG, JPA, PF.

Statistical analyses: HG, MADA, PF.

All authors have read and approved the final manuscript.
Acknowledgements

Not applicable.

Authors' Information

Not applicable.

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FIGURE LEGENDS

**Figure 1.** Occlusal quality control of the cost-effective mounted models was performed using 40 µm articulating paper. This step also represents the first procedure when fabricating an anterior or posterior resin-bonded bridge. Ideally, after occlusal equilibration of the prosthetic piece, the initial occlusion should be accurately reestablished.

<figure><img src="image_2.png" /></figure>
**Figure 2.** Step-by-step preparation of a PC-RBFDP with premolar support, explained to the participants step-by step during the session. a) Intraenamel parallelization of the proximal surface, maximizing height; b) Visualization of the proximal micro-preparation; c) Palatal intra-enamel preparation, stopping before the mesial marginal ridge of the supporting tooth; d) Intra-enamel preparation of the groove floor; e) Visualization of the intra-enamel contours of the preparation in the occlusal view; f) Visualization of the intra-enamel contours of the preparation in the palatal view; g) Occlusal intra-enamel reduction; h) Polishing of the preparation; i) Visualization of the final enamel micro-preparation in the buccal view.

<figure><img src="image_3.png" /></figure>
**Figure 3.** Examples of the various provisional restorations planned in advance of the hands-on session to demonstrate to participants how to fabricate temporaries, with particular attention given to the design of convex pontics at the gingival interface to ensure optimal aesthetic integration upon request.

<figure><img src="image_4.png" /></figure>
**Figure 4.** 3D printed analogs of the prepared teeth (central incisor and first premolar) are clearly distinguishable by their slight color difference. This setup enables participants to assess the quality of their own preparations by comparing them with these standardized “ideal” teeth. It also allows all participants to proceed with bonding the same prefabricated prosthetic component, ensuring consistency and a smooth workflow during the hands-on session.

<figure><img src="image_5.png" /></figure>
<figure><img src="image_6.png" /><figcaption>**Figure 5.** STL designs of RBFDPs used in this hands-on process after printing for learning bonding procedures.</figcaption></figure>

<figure><img src="image_7.png" /></figure>
**Figure 6.** Step-by-step luting protocol of a PC-RBFDP with premolar support, explained to participants step-by step during the session. a) Occlusal try-in to assess the fit of the PC-RBFDP; b) Buccal view of the try-in, evaluating adaptation and pontic compression; c) Isolation with rubber dam and positioning using the repositioning key; d) Air-abrasion of the intaglio surface of the retainer with 50 µm aluminum oxide; e) Application of a universal primer to the intaglio surface; f) Enamel etching of the abutment preparation; g) Application of a universal adhesive to the abutment tooth; h) Placement of the PC-RBFDP in the repositioning key prior to the application of adhesive resin on the intaglio surface; i) Seating of the PC-RBFDP with visible excess adhesive resin cement; j) Removal of excess material using a tack-curing technique; k) Polishing of the cement margins; l) Final check of occlusal integration.

<figure><img src="image_8.png" /></figure>