The impact of hand dominance and retractor design on intraoral scanning trueness during simulation-based digital dentistry training: an in vitro study

The impact of hand dominance and retractor design on intraoral scanning trueness during simulation-based digital dentistry training: an in vitro study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The impact of hand dominance and retractor design on intraoral scanning trueness during simulation-based digital dentistry training: an in vitro study Cemre Nilüfer Çınkır¹, Gökçe Meriç², Münir Demirel¹, Mustafa Borga Dönmez¹, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8923269/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Background Intraoral scans have become an integral component of contemporary dental education. While auxiliary devices such as retractors are commonly used to improve visibility and access, their influence on scanning performance during early digital skill acquisition remains insufficiently explored. This study aimed to evaluate the effect of hand dominance and retractor design on the trueness of intraoral scans performed by undergraduate dental students. Methods Eighteen undergraduate dental students with no prior experience in digital intraoral scanning participated in this experimental study. Participants were categorized according to hand dominance (right- vs. left-handed). Each student performed intraoral scans on a standardized dental phantom model (FUJI F-28JAW; Fuji, Tokyo, Japan) using an intraoral scanner (Primescan; Dentsply Sirona, Bensheim, Germany) under four retraction conditions: no retraction, dental mirror-assisted retraction, whitening cheek retractor, and OptraGate lip retractor. To ensure comparable early learning exposure among novice users, all retraction techniques were applied in a fixed sequence. Scan trueness was assessed by calculating the root mean square values, obtained by superimposing the intraoral scanner scans over a high-precision laboratory scanner (E4) reference scan. Data were analyzed using a mixed-design repeated measures analysis of variance test (α = 0.05). Results Statistical analysis showed that the retractor type significantly influenced the intraoral scan deviations (p = 0.041), whereas hand dominance (p = 0.641) and the interaction between main factors had no significant effect on measured deviations (p = 0.501). Deviation values were significantly lower with the whitening retractor compared with the OptraGate lip retractor (p = 0.011), while no significant differences in deviation were found among the remaining retraction techniques. Conclusions Hand dominance appears to play a limited role within a standardized digital workflow, whereas retractor design influenced intraoral scanning performance during early digital skill acquisition. From a health professions education perspective, auxiliary equipment such as retractors should be regarded as modifiable components of the learning environment, rather than merely as clinical accessories. Dental Impression Technique Dental Education Psychomotor Performance Ergonomics Dental Instruments Figures Figure 1 Figure 2 BACKGROUND The rapid development of digital technologies has profoundly transformed modern dental practice, rendering intraoral digital scanners (IOS) an essential component of dental education [ 1 ]. As digital workflows increasingly replace conventional procedures, mastering digital impression-making has become a fundamental clinical competency for dental students [ 2 ]. Compared with conventional impressions, IOSs offer significant advantages, including enhanced patient comfort, increased procedural efficiency, and improved predictability once the oral environment is digitized [ 3 ]. Additionally, evidence from simulation-based training indicates that even inexperienced students can successfully acquire the technical skills required for digital workflows, with many expressing a clear preference for IOS over conventional impressions [ 4 ]. However, acquiring competence in digital impression-making extends beyond mere technical execution. It involves the integration of hand–eye coordination, ergonomics, instrument handling, and complex psychomotor skill development [ 5 ]. In the context of digital impression-making, scanning accuracy is conventionally defined by two complementary components: trueness, which describes the closeness of a scan to a reference dataset, and precision, which reflects the repeatability of measurements under unchanged conditions [ 6 ]. In the early stages of digital skill acquisition, performance variability is strongly influenced by rapid learning effects, ergonomic adaptation, and workflow familiarization. Under such conditions, trueness is considered a particularly relevant outcome measure, as it reflects the learner’s ability to capture anatomically faithful digital representations, whereas precision becomes more informative once motor execution stabilizes with experience. Accordingly, focusing on trueness allows meaningful evaluation of novice intraoral scanning performance within simulation-based educational settings. Within this framework, handedness defined as right- or left-hand dominance may influence motor skill acquisition and learning efficiency. Existing evidence regarding the effect of handedness on motor performance remains inconclusive and appears to vary according to task type, complexity, and performance metrics. While several studies report no significant difference in motor skill learning between right- and left-handed individuals [ 7 , 8 ], others suggest that right-handers may demonstrate superior speed and accuracy [ 9 ]. Conversely, left-handers have been reported to exhibit enhanced fine-motor performance in bimanual tasks or when using their non-dominant hand [ 10 ]. Despite these findings, few studies have examined the role of hand dominance within clinical dentistry [ 11 , 12 ], and only one study to date has specifically addressed digital impression procedures [ 13 ]. Because psychomotor performance is shaped not only by intrinsic learner characteristics but also by task constraints and the tools used to perform the task, auxiliary equipment warrants particular attention in dental training contexts. In dentistry retractors play a critical role in facilitating intraoral access, optimizing visibility, and maintaining a stable operative field, thereby supporting efficient and accurate clinical procedures [ 14 ]. By displacing soft tissues and improving ergonomic working conditions, retractors may enhance procedural accuracy while also reducing cognitive load and supporting attentional focus during intraoral scanning tasks [ 15 ]. From a health professions education perspective, learning outcomes in digitally mediated psychomotor skills depend on the alignment between learner characteristics, task demands, and instructional design [ 16 , 17 ]. Accordingly, auxiliary devices such as retractors should be viewed not merely as passive clinical accessories, but as modifiable elements of the learning environment that can influence visual access, posture, and motor coordination, thereby shaping skill acquisition in novice learners [ 18 , 19 ]. Despite the widespread integration of intraoral scanners into undergraduate dental curricula, empirical evidence examining how ergonomic learning conditions—particularly the interaction between auxiliary equipment design and individual learner characteristics such as hand dominance—affect digital impression learning remains limited. Addressing this gap is essential for informing learner-centered instructional design and optimizing simulation-based psychomotor training in digital dentistry education [ 20 ]. Therefore, grounded in a theoretical framework informed by principles describing how complex motor skills are acquired through practice and feedback, as well as how mental effort and information processing demands influence learning, the present study aimed to investigate the influence of hand dominance and retractor type on intraoral scanning performance among right- and left-handed undergraduate dental students. Beyond quantifying scan trueness, this study seeks to elucidate how ergonomic alignment between auxiliary equipment and learner characteristics influences the learning process during simulation-based training. The null hypothesis was that hand dominance and retractor type would not significantly affect the trueness of digital impressions obtained by dental students in a clinical simulation setting. METHODS Study design and ethics This study was designed as an experimental, controlled investigation to evaluate the effect of different retraction techniques on intraoral scanning performance in undergraduate dental students with different hand dominance. All procedures involving human participants were approved by the Biruni University Scientific Committee (Approval No: 2024/BİAEK/14–35) and conducted in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments. Participants Eighteen undergraduate dental students from Biruni University were recruited as operators. All participants were at similar academic levels and had no prior experience with digital intraoral impression systems, in order to eliminate the potential influence of operator experience. Hand dominance was self-reported and used to divide participants into two equal groups: right-hand dominant (n = 9) and left-hand dominant (n = 9). An a priori power analysis was conducted using G*Power 3.1 (Heinrich Heine University, Düsseldorf, Germany) for a mixed-design ANOVA with one between-subject factor (hand dominance; 2 levels) and one within-subject factor (retraction technique; 4 levels). With a significance level of α = 0.05, an effect size of f = 0.854, numerator degrees of freedom = 24, and denominator degrees of freedom = 180, the calculated statistical power (1 – β) was 1.00, indicating that 10 repetitions per condition (40 scans per operator) were sufficient to detect meaningful differences in surface deviation outcomes. Study design and procedures The study followed a 2 × 4 mixed factorial design, with hand dominance (right-handed vs. left-handed) as the between-subject factor and retraction technique as the within-subject factor, comprising four levels: (1) no retraction aid (control), (2) dental mirror (standard examination mirror used for cheek retraction), (3) whitening cheek retractor (Cotisen Cheek Retractor, C type; Huanghua Promisee Dental Co., Ltd), and (4) OptraGate lip retractor (OptraGate Assortment; Ivoclar AG). Because all participants were novice users of intraoral scanning, the order of retraction techniques was not randomized. Instead, all students performed the scanning procedures in a fixed sequence (no retractor, mirror-assisted retraction, whitening cheek retractor, and OptraGate lip retractor). This approach was intentionally adopted to standardize early learning exposure and ensure comparable familiarization with the scanning workflow across participants, thereby minimizing variability related to differential learning curves rather than retraction conditions. Each student performed intraoral scanning using all retraction techniques in the same predefined order. For each technique, ten scans were obtained, resulting in a total of 40 scans per student (4 techniques × 10 repetitions). Across all participants, a total of 720 scans were collected, with 360 scans performed by right-hand dominant students and 360 scans by left-hand dominant students (Fig. 1 ). To reduce operator fatigue, scanning sessions were distributed across multiple days with standardized rest intervals. Prior to data collection, all students received standardized orientation training on scanner handling and scanning strategy to ensure procedural consistency. Phantom model and scanning protocol Phantom model and scanning protocol All scans were performed on a standardized 28-tooth full-arch dental phantom model (FUJI F-28JAW; Fuji, Tokyo, Japan), representing a fully dentate maxillary arch, in the Phantom Simulation Laboratory of the Faculty of Dentistry at Biruni University. Environmental conditions were controlled throughout the study (room temperature: 22–24°C; ambient illumination: 5500 K LED lighting). Intraoral scans were acquired using a single intraoral scanner (Primescan; Dentsply Sirona, Bensheim, Germany) operating under the highest quality setting. The average scanning duration was standardized at approximately 2–3 minutes per scan. Each scan followed a standardized three-step scanning sequence: (1) occlusal surfaces, (2) buccal surfaces, and (3) lingual surfaces. Scanner calibration and routine maintenance were performed before each session according to the manufacturer’s recommendations. Phantom model positioning and dental chair configuration were kept constant throughout the study. Reference scan acquisition and deviation analysis A high-precision reference dataset of the phantom model was obtained using a laboratory scanner (3Shape E4; 3Shape, Copenhagen, Denmark) and served as the digital reference model for trueness evaluation. Following isolation of the reference scan geometry, all intraoral scan datasets were exported in STL format at maximum resolution and imported into reverse-engineering software (Geomagic Control X Viewer, version 2022.1; 3D Systems, Rock Hill, SC, USA) for three-dimensional deviation analysis. The reference model was first loaded into the software environment. Subsequently, each student-generated intraoral scan was individually superimposed onto the reference dataset. The alignment protocol consisted of sequential application of initial alignment, best-fit alignment, and 3D compare functions, which were applied consistently to all scans. Deviation results were visualized using color-coded deviation maps (Fig. 2 ). Positive and negative deviations were displayed using a standardized color scale, with dark red and dark blue representing the maximum positive and negative deviations, respectively, corresponding to a ± 100 µm deviation range. Deviations within the acceptable tolerance limits (± 20 µm) were displayed in green. Trueness was quantified as the root mean square (RMS) deviation (µm) between the intraoral scan and the reference dataset within the defined region of interest (ROI). Statistical analysis Statistical analysis was performed using a mixed-design repeated measures analysis of variance (ANOVA), with hand dominance as the between-subject factor and retraction technique as the within-subject factor. When the sphericity assumption was violated, the Huynh–Feldt correction was applied. Post hoc comparisons were conducted using Bonferroni-adjusted tests. All analyses were performed using IBM SPSS Statistics (version 25; IBM Corp., Armonk, NY, USA), with a significance level set at α = 0.05. RESULTS The sphericity assumption for repeated measures was evaluated using Mauchly’s test and was found to be violated (W = 0.916, χ²(5) = 15.52, p = 0.008). Accordingly, the Huynh–Feldt correction was applied (ε = 0.967). The assumption of homogeneity of variance was assessed using Levene’s test and was met for all RMS measurements (p ≥ 0.175). The repeated-measures analysis with the Huynh–Feldt correction revealed that hand dominance did not have a significant main effect on intraoral scanning trueness (F(1, 178) = 0.22, p = 0.641, partial η² =0.001). In contrast, retractor type showed a statistically significant effect on scanning trueness (F(2.90, 516.18) = 2.81, p = 0.041, partial η² =0.016). No significant interaction between hand dominance and retractor type was observed (F(2.90, 516.18) = 0.78, p = 0.501, partial η² =0.004). Bonferroni-adjusted pairwise comparisons revealed a statistically significant difference between the whitening cheek retractor and the OptraGate lip retractor, with the whitening cheek retractor exhibiting significantly lower deviations (p = 0.011). No significant differences were observed when the remaining pairwise comparisons were considered (p ≥ .141). Descriptive statistics of RMS deviation values (µm), representing intraoral scan trueness, according to hand dominance and retraction technique are presented in Table 1. DISCUSSION The present study evaluated the influence of hand dominance on intraoral scanning trueness in undergraduate dental students and assessed the effect of different retractor types. Hand dominance and its interaction with retractor type did not significantly affect scanning trueness, whereas retractor type alone had a significant effect. Bonferroni-corrected pairwise comparisons revealed a significant difference in RMS values between the whitening cheek retractor and the OptraGate lip retractor. These results highlight the importance of auxiliary equipment selection in digital impression procedures and support previous evidence emphasizing the role of ergonomics and soft tissue management in psychomotor performance during dental education [ 5 , 19 , 21 ]. Contrary to assumptions that hand dominance may affect fine motor tasks requiring bimanual coordination [ 8 ], hand dominance did not significantly influence scanning trueness in this study, nor did it interact with retractor type. This aligns with previous reports suggesting that the effect of handedness on motor skill acquisition is task-dependent and may be less pronounced in procedures supported by standardized workflows and digitally guided systems [ 7 , 8 ]. The structured scanning protocol and the use of a highly intuitive intraoral scanner may have minimized variability related to operator laterality. With respect to retraction conditions, no statistically significant differences were observed among the no-retraction, dental mirror–assisted retraction, and whitening cheek retractor conditions, with comparable mean RMS deviation values of 254.43 ± 42.07 µm, 252.49 ± 43.43 µm, and 245.57 ± 30.68 µm, respectively. Similarly, no significant differences were detected between the no-retraction and dental mirror conditions and the OptraGate lip retractor (256.31 ± 38.72 µm). These findings indicate that neither manual soft tissue management nor the use of a circumferential lip retractor alone substantially alters scanning trueness in novice operators, likely because the standardized scanning protocol and the absence of dynamic intraoral variables in a simulation-based setting limit the relative impact of most soft tissue displacement techniques, particularly those involving minimal or manual retraction, thereby masking differences among similar retraction approaches, on overall scan accuracy. A statistically significant difference was observed only between the whitening cheek retractor and the OptraGate lip retractor. This finding suggests that specific retractor design features and localized soft tissue displacement patterns—rather than the mere presence or absence of retraction—may influence intraoral scanning trueness during early digital skill acquisition. Differences in rigidity, coverage area, and the distribution of tissue tension may differentially affect scanner access and line-of-sight continuity, thereby contributing to localized deviations during full-arch scanning. While the difference in mean values appears limited, interpretation of these findings should consider the overall magnitude of the measured deviations as well as the relative nature of comparisons within a standardized experimental framework. Previous in vivo studies conducted under clinical conditions with experienced operators have reported substantially lower trueness values, typically ranging from 20 to 92 µm for single-unit and full-arch scans [ 22 , 23 ]. In contrast, in vitro investigations using phantom models—particularly those involving full-arch scanning and novice operators—have consistently reported higher trueness deviations, often exceeding 150–300 µm [ 24 , 25 ]. The trueness values observed in the present study fall within this reported in vitro range, supporting the assumption that the elevated deviations are primarily attributable to the simulation-based setting and early learning phase of the operators rather than methodological error. Had the measured deviations substantially exceeded those reported in comparable in vitro studies, the interpretability of the observed intergroup differences would be compromised; however, their consistency with published phantom-based data supports the validity of the present measurements. Within this controlled framework, the relative differences observed between retraction systems remain meaningful and were statistically significant, indicating that retractor design exerted a measurable effect on scanning trueness under standardized conditions. Therefore, while direct clinical extrapolation of the absolute trueness values should be approached with caution, the observed differences suggest that retraction technique may influence intraoral scanning performance during the early stages of digital skill acquisition. The observed difference in scanning trueness between the whitening cheek retractor and the OptraGate lip retractor can be attributed to differences in retractor design and soft tissue displacement characteristics. Whitening cheek retractors are typically rigid and provide localized, static retraction, which may result in uneven displacement of the lips and cheeks and increased soft tissue interference in the scanning field. In contrast, the OptraGate lip retractor provides circumferential, elastic retraction with more homogeneous soft tissue tension, thereby improving visibility and scanner access to vestibular and buccal surfaces. Such uniform displacement may reduce soft tissue overlap and shadowing effects, which have been reported as contributors to local scanning deviations in complete-arch acquisitions. The IOS used in this study (Primescan) has previously been reported to receive high ratings for scanning speed, workflow efficiency, and image sharpness, features that are known to reduce cognitive load and facilitate early skill acquisition in dental students [ 8 , 26 ]. This may partly explain why hand dominance did not emerge as a significant factor influencing scanning trueness. As the study targeted the early phase of digital skill acquisition, trueness was selected as the primary outcome, since performance variability at this stage is strongly influenced by rapid learning effects and trueness represents a more clinically meaningful indicator of novice scanning performance than precision, which becomes more informative once motor execution stabilizes according to ISO-based definitions of measurement accuracy [ 6 ]. All participants completed the scanning procedures using a fixed sequence of retraction conditions, progressing from no retraction to mirror-assisted retraction, whitening cheek retractor, and finally the OptraGate lip retractor. This standardized order ensured comparable learning exposure across operators but may have introduced a cumulative practice effect, potentially contributing to increased scanning proficiency during later measurements. To characterize the early learning curve while minimizing short-term learning variability, each operator performed ten consecutive scans per retraction condition on the same day, consistent with evidence indicating that approximately ten scans are sufficient to capture early intraoral scanning performance stabilization [ 27 ]. Although the fixed sequence may have partially influenced absolute trueness values independent of retractor type, the consistent application of this protocol across all participants allows relative comparisons between retraction techniques to remain valid and clinically informative. Despite the strengths of the present study, several limitations should be considered when interpreting the findings. First, the study was conducted under simulation-based, in vitro conditions using a maxillary fully dentate phantom model and novice undergraduate students. This design allowed for a high degree of standardization and effective control of confounding variables during the early stages of digital skill acquisition; however, it inherently limits the generalizability of the results to real clinical environments. All scans were obtained under controlled conditions, excluding clinically relevant factors such as saliva contamination, dynamic soft tissue behavior, patient movement, restricted mouth opening, and operator–patient interaction. The presence of saliva has been shown to significantly affect the accuracy of digital implant transfer, and variations in soft tissue conditions may similarly influence clinical scanning outcomes [ 28 ]. Previous investigations have also demonstrated that intraoral scanning accuracy can be significantly influenced by these clinical variables, as well as by anatomical complexity and scan span, particularly under in vivo conditions [ 29 ]. Therefore, future clinical (in vivo) studies are necessary to confirm the ecological validity of the present findings and to determine whether the observed effects of retractor design persist under real-world clinical constraints. Second, the experimental model was limited to a complete dentate maxillary arch, which does not reflect the wide range of anatomical and prosthetic scenarios encountered in daily clinical practice. Prior in vitro and clinical evidence indicates that scanner accuracy and trueness may vary considerably in cases involving partially edentulous arches, fully edentulous arches, extended scan spans, or the presence of implant scan bodies, where the lack of anatomical landmarks and increased surface discontinuity pose additional challenges [ 30 , 31 ]. The influence of soft tissue retraction systems may therefore be more pronounced—or differ in magnitude—in such complex scanning situations. Consequently, future in vitro studies incorporating diverse model designs, including partially and fully edentulous arches as well as implant-supported configurations, are warranted to comprehensively evaluate the interaction between retraction systems, anatomical complexity, and scanning performance. Third, the study evaluated a limited number of retraction systems, focusing on commonly used educational and clinical devices. Although significant differences were detected between the two retractor designs tested, additional systems with varying rigidity, elasticity, and coverage area should be investigated to better characterize how specific design features influence scanning trueness and ergonomic performance. Similarly, only a single intraoral scanner was used. Given that different intraoral scanning systems employ distinct optical principles, scanning algorithms, and real-time stitching strategies that can affect trueness and precision, future research should incorporate multiple scanners to assess whether the interaction between retractor design and scanning performance is device-dependent [ 32 ]. Fourth, deviation analysis was performed using a single metrology software and an RMS-based evaluation approach, which may yield different absolute deviation values compared with alternative alignment strategies or region-specific analysis methods. In addition, the study focused on trueness as an outcome measure, as performance variability during early digital skill acquisition is predominantly reflected in deviations from the reference rather than in scan-to-scan reproducibility. Finally, only full-arch scans were evaluated; therefore, the effects of retraction techniques on quadrant-based or localized scanning tasks remain to be investigated. Future studies extending the present methodology to implant-supported restorations, partially edentulous arches, and complete denture workflows, while incorporating diverse scanning and analysis strategies, would provide a more comprehensive understanding of how ergonomic factors and auxiliary equipment influence digital impression performance across varying levels of clinical complexity. CONCLUSION Within the limitations of this simulation-based study, hand dominance did not significantly influence intraoral scanning trueness during early digital skill acquisition when a standardized scanning protocol was employed. In contrast, retractor type had a measurable effect on scanning accuracy, with differences observed between the whitening cheek retractor and the OptraGate lip retractor. These findings suggest that specific retractor design features, such as rigidity, coverage area, and soft tissue displacement patterns, can influence scanner access and line-of-sight continuity, thereby affecting trueness. From an educational perspective, auxiliary equipment should be considered a modifiable element of the digital learning environment rather than merely a passive clinical tool. Incorporating ergonomic and equipment-related considerations into intraoral scanning training may enhance scan consistency and better prepare students for clinical digital workflows. Future studies should investigate these effects in vivo and across diverse anatomical scenarios, including partially and fully edentulous arches and implant-supported restorations. Abbreviations ANOVA – Analysis of variance ISO – International Organization for Standardization IOS – Intraoral scanner LED – Light-emitting diode RMS – Root mean square STL – Standard tessellation language Declarations Ethics approval and consent to participate This study was approved by the Biruni University Ethics Committee (Approval No: 2024/BİAEK/14-35). All procedures involving human participants were conducted in accordance with the ethical standards of the Declaration of Helsinki and its later amendments. Written informed consent to participate was obtained from all participants prior to the study. Consent for publication Not applicable. Availability of data and materials The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Authors’ contributions CNC and GM contributed to the conception and design of the study. CNC, GM, and MD contributed to data acquisition. CNC and GM performed the statistical analysis and interpreted the data. AADT and MD contributed to manuscript drafting and critical revision for important intellectual content. All authors read and approved the final manuscript. Acknowledgements The authors would like to thank the undergraduate dental students who participated in this study and the staff of the Phantom Simulation Laboratory, Faculty of Dentistry, Biruni University, for their support during data collection. References Liu CM, Hsu MH, Ng MY, Yu CH. Digital integration in dental education: a novel self-directed learning model using intraoral scanners for tooth preparation training. 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J Dent . 2025;161:105973. https://doi.org/10.1016/j.jdent.2025.105973 Table Table 1. Descriptive statistics of intraoral scan trueness (RMS deviation, µm) according to hand dominance and retraction technique. Right-handed Left-handed Total No-retraction 256.59 ± 38.88 252.27 ± 45.15 254.43 ± 42.07 ab Dental mirror 255.96 ± 53.00 249.02 ± 30.98 252.49 ± 43.43 ab Whitening retractor 244.81 ± 29.12 246.33 ± 32.30 245.57 ± 30.68 a OptraGate lip retractor 254.47 ± 38.35 258.15 ± 39.21 256.31 ± 38.72 b *Values represent RMS deviation (µm) indicating scan trueness. *Different superscript letters indicate statistically significant differences between retraction techniques (Bonferroni-adjusted post hoc comparisons, p < .05). Groups sharing the same letter are not significantly different. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 22 Apr, 2026 Reviewers agreed at journal 16 Apr, 2026 Reviewers invited by journal 16 Apr, 2026 Editor invited by journal 19 Mar, 2026 Editor assigned by journal 20 Feb, 2026 Submission checks completed at journal 20 Feb, 2026 First submitted to journal 20 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8923269","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":627590478,"identity":"610e2213-c680-4980-919c-7d4609287f76","order_by":0,"name":"Cemre Nilüfer Çınkır¹","email":"","orcid":"","institution":"Biruni University","correspondingAuthor":false,"prefix":"","firstName":"Cemre","middleName":"Nilüfer","lastName":"Çınkır¹","suffix":""},{"id":627590482,"identity":"bfc7e6a9-c835-4346-9991-c2ef11df07c2","order_by":1,"name":"Gökçe Meriç²","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1klEQVRIiWNgGAWjYFACNhjFfICBsYE0LWwJJGphYOAxIE6LvHtb4oePOTb5fOxnvkn83GEjx8B++OgGfFoMzxw7LDlzW5plG0/uNsneM2nGDDxpaTfwapmR3sbMu+2wAZsE7zYJ3rbDiQ0SPGaEtfzd9h+oheeZ5F9itMhLpB1jZtx2AKSFTZooWwx4jiVL9m5LNmDjSTO2lm1LM2Yj5Bf59jbDDz+32RnItx9+ePNtm40cP/vhY/htOYBgs0iASDYcKhG2NCDYzB8IqR4Fo2AUjIKRCQAFuEXSeyOs/QAAAABJRU5ErkJggg==","orcid":"","institution":"Gazi University","correspondingAuthor":true,"prefix":"","firstName":"Gökçe","middleName":"","lastName":"Meriç²","suffix":""},{"id":627590485,"identity":"6825abd1-c489-4504-9aec-e31ce0386489","order_by":2,"name":"Münir Demirel¹","email":"","orcid":"","institution":"Biruni University","correspondingAuthor":false,"prefix":"","firstName":"Münir","middleName":"","lastName":"Demirel¹","suffix":""},{"id":627590488,"identity":"8b1c9860-2dd8-42f1-a46e-9b735f35a026","order_by":3,"name":"Mustafa Borga Dönmez¹","email":"","orcid":"","institution":"Biruni University","correspondingAuthor":false,"prefix":"","firstName":"Mustafa","middleName":"Borga","lastName":"Dönmez¹","suffix":""},{"id":627590489,"identity":"be539751-bbc8-4c7c-b194-0c856e6599ed","order_by":4,"name":"Almira Ada Diken Türksayar¹","email":"","orcid":"","institution":"Biruni University","correspondingAuthor":false,"prefix":"","firstName":"Almira","middleName":"Ada Diken","lastName":"Türksayar¹","suffix":""}],"badges":[],"createdAt":"2026-02-20 07:23:12","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8923269/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8923269/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107834012,"identity":"776ef4b3-5d3e-411d-b48d-a9a3da63fe2c","added_by":"auto","created_at":"2026-04-26 15:42:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":246664,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eSchematic illustration of the experimental groups according to hand dominance and retraction technique.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8923269/v1/3c65edec9c0f72ef779a141c.png"},{"id":107834013,"identity":"08224e03-a159-4668-8da4-ed2c5dc026bf","added_by":"auto","created_at":"2026-04-26 15:42:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":247408,"visible":true,"origin":"","legend":"\u003cp\u003eWorkflow of three-dimensional deviation analysis and representative color-coded deviation map. Following isolation and alignment of the reference and intraoral scan datasets, deviations were visualized using a standardized color scale. Green indicates deviations within ±20 µm, whereas dark blue and dark red represent the maximum negative and positive deviations (±100 µm), respectively.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8923269/v1/3da3a0be6ef92cbfdf50e596.png"},{"id":108181016,"identity":"cc1dc392-6988-4d40-9eb4-d664177051ed","added_by":"auto","created_at":"2026-04-30 08:56:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":821224,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8923269/v1/83d53a5d-b842-40a0-9432-d3ac7e5b6a9d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The impact of hand dominance and retractor design on intraoral scanning trueness during simulation-based digital dentistry training: an in vitro study","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eThe rapid development of digital technologies has profoundly transformed modern dental practice, rendering intraoral digital scanners (IOS) an essential component of dental education [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. As digital workflows increasingly replace conventional procedures, mastering digital impression-making has become a fundamental clinical competency for dental students [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Compared with conventional impressions, IOSs offer significant advantages, including enhanced patient comfort, increased procedural efficiency, and improved predictability once the oral environment is digitized [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Additionally, evidence from simulation-based training indicates that even inexperienced students can successfully acquire the technical skills required for digital workflows, with many expressing a clear preference for IOS over conventional impressions [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, acquiring competence in digital impression-making extends beyond mere technical execution. It involves the integration of hand\u0026ndash;eye coordination, ergonomics, instrument handling, and complex psychomotor skill development [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In the context of digital impression-making, scanning accuracy is conventionally defined by two complementary components: trueness, which describes the closeness of a scan to a reference dataset, and precision, which reflects the repeatability of measurements under unchanged conditions [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In the early stages of digital skill acquisition, performance variability is strongly influenced by rapid learning effects, ergonomic adaptation, and workflow familiarization. Under such conditions, trueness is considered a particularly relevant outcome measure, as it reflects the learner\u0026rsquo;s ability to capture anatomically faithful digital representations, whereas precision becomes more informative once motor execution stabilizes with experience. Accordingly, focusing on trueness allows meaningful evaluation of novice intraoral scanning performance within simulation-based educational settings.\u003c/p\u003e \u003cp\u003eWithin this framework, handedness defined as right- or left-hand dominance may influence motor skill acquisition and learning efficiency. Existing evidence regarding the effect of handedness on motor performance remains inconclusive and appears to vary according to task type, complexity, and performance metrics. While several studies report no significant difference in motor skill learning between right- and left-handed individuals [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], others suggest that right-handers may demonstrate superior speed and accuracy [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Conversely, left-handers have been reported to exhibit enhanced fine-motor performance in bimanual tasks or when using their non-dominant hand [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Despite these findings, few studies have examined the role of hand dominance within clinical dentistry [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], and only one study to date has specifically addressed digital impression procedures [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBecause psychomotor performance is shaped not only by intrinsic learner characteristics but also by task constraints and the tools used to perform the task, auxiliary equipment warrants particular attention in dental training contexts. In dentistry retractors play a critical role in facilitating intraoral access, optimizing visibility, and maintaining a stable operative field, thereby supporting efficient and accurate clinical procedures [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. By displacing soft tissues and improving ergonomic working conditions, retractors may enhance procedural accuracy while also reducing cognitive load and supporting attentional focus during intraoral scanning tasks [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. From a health professions education perspective, learning outcomes in digitally mediated psychomotor skills depend on the alignment between learner characteristics, task demands, and instructional design [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Accordingly, auxiliary devices such as retractors should be viewed not merely as passive clinical accessories, but as modifiable elements of the learning environment that can influence visual access, posture, and motor coordination, thereby shaping skill acquisition in novice learners [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Despite the widespread integration of intraoral scanners into undergraduate dental curricula, empirical evidence examining how ergonomic learning conditions\u0026mdash;particularly the interaction between auxiliary equipment design and individual learner characteristics such as hand dominance\u0026mdash;affect digital impression learning remains limited. Addressing this gap is essential for informing learner-centered instructional design and optimizing simulation-based psychomotor training in digital dentistry education [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, grounded in a theoretical framework informed by principles describing how complex motor skills are acquired through practice and feedback, as well as how mental effort and information processing demands influence learning, the present study aimed to investigate the influence of hand dominance and retractor type on intraoral scanning performance among right- and left-handed undergraduate dental students. Beyond quantifying scan trueness, this study seeks to elucidate how ergonomic alignment between auxiliary equipment and learner characteristics influences the learning process during simulation-based training. The null hypothesis was that hand dominance and retractor type would not significantly affect the trueness of digital impressions obtained by dental students in a clinical simulation setting.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and ethics\u003c/h2\u003e \u003cp\u003eThis study was designed as an experimental, controlled investigation to evaluate the effect of different retraction techniques on intraoral scanning performance in undergraduate dental students with different hand dominance. All procedures involving human participants were approved by the Biruni University Scientific Committee (Approval No: 2024/BİAEK/14\u0026ndash;35) and conducted in accordance with the ethical standards of the 1964 Declaration of Helsinki and its later amendments.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eParticipants\u003c/h3\u003e\n\u003cp\u003eEighteen undergraduate dental students from Biruni University were recruited as operators. All participants were at similar academic levels and had no prior experience with digital intraoral impression systems, in order to eliminate the potential influence of operator experience. Hand dominance was self-reported and used to divide participants into two equal groups: right-hand dominant (n\u0026thinsp;=\u0026thinsp;9) and left-hand dominant (n\u0026thinsp;=\u0026thinsp;9). An a priori power analysis was conducted using G*Power 3.1 (Heinrich Heine University, D\u0026uuml;sseldorf, Germany) for a mixed-design ANOVA with one between-subject factor (hand dominance; 2 levels) and one within-subject factor (retraction technique; 4 levels). With a significance level of α\u0026thinsp;=\u0026thinsp;0.05, an effect size of f\u0026thinsp;=\u0026thinsp;0.854, numerator degrees of freedom\u0026thinsp;=\u0026thinsp;24, and denominator degrees of freedom\u0026thinsp;=\u0026thinsp;180, the calculated statistical power (1 \u0026ndash; β) was 1.00, indicating that 10 repetitions per condition (40 scans per operator) were sufficient to detect meaningful differences in surface deviation outcomes.\u003c/p\u003e\n\u003ch3\u003eStudy design and procedures\u003c/h3\u003e\n\u003cp\u003eThe study followed a 2 \u0026times; 4 mixed factorial design, with hand dominance (right-handed vs. left-handed) as the between-subject factor and retraction technique as the within-subject factor, comprising four levels: (1) no retraction aid (control), (2) dental mirror (standard examination mirror used for cheek retraction), (3) whitening cheek retractor (Cotisen Cheek Retractor, C type; Huanghua Promisee Dental Co., Ltd), and (4) OptraGate lip retractor (OptraGate Assortment; Ivoclar AG).\u003c/p\u003e \u003cp\u003e Because all participants were novice users of intraoral scanning, the order of retraction techniques was not randomized. Instead, all students performed the scanning procedures in a fixed sequence (no retractor, mirror-assisted retraction, whitening cheek retractor, and OptraGate lip retractor). This approach was intentionally adopted to standardize early learning exposure and ensure comparable familiarization with the scanning workflow across participants, thereby minimizing variability related to differential learning curves rather than retraction conditions. Each student performed intraoral scanning using all retraction techniques in the same predefined order. For each technique, ten scans were obtained, resulting in a total of 40 scans per student (4 techniques \u0026times; 10 repetitions). Across all participants, a total of 720 scans were collected, with 360 scans performed by right-hand dominant students and 360 scans by left-hand dominant students (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). To reduce operator fatigue, scanning sessions were distributed across multiple days with standardized rest intervals. Prior to data collection, all students received standardized orientation training on scanner handling and scanning strategy to ensure procedural consistency.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003ePhantom model and scanning protocol\u003c/h3\u003e\n\u003cdiv class=\"Heading\"\u003ePhantom model and scanning protocol\u003c/div\u003e \u003cp\u003eAll scans were performed on a standardized 28-tooth full-arch dental phantom model (FUJI F-28JAW; Fuji, Tokyo, Japan), representing a fully dentate maxillary arch, in the Phantom Simulation Laboratory of the Faculty of Dentistry at Biruni University. Environmental conditions were controlled throughout the study (room temperature: 22\u0026ndash;24\u0026deg;C; ambient illumination: 5500 K LED lighting).\u003c/p\u003e \u003cp\u003eIntraoral scans were acquired using a single intraoral scanner (Primescan; Dentsply Sirona, Bensheim, Germany) operating under the highest quality setting. The average scanning duration was standardized at approximately 2\u0026ndash;3 minutes per scan. Each scan followed a standardized three-step scanning sequence: (1) occlusal surfaces, (2) buccal surfaces, and (3) lingual surfaces. Scanner calibration and routine maintenance were performed before each session according to the manufacturer\u0026rsquo;s recommendations. Phantom model positioning and dental chair configuration were kept constant throughout the study.\u003c/p\u003e \u003cp\u003e \u003cb\u003eReference scan acquisition and deviation analysis\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA high-precision reference dataset of the phantom model was obtained using a laboratory scanner (3Shape E4; 3Shape, Copenhagen, Denmark) and served as the digital reference model for trueness evaluation. Following isolation of the reference scan geometry, all intraoral scan datasets were exported in STL format at maximum resolution and imported into reverse-engineering software (Geomagic Control X Viewer, version 2022.1; 3D Systems, Rock Hill, SC, USA) for three-dimensional deviation analysis.\u003c/p\u003e \u003cp\u003eThe reference model was first loaded into the software environment. Subsequently, each student-generated intraoral scan was individually superimposed onto the reference dataset. The alignment protocol consisted of sequential application of initial alignment, best-fit alignment, and 3D compare functions, which were applied consistently to all scans. Deviation results were visualized using color-coded deviation maps (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Positive and negative deviations were displayed using a standardized color scale, with dark red and dark blue representing the maximum positive and negative deviations, respectively, corresponding to a\u0026thinsp;\u0026plusmn;\u0026thinsp;100 \u0026micro;m deviation range. Deviations within the acceptable tolerance limits (\u0026plusmn;\u0026thinsp;20 \u0026micro;m) were displayed in green. Trueness was quantified as the root mean square (RMS) deviation (\u0026micro;m) between the intraoral scan and the reference dataset within the defined region of interest (ROI).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was performed using a mixed-design repeated measures analysis of variance (ANOVA), with hand dominance as the between-subject factor and retraction technique as the within-subject factor. When the sphericity assumption was violated, the Huynh\u0026ndash;Feldt correction was applied. Post hoc comparisons were conducted using Bonferroni-adjusted tests. All analyses were performed using IBM SPSS Statistics (version 25; IBM Corp., Armonk, NY, USA), with a significance level set at α\u0026thinsp;=\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe sphericity assumption for repeated measures was evaluated using Mauchly\u0026rsquo;s test and was found to be violated (W\u0026thinsp;=\u0026thinsp;0.916, χ\u0026sup2;(5)\u0026thinsp;=\u0026thinsp;15.52, p\u0026thinsp;=\u0026thinsp;0.008). Accordingly, the Huynh\u0026ndash;Feldt correction was applied (ε\u0026thinsp;=\u0026thinsp;0.967). The assumption of homogeneity of variance was assessed using Levene\u0026rsquo;s test and was met for all RMS measurements (p\u0026thinsp;\u0026ge;\u0026thinsp;0.175).\u003c/p\u003e \u003cp\u003eThe repeated-measures analysis with the Huynh\u0026ndash;Feldt correction revealed that hand dominance did not have a significant main effect on intraoral scanning trueness (F(1, 178)\u0026thinsp;=\u0026thinsp;0.22, p\u0026thinsp;=\u0026thinsp;0.641, partial η\u0026sup2; =0.001). In contrast, retractor type showed a statistically significant effect on scanning trueness (F(2.90, 516.18)\u0026thinsp;=\u0026thinsp;2.81, p\u0026thinsp;=\u0026thinsp;0.041, partial η\u0026sup2; =0.016). No significant interaction between hand dominance and retractor type was observed (F(2.90, 516.18)\u0026thinsp;=\u0026thinsp;0.78, p\u0026thinsp;=\u0026thinsp;0.501, partial η\u0026sup2; =0.004).\u003c/p\u003e \u003cp\u003eBonferroni-adjusted pairwise comparisons revealed a statistically significant difference between the whitening cheek retractor and the OptraGate lip retractor, with the whitening cheek retractor exhibiting significantly lower deviations (p\u0026thinsp;=\u0026thinsp;0.011). No significant differences were observed when the remaining pairwise comparisons were considered (p \u0026ge; .141). Descriptive statistics of RMS deviation values (\u0026micro;m), representing intraoral scan trueness, according to hand dominance and retraction technique are presented in Table\u0026nbsp;1.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe present study evaluated the influence of hand dominance on intraoral scanning trueness in undergraduate dental students and assessed the effect of different retractor types. Hand dominance and its interaction with retractor type did not significantly affect scanning trueness, whereas retractor type alone had a significant effect. Bonferroni-corrected pairwise comparisons revealed a significant difference in RMS values between the whitening cheek retractor and the OptraGate lip retractor. These results highlight the importance of auxiliary equipment selection in digital impression procedures and support previous evidence emphasizing the role of ergonomics and soft tissue management in psychomotor performance during dental education [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eContrary to assumptions that hand dominance may affect fine motor tasks requiring bimanual coordination [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], hand dominance did not significantly influence scanning trueness in this study, nor did it interact with retractor type. This aligns with previous reports suggesting that the effect of handedness on motor skill acquisition is task-dependent and may be less pronounced in procedures supported by standardized workflows and digitally guided systems [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The structured scanning protocol and the use of a highly intuitive intraoral scanner may have minimized variability related to operator laterality.\u003c/p\u003e \u003cp\u003eWith respect to retraction conditions, no statistically significant differences were observed among the no-retraction, dental mirror\u0026ndash;assisted retraction, and whitening cheek retractor conditions, with comparable mean RMS deviation values of 254.43\u0026thinsp;\u0026plusmn;\u0026thinsp;42.07 \u0026micro;m, 252.49\u0026thinsp;\u0026plusmn;\u0026thinsp;43.43 \u0026micro;m, and 245.57\u0026thinsp;\u0026plusmn;\u0026thinsp;30.68 \u0026micro;m, respectively. Similarly, no significant differences were detected between the no-retraction and dental mirror conditions and the OptraGate lip retractor (256.31\u0026thinsp;\u0026plusmn;\u0026thinsp;38.72 \u0026micro;m). These findings indicate that neither manual soft tissue management nor the use of a circumferential lip retractor alone substantially alters scanning trueness in novice operators, likely because the standardized scanning protocol and the absence of dynamic intraoral variables in a simulation-based setting limit the relative impact of most soft tissue displacement techniques, particularly those involving minimal or manual retraction, thereby masking differences among similar retraction approaches, on overall scan accuracy.\u003c/p\u003e \u003cp\u003eA statistically significant difference was observed only between the whitening cheek retractor and the OptraGate lip retractor. This finding suggests that specific retractor design features and localized soft tissue displacement patterns\u0026mdash;rather than the mere presence or absence of retraction\u0026mdash;may influence intraoral scanning trueness during early digital skill acquisition. Differences in rigidity, coverage area, and the distribution of tissue tension may differentially affect scanner access and line-of-sight continuity, thereby contributing to localized deviations during full-arch scanning.\u003c/p\u003e \u003cp\u003eWhile the difference in mean values appears limited, interpretation of these findings should consider the overall magnitude of the measured deviations as well as the relative nature of comparisons within a standardized experimental framework. Previous in vivo studies conducted under clinical conditions with experienced operators have reported substantially lower trueness values, typically ranging from 20 to 92 \u0026micro;m for single-unit and full-arch scans [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In contrast, in vitro investigations using phantom models\u0026mdash;particularly those involving full-arch scanning and novice operators\u0026mdash;have consistently reported higher trueness deviations, often exceeding 150\u0026ndash;300 \u0026micro;m [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe trueness values observed in the present study fall within this reported in vitro range, supporting the assumption that the elevated deviations are primarily attributable to the simulation-based setting and early learning phase of the operators rather than methodological error. Had the measured deviations substantially exceeded those reported in comparable in vitro studies, the interpretability of the observed intergroup differences would be compromised; however, their consistency with published phantom-based data supports the validity of the present measurements. Within this controlled framework, the relative differences observed between retraction systems remain meaningful and were statistically significant, indicating that retractor design exerted a measurable effect on scanning trueness under standardized conditions. Therefore, while direct clinical extrapolation of the absolute trueness values should be approached with caution, the observed differences suggest that retraction technique may influence intraoral scanning performance during the early stages of digital skill acquisition.\u003c/p\u003e \u003cp\u003eThe observed difference in scanning trueness between the whitening cheek retractor and the OptraGate lip retractor can be attributed to differences in retractor design and soft tissue displacement characteristics. Whitening cheek retractors are typically rigid and provide localized, static retraction, which may result in uneven displacement of the lips and cheeks and increased soft tissue interference in the scanning field. In contrast, the OptraGate lip retractor provides circumferential, elastic retraction with more homogeneous soft tissue tension, thereby improving visibility and scanner access to vestibular and buccal surfaces. Such uniform displacement may reduce soft tissue overlap and shadowing effects, which have been reported as contributors to local scanning deviations in complete-arch acquisitions.\u003c/p\u003e \u003cp\u003eThe IOS used in this study (Primescan) has previously been reported to receive high ratings for scanning speed, workflow efficiency, and image sharpness, features that are known to reduce cognitive load and facilitate early skill acquisition in dental students [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. This may partly explain why hand dominance did not emerge as a significant factor influencing scanning trueness. As the study targeted the early phase of digital skill acquisition, trueness was selected as the primary outcome, since performance variability at this stage is strongly influenced by rapid learning effects and trueness represents a more clinically meaningful indicator of novice scanning performance than precision, which becomes more informative once motor execution stabilizes according to ISO-based definitions of measurement accuracy [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAll participants completed the scanning procedures using a fixed sequence of retraction conditions, progressing from no retraction to mirror-assisted retraction, whitening cheek retractor, and finally the OptraGate lip retractor. This standardized order ensured comparable learning exposure across operators but may have introduced a cumulative practice effect, potentially contributing to increased scanning proficiency during later measurements. To characterize the early learning curve while minimizing short-term learning variability, each operator performed ten consecutive scans per retraction condition on the same day, consistent with evidence indicating that approximately ten scans are sufficient to capture early intraoral scanning performance stabilization [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Although the fixed sequence may have partially influenced absolute trueness values independent of retractor type, the consistent application of this protocol across all participants allows relative comparisons between retraction techniques to remain valid and clinically informative.\u003c/p\u003e \u003cp\u003eDespite the strengths of the present study, several limitations should be considered when interpreting the findings. First, the study was conducted under simulation-based, in vitro conditions using a maxillary fully dentate phantom model and novice undergraduate students. This design allowed for a high degree of standardization and effective control of confounding variables during the early stages of digital skill acquisition; however, it inherently limits the generalizability of the results to real clinical environments. All scans were obtained under controlled conditions, excluding clinically relevant factors such as saliva contamination, dynamic soft tissue behavior, patient movement, restricted mouth opening, and operator\u0026ndash;patient interaction. The presence of saliva has been shown to significantly affect the accuracy of digital implant transfer, and variations in soft tissue conditions may similarly influence clinical scanning outcomes [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Previous investigations have also demonstrated that intraoral scanning accuracy can be significantly influenced by these clinical variables, as well as by anatomical complexity and scan span, particularly under in vivo conditions [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Therefore, future clinical (in vivo) studies are necessary to confirm the ecological validity of the present findings and to determine whether the observed effects of retractor design persist under real-world clinical constraints.\u003c/p\u003e \u003cp\u003eSecond, the experimental model was limited to a complete dentate maxillary arch, which does not reflect the wide range of anatomical and prosthetic scenarios encountered in daily clinical practice. Prior in vitro and clinical evidence indicates that scanner accuracy and trueness may vary considerably in cases involving partially edentulous arches, fully edentulous arches, extended scan spans, or the presence of implant scan bodies, where the lack of anatomical landmarks and increased surface discontinuity pose additional challenges [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The influence of soft tissue retraction systems may therefore be more pronounced\u0026mdash;or differ in magnitude\u0026mdash;in such complex scanning situations. Consequently, future in vitro studies incorporating diverse model designs, including partially and fully edentulous arches as well as implant-supported configurations, are warranted to comprehensively evaluate the interaction between retraction systems, anatomical complexity, and scanning performance.\u003c/p\u003e \u003cp\u003eThird, the study evaluated a limited number of retraction systems, focusing on commonly used educational and clinical devices. Although significant differences were detected between the two retractor designs tested, additional systems with varying rigidity, elasticity, and coverage area should be investigated to better characterize how specific design features influence scanning trueness and ergonomic performance. Similarly, only a single intraoral scanner was used. Given that different intraoral scanning systems employ distinct optical principles, scanning algorithms, and real-time stitching strategies that can affect trueness and precision, future research should incorporate multiple scanners to assess whether the interaction between retractor design and scanning performance is device-dependent [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFourth, deviation analysis was performed using a single metrology software and an RMS-based evaluation approach, which may yield different absolute deviation values compared with alternative alignment strategies or region-specific analysis methods. In addition, the study focused on trueness as an outcome measure, as performance variability during early digital skill acquisition is predominantly reflected in deviations from the reference rather than in scan-to-scan reproducibility. Finally, only full-arch scans were evaluated; therefore, the effects of retraction techniques on quadrant-based or localized scanning tasks remain to be investigated.\u003c/p\u003e \u003cp\u003eFuture studies extending the present methodology to implant-supported restorations, partially edentulous arches, and complete denture workflows, while incorporating diverse scanning and analysis strategies, would provide a more comprehensive understanding of how ergonomic factors and auxiliary equipment influence digital impression performance across varying levels of clinical complexity.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eWithin the limitations of this simulation-based study, hand dominance did not significantly influence intraoral scanning trueness during early digital skill acquisition when a standardized scanning protocol was employed. In contrast, retractor type had a measurable effect on scanning accuracy, with differences observed between the whitening cheek retractor and the OptraGate lip retractor. These findings suggest that specific retractor design features, such as rigidity, coverage area, and soft tissue displacement patterns, can influence scanner access and line-of-sight continuity, thereby affecting trueness. From an educational perspective, auxiliary equipment should be considered a modifiable element of the digital learning environment rather than merely a passive clinical tool. Incorporating ergonomic and equipment-related considerations into intraoral scanning training may enhance scan consistency and better prepare students for clinical digital workflows. Future studies should investigate these effects in vivo and across diverse anatomical scenarios, including partially and fully edentulous arches and implant-supported restorations.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eANOVA \u0026ndash; Analysis of variance\u003c/p\u003e\n\u003cp\u003eISO \u0026ndash; International Organization for Standardization\u003c/p\u003e\n\u003cp\u003eIOS \u0026ndash; Intraoral scanner\u003c/p\u003e\n\u003cp\u003eLED \u0026ndash; Light-emitting diode\u003c/p\u003e\n\u003cp\u003eRMS \u0026ndash; Root mean square\u003c/p\u003e\n\u003cp\u003eSTL \u0026ndash; Standard tessellation language\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Biruni University Ethics Committee (Approval No: 2024/BİAEK/14-35). All procedures involving human participants were conducted in accordance with the ethical standards of the Declaration of Helsinki and its later amendments. Written informed consent to participate was obtained from all participants prior to the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCNC and GM contributed to the conception and design of the study. CNC, GM, and MD contributed to data acquisition. CNC and GM performed the statistical analysis and interpreted the data. AADT and MD contributed to manuscript drafting and critical revision for important intellectual content. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank the undergraduate dental students who participated in this study and the staff of the Phantom Simulation Laboratory, Faculty of Dentistry, Biruni University, for their support during data collection.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLiu CM, Hsu MH, Ng MY, Yu CH. 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Accuracy of intraoral scans in vivo. \u003cem\u003eJ Prosthet Dent\u003c/em\u003e. 2022;128(6):1303\u0026ndash;1309. https://doi.org/10.1016/j.prosdent.2021.03.007\u003c/li\u003e\n\u003cli\u003eWaldecker M, B\u0026ouml;micke W, Behnisch R, et al. In-vitro accuracy of complete arch scans. \u003cem\u003eJ Prosthodont Res\u003c/em\u003e. 2022;66(4):538\u0026ndash;545. https://doi.org/10.2186/jpr.JPR_D_21_00100\u003c/li\u003e\n\u003cli\u003eAchmadi AA, Rikmasari R, Oscandar F, Novianti VMP. Accuracy of edentulous arch impressions. \u003cem\u003eBDJ Open\u003c/em\u003e. 2025;11(1). https://doi.org/10.1038/s41405-025-00300-4\u003c/li\u003e\n\u003cli\u003eGrande F, Nuytens P, Zahabiyoun DS, et al. Factors influencing intraoral implant scan accuracy. \u003cem\u003eJ Dent\u003c/em\u003e. 2025;161:105973. https://doi.org/10.1016/j.jdent.2025.105973\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eDescriptive statistics of intraoral scan trueness (RMS deviation, \u0026micro;m) according to hand dominance and retraction technique.\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"638\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRight-handed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 146px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLeft-handed\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eNo-retraction\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e256.59 \u0026plusmn; 38.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 146px;\"\u003e\n \u003cp\u003e252.27 \u0026plusmn; 45.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e254.43 \u0026plusmn; 42.07\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eDental mirror\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e255.96 \u0026plusmn; 53.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 146px;\"\u003e\n \u003cp\u003e249.02 \u0026plusmn; 30.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e252.49 \u0026plusmn; 43.43\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWhitening retractor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e244.81 \u0026plusmn; 29.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 146px;\"\u003e\n \u003cp\u003e246.33 \u0026plusmn; 32.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e245.57 \u0026plusmn; 30.68\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 158px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOptraGate lip retractor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 156px;\"\u003e\n \u003cp\u003e254.47 \u0026plusmn; 38.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 146px;\"\u003e\n \u003cp\u003e258.15 \u0026plusmn; 39.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 178px;\"\u003e\n \u003cp\u003e256.31 \u0026plusmn; 38.72\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e*Values represent RMS deviation (\u0026micro;m) indicating scan trueness.\u003c/p\u003e\n\u003cp\u003e*Different superscript letters indicate statistically significant differences between retraction techniques (Bonferroni-adjusted post hoc comparisons, p \u0026lt; .05).\u003c/p\u003e\n\u003cp\u003eGroups sharing the same letter are not significantly different.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-medical-education","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"meed","sideBox":"Learn more about [BMC Medical Education](http://bmcmededuc.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/meed/default.aspx","title":"BMC Medical Education","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Dental Impression Technique, Dental Education, Psychomotor Performance, Ergonomics, Dental Instruments","lastPublishedDoi":"10.21203/rs.3.rs-8923269/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8923269/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eIntraoral scans have become an integral component of contemporary dental education. While auxiliary devices such as retractors are commonly used to improve visibility and access, their influence on scanning performance during early digital skill acquisition remains insufficiently explored. This study aimed to evaluate the effect of hand dominance and retractor design on the trueness of intraoral scans performed by undergraduate dental students.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eEighteen undergraduate dental students with no prior experience in digital intraoral scanning participated in this experimental study. Participants were categorized according to hand dominance (right- vs. left-handed). Each student performed intraoral scans on a standardized dental phantom model (FUJI F-28JAW; Fuji, Tokyo, Japan) using an intraoral scanner (Primescan; Dentsply Sirona, Bensheim, Germany) under four retraction conditions: no retraction, dental mirror-assisted retraction, whitening cheek retractor, and OptraGate lip retractor. To ensure comparable early learning exposure among novice users, all retraction techniques were applied in a fixed sequence. Scan trueness was assessed by calculating the root mean square values, obtained by superimposing the intraoral scanner scans over a high-precision laboratory scanner (E4) reference scan. Data were analyzed using a mixed-design repeated measures analysis of variance test (α\u0026thinsp;=\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eStatistical analysis showed that the retractor type significantly influenced the intraoral scan deviations (p\u0026thinsp;=\u0026thinsp;0.041), whereas hand dominance (p\u0026thinsp;=\u0026thinsp;0.641) and the interaction between main factors had no significant effect on measured deviations (p\u0026thinsp;=\u0026thinsp;0.501). Deviation values were significantly lower with the whitening retractor compared with the OptraGate lip retractor (p\u0026thinsp;=\u0026thinsp;0.011), while no significant differences in deviation were found among the remaining retraction techniques.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eHand dominance appears to play a limited role within a standardized digital workflow, whereas retractor design influenced intraoral scanning performance during early digital skill acquisition. From a health professions education perspective, auxiliary equipment such as retractors should be regarded as modifiable components of the learning environment, rather than merely as clinical accessories.\u003c/p\u003e","manuscriptTitle":"The impact of hand dominance and retractor design on intraoral scanning trueness during simulation-based digital dentistry training: an in vitro study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-26 15:42:22","doi":"10.21203/rs.3.rs-8923269/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-22T08:42:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"53200312863833805849439639124402374361","date":"2026-04-17T02:52:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-16T15:00:23+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-19T14:45:42+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-21T01:09:59+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-21T01:09:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Medical Education","date":"2026-02-20T07:11:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-medical-education","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"meed","sideBox":"Learn more about [BMC Medical Education](http://bmcmededuc.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/meed/default.aspx","title":"BMC Medical Education","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fd818d03-3511-4d7d-8bce-e339ee71f42b","owner":[],"postedDate":"April 26th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-26T15:42:22+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-26 15:42:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8923269","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8923269","identity":"rs-8923269","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}