Do we need microscopes for restorative treatment procedures? A pilot study in dental students´ education environment

Do we need microscopes for restorative treatment procedures? 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A pilot study in dental students´ education environment Elisabeth Prause, Jonas Rechlin, Simon Peroz, Anna Steinke, Manja Stein-Lausnitz, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8167599/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 26 Feb, 2026 Read the published version in BMC Medical Education → Version 1 posted 18 You are reading this latest preprint version Abstract Background The integration of magnification devices into dental education is widely recommended, yet evidence regarding their impact on student performance remains limited. This study evaluated the effect of dental loupes (DL) and dental operating microscopes (OPMI) on the quality of crown preparation and provisional restoration among preclinical and clinical dental students compared with standard protective glasses (SG). Methods Sixty dental students participated: 30 preclinical (fifth semester) and 30 clinical (ninth semester). Participants were randomly assigned to three groups: DL (ZEISS EyeMag Pro S 3.5×400), OPMI (ZEISS EXTARO 300), or SG (control). Each prepared a crown and a provisional restoration. Outcomes were assessed conventionally (expert ratings) and digitally (objective parameters). Performance differences were analyzed using generalized estimating equations (p < 0.05). Results Optical magnification significantly improved restorative performance compared with SG. Preclinical students using OPMI achieved the highest overall scores, while clinical students performed best with DL. GEE confirmed significant differences between OPMI and SG, but not between preclinical and clinical groups. Conclusions Optical magnification improved restorative outcomes compared with standard glasses. OPMI use was most beneficial in preclinical training, whereas DL appeared more advantageous in clinical settings. Integrating optical magnification into dental education enhances skill acquisition and clinical quality. OPMI supports precision and fine motor skills in preclinical training, while DL offers visual improvement with greater ergonomics and workflow flexibility in clinical practice. Tailoring magnification strategies to the training stage may optimize educational and clinical performance. magnification education dentistry dental loupes dental operating microscope restorative dentistry Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Background In dentistry, the ability to perform precise tooth preparations is crucial for successful restorative treatments ( 1 ). The use of magnification devices such as dental loupes (DL) and dental operating microscopes (OPMI) has gained increasing attention in dental education due to their potential to enhance the visualization of morphological details, ultimately leading to improved preparation quality ( 1 , 2 ). While some studies suggest that loupes contribute to better preparation accuracy, others have found no significant effect on the quality of full-coverage crown preparations or on the visual acuity of dental students ( 1 , 3 , 4 ). Another study revealed that the application of higher magnification during tooth preparation significantly influenced the extent of marginal discrepancies in computer-aided design (CAD) / computer-aided manufacturing (CAM) crowns ( 5 ). Preparations performed with fine-grit diamond rotary instruments under microscopic magnification, exceeding that provided by loupes, resulted in superior marginal adaptation characterized by smaller gap dimensions ( 5 ). Minimally invasive preparation techniques have become the standard of care, as preserving tooth structure directly influences treatment adherence and the longevity of restorations. The use of modern optical magnification devices, in combination with appropriate lighting systems, may contribute to achieving these conditions ( 6 , 7 ). DL have been established for many year and studies have been widely published regarding advantages of DL ( 6 , 8 – 12 ). Contrary, literature about OPMI is reduced. It is known that OPMI offer the highest magnification degree of all magnification devices and the most neutral working posture ( 13 , 14 ) and it is used for endodontic treatment procedures ( 15 , 16 ). Furthermore, dentist´s posture is improved and ergonomic benefits are proven ( 13 , 14 ). Studies showed that both magnification devices had a positive impact on dental treatment procedure ( 13 ). So far, no data is available regarding the use of OPMI in dental education for restorative treatment procedures. Interestingly, while magnification is widely recognized for its benefits, its implementation in dental education remains inconsistent. Nearly one-quarter of all magnification users have indicated that they are unlikely to use magnification in the teaching environment, even though they may rely on it in private practice ( 17 ). Several explanations have been given for this discrepancy, including institutional resistance and personal preference ( 17 ). Therefore, only a small amount of educational institutions supports its introduction in the first year of the curriculum, even though it could be proven that magnification positively impacted undergraduates dental students´ performance in cavity preparations ( 1 , 9 ). Furthermore, improvements could be shown regarding posture, hand skills and procedure quality ( 13 , 18 ). These findings suggest that educational institutions should address faculty concerns and resistance before mandating the use of magnification devices in dental training programs. However, the implementation of magnification devices in the curriculum can be used at any stage of clinical experience, regardless of professional skill level ( 6 ). Adequate training is recommended to ensure proper utilization and maximize its benefits ( 6 , 19 ). In preclinical restorative training, students are still developing their skills and must work within a limited operative field that requires high-precision movements ( 6 ). Magnification devices offer significant advantages by improving visual perception, enhancing hand-eye coordination and facilitating spatial awareness, thereby allowing for more detailed observation of dental cavities ( 4 , 6 ). Improved magnification ensures greater precision in workflow and provides better visibility during restorative treatments ( 1 , 9 ). This, in turn, facilitates the detection of restoration margins regarding restorative dentistry. Furthermore, the removal of excess composite resin, and more precise finishing of preparation edges, ultimately minimizing unnecessary tooth structure removal would be advantageous ( 20 , 21 ). However, despite these potential benefits, further research is needed to assess the long-term effects of OPMI on both the learning process of dental students and the overall quality of dental treatments. This pilot study aims to evaluate the impact of magnification devices on the preparation quality and working techniques of preclinical and clinical dental students. The null hypothesis to test is that with the help of OPMI significantly better results compared to DL and SG were achieved. 2. Methods The present clinical study was approved by the local Ethics Committee in 2020 (application number: EA1/25a0/23). Since then, it is being conducted in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research. Sixty dental students were recruited for the preparation exercise. The cohort consisted of 30 students from the 5th preclinical semester and 30 students from the 9th clinical semester. The average age of the study participants was 24.7 years. A total of 20 male and 40 female students participated. On average, students in the 9th semester were two years older than those in the 5th semester. Participants were recruited via flyers and seminar presentations and randomly assigned to three groups. All received oral and written information about the study, with sufficient time to give informed consent; participation required a signed consent form, and data were pseudonymized. Groups differed by magnification device: (1) protective eyewear without magnification (Virtua safety glasses, 3M), (2) dental loupes with headlamp (ZEISS EyeMag Pro S 3.5×), and (3) dental operating microscope (ZEISS EXTARO 300). Each group received an introductory session on their device. Loupes had fixed magnification (3.5×, 40 cm working distance), while microscopes allowed adjustable magnification; interpupillary distance and viewing angle were adjusted for ergonomic posture. The task was preparation of a right maxillary central incisor for an unveneered lithium disilicate crown and fabrication of a provisional restoration (Luxatemp Auto Plus, DMG) within 150 minutes. Preparation followed preclinical standards, with workflow and remaining time displayed on a screen. Models, provisional restorations, and silicone keys were collected, and teeth were scanned (Primescan, Dentsply Sirona). Evaluation was analog and digital. Analog assessment used a dental model and periodontal probe (PA probe/UNC15, HuFriedy Group) by three raters (student, dentist, senior consultant) under natural light, based on preclinical scoring sheets (Tables 1 and 2). Table 2 Another analogue evaluation criteria for the provisional restoration, again based on preclinical criteria. Digital assessment compared scans to a master model using prepCheck software, generating color-coded deviation maps for scoring. Scores (0–3) were identical for both methods; provisional restorations were assessed only conventionally. Five assessments were performed: analog provisional, analog preparation, digital preparation, combined preparation, and overall assessment. To perform statistical analyses, SPSS 28.0 (IBM) and the online tool DataTab (DATAtab e.U.) was used. Statistical significance was set as p < 0.05 probability level. Inter-rater agreement was evaluated using the intraclass correlation coefficient (ICC), and Bland-Altman plots assessed method agreement. Differences between semesters and magnification aids were analyzed using Generalized Estimating Equations (GEE), accounting for rater clustering. 3. Results The results of this study indicate that the use of magnification aids generally improved evaluation outcomes, with variations depending on semester and assessment method. Ninth-semester students consistently achieved higher scores than those in the fifth semester. The three evaluators (student, dentist, senior consultant) showed differing assessment tendencies, with the greatest variability observed in digital preparation evaluations. Correlations between age, working hours, and outcomes were mostly nonsignificant, and gender had no effect. Analysis of average percentage scores relative to maximum achievable points revealed distinct performance patterns depending on the magnification aid (Table 3 ). Across both semesters, students using the OPMI achieved the highest mean scores in preparation assessments—74.68% in conventional and 69.13% in digital evaluations—followed by the DL group (70.08% and 64.68%, respectively). The SG group consistently showed the lowest results (68.02% conventional, 60.00% digital). Similar trends were found in overall evaluations, where DL users reached the highest mean score (65.63%), followed by OPMI (63.32%) and SG (59.64%). In the evaluation of provisional restorations, ninth-semester students using DL achieved the best results (≈ 60%), while fifth-semester students with OPMI scored lowest (36.54%). Comparing semesters, fifth-semester students performed best with OPMI, particularly in preparation and overall evaluations, whereas ninth-semester students using DL slightly outperformed the OPMI group in digital and combined assessments. Across all measures, SG use was associated with the lowest performance (Table 3 ). Overall, both OPMI and DL contributed to superior results, while reliance on SG limited performance. In the fifth semester, OPMI users achieved the highest conventional (75.9%) and digital (72.4%) preparation scores, resulting in a combined mean of 65.0% (Fig. 1 ). In contrast, DL users led in the ninth semester with 73.9% (conventional) and 72.8% (digital), corresponding to a combined mean of 69.7% (Fig. 2 ). When all data were pooled, the DL group achieved the highest preparation averages (70.9% conventional; 64.6% digital; 72.2% combined) and the best overall results (65.6%), followed by OPMI (63.3%), while SG consistently ranked lowest (Table 3 , Fig. 3 ). Interrater reliability analysis using the Intraclass Correlation Coefficient (ICC) showed the highest agreement for conventional preparation (ICC = 0.827), followed by provisional restoration (ICC = 0.779) and overall evaluation (ICC = 0.771). The lowest reliability occurred in the digital preparation evaluation (ICC = 0.615), indicating greater variability among evaluators. All ICC values were statistically significant (p < 0.001). Due to the clustered data structure (three evaluations per work), Generalized Estimating Equations (GEE) were applied to account for within-cluster correlations. The GEE analysis revealed significant differences between magnification aids. In the fifth semester, the OPMI group performed significantly better than the SG group in conventional (p = 0.006), digital (p = 0.028), and combined preparation assessments (p = 0.003). Additionally, the DL and OPMI groups differed significantly in digital preparation (p = 0.004). In the ninth semester, significant differences were found between SG and DL in digital (p = 0.015) and combined (p = 0.040) preparation. Across all semesters, a significant difference was observed between SG and OPMI in digital preparation (p = 0.018). No significant differences emerged between semesters when comparing overall performance (p > 0.05). In summary, OPMI and DL use were associated with superior performance in both preparation and overall assessments, while SG resulted in consistently lower outcomes. Interrater agreement was highest in conventional and provisional restoration evaluations, and lowest for digital assessments (Fig. 4 ). 4. Discussion The present pilot study aimed to evaluate the impact of magnification devices on preparation quality and working techniques of dental students. The null hypothesis that OPMI achieved significantly better results than DL had to be rejected. Both OPMI and DL led to better performance compared with SG. Ninth-semester students achieved superior results, likely due to greater manual skill and prior experience with DL. The general performance improvement observed with magnification devices aligns with earlier findings ( 8 , 9 , 22 ). Studies have shown that DL enhances psychomotor skills, reduces task time, and improves performance quality, although some reported no statistically significant differences between groups ( 8 , 23 ) ( 12 , 24 , 25 ). In line with prior work, preclinical students in the present study showed a pronounced learning curve with OPMI, possibly due to higher motivation and novelty of the technique. Clinical students performed better overall, likely owing to existing practical skills. Thus, magnification aids improved performance in general, though not with statistically significant skill progression, and no clear preference emerged between OPMI and DL. No correlation between working time, age, and preparation results was observed. Both digital and analogue evaluations were applied, assessed by three raters with different experience levels. High interrater consistency was found, and no significant differences between digital and conventional assessments were detected. Hence, neither evaluation method proved superior. Previous studies have shown that conventional assessments can be subjective and inconsistent ( 26 – 29 ), potentially undermining student confidence ( 30 , 31 ). Digital systems, by contrast, tend to offer more objective and reproducible feedback ( 26 , 27 , 32 – 37 ). However, some authors noted that purely digital systems may not validly assess all aspects of students’ work ( 26 , 32 ). Integrating digital and traditional feedback is therefore recommended to balance objectivity and pedagogical value ( 26 , 33 , 38 – 43 ). Traditional feedback tools such as checklists or visual diagrams can be subjective ( 44 – 46 ). Previous studies reported low interrater agreement among faculty ( 26 ), whereas the present study achieved an ICC > 0.827, indicating excellent reliability. Literature also shows that students often overestimate their own performance compared to teachers ( 45 , 47 , 48 ). Including student self-evaluation and repeated blinded assessments in future research could provide valuable insights. Digital assessment tools like prepCheck reduce subjectivity by comparing student preparations with calibrated master models, offering visualized deviations within defined tolerance levels ( 27 , 45 , 46 ). Such systems can be adapted to training level and allow longitudinal performance tracking, enhancing feedback quality ( 45 , 49 ). Despite their advantages, implementation requires financial investment and sufficient training time for both staff and students ( 45 , 46 ). Once integrated, these systems can improve motivation, learning outcomes, and teaching efficiency ( 27 , 45 ). Magnification devices also contribute to ergonomic improvement. The use of OPMI has been shown to enhance head and neck posture by 50% and shoulder posture by 23.6% (p < .0001), whereas DL resulted in smaller improvements of 11.9% and 5.9%, respectively (p = .0012; p = .0413) ( 50 ). Several studies confirm that magnification supports ergonomic posture development, particularly in inexperienced students ( 22 , 24 , 51 – 57 ). Since posture parameters were not assessed in the present study, future research should address this aspect more comprehensively. Future investigations should further analyze the learning curve and systematically rotate students among magnification devices. Repeated testing at regular intervals with larger, more heterogeneous cohorts (regarding experience, gender, and age) would allow robust conclusions. Expanding the number of raters per experience level and maintaining both digital and analogue evaluation methods are recommended to strengthen reliability and comparability. 5. Conclusions The present study was the first one to examine the use of different magnification devices on students performing a preparation and a provisional restoration. The use of visual magnification aids (OPMI and DL) can significantly enhance the quality of dental preparation and restoration procedures in dental education. While both tools proved superior to SG, their effectiveness varied depending on the students' clinical experience and familiarity with the device. Dental microscopes were particularly advantageous for preclinical students whereas magnifying loupes yielded better results among clinical students. The findings underscore the importance of structured training and adequate familiarization to optimize the benefits of magnification tools. Moreover, the combination of conventional and digital assessment methods provided the most consistent evaluation outcomes, emphasizing the need for standardized, objective grading systems. Integrating optical aids into dental curricula from the preclinical stage appears to be a valuable strategy for improving practical skills and fostering ergonomic working habits. Future longitudinal research with larger cohorts and expanded ergonomic parameters is needed to better understand the long-term impact of magnification devices on learning success, clinical performance, and student health. Abbreviations DL: Dental loupes OPMI: dental operating microscope SG: protective glasses CAD/CAM: computer-aided design / computer-aided manufacturing GEE: Generalized Estimating Equations ICC: Intraclass Correlation Coefficient Declarations Ethics approval and consent to participate The present clinical study was approved by the Ethics Committee of the Charité-Universitätsmedizin Berlin in 2020 (application number: EA1/250/23). Since then, it is being conducted in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research. Informed consent was obtained from all of the participants. Consent for publication Not applicable Availability of data and materials The datasets used and/or analysed 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 work was supported by Carl Zeiss Meditec AG, Jena, Germany. Authors´ contributions Elisabeth Prause: conceptualization, organization of the study, writing of the manuscript, approved the submitted version of the manuscript Jonas Rechlin: methodology, organization of the study, statistical evaluation, approved the submitted version of the manuscript Simon Peroz: methodology, organization of the study, evaluation, approved the submitted version of the manuscript Anna Steinke: methodology, organization of the study, evaluation, approved the submitted version of the manuscript Manja von Stein-Lausnitz: supervision, administration, evaluation, approved the submitted version of the manuscript Florian Beuer: supervision, project administration, review of the manuscript, approved the submitted version of the manuscript References Ramesh A, Junxi Guo A, Patel HJ, Huang J, Huang CC, de Mello-Neto JM, et al. The impact of magnification on undergraduate dental students' performance during cavity preparations: A systematic review. 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Supplementary Files Tables.docx Cite Share Download PDF Status: Published Journal Publication published 26 Feb, 2026 Read the published version in BMC Medical Education → Version 1 posted Editorial decision: Revision requested 12 Jan, 2026 Reviews received at journal 09 Jan, 2026 Reviews received at journal 22 Dec, 2025 Reviews received at journal 10 Dec, 2025 Reviewers agreed at journal 10 Dec, 2025 Reviewers agreed at journal 10 Dec, 2025 Reviewers agreed at journal 09 Dec, 2025 Reviews received at journal 09 Dec, 2025 Reviews received at journal 08 Dec, 2025 Reviewers agreed at journal 08 Dec, 2025 Reviewers agreed at journal 08 Dec, 2025 Reviewers agreed at journal 08 Dec, 2025 Reviewers agreed at journal 30 Nov, 2025 Reviewers invited by journal 27 Nov, 2025 Editor assigned by journal 27 Nov, 2025 Editor invited by journal 27 Nov, 2025 Submission checks completed at journal 26 Nov, 2025 First submitted to journal 26 Nov, 2025 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. 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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-8167599","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":552885496,"identity":"f6a36a46-c282-4bc1-83aa-98b4586cb504","order_by":0,"name":"Elisabeth Prause","email":"data:image/png;base64,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","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":true,"prefix":"","firstName":"Elisabeth","middleName":"","lastName":"Prause","suffix":""},{"id":552885497,"identity":"6a6596a5-dff4-4f1f-ba04-385982f7773e","order_by":1,"name":"Jonas Rechlin","email":"","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":false,"prefix":"","firstName":"Jonas","middleName":"","lastName":"Rechlin","suffix":""},{"id":552885498,"identity":"b22c224a-a126-438a-a44e-e3e89719cb45","order_by":2,"name":"Simon Peroz","email":"","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":false,"prefix":"","firstName":"Simon","middleName":"","lastName":"Peroz","suffix":""},{"id":552885499,"identity":"cafe48a3-5d12-481a-859b-f35678caf7fe","order_by":3,"name":"Anna Steinke","email":"","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":false,"prefix":"","firstName":"Anna","middleName":"","lastName":"Steinke","suffix":""},{"id":552885500,"identity":"08740c61-21cd-475f-acfb-e81b2111cbd6","order_by":4,"name":"Manja Stein-Lausnitz","email":"","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":false,"prefix":"","firstName":"Manja","middleName":"","lastName":"Stein-Lausnitz","suffix":""},{"id":552885501,"identity":"f9f43e95-716b-4f8b-bbb2-d2b0006322ef","order_by":5,"name":"Florian Beuer","email":"","orcid":"","institution":"Charité- Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt- Universität zu Berlin","correspondingAuthor":false,"prefix":"","firstName":"Florian","middleName":"","lastName":"Beuer","suffix":""}],"badges":[],"createdAt":"2025-11-20 20:08:03","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8167599/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8167599/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12909-026-08904-6","type":"published","date":"2026-02-26T15:59:10+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":97264806,"identity":"3ce13e70-9a3e-447e-98a1-2a627478865f","added_by":"auto","created_at":"2025-12-02 14:24:45","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":307224,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/957354d8200f9e3748937651.docx"},{"id":97264794,"identity":"e870c8f7-4293-4d90-ae54-920ccb10f210","added_by":"auto","created_at":"2025-12-02 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14:24:47","extension":"xml","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":148031,"visible":true,"origin":"","legend":"","description":"","filename":"10475ee0d9984783a9784d264a3ccadb1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/fe64d31287c51887f9f1e367.xml"},{"id":97264783,"identity":"66542d6f-d55e-4825-8e8f-76e530947dc5","added_by":"auto","created_at":"2025-12-02 14:24:41","extension":"html","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":162945,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/aa3977228c66d4768e14a734.html"},{"id":97264798,"identity":"a3a91c32-0e73-42e1-9974-befe6ba39bd4","added_by":"auto","created_at":"2025-12-02 14:24:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":44415,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentation of the results from various assessments conducted during the fifth semester, measured in percentage scores. The evaluated categories include the \u003cstrong\u003eProvisional Restoration Assessment\u003c/strong\u003e, the \u003cstrong\u003eConventional Preparation Assessment\u003c/strong\u003e, the \u003cstrong\u003eDigital Preparation Assessment\u003c/strong\u003e, the \u003cstrong\u003eCombined Preparation Assessment\u003c/strong\u003e, and the \u003cstrong\u003eOverall Evaluation.\u003c/strong\u003e The three assessed groups, SG (gray), DL (light blue), and OPMI (dark blue), display different performance levels.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/7089294fa637d55b8db86922.png"},{"id":97264810,"identity":"7b8c6831-b7c5-48fe-ba30-76b2b218710c","added_by":"auto","created_at":"2025-12-02 14:24:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":74866,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentation of the results from various assessments conducted during the ninth semester, measured in percentage scores. The evaluated categories include the \u003cstrong\u003eprovisional restoration assessment\u003c/strong\u003e, the \u003cstrong\u003econventional preparation assessment\u003c/strong\u003e, the \u003cstrong\u003edigital preparation assessment\u003c/strong\u003e, the \u003cstrong\u003ecombined preparation assessment\u003c/strong\u003e, and the \u003cstrong\u003eoverall evaluation.\u003c/strong\u003e The three assessed groups, SG (gray), DL (light blue), and OPMI (dark blue), display different performance levels.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/460add098531c9f13e5e136c.png"},{"id":97264797,"identity":"31597231-21f2-4dd6-8583-b805547d2087","added_by":"auto","created_at":"2025-12-02 14:24:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":45045,"visible":true,"origin":"","legend":"\u003cp\u003eComparison between the 5\u003csup\u003eth\u003c/sup\u003e and 9\u003csup\u003eth\u003c/sup\u003e semester regarding the different evaluated parameters (provisional restoration, conventional and digital preparation, combined preparation assessment and overall evaluation). The different study groups (DL and OPMI) and the control group (SG) were evaluated. There were only significant differences with respect to the digital preparation assessment (OPMI) and the combined preparation assessment (SG and OPMI).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/abcd57fe3c37e3d0dc9af53c.png"},{"id":97264780,"identity":"c692b025-788d-4bae-b111-73baa79bee65","added_by":"auto","created_at":"2025-12-02 14:24:40","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":47115,"visible":true,"origin":"","legend":"\u003cp\u003eRater evaluation regarding the different parameters (provisional restoration, conventional and digital preparation, combines preparation assessment and overall evaluation). Students´ evaluation is shown in light blue, dentists´ evaluation is depicted in dark blue whereas the senior consultants´ evaluation is represented in red. There was a general high agreement for all evaluated parameters between the raters despite their different level of experience.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/11f2213b9e952d2755d15934.png"},{"id":103765849,"identity":"a14d56e3-4f4e-4a0a-a6c9-4f89c2b6b721","added_by":"auto","created_at":"2026-03-02 16:10:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":832972,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/c1f4a72e-7248-43d5-a845-8da1b1fead66.pdf"},{"id":97264784,"identity":"b059bedc-3087-497e-a20c-25e20804d167","added_by":"auto","created_at":"2025-12-02 14:24:41","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":27236,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-8167599/v1/85d18b99bf6ad5f305e70fd3.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eDo we need microscopes for restorative treatment procedures? A pilot study in dental students´ education environment\u003c/p\u003e","fulltext":[{"header":"1. Background","content":"\u003cp\u003eIn dentistry, the ability to perform precise tooth preparations is crucial for successful restorative treatments (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). The use of magnification devices such as dental loupes (DL) and dental operating microscopes (OPMI) has gained increasing attention in dental education due to their potential to enhance the visualization of morphological details, ultimately leading to improved preparation quality (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). While some studies suggest that loupes contribute to better preparation accuracy, others have found no significant effect on the quality of full-coverage crown preparations or on the visual acuity of dental students (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). Another study revealed that the application of higher magnification during tooth preparation significantly influenced the extent of marginal discrepancies in computer-aided design (CAD) / computer-aided manufacturing (CAM) crowns (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Preparations performed with fine-grit diamond rotary instruments under microscopic magnification, exceeding that provided by loupes, resulted in superior marginal adaptation characterized by smaller gap dimensions (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eMinimally invasive preparation techniques have become the standard of care, as preserving tooth structure directly influences treatment adherence and the longevity of restorations. The use of modern optical magnification devices, in combination with appropriate lighting systems, may contribute to achieving these conditions (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). DL have been established for many year and studies have been widely published regarding advantages of DL (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR9 CR10 CR11\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e). Contrary, literature about OPMI is reduced. It is known that OPMI offer the highest magnification degree of all magnification devices and the most neutral working posture (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e) and it is used for endodontic treatment procedures (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e). Furthermore, dentist\u0026acute;s posture is improved and ergonomic benefits are proven (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e). Studies showed that both magnification devices had a positive impact on dental treatment procedure (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e). So far, no data is available regarding the use of OPMI in dental education for restorative treatment procedures.\u003c/p\u003e\u003cp\u003eInterestingly, while magnification is widely recognized for its benefits, its implementation in dental education remains inconsistent. Nearly one-quarter of all magnification users have indicated that they are unlikely to use magnification in the teaching environment, even though they may rely on it in private practice (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Several explanations have been given for this discrepancy, including institutional resistance and personal preference (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e). Therefore, only a small amount of educational institutions supports its introduction in the first year of the curriculum, even though it could be proven that magnification positively impacted undergraduates dental students\u0026acute; performance in cavity preparations (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). Furthermore, improvements could be shown regarding posture, hand skills and procedure quality (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). These findings suggest that educational institutions should address faculty concerns and resistance before mandating the use of magnification devices in dental training programs.\u003c/p\u003e\u003cp\u003eHowever, the implementation of magnification devices in the curriculum can be used at any stage of clinical experience, regardless of professional skill level (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Adequate training is recommended to ensure proper utilization and maximize its benefits (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e). In preclinical restorative training, students are still developing their skills and must work within a limited operative field that requires high-precision movements (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). Magnification devices offer significant advantages by improving visual perception, enhancing hand-eye coordination and facilitating spatial awareness, thereby allowing for more detailed observation of dental cavities (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eImproved magnification ensures greater precision in workflow and provides better visibility during restorative treatments (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). This, in turn, facilitates the detection of restoration margins regarding restorative dentistry. Furthermore, the removal of excess composite resin, and more precise finishing of preparation edges, ultimately minimizing unnecessary tooth structure removal would be advantageous (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e). However, despite these potential benefits, further research is needed to assess the long-term effects of OPMI on both the learning process of dental students and the overall quality of dental treatments.\u003c/p\u003e\u003cp\u003eThis pilot study aims to evaluate the impact of magnification devices on the preparation quality and working techniques of preclinical and clinical dental students. The null hypothesis to test is that with the help of OPMI significantly better results compared to DL and SG were achieved.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cp\u003eThe present clinical study was approved by the local Ethics Committee in 2020 (application number: EA1/25a0/23). Since then, it is being conducted in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research.\u003c/p\u003e\n\u003cp\u003eSixty dental students were recruited for the preparation exercise. The cohort consisted of 30 students from the 5th preclinical semester and 30 students from the 9th clinical semester. The average age of the study participants was 24.7 years. A total of 20 male and 40 female students participated. On average, students in the 9th semester were two years older than those in the 5th semester.\u003c/p\u003e\n\u003cp\u003eParticipants were recruited via flyers and seminar presentations and randomly assigned to three groups. All received oral and written information about the study, with sufficient time to give informed consent; participation required a signed consent form, and data were pseudonymized.\u003c/p\u003e\n\u003cp\u003eGroups differed by magnification device: (1) protective eyewear without magnification (Virtua safety glasses, 3M), (2) dental loupes with headlamp (ZEISS EyeMag Pro S 3.5×), and (3) dental operating microscope (ZEISS EXTARO 300). Each group received an introductory session on their device. Loupes had fixed magnification (3.5×, 40 cm working distance), while microscopes allowed adjustable magnification; interpupillary distance and viewing angle were adjusted for ergonomic posture.\u003c/p\u003e\n\u003cp\u003eThe task was preparation of a right maxillary central incisor for an unveneered lithium disilicate crown and fabrication of a provisional restoration (Luxatemp Auto Plus, DMG) within 150 minutes. Preparation followed preclinical standards, with workflow and remaining time displayed on a screen. Models, provisional restorations, and silicone keys were collected, and teeth were scanned (Primescan, Dentsply Sirona).\u003c/p\u003e\n\u003cp\u003eEvaluation was analog and digital. Analog assessment used a dental model and periodontal probe (PA probe/UNC15, HuFriedy Group) by three raters (student, dentist, senior consultant) under natural light, based on preclinical scoring sheets (Tables 1 and 2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable\u0026nbsp;2\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAnother analogue evaluation criteria for the provisional restoration, again based on preclinical criteria.\u003c/p\u003e\n\u003cp\u003eDigital assessment compared scans to a master model using prepCheck software, generating color-coded deviation maps for scoring. Scores (0–3) were identical for both methods; provisional restorations were assessed only conventionally. Five assessments were performed: analog provisional, analog preparation, digital preparation, combined preparation, and overall assessment.\u003c/p\u003e\n\u003cp\u003eTo perform statistical analyses, SPSS 28.0 (IBM) and the online tool DataTab (DATAtab e.U.) was used. Statistical significance was set as p \u0026lt; 0.05 probability level. Inter-rater agreement was evaluated using the intraclass correlation coefficient (ICC), and Bland-Altman plots assessed method agreement. Differences between semesters and magnification aids were analyzed using Generalized Estimating Equations (GEE), accounting for rater clustering.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cp\u003eThe results of this study indicate that the use of magnification aids generally improved evaluation outcomes, with variations depending on semester and assessment method. Ninth-semester students consistently achieved higher scores than those in the fifth semester. The three evaluators (student, dentist, senior consultant) showed differing assessment tendencies, with the greatest variability observed in digital preparation evaluations. Correlations between age, working hours, and outcomes were mostly nonsignificant, and gender had no effect.\u003c/p\u003e\n\u003cp\u003eAnalysis of average percentage scores relative to maximum achievable points revealed distinct performance patterns depending on the magnification aid (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Across both semesters, students using the OPMI achieved the highest mean scores in preparation assessments\u0026mdash;74.68% in conventional and 69.13% in digital evaluations\u0026mdash;followed by the DL group (70.08% and 64.68%, respectively). The SG group consistently showed the lowest results (68.02% conventional, 60.00% digital). Similar trends were found in overall evaluations, where DL users reached the highest mean score (65.63%), followed by OPMI (63.32%) and SG (59.64%). In the evaluation of provisional restorations, ninth-semester students using DL achieved the best results (\u0026asymp;\u0026thinsp;60%), while fifth-semester students with OPMI scored lowest (36.54%).\u003c/p\u003e\n\u003cp\u003eComparing semesters, fifth-semester students performed best with OPMI, particularly in preparation and overall evaluations, whereas ninth-semester students using DL slightly outperformed the OPMI group in digital and combined assessments. Across all measures, SG use was associated with the lowest performance (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). Overall, both OPMI and DL contributed to superior results, while reliance on SG limited performance.\u003c/p\u003e\n\u003cp\u003eIn the fifth semester, OPMI users achieved the highest conventional (75.9%) and digital (72.4%) preparation scores, resulting in a combined mean of 65.0% (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eIn contrast, DL users led in the ninth semester with 73.9% (conventional) and 72.8% (digital), corresponding to a combined mean of 69.7% (Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eWhen all data were pooled, the DL group achieved the highest preparation averages (70.9% conventional; 64.6% digital; 72.2% combined) and the best overall results (65.6%), followed by OPMI (63.3%), while SG consistently ranked lowest (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003eInterrater reliability analysis using the Intraclass Correlation Coefficient (ICC) showed the highest agreement for conventional preparation (ICC\u0026thinsp;=\u0026thinsp;0.827), followed by provisional restoration (ICC\u0026thinsp;=\u0026thinsp;0.779) and overall evaluation (ICC\u0026thinsp;=\u0026thinsp;0.771). The lowest reliability occurred in the digital preparation evaluation (ICC\u0026thinsp;=\u0026thinsp;0.615), indicating greater variability among evaluators. All ICC values were statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\n\u003cp\u003eDue to the clustered data structure (three evaluations per work), Generalized Estimating Equations (GEE) were applied to account for within-cluster correlations. The GEE analysis revealed significant differences between magnification aids. In the fifth semester, the OPMI group performed significantly better than the SG group in conventional (p\u0026thinsp;=\u0026thinsp;0.006), digital (p\u0026thinsp;=\u0026thinsp;0.028), and combined preparation assessments (p\u0026thinsp;=\u0026thinsp;0.003). Additionally, the DL and OPMI groups differed significantly in digital preparation (p\u0026thinsp;=\u0026thinsp;0.004). In the ninth semester, significant differences were found between SG and DL in digital (p\u0026thinsp;=\u0026thinsp;0.015) and combined (p\u0026thinsp;=\u0026thinsp;0.040) preparation. Across all semesters, a significant difference was observed between SG and OPMI in digital preparation (p\u0026thinsp;=\u0026thinsp;0.018). No significant differences emerged between semesters when comparing overall performance (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\n\u003cp\u003eIn summary, OPMI and DL use were associated with superior performance in both preparation and overall assessments, while SG resulted in consistently lower outcomes. Interrater agreement was highest in conventional and provisional restoration evaluations, and lowest for digital assessments (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\n"},{"header":"4. Discussion","content":"\u003cp\u003eThe present pilot study aimed to evaluate the impact of magnification devices on preparation quality and working techniques of dental students. The null hypothesis that OPMI achieved significantly better results than DL had to be rejected. Both OPMI and DL led to better performance compared with SG. Ninth-semester students achieved superior results, likely due to greater manual skill and prior experience with DL. The general performance improvement observed with magnification devices aligns with earlier findings (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e). Studies have shown that DL enhances psychomotor skills, reduces task time, and improves performance quality, although some reported no statistically significant differences between groups (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e) (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn line with prior work, preclinical students in the present study showed a pronounced learning curve with OPMI, possibly due to higher motivation and novelty of the technique. Clinical students performed better overall, likely owing to existing practical skills. Thus, magnification aids improved performance in general, though not with statistically significant skill progression, and no clear preference emerged between OPMI and DL. No correlation between working time, age, and preparation results was observed.\u003c/p\u003e\u003cp\u003eBoth digital and analogue evaluations were applied, assessed by three raters with different experience levels. High interrater consistency was found, and no significant differences between digital and conventional assessments were detected. Hence, neither evaluation method proved superior. Previous studies have shown that conventional assessments can be subjective and inconsistent (\u003cspan additionalcitationids=\"CR27 CR28\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e), potentially undermining student confidence (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e). Digital systems, by contrast, tend to offer more objective and reproducible feedback (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan additionalcitationids=\"CR33 CR34 CR35 CR36\" citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e). However, some authors noted that purely digital systems may not validly assess all aspects of students\u0026rsquo; work (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e). Integrating digital and traditional feedback is therefore recommended to balance objectivity and pedagogical value (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan additionalcitationids=\"CR39 CR40 CR41 CR42\" citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eTraditional feedback tools such as checklists or visual diagrams can be subjective (\u003cspan additionalcitationids=\"CR45\" citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e). Previous studies reported low interrater agreement among faculty (\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e), whereas the present study achieved an ICC\u0026thinsp;\u0026gt;\u0026thinsp;0.827, indicating excellent reliability. Literature also shows that students often overestimate their own performance compared to teachers (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e). Including student self-evaluation and repeated blinded assessments in future research could provide valuable insights.\u003c/p\u003e\u003cp\u003eDigital assessment tools like prepCheck reduce subjectivity by comparing student preparations with calibrated master models, offering visualized deviations within defined tolerance levels (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e). Such systems can be adapted to training level and allow longitudinal performance tracking, enhancing feedback quality (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e). Despite their advantages, implementation requires financial investment and sufficient training time for both staff and students (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e). Once integrated, these systems can improve motivation, learning outcomes, and teaching efficiency (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eMagnification devices also contribute to ergonomic improvement. The use of OPMI has been shown to enhance head and neck posture by 50% and shoulder posture by 23.6% (p\u0026thinsp;\u0026lt;\u0026thinsp;.0001), whereas DL resulted in smaller improvements of 11.9% and 5.9%, respectively (p\u0026thinsp;=\u0026thinsp;.0012; p\u0026thinsp;=\u0026thinsp;.0413) (\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e). Several studies confirm that magnification supports ergonomic posture development, particularly in inexperienced students (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan additionalcitationids=\"CR52 CR53 CR54 CR55 CR56\" citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e57\u003c/span\u003e). Since posture parameters were not assessed in the present study, future research should address this aspect more comprehensively.\u003c/p\u003e\u003cp\u003eFuture investigations should further analyze the learning curve and systematically rotate students among magnification devices. Repeated testing at regular intervals with larger, more heterogeneous cohorts (regarding experience, gender, and age) would allow robust conclusions. Expanding the number of raters per experience level and maintaining both digital and analogue evaluation methods are recommended to strengthen reliability and comparability.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eThe present study was the first one to examine the use of different magnification devices on students performing a preparation and a provisional restoration. The use of visual magnification aids (OPMI and DL) can significantly enhance the quality of dental preparation and restoration procedures in dental education. While both tools proved superior to SG, their effectiveness varied depending on the students' clinical experience and familiarity with the device. Dental microscopes were particularly advantageous for preclinical students whereas magnifying loupes yielded better results among clinical students.\u003c/p\u003e\u003cp\u003eThe findings underscore the importance of structured training and adequate familiarization to optimize the benefits of magnification tools. Moreover, the combination of conventional and digital assessment methods provided the most consistent evaluation outcomes, emphasizing the need for standardized, objective grading systems. Integrating optical aids into dental curricula from the preclinical stage appears to be a valuable strategy for improving practical skills and fostering ergonomic working habits. Future longitudinal research with larger cohorts and expanded ergonomic parameters is needed to better understand the long-term impact of magnification devices on learning success, clinical performance, and student health.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eDL: Dental loupes\u003c/p\u003e\n\u003cp\u003eOPMI: dental operating microscope\u003c/p\u003e\n\u003cp\u003eSG: protective glasses\u003c/p\u003e\n\u003cp\u003eCAD/CAM: computer-aided design / computer-aided manufacturing\u003c/p\u003e\n\u003cp\u003eGEE: Generalized Estimating Equations\u003c/p\u003e\n\u003cp\u003eICC: Intraclass Correlation Coefficient\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe present clinical study was approved by the Ethics Committee of the Charit\u0026eacute;-Universit\u0026auml;tsmedizin Berlin in 2020 (application number: EA1/250/23). Since then, it is being conducted in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eInformed consent was obtained from all of the participants.\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 used and/or analysed 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 work was supported by\u0026nbsp;Carl Zeiss Meditec AG, Jena, Germany.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026acute; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eElisabeth Prause: conceptualization, organization of the study, writing of the manuscript, approved the submitted version of the manuscript\u003c/p\u003e\n\u003cp\u003eJonas Rechlin: methodology, organization of the study, statistical evaluation, approved the submitted version of the manuscript\u003c/p\u003e\n\u003cp\u003eSimon Peroz: methodology, organization of the study, evaluation, approved the submitted version of the manuscript\u003c/p\u003e\n\u003cp\u003eAnna Steinke: methodology, organization of the study, evaluation, approved the submitted version of the manuscript\u003c/p\u003e\n\u003cp\u003eManja von Stein-Lausnitz: supervision, administration, evaluation, approved the submitted version of the manuscript\u003c/p\u003e\n\u003cp\u003eFlorian Beuer: supervision, project administration, review of the manuscript, approved the submitted version of the manuscript\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRamesh A, Junxi Guo A, Patel HJ, Huang J, Huang CC, de Mello-Neto JM, et al. 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[Effects of loupes and microscope on laminate veneer preparation]. Beijing Da Xue Xue Bao Yi Xue Ban. 2019;51(1):100\u0026ndash;4.\u003c/li\u003e\n\u003cli\u003eSchepke U, van Wulfften Palthe ME, Meisberger EW, Kerdijk W, Cune MS, Blok B. Digital assessment of a retentive full crown preparation-An evaluation of prepCheck in an undergraduate pre-clinical teaching environment. Eur J Dent Educ. 2020;24(3):407\u0026ndash;24.\u003c/li\u003e\n\u003cli\u003eRenne WG, McGill ST, Mennito AS, Wolf BJ, Marlow NM, Shaftman S, et al. E4D compare software: an alternative to faculty grading in dental education. J Dent Educ. 2013;77(2):168\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eSatterthwaite JD, Grey NJ. Peer-group assessment of pre-clinical operative skills in restorative dentistry and comparison with experienced assessors. Eur J Dent Educ. 2008;12(2):99\u0026ndash;102.\u003c/li\u003e\n\u003cli\u003eSharaf AA, AbdelAziz AM, El Meligy OA. Intra- and inter-examiner variability in evaluating preclinical pediatric dentistry operative procedures. J Dent Educ. 2007;71(4):540\u0026ndash;4.\u003c/li\u003e\n\u003cli\u003eHenzi D, Davis E, Jasinevicius R, Hendricson W. North American dental students\u0026apos; perspectives about their clinical education. J Dent Educ. 2006;70(4):361\u0026ndash;77.\u003c/li\u003e\n\u003cli\u003eHenzi D, Davis E, Jasinevicius R, Hendricson W. In the students\u0026apos; own words: what are the strengths and weaknesses of the dental school curriculum? J Dent Educ. 2007;71(5):632\u0026ndash;45.\u003c/li\u003e\n\u003cli\u003eTaylor CL, Grey NJ, Satterthwaite JD. A comparison of grades awarded by peer assessment, faculty and a digital scanning device in a pre-clinical operative skills course. Eur J Dent Educ. 2013;17(1):e16\u0026ndash;21.\u003c/li\u003e\n\u003cli\u003eKateeb ET, Kamal MS, Kadamani AM, Abu Hantash RO, Abu Arqoub MM. Utilising an innovative digital software to grade pre-clinical crown preparation exercise. Eur J Dent Educ. 2017;21(4):220\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eLenherr P, Marinello CP. [prepCheck computer-supported objective evaluation of students preparation in preclinical simulation laboratory]. Swiss Dent J. 2014;124(10):1085\u0026ndash;92.\u003c/li\u003e\n\u003cli\u003eEsser C, Kerschbaum T, Winkelmann V, Krage T, Faber FJ. A comparison of the visual and technical assessment of preparations made by dental students. Eur J Dent Educ. 2006;10(3):157\u0026ndash;61.\u003c/li\u003e\n\u003cli\u003eCardoso JA, Barbosa C, Fernandes S, Silva CL, Pinho A. Reducing subjectivity in the evaluation of pre-clinical dental preparations for fixed prosthodontics using the Kavo PrepAssistant. Eur J Dent Educ. 2006;10(3):149\u0026ndash;56.\u003c/li\u003e\n\u003cli\u003eKournetas N, Jaeger B, Axmann D, Groten M, Lachmann S, Weber H, et al. Assessing the reliability of a digital preparation assistant system used in dental education. J Dent Educ. 2004;68(12):1228\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eKwon SR, Restrepo-Kennedy N, Dawson DV, Hernandez M, Denehy G, Blanchette D, et al. Dental anatomy grading: comparison between conventional visual and a novel digital assessment technique. J Dent Educ. 2014;78(12):1655\u0026ndash;62.\u003c/li\u003e\n\u003cli\u003eHamil LM, Mennito AS, Renn\u0026eacute; WG, Vuthiganon J. Dental students\u0026apos; opinions of preparation assessment with E4D compare software versus traditional methods. J Dent Educ. 2014;78(10):1424\u0026ndash;31.\u003c/li\u003e\n\u003cli\u003eCho GC, Chee WW, Tan DT. Dental students\u0026apos; ability to evaluate themselves in fixed prosthodontics. J Dent Educ. 2010;74(11):1237\u0026ndash;42.\u003c/li\u003e\n\u003cli\u003eKwon SR, Hern\u0026aacute;ndez M, Blanchette DR, Lam MT, Gratton DG, Aquilino SA. Effect of Computer-Assisted Learning on Students\u0026apos; Dental Anatomy Waxing Performance. J Dent Educ. 2015;79(9):1093\u0026ndash;100.\u003c/li\u003e\n\u003cli\u003eBrowning WD, Reifeis P, Willis L, Kirkup ML. Including CAD/CAM dentistry in a dental school curriculum. J Indiana Dent Assoc. 2013;92(4):40\u0026ndash;5, 7.\u003c/li\u003e\n\u003cli\u003eWelk A, Splieth C, Wierinck E, Gilpatrick RO, Meyer G. Computer-assisted learning and simulation systems in dentistry--a challenge to society. Int J Comput Dent. 2006;9(3):253\u0026ndash;65.\u003c/li\u003e\n\u003cli\u003eGuenzel PJ, Knight GW, Feil PH. Designing preclinical instruction of psychomotor skills (IV)--Instructional engineering: evaluation phase. J Dent Educ. 1995;59(4):489\u0026ndash;94.\u003c/li\u003e\n\u003cli\u003eJorquera G, S\u0026aacute;nchez JP, Sampaio CS, Atria P, Fern\u0026aacute;ndez E. Improvement preclinical and clinical skills for dental preparations using assisted training software. Eur J Dent Educ. 2021;25(4):856\u0026ndash;63.\u003c/li\u003e\n\u003cli\u003eGratton DG, Kwon SR, Blanchette D, Aquilino SA. Impact of Digital Tooth Preparation Evaluation Technology on Preclinical Dental Students\u0026apos; Technical and Self-Evaluation Skills. J Dent Educ. 2016;80(1):91\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eSan Diego JP, Newton T, Quinn BF, Cox MJ, Woolford MJ. Levels of agreement between student and staff assessments of clinical skills in performing cavity preparation in artificial teeth. Eur J Dent Educ. 2014;18(1):58\u0026ndash;64.\u003c/li\u003e\n\u003cli\u003eFuller JL. The effects of training and criterion models on interjudge reliability. J Dent Educ. 1972;36(4):19\u0026ndash;22.\u003c/li\u003e\n\u003cli\u003ePark CF, Sheinbaum JM, Tamada Y, Chandiramani R, Lian L, Lee C, et al. Dental Students\u0026apos; Perceptions of Digital Assessment Software for Preclinical Tooth Preparation Exercises. J Dent Educ. 2017;81(5):597\u0026ndash;603.\u003c/li\u003e\n\u003cli\u003eBud M, Pricope R, Pop RC, Onaca R, Swerts PJ, Lucaciu O, et al. Comparative analysis of preclinical dental students\u0026apos; working postures using dental loupes and dental operating microscope. Eur J Dent Educ. 2021;25(3):516\u0026ndash;23.\u003c/li\u003e\n\u003cli\u003eCongdon LM, Tolle SL, Darby M. Magnification loupes in U.S. entry-level dental hygiene programs--occupational health and safety. J Dent Hyg. 2012;86(3):215\u0026ndash;22.\u003c/li\u003e\n\u003cli\u003eFarook SA, Stokes RJ, Davis AK, Sneddon K, Collyer J. Use of dental loupes among dental trainers and trainees in the UK. J Investig Clin Dent. 2013;4(2):120\u0026ndash;3.\u003c/li\u003e\n\u003cli\u003eWajngarten D, Garcia P. Effect of magnification devices on dental students\u0026apos; visual acuity. PLoS One. 2019;14(3):e0212793.\u003c/li\u003e\n\u003cli\u003eDable RA, Wasnik PB, Yeshwante BJ, Musani SI, Patil AK, Nagmode SN. Postural Assessment of Students Evaluating the Need of Ergonomic Seat and Magnification in Dentistry. J Indian Prosthodont Soc. 2014;14(Suppl 1):51\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eEichenberger M, Perrin P, Ramseyer ST, Lussi A. Visual Acuity and Experience with Magnification Devices in Swiss Dental Practices. Oper Dent. 2015;40(4):E142\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eHayes MJ, Taylor JA, Smith DR. Introducing loupes to clinical practice: dental hygienists experiences and opinions. Int J Dent Hyg. 2016;14(3):226\u0026ndash;30.\u003c/li\u003e\n\u003cli\u003eFriedman MJ. Magnification in a restorative dental practice: from loupes to microscopes. Compendium of Continuing Education in Dentistry (Jamesburg, NJ: 1995). 2004;25(1):48, 50, 3\u0026ndash;5.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"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":"magnification, education, dentistry, dental loupes, dental operating microscope, restorative dentistry","lastPublishedDoi":"10.21203/rs.3.rs-8167599/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8167599/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eThe integration of magnification devices into dental education is widely recommended, yet evidence regarding their impact on student performance remains limited. This study evaluated the effect of dental loupes (DL) and dental operating microscopes (OPMI) on the quality of crown preparation and provisional restoration among preclinical and clinical dental students compared with standard protective glasses (SG).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eSixty dental students participated: 30 preclinical (fifth semester) and 30 clinical (ninth semester). Participants were randomly assigned to three groups: DL (ZEISS EyeMag Pro S 3.5\u0026times;400), OPMI (ZEISS EXTARO 300), or SG (control). Each prepared a crown and a provisional restoration. Outcomes were assessed conventionally (expert ratings) and digitally (objective parameters). Performance differences were analyzed using generalized estimating equations (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eOptical magnification significantly improved restorative performance compared with SG. Preclinical students using OPMI achieved the highest overall scores, while clinical students performed best with DL. GEE confirmed significant differences between OPMI and SG, but not between preclinical and clinical groups.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eOptical magnification improved restorative outcomes compared with standard glasses. OPMI use was most beneficial in preclinical training, whereas DL appeared more advantageous in clinical settings. Integrating optical magnification into dental education enhances skill acquisition and clinical quality. OPMI supports precision and fine motor skills in preclinical training, while DL offers visual improvement with greater ergonomics and workflow flexibility in clinical practice. Tailoring magnification strategies to the training stage may optimize educational and clinical performance.\u003c/p\u003e","manuscriptTitle":"Do we need microscopes for restorative treatment procedures? 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