Novel Digitally Customized Horizontal Torque Extension for Mechanical Evaluation of Implant Abutment Screw

Novel Digitally Customized Horizontal Torque Extension for Mechanical Evaluation of Implant Abutment Screw | 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 Article Novel Digitally Customized Horizontal Torque Extension for Mechanical Evaluation of Implant Abutment Screw Mai Ahmed Yousry El-Sheikh, Sara Reda Sammour, Bassem Nabil Elfahl, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9026603/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 10 You are reading this latest preprint version Abstract Statement of the Problem : Conventional vertical torque devices are difficult to use intraorally, especially in posterior regions, limiting accurate chairside assessment of implant abutment screw stability and underscoring the need for an intraoral-compatible torque measurement approach without loss of accuracy. Purpose : This study aimed to develop and validate a customized horizontal torque arm intended to enable intraoral mechanical evaluation of abutment screw loosening, and to compare its performance with the original vertical torque device under laboratory conditions. Materials and Methods : A horizontal torque extension was designed using computer-aided design and fabricated from medical-grade stainless steel (316L) by 5-axis CNC milling. The device incorporated proximal and distal hexagonal interfaces to connect a digital torque gauge and a standard implant screwdriver, enabling torque transmission at a 90° orientation. Titanium implant–abutment assemblies (n = 17) were embedded in acrylic resin blocks, and abutment screws were tightened to 20 Ncm, and subjected to removal torque testing using both vertical (original) and horizontal (customized) configurations. The percentage of removal torque loss (%RTL) was calculated. Statistical analysis was performed using software released in 2020; data normality was assessed with the Shapiro–Wilk test, and normally distributed variables were compared using the student’s t-test with a significance level of 0.05. Results : The vertical (original) device demonstrated a mean simulated removal torque loss (18.62 ± 1.29%), while the customized horizontal arm showed a mean value (17.85 ± 1.45%); the difference was not statistically significant (p = 0.114), indicating comparable removal torque measurements between the two methods. Conclusions : The customized horizontal torque arm showed accuracy comparable to the conventional vertical device and enables direct intraoral assessment of screw stability, particularly in posterior regions, making it a practical tool for both clinical and laboratory implant–abutment evaluation. Clinical Implications The customized horizontal torque extension allows accurate intraoral evaluation of abutment screw stability in a clinically realistic orientation, particularly in posterior regions with limited access. Its comparable accuracy to conventional vertical devices supports its use for early detection of preload loss and screw loosening. This may help prevent mechanical complications and improve long-term maintenance of implant-supported restorations. Physical sciences/Engineering Health sciences/Health care Health sciences/Medical research Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 INTRODUCTION Implant therapy requires careful integration of biological, mechanical, and aesthetic considerations, with long-term success largely dependent on the ability of implants and their components to withstand functional loading. Although dental implants are generally reliable, most complications are mechanical in nature, commonly including screw loosening or fracture, micromovements, microgap formation, and fractures of the abutment, fixture, or superstructure. 1 Implant systems are designed with a mechanical weak link typically the abutment screw intended to fail under excessive load to protect the implant and surrounding tissues. Among mechanical complications of implant-supported restorations, abutment screw loosening is one of the most frequently reported, with incidences up to 12.7% in single crowns and 6.7% in fixed partial dentures. Screw loosening may promote granulation tissue formation at the implant–abutment interface, increasing the risk of fistulae and soft tissue inflammation. Therefore, maintaining adequate tightening and long-term screw stability is critical for the longevity of implant-supported prostheses. 2 Screws play a critical role in implant systems by connecting the abutment to the implant and securing the prosthesis through the generation of preload, the clamping force produced during tightening that stabilizes the joint against occlusal and lateral forces. Preload arises from elastic screw elongation but may be reduced by improper torque application, frictional losses, bending forces, and embedment relaxation. Embedment relaxation, caused by the settling of microscopic surface irregularities at the screw–abutment interface shortly after tightening, can reduce preload by approximately 2–10%, thereby increasing the risk of screw loosening. When joint-separating forces exceed the remaining clamping force, loosening occurs, underscoring the importance of applying the manufacturer-recommended torque to maintain the screw within its elastic range and ensure long-term prosthetic stability. 3 – 5 Assessing screw stability intra-orally is clinically advantageous because it reflects the actual performance of the implant–abutment screw joint under functional conditions, incorporating patient-specific factors such as dynamic occlusal loading, parafunctional activity, saliva, and thermal fluctuations that cannot be fully reproduced in laboratory settings. Intra-oral evaluation facilitates early detection of preload loss and screw loosening, enabling timely intervention and reducing the risk of mechanical failure and biological complications. 6 In contrast, in vitro methods including static torque testing, cyclic loading, reverse torque value measurements, screw elongation analysis, strain-gauge–based preload assessment, mechanical protractors, resonance frequency analysis, predictive analytical models, microleakage testing, and removal torque evaluation provide standardized and controlled conditions that are valuable for comparing implant designs, materials, and connection geometries but lack the complexity of the oral environment and may not reliably predict clinical outcomes. Removal torque measurement provides a highly accurate and direct assessment of the residual preload within the implant–abutment connection. Nevertheless, its application is predominantly restricted to laboratory conditions or requires removal of the prosthetic restoration, which limits its practicality for routine intra-oral clinical evaluation. 7 – 14 Digital torque gauges are widely used to measure the torque applied to abutment and prosthetic screws, providing objective and precise quantification of preload. These devices are highly reliable in laboratory settings and allow clinicians or researchers to ensure that screws are tightened to the manufacturer’s recommended torque values. Torque gauges can also measure detorque or removal torque, which reflects the remaining preload in the screw joint and serves as a direct indicator of screw stability. Despite their accuracy, conventional torque gauges are typically designed for vertical use and are often too bulky for intraoral application, especially in posterior regions, limiting their utility in routine clinical practice. 15 – 17 Although reverse-torque testing is not routinely performed during recall visits, certain clinical situations—such as recurrent screw loosening or uncertainty regarding abutment seating— may benefit from objective stability assessment. However, most torque-measuring devices are designed for extraoral use and do not account for the restricted access and angulation challenges of the oral cavity, limiting their clinical relevance. 18 , 19 To address this limitation, a customized horizontal torque arm was developed to adapt a digital torque gauge for intraoral orientation and enable a more clinically representative evaluation of screw loosening. Its performance was assessed under laboratory conditions and compared with that of a conventional vertical torque gauge. Unlike contra-angle torque drivers, which use internal gears that cause friction and reduce accuracy, the customized device uses a rigid, non-geared torque arm directly connected to the digital gauge. This design minimizes mechanical loss and allows more accurate torque measurement. 20 The null hypothesis of this study was that there would be no significant difference in removal-torque measurements between the standard vertical torque gauge and the customized horizontal torque arm. MATERIAL AND METHODS Sample size was determined using power analysis (G*Power v3.1.9.6; Heinrich Heine University Düsseldorf, Germany). Based on an effect size of *f* = 0.65, α = 0.05, and 95% power, 34 samples were required and equally allocated to the vertical and horizontal groups (n = 17 each). The manufacturer-supplied standard ratchet (Schütz Impla Dental Group) served as the reference device. It is a hand-held mechanical torque applicator with an internal hexagonal interface and an integrated locking mechanism for screwdriver engagement, providing visual calibration markings but no digital torque-recording capability (Fig. 1 ). The customized horizontal torque extension was designed as a rigid, single-piece component with a proximal hexagonal drive for connection to a digital torque gauge hexed socket and a distal end for engaging the implant screwdriver. The distal head had a smoothly rounded external profile to enhance intraoral access and used a friction-retained interface with a laterally positioned flattened steel-ball locking mechanism to ensure secure retention and prevent disengagement during torque application. A solid internal shaft connected the proximal and distal interfaces, enabling efficient torque transmission with minimal backlash at a 90° orientation while maintaining coaxial alignment and mechanical stability. During operation, torque from the digital gauge was transmitted through the internal shaft as a predominantly pure torsional load. Hexagonal engagement and coaxial alignment minimized mechanical losses and off-axis forces, ensuring that the torque recorded by the gauge closely matched the torque delivered to the implant screw in a horizontal orientation. A 2D engineering drawing was created for design planning (Fig. 2 ), and digital modeling was performed using a dental CAD platform (Exocad GmbH). The extension featured a distal head with a 6.35-mm opening and an internal flattened steel-ball locking mechanism for secure screwdriver retention, a shaft (65.1 mm length, 6.4 mm diameter) optimized for strength and intraoral access, and a proximal 11.0-mm hexagonal drive to ensure stable engagement with the digital torque gauge. During the CAD process, parametric modeling tools (extrude, revolve, cut, and fillet operations) were applied to control geometry and alignment. Concentricity between the proximal and distal interfaces was verified by digital assembly simulation, and tolerances of ± 0.05 mm were specified for all critical engagement areas. A medical-grade surface finish (Ra 0.8–1.6 µm) was targeted to reduce interfacial wear and enhance biocompatibility. The final design was exported in both STEP and STL formats for milling (Fig. 3 ). The extension was manufactured from medical-grade stainless steel 316L using a 5-axis CNC milling machine, selected for its corrosion resistance, biocompatibility, and torsional stability. Controlled roughing and finishing passes with regulated coolant flow were used to maintain dimensional accuracy, particularly at the hexagonal interfaces and internal locking region. After milling, the device was polished with progressively finer abrasives to achieve a clinical-grade surface finish (Ra 0.8–1.6 µm). Dimensional accuracy was verified using a digital caliper and a coordinate measuring machine (CMM), with emphasis on the proximal hexagonal interface designed to engage the digital torque gauge. Comparative testing against the original torque gauge driver confirmed precise seating, angular stability, and secure locking without perceptible play (Fig. 4 a&b). The distal head was also evaluated and demonstrated stable adaptation to the screwdriver shaft, replicating the manufacturer’s ratchet locking mechanism via an internal ball-locking system (Fig. 5 ). The customized horizontal extension precisely replicated the original ratchet’s dimensions and geometry, ensuring accurate engagement and identical handling during torque application (Fig. 6 ). Verification confirmed mechanical compatibility and functional equivalence of the customized horizontal extension with the digital torque gauge and screwdriver, replicating the geometry and handling of the original ratchet (Fig. 7 ). To evaluate the accuracy of the customized horizontal extension, removal torque values obtained with the horizontal configuration were compared to those obtained with the original vertical configuration of the digital torque gauge. A standardized experimental setup was developed to ensure reproducibility and to minimize confounding variables. Commercially available titanium implants (4.2 × 9.5 mm; Schütz Dental GmbH, Dieselstr.5-6.61191) were used for all tests. To standardize specimen positioning, a custom two-part metallic mold was fabricated. The mold consisted of a circular stainless-steel base (thickness: 2 mm) with a central access hole aligned with the screw channel of the cylindrical housing. This design allowed precise placement of the implant fixture while preventing resin overflow into the internal channel during polymerization. The cylindrical housing was inserted into the base to create a mold cavity for embedding (Fig. 8 ). Autopolymerizing acrylic resin (Orthoplast, Vertex-Dental) was prepared according to the manufacturer’s instructions and injected into the mold using a syringe. Implants were positioned perpendicular to the base using the implant mount to ensure axial alignment (Fig. 9 ). After polymerization, the acrylic blocks were removed, finished, and polished to obtain smooth, uniform surfaces, with the 2-mm base thickness maintaining the implants in a standardized 2-mm supracrestal position. A custom cylindrical holder with a central seating hole was used to stabilize specimens during torque testing and prevent rotational displacement; the holder was securely fixed to the testing table, and each specimen was further secured with four radial screws. Straight titanium abutments were connected to the implants using titanium abutment screws, which were tightened to 20 Ncm with a vertically oriented digital torque gauge (HTG2-200Nc, IMADA). After a 10-minute interval to allow for settling, the screws were retightened to 20 Ncm to compensate for preload loss. Removal torque was measured to determine preload loss, which was then used to compare the performance of the device in two configurations: the manufacturer’s standard vertical setup and a customized horizontal configuration. (Fig. 10 a& b). In the vertical setup, the digital torque gauge was connected directly to the implant screwdriver, allowing straightforward measurement along the implant’s long axis. In the horizontal setup, the torque gauge was attached via a customized horizontal extension, enabling measurement in orientations that better simulate clinical access limitations. To minimize operator variability, all torque applications and removals were performed by a single examiner. Removal torque values were recorded in Newton-centimeters (Ncm), and the percentage of removal torque loss (%RTL) was calculated using the formula: Loss ratio of removal torque before loading (%) = (Tightening torque – Removal torque before loading)/ (Tightening torque) ×100. This formula standardized the measurement of preload loss across both testing configurations. Data were fed to the computer and analyzed using IBM SPSS software package version 27.0. (Armonk, NY: IBM Corp, released in 2020). For continuous data, they were tested for normality by the Shapiro-Wilk test. Quantitative data were expressed as range (minimum and maximum), mean, standard deviation and median Student t-test was used to compare two groups for normally distributed quantitative variables. Significance of the obtained results was judged at the 5% level. RESULTS The vertical (original device) group demonstrated a slightly higher mean simulated removal torque loss (%RTL) (18.62 ± 1.29) compared with the horizontal group (17.85 ± 1.45). However, this difference was not statistically significant (Student’s t-test, t = 1.625, p = 0.114). The mean difference between the two groups was 0.77 ± 0.47, with a 95% confidence interval ranging from − 0.19 to 1.72, indicating comparable removal torque loss between the vertical and horizontal torque application methods. (Table 1 ). These results indicate that the customized horizontal arm provides removal torque measurements comparable to those obtained with the original vertical torque device. Table 1 Comparison between vertical and horizontal groups according to simulated removal torque loss (%RTL) Parameter Vertical group (n = 17) Horizontal group (n = 17) t p RTL (%) Mean ± SD 18.62 ± 1.29 17.85 ± 1.45 1.625 0.114 Median (Min. – Max.) 18.50 (16.40–20.80) 18.10 (14.80–20.20) Mean difference ± SE 0.765 ± 0.470 95% CI of the difference -0.194–1.723 RTL = removal torque loss; SD = standard deviation; SE = standard error; CI = confidence interval. Comparisons between groups were performed using the student’s t test. Statistical significance was set at α = 0.05. DISCUSSION At the outset of this study, the null hypothesis stated that there would be no significant difference in removal torque loss (%RTL) between the vertical (original device) and horizontal (customized extension) configurations was accepted. Statistical analysis confirmed this, with no significant difference observed, indicating that the custom-fabricated horizontal torque extension provides removal torque measurements comparable to the standard vertical device. The custom horizontal torque arm was developed by integrating dental prosthetic requirements with principles of mechanical design and precision engineering. The design process involved a stepwise approach, beginning with reverse-engineering the original Schutz Impla ratchet. Key mechanical elements, including the proximal hexagonal drive interface, locking mechanism, and ergonomic handle, were identified to establish a functionally equivalent horizontal system. This approach ensured that the custom extension preserved the engagement behavior and torque transfer characteristics of the original ratchet. In addition, replicating the ratchet head’s internal concavity and incorporating a steel locking ball mechanism provided secure tool retention, which is critical to prevent disengagement during intraoral use. 22 Digital modeling of the horizontal arm using Exocad allowed precise control of geometry, tolerances, and interfaces, enabling virtual fit testing and reducing prototyping errors. Hexagonal interfaces at both ends ensured compatibility with the implant screwdriver and torque gauge, while ± 0.05 mm tolerance and Ra 0.8–1.6 µm surface finish met precision engineering standards. 23 The horizontal arm was CNC-milled from 316L stainless steel for its mechanical strength, corrosion resistance, and biocompatibility. Cooling and lubrication during machining preserved material integrity, while post-milling polishing improved surface smoothness, minimizing bacterial adhesion and enhancing intraoral handling. 24 Verification with coordinate measuring machines (CMMs) confirmed dimensional fidelity of critical areas, such as the hex interface and locking mechanism, ensuring precision consistent with best practices in implant engineering. 25 Abutment screws were tightened to 20 Ncm using a digital torque gauge, following the manufacturer’s recommendations. Achieving the optimal torque is critical for long-term prosthetic stability, as it generates preload—the initial tensile force within the screw that maintains the implant-abutment connection. Ten minutes after initial tightening, all screws were retorqued to compensate for preload loss due to the settling effect, which smooths micro-irregularities on the screw surfaces. Preload must remain below 75–80% of the material’s elastic limit; if forces applied to the system are higher than the preload, screw loosening can occur. 26 The results of this study showed measurable torque loss. This finding is supported by previous studies in conical hybrid implants, which reported early screw loosening due to preload reduction. 2 The initial reduction in removal torque (%RTL) is primarily attributed to the settling effect (embedment relaxation) and screw geometry, which diminish the applied preload even before functional loading. 27 Tightening a prosthetic abutment creates forces at screw head, the implant–abutment interface, and screw threads. Only about 10% of the applied torque is converted into preload, while the remaining torque is lost due to settling. In titanium alloy screws, up to 20% of the initial torque may be lost even before functional loading. 28 In the present study, although torque loss increased before loading in all test groups, no loosening of the screws was detected, indicating that the remaining tightening torque was sufficient to maintain clinical stability. The lack of a significant difference in removal torque loss between the vertical and horizontal configurations can be explained by the rigid design of the horizontal extension. Torque, defined as the product of force and the perpendicular distance from the axis of rotation, is theoretically independent of the orientation of the delivery device, provided the torque vector is aligned with the screw’s rotational axis and energy loss through deformation or misalignment is minimal. In the customized horizontal design, the force applied at the digital torque gauge is transmitted through a rigid, hexagonally interfaced extension with a locking mechanism modeled after the original ratchet, minimizing mechanical play or rotational lag. The use of stainless steel 316L ensures dimensional stability and resistance to torsional deformation, further preserving torque integrity. 29 Previous studies have shown that, when the tool axis is properly aligned with the screw axis and contact surfaces are rigidly engaged, the orientation of the delivery tool horizontal or vertical does not significantly affect torque accuracy. 30 This mechanical principle explains the comparable torque loss observed between the vertical and customized horizontal configurations in this study, confirming that the custom extension successfully preserves the functional behavior of the original device. CONCLUSION Based on the findings of this in vitro study, the customized horizontal torque arm demonstrated removal torque measurements comparable to those obtained with a standard vertical torque gauge. Its horizontal configuration enabled intraoral applicability, including improved access to posterior regions, while allowing accurate assessment of abutment screw stability under clinically representative conditions across different implant systems. Collectively, these findings support the horizontal torque arm as a practical and reliable tool for both experimental evaluation and potential chairside monitoring of implant–abutment mechanical stability. Declarations Competing interests: None Funding: This research received no external funding. Author Contribution M.A.Y.E.-S. and S.R.S. conceived and designed the study. M.A.Y.E.-S. performed the experiments, collected the data, and conducted the statistical analysis. M.A.Y.E.-S. and S.R.S. supervised the experimental procedures. B.N.E. contributed to methodological design and interpretation of the results. A.A.E.-G. and M.M.E.-S. supervised the research and critically revised the manuscript. S.R.S. and M.A.Y.E.-S. wrote the main manuscript text. All authors reviewed and approved the final manuscript. Data Availability The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request. References Heitz-Mayfield LJA. Peri-implant mucositis and peri-implantitis: key features and differences. Br Dent J 2024; 236:791–4. El-Sheikh MAY, Mostafa TMN, El-Sheikh MM. Effect of different angulations and collar lengths of conical hybrid implant abutment on screw loosening after dynamic cyclic loading. Int J Implant Dent 2018; 4:1–10. Siamos G, Winkler S, Boberick KG. Relationship between implant preload and screw loosening on implant-supported prostheses. J Oral Implantol 2002; 28:67–73. Misch CE. 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Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 12 May, 2026 Reviews received at journal 12 May, 2026 Reviewers agreed at journal 21 Apr, 2026 Reviews received at journal 18 Apr, 2026 Reviewers agreed at journal 15 Apr, 2026 Reviewers invited by journal 15 Apr, 2026 Editor invited by journal 08 Apr, 2026 Editor assigned by journal 23 Mar, 2026 Submission checks completed at journal 11 Mar, 2026 First submitted to journal 11 Mar, 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. 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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-9026603","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":626841213,"identity":"5dabea5a-e34e-4933-9446-28bc4de7311b","order_by":0,"name":"Mai Ahmed Yousry El-Sheikh","email":"","orcid":"","institution":"Tanta University","correspondingAuthor":false,"prefix":"","firstName":"Mai","middleName":"Ahmed Yousry","lastName":"El-Sheikh","suffix":""},{"id":626841214,"identity":"07480a7d-12b4-4a36-a4ea-a6e235382281","order_by":1,"name":"Sara Reda Sammour","email":"data:image/png;base64,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","orcid":"","institution":"Tanta University","correspondingAuthor":true,"prefix":"","firstName":"Sara","middleName":"Reda","lastName":"Sammour","suffix":""},{"id":626841215,"identity":"21a69aac-e3e9-40ff-92ef-c6727d0b5dd8","order_by":2,"name":"Bassem Nabil Elfahl","email":"","orcid":"","institution":"Tanta University","correspondingAuthor":false,"prefix":"","firstName":"Bassem","middleName":"Nabil","lastName":"Elfahl","suffix":""},{"id":626841216,"identity":"c7d92783-e966-481e-a5bb-495f86fdd8fa","order_by":3,"name":"Attiah Aly El-Gendy","email":"","orcid":"","institution":"Tanta University","correspondingAuthor":false,"prefix":"","firstName":"Attiah","middleName":"Aly","lastName":"El-Gendy","suffix":""},{"id":626841217,"identity":"5d1b740b-99f0-4e96-abc3-001c0c9107a2","order_by":4,"name":"Mohamed Maamoun El-Sheikh","email":"","orcid":"","institution":"Tanta University","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"Maamoun","lastName":"El-Sheikh","suffix":""}],"badges":[],"createdAt":"2026-03-04 06:39:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9026603/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9026603/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107623321,"identity":"dc80b327-cab0-410e-9bec-d07d4acb0626","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":13785,"visible":true,"origin":"","legend":"\u003cp\u003eManufacturer’s original ratchet showing key components. (a) Hex slot, (b) locking latch, (c) shaft, (d) torque scale.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/ac070852ef041a511ee59453.jpg"},{"id":107707357,"identity":"7f26860c-c4ae-4b45-8237-3d8cc98f19f1","added_by":"auto","created_at":"2026-04-24 09:20:08","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":10336,"visible":true,"origin":"","legend":"\u003cp\u003eTechnical drawing of customized horizontal torque extension illustrating key dimensions and structural components.\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/02bb9be85d8909c208980090.jpg"},{"id":107623323,"identity":"9dea05e7-a6f7-413c-98b4-46cffa74feb3","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":16055,"visible":true,"origin":"","legend":"\u003cp\u003eComputer-aided design (CAD) model of customized horizontal torque extension: (A) overall view, (B) distal opening for screwdriver engagement, and (C) proximal hexagonal interface for digital torque gauge connection\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/7e598b9dec3abe0ea73fc833.jpg"},{"id":107623324,"identity":"595d5a6d-aeb5-435d-a1d2-cc91a8bb2580","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":50154,"visible":true,"origin":"","legend":"\u003cp\u003eA, Proximal hexagonal drive of the customized horizontal torque extension (left) and the original torque gauge driver (right). B, Customized proximal hexagonal drive (left), digital torque gauge hexagonal socket (center), and original torque gauge driver (right).\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/800f773e0f5cb6227244f1f0.jpg"},{"id":107623325,"identity":"55d92495-55b6-45d6-8367-ddc41ae022fa","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24911,"visible":true,"origin":"","legend":"\u003cp\u003ecustomized horizontal torque extension (left) with an internal ball-locking mechanism used for screwdriver engagement in distal head, compared with original ratchet head (right).\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/4f18ba60df8889f0a21c31c2.jpg"},{"id":107705886,"identity":"06ff3dea-3292-4e3e-93ab-36ef62ba0eb7","added_by":"auto","created_at":"2026-04-24 09:15:38","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":13040,"visible":true,"origin":"","legend":"\u003cp\u003eHorizontally customized digital torque arm (left) designed for intraoral application, alongside standard manufacturer’s ratchet (right).\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/af8aefe8a9db0c62ec24b52d.jpg"},{"id":107623327,"identity":"e9c9822b-bbbd-430d-b453-a1266efdcbdf","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":54117,"visible":true,"origin":"","legend":"\u003cp\u003eA, standard vertically oriented digital torque gauge. B, customized horizontal torque extension fully seated within hexagonal receiving socket of digital torque gauge.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/39c6ea6b39dfe8a234980647.jpg"},{"id":107623328,"identity":"c09cf013-411b-4c80-aa97-9515dc44e025","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":23242,"visible":true,"origin":"","legend":"\u003cp\u003eCustom two-part metallic mold consisting of a cylindrical component and a 2-mm-thick stainless-steel base used for standardized implant positioning.\u003c/p\u003e","description":"","filename":"8.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/59c60a44d1738cb5a0ac9e78.jpg"},{"id":107707477,"identity":"e27f044d-d113-4cb8-abfb-0bae525a82f2","added_by":"auto","created_at":"2026-04-24 09:20:25","extension":"jpg","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":38950,"visible":true,"origin":"","legend":"\u003cp\u003eAcrylic block embedding implant fixture, with fixture positioned centrally and perpendicular to the base.\u003c/p\u003e","description":"","filename":"9.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/3d7dd759ac03d54b092a0161.jpg"},{"id":107623330,"identity":"3d6833dc-388f-4568-9782-c1e037878c76","added_by":"auto","created_at":"2026-04-23 10:06:55","extension":"jpg","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":56366,"visible":true,"origin":"","legend":"\u003cp\u003eMeasurement of preload loss using digital torque gauges: (A) vertical configuration with original gauge, and (B) horizontal configuration with customized extension.\u003c/p\u003e","description":"","filename":"10.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/1672c74b838faab48592ba0a.jpg"},{"id":107709435,"identity":"2348e36a-3341-45ae-aa8b-576225f9c3aa","added_by":"auto","created_at":"2026-04-24 09:35:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":505065,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9026603/v1/b6b688c7-2e3f-4ea5-82e1-f838584e25e5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eNovel Digitally Customized Horizontal Torque Extension for Mechanical Evaluation of Implant Abutment Screw\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eImplant therapy requires careful integration of biological, mechanical, and aesthetic considerations, with long-term success largely dependent on the ability of implants and their components to withstand functional loading. Although dental implants are generally reliable, most complications are mechanical in nature, commonly including screw loosening or fracture, micromovements, microgap formation, and fractures of the abutment, fixture, or superstructure.\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eImplant systems are designed with a mechanical weak link typically the abutment screw intended to fail under excessive load to protect the implant and surrounding tissues. Among mechanical complications of implant-supported restorations, abutment screw loosening is one of the most frequently reported, with incidences up to 12.7% in single crowns and 6.7% in fixed partial dentures. Screw loosening may promote granulation tissue formation at the implant\u0026ndash;abutment interface, increasing the risk of fistulae and soft tissue inflammation. Therefore, maintaining adequate tightening and long-term screw stability is critical for the longevity of implant-supported prostheses.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eScrews play a critical role in implant systems by connecting the abutment to the implant and securing the prosthesis through the generation of preload, the clamping force produced during tightening that stabilizes the joint against occlusal and lateral forces. Preload arises from elastic screw elongation but may be reduced by improper torque application, frictional losses, bending forces, and embedment relaxation. Embedment relaxation, caused by the settling of microscopic surface irregularities at the screw\u0026ndash;abutment interface shortly after tightening, can reduce preload by approximately 2\u0026ndash;10%, thereby increasing the risk of screw loosening. When joint-separating forces exceed the remaining clamping force, loosening occurs, underscoring the importance of applying the manufacturer-recommended torque to maintain the screw within its elastic range and ensure long-term prosthetic stability.\u003csup\u003e\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eAssessing screw stability intra-orally is clinically advantageous because it reflects the actual performance of the implant\u0026ndash;abutment screw joint under functional conditions, incorporating patient-specific factors such as dynamic occlusal loading, parafunctional activity, saliva, and thermal fluctuations that cannot be fully reproduced in laboratory settings. Intra-oral evaluation facilitates early detection of preload loss and screw loosening, enabling timely intervention and reducing the risk of mechanical failure and biological complications.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e In contrast, in vitro methods including static torque testing, cyclic loading, reverse torque value measurements, screw elongation analysis, strain-gauge\u0026ndash;based preload assessment, mechanical protractors, resonance frequency analysis, predictive analytical models, microleakage testing, and removal torque evaluation provide standardized and controlled conditions that are valuable for comparing implant designs, materials, and connection geometries but lack the complexity of the oral environment and may not reliably predict clinical outcomes. Removal torque measurement provides a highly accurate and direct assessment of the residual preload within the implant\u0026ndash;abutment connection. Nevertheless, its application is predominantly restricted to laboratory conditions or requires removal of the prosthetic restoration, which limits its practicality for routine intra-oral clinical evaluation.\u003csup\u003e\u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11 CR12 CR13\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eDigital torque gauges are widely used to measure the torque applied to abutment and prosthetic screws, providing objective and precise quantification of preload. These devices are highly reliable in laboratory settings and allow clinicians or researchers to ensure that screws are tightened to the manufacturer\u0026rsquo;s recommended torque values. Torque gauges can also measure detorque or removal torque, which reflects the remaining preload in the screw joint and serves as a direct indicator of screw stability. Despite their accuracy, conventional torque gauges are typically designed for vertical use and are often too bulky for intraoral application, especially in posterior regions, limiting their utility in routine clinical practice.\u003csup\u003e\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eAlthough reverse-torque testing is not routinely performed during recall visits, certain clinical situations\u0026mdash;such as recurrent screw loosening or uncertainty regarding abutment seating\u0026mdash; may benefit from objective stability assessment. However, most torque-measuring devices are designed for extraoral use and do not account for the restricted access and angulation challenges of the oral cavity, limiting their clinical relevance.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003eTo address this limitation, a customized horizontal torque arm was developed to adapt a digital torque gauge for intraoral orientation and enable a more clinically representative evaluation of screw loosening. Its performance was assessed under laboratory conditions and compared with that of a conventional vertical torque gauge. Unlike contra-angle torque drivers, which use internal gears that cause friction and reduce accuracy, the customized device uses a rigid, non-geared torque arm directly connected to the digital gauge. This design minimizes mechanical loss and allows more accurate torque measurement.\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e The null hypothesis of this study was that there would be no significant difference in removal-torque measurements between the standard vertical torque gauge and the customized horizontal torque arm.\u003c/p\u003e"},{"header":"MATERIAL AND METHODS","content":"\u003cp\u003eSample size was determined using power analysis (G*Power v3.1.9.6; Heinrich Heine University D\u0026uuml;sseldorf, Germany). Based on an effect size of *f* = 0.65, α\u0026thinsp;=\u0026thinsp;0.05, and 95% power, 34 samples were required and equally allocated to the vertical and horizontal groups (n\u0026thinsp;=\u0026thinsp;17 each).\u003c/p\u003e \u003cp\u003eThe manufacturer-supplied standard ratchet (Sch\u0026uuml;tz Impla Dental Group) served as the reference device. It is a hand-held mechanical torque applicator with an internal hexagonal interface and an integrated locking mechanism for screwdriver engagement, providing visual calibration markings but no digital torque-recording capability (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe customized horizontal torque extension was designed as a rigid, single-piece component with a proximal hexagonal drive for connection to a digital torque gauge hexed socket and a distal end for engaging the implant screwdriver. The distal head had a smoothly rounded external profile to enhance intraoral access and used a friction-retained interface with a laterally positioned flattened steel-ball locking mechanism to ensure secure retention and prevent disengagement during torque application. A solid internal shaft connected the proximal and distal interfaces, enabling efficient torque transmission with minimal backlash at a 90\u0026deg; orientation while maintaining coaxial alignment and mechanical stability.\u003c/p\u003e \u003cp\u003eDuring operation, torque from the digital gauge was transmitted through the internal shaft as a predominantly pure torsional load. Hexagonal engagement and coaxial alignment minimized mechanical losses and off-axis forces, ensuring that the torque recorded by the gauge closely matched the torque delivered to the implant screw in a horizontal orientation.\u003c/p\u003e \u003cp\u003eA 2D engineering drawing was created for design planning (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), and digital modeling was performed using a dental CAD platform (Exocad GmbH). The extension featured a distal head with a 6.35-mm opening and an internal flattened steel-ball locking mechanism for secure screwdriver retention, a shaft (65.1 mm length, 6.4 mm diameter) optimized for strength and intraoral access, and a proximal 11.0-mm hexagonal drive to ensure stable engagement with the digital torque gauge.\u003c/p\u003e \u003cp\u003eDuring the CAD process, parametric modeling tools (extrude, revolve, cut, and fillet operations) were applied to control geometry and alignment. Concentricity between the proximal and distal interfaces was verified by digital assembly simulation, and tolerances of \u0026plusmn;\u0026thinsp;0.05 mm were specified for all critical engagement areas. A medical-grade surface finish (Ra 0.8\u0026ndash;1.6 \u0026micro;m) was targeted to reduce interfacial wear and enhance biocompatibility. The final design was exported in both STEP and STL formats for milling (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe extension was manufactured from medical-grade stainless steel 316L using a 5-axis CNC milling machine, selected for its corrosion resistance, biocompatibility, and torsional stability. Controlled roughing and finishing passes with regulated coolant flow were used to maintain dimensional accuracy, particularly at the hexagonal interfaces and internal locking region. After milling, the device was polished with progressively finer abrasives to achieve a clinical-grade surface finish (Ra 0.8\u0026ndash;1.6 \u0026micro;m). Dimensional accuracy was verified using a digital caliper and a coordinate measuring machine (CMM), with emphasis on the proximal hexagonal interface designed to engage the digital torque gauge. Comparative testing against the original torque gauge driver confirmed precise seating, angular stability, and secure locking without perceptible play (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea\u0026amp;b). The distal head was also evaluated and demonstrated stable adaptation to the screwdriver shaft, replicating the manufacturer\u0026rsquo;s ratchet locking mechanism via an internal ball-locking system (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The customized horizontal extension precisely replicated the original ratchet\u0026rsquo;s dimensions and geometry, ensuring accurate engagement and identical handling during torque application (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e). Verification confirmed mechanical compatibility and functional equivalence of the customized horizontal extension with the digital torque gauge and screwdriver, replicating the geometry and handling of the original ratchet (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo evaluate the accuracy of the customized horizontal extension, removal torque values obtained with the horizontal configuration were compared to those obtained with the original vertical configuration of the digital torque gauge. A standardized experimental setup was developed to ensure reproducibility and to minimize confounding variables.\u003c/p\u003e \u003cp\u003eCommercially available titanium implants (4.2 \u0026times; 9.5 mm; Sch\u0026uuml;tz Dental GmbH, Dieselstr.5-6.61191) were used for all tests. To standardize specimen positioning, a custom two-part metallic mold was fabricated. The mold consisted of a circular stainless-steel base (thickness: 2 mm) with a central access hole aligned with the screw channel of the cylindrical housing. This design allowed precise placement of the implant fixture while preventing resin overflow into the internal channel during polymerization. The cylindrical housing was inserted into the base to create a mold cavity for embedding (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAutopolymerizing acrylic resin (Orthoplast, Vertex-Dental) was prepared according to the manufacturer\u0026rsquo;s instructions and injected into the mold using a syringe. Implants were positioned perpendicular to the base using the implant mount to ensure axial alignment (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e). After polymerization, the acrylic blocks were removed, finished, and polished to obtain smooth, uniform surfaces, with the 2-mm base thickness maintaining the implants in a standardized 2-mm supracrestal position.\u003c/p\u003e \u003cp\u003eA custom cylindrical holder with a central seating hole was used to stabilize specimens during torque testing and prevent rotational displacement; the holder was securely fixed to the testing table, and each specimen was further secured with four radial screws. Straight titanium abutments were connected to the implants using titanium abutment screws, which were tightened to 20 Ncm with a vertically oriented digital torque gauge (HTG2-200Nc, IMADA). After a 10-minute interval to allow for settling, the screws were retightened to 20 Ncm to compensate for preload loss.\u003c/p\u003e \u003cp\u003eRemoval torque was measured to determine preload loss, which was then used to compare the performance of the device in two configurations: the manufacturer\u0026rsquo;s standard vertical setup and a customized horizontal configuration. (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003ea\u0026amp; b). In the vertical setup, the digital torque gauge was connected directly to the implant screwdriver, allowing straightforward measurement along the implant\u0026rsquo;s long axis. In the horizontal setup, the torque gauge was attached via a customized horizontal extension, enabling measurement in orientations that better simulate clinical access limitations. To minimize operator variability, all torque applications and removals were performed by a single examiner.\u003c/p\u003e \u003cp\u003eRemoval torque values were recorded in Newton-centimeters (Ncm), and the percentage of removal torque loss (%RTL) was calculated using the formula: Loss ratio of removal torque before loading (%) = (Tightening torque \u0026ndash; Removal torque before loading)/ (Tightening torque) \u0026times;100. This formula standardized the measurement of preload loss across both testing configurations. Data were fed to the computer and analyzed using IBM SPSS software package version 27.0. (Armonk, NY: IBM Corp, released in 2020). For continuous data, they were tested for normality by the Shapiro-Wilk test. Quantitative data were expressed as range (minimum and maximum), mean, standard deviation and median Student t-test was used to compare two groups for normally distributed quantitative variables. Significance of the obtained results was judged at the 5% level.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eThe vertical (original device) group demonstrated a slightly higher mean simulated removal torque loss (%RTL) (18.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.29) compared with the horizontal group (17.85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.45). However, this difference was not statistically significant (Student\u0026rsquo;s t-test, t\u0026thinsp;=\u0026thinsp;1.625, p\u0026thinsp;=\u0026thinsp;0.114). The mean difference between the two groups was 0.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.47, with a 95% confidence interval ranging from \u0026minus;\u0026thinsp;0.19 to 1.72, indicating comparable removal torque loss between the vertical and horizontal torque application methods. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). These results indicate that the customized horizontal arm provides removal torque measurements comparable to those obtained with the original vertical torque device.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison between vertical and horizontal groups according to simulated removal torque loss (%RTL)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVertical group\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHorizontal group\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;17)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRTL (%) Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e17.85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1.625\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.114\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedian (Min. \u0026ndash; Max.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18.50\u003c/p\u003e \u003cp\u003e(16.40\u0026ndash;20.80)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.10\u003c/p\u003e \u003cp\u003e(14.80\u0026ndash;20.20)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean difference\u0026thinsp;\u0026plusmn;\u0026thinsp;SE\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e0.765\u0026thinsp;\u0026plusmn;\u0026thinsp;0.470\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e95% CI of the difference\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e-0.194\u0026ndash;1.723\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eRTL\u0026thinsp;=\u0026thinsp;removal torque loss; SD\u0026thinsp;=\u0026thinsp;standard deviation; SE\u0026thinsp;=\u0026thinsp;standard error; CI\u0026thinsp;=\u0026thinsp;confidence interval. Comparisons between groups were performed using the student\u0026rsquo;s \u003cem\u003et\u003c/em\u003e test. Statistical significance was set at α\u0026thinsp;=\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eAt the outset of this study, the null hypothesis stated that there would be no significant difference in removal torque loss (%RTL) between the vertical (original device) and horizontal (customized extension) configurations was accepted. Statistical analysis confirmed this, with no significant difference observed, indicating that the custom-fabricated horizontal torque extension provides removal torque measurements comparable to the standard vertical device.\u003c/p\u003e \u003cp\u003eThe custom horizontal torque arm was developed by integrating dental prosthetic requirements with principles of mechanical design and precision engineering. The design process involved a stepwise approach, beginning with reverse-engineering the original Schutz Impla ratchet. Key mechanical elements, including the proximal hexagonal drive interface, locking mechanism, and ergonomic handle, were identified to establish a functionally equivalent horizontal system. This approach ensured that the custom extension preserved the engagement behavior and torque transfer characteristics of the original ratchet. In addition, replicating the ratchet head\u0026rsquo;s internal concavity and incorporating a steel locking ball mechanism provided secure tool retention, which is critical to prevent disengagement during intraoral use.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eDigital modeling of the horizontal arm using Exocad allowed precise control of geometry, tolerances, and interfaces, enabling virtual fit testing and reducing prototyping errors. Hexagonal interfaces at both ends ensured compatibility with the implant screwdriver and torque gauge, while\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05 mm tolerance and Ra 0.8\u0026ndash;1.6 \u0026micro;m surface finish met precision engineering standards.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e The horizontal arm was CNC-milled from 316L stainless steel for its mechanical strength, corrosion resistance, and biocompatibility. Cooling and lubrication during machining preserved material integrity, while post-milling polishing improved surface smoothness, minimizing bacterial adhesion and enhancing intraoral handling.\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e Verification with coordinate measuring machines (CMMs) confirmed dimensional fidelity of critical areas, such as the hex interface and locking mechanism, ensuring precision consistent with best practices in implant engineering.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eAbutment screws were tightened to 20 Ncm using a digital torque gauge, following the manufacturer\u0026rsquo;s recommendations. Achieving the optimal torque is critical for long-term prosthetic stability, as it generates preload\u0026mdash;the initial tensile force within the screw that maintains the implant-abutment connection. Ten minutes after initial tightening, all screws were retorqued to compensate for preload loss due to the settling effect, which smooths micro-irregularities on the screw surfaces. Preload must remain below 75\u0026ndash;80% of the material\u0026rsquo;s elastic limit; if forces applied to the system are higher than the preload, screw loosening can occur.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe results of this study showed measurable torque loss. This finding is supported by previous studies in conical hybrid implants, which reported early screw loosening due to preload reduction.\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003eThe initial reduction in removal torque (%RTL) is primarily attributed to the settling effect (embedment relaxation) and screw geometry, which diminish the applied preload even before functional loading.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eTightening a prosthetic abutment creates forces at screw head, the implant\u0026ndash;abutment interface, and screw threads. Only about 10% of the applied torque is converted into preload, while the remaining torque is lost due to settling. In titanium alloy screws, up to 20% of the initial torque may be lost even before functional loading.\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e In the present study, although torque loss increased before loading in all test groups, no loosening of the screws was detected, indicating that the remaining tightening torque was sufficient to maintain clinical stability.\u003c/p\u003e \u003cp\u003eThe lack of a significant difference in removal torque loss between the vertical and horizontal configurations can be explained by the rigid design of the horizontal extension. Torque, defined as the product of force and the perpendicular distance from the axis of rotation, is theoretically independent of the orientation of the delivery device, provided the torque vector is aligned with the screw\u0026rsquo;s rotational axis and energy loss through deformation or misalignment is minimal. In the customized horizontal design, the force applied at the digital torque gauge is transmitted through a rigid, hexagonally interfaced extension with a locking mechanism modeled after the original ratchet, minimizing mechanical play or rotational lag. The use of stainless steel 316L ensures dimensional stability and resistance to torsional deformation, further preserving torque integrity.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003ePrevious studies have shown that, when the tool axis is properly aligned with the screw axis and contact surfaces are rigidly engaged, the orientation of the delivery tool horizontal or vertical does not significantly affect torque accuracy.\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e This mechanical principle explains the comparable torque loss observed between the vertical and customized horizontal configurations in this study, confirming that the custom extension successfully preserves the functional behavior of the original device.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eBased on the findings of this in vitro study, the customized horizontal torque arm demonstrated removal torque measurements comparable to those obtained with a standard vertical torque gauge. Its horizontal configuration enabled intraoral applicability, including improved access to posterior regions, while allowing accurate assessment of abutment screw stability under clinically representative conditions across different implant systems. Collectively, these findings support the horizontal torque arm as a practical and reliable tool for both experimental evaluation and potential chairside monitoring of implant\u0026ndash;abutment mechanical stability.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests:\u003c/h2\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eThis research received no external funding.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.A.Y.E.-S. and S.R.S. conceived and designed the study. M.A.Y.E.-S. performed the experiments, collected the data, and conducted the statistical analysis. M.A.Y.E.-S. and S.R.S. supervised the experimental procedures. B.N.E. contributed to methodological design and interpretation of the results. A.A.E.-G. and M.M.E.-S. supervised the research and critically revised the manuscript. S.R.S. and M.A.Y.E.-S. wrote the main manuscript text. All authors reviewed and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHeitz-Mayfield LJA. Peri-implant mucositis and peri-implantitis: key features and differences. Br Dent J 2024; 236:791\u0026ndash;4.\u003c/li\u003e\n\u003cli\u003eEl-Sheikh MAY, Mostafa TMN, El-Sheikh MM. Effect of different angulations and collar lengths of conical hybrid implant abutment on screw loosening after dynamic cyclic loading. Int J Implant Dent 2018; 4:1\u0026ndash;10.\u003c/li\u003e\n\u003cli\u003eSiamos G, Winkler S, Boberick KG. Relationship between implant preload and screw loosening on implant-supported prostheses. J Oral Implantol 2002; 28:67\u0026ndash;73.\u003c/li\u003e\n\u003cli\u003eMisch CE. Principles for abutment and prosthetic screws and screw-retained components and prostheses. In: Dental Implant Prosthetics. 2nd ed. St. Louis: Elsevier; 2015. p. 203\u0026ndash;25.\u003c/li\u003e\n\u003cli\u003eWinkler S, Ring K, Ring JD, Boberick KG. Implant screw mechanics and the settling effect: an overview. J Oral Implantol 2003; 29:242\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eLee KY, Shin KS. Clinical study on screw loosening in dental implant prostheses: a 6-year retrospective study. J Korean Assoc Oral Maxillofac Surg. 2020;46:133-42.\u003c/li\u003e\n\u003cli\u003eHaack JE, Sakaguchi RL, Sun T, Coffey JP. Elongation and preload stress in dental implant abutment screws. Int J Oral Maxillofac Implants 1995; 10:529\u0026ndash;36.\u003c/li\u003e\n\u003cli\u003eTan BF, Tan KB, Nicholls JI. Critical bending moment of implant-abutment screw joint interfaces: effect of torque levels and implant diameter. Int J Oral Maxillofac Implants 2004; 19:701\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eHanses G, Smedberg JI, Nilner K. Analysis of a device for assessment of abutment and prosthesis screw loosening in oral implants. Clin Oral Implants Res 2002; 13:641\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eDincer Kose O, Karatasli B, Demircan S, Kose TE, Cene E, Aya SA, et al. In vitro evaluation of manual torque values applied to implant-abutment complex by different clinicians and abutment screw loosening. Biomed Res Int 2017; 2017:1\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eMiyashita M, Ogawa T, Naito H, Shibamoto A, Wang AS, Shobara K, et al. Evaluation of implant screw loosening by resonance frequency analysis with triaxial piezoelectric pick-up: in vitro model and in vivo animal study. Clin Oral Investig 2018; 22:2129\u0026ndash;34.\u003c/li\u003e\n\u003cli\u003eArmentia M, Abasolo M, Coria I, Bouzid AH. On the use of a simplified slip limit equation to predict screw self-loosening of dental implants subjected to external cycling loading. Appl Sci 2020; 10:1\u0026ndash;15.\u003c/li\u003e\n\u003cli\u003eSahin C, Ayyildiz S. Correlation between microleakage and screw loosening at implant-abutment connection. J Adv Prosthodont 2014; 6:1\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eFerreira MB, Delben JA, Barao VAR, Faverani LP, Dos Santos PH, Assuncao WG. Evaluation of torque maintenance of abutment and cylinder screws with morse taper implants. J Craniofac Surg 2012;23: e556\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eWeiss EI, Kozak D, Gross MD. Effect of repeated closures on opening torque values in seven abutment-implant systems. J Prosthet Dent 2000; 84:180\u0026ndash;5.\u003c/li\u003e\n\u003cli\u003eRodrigues Neto DJ, Cerutti-Kopplin D, Do Valle AL, Pereira JR. A method of assessing the effectiveness of the friction fit interface by measuring reverse torque. J Prosthet Dent 2014; 112:878\u0026ndash;83.\u003c/li\u003e\n\u003cli\u003eVillarinho EA, Cervieri A, Shinkai RSA, Grossi ML, Teixeira ER. The effect of a positioning index on the biomechanical stability of tapered implant-abutment connections. J Oral Implantol 2015; 41:145\u0026ndash;51.\u003c/li\u003e\n\u003cli\u003eNokar S, Hajimiragha H, Sadighpour L, Mostafavi AS. Evaluation of reverse torque values and failure loads of three different abutment designs with internal connections. Dent Res J (Isfahan). 2020;17:439-46.\u003c/li\u003e\n\u003cli\u003eSameera Y, Rai R. Tightening torque of implant abutment using hand drivers against torque wrench and its effect on the internal surface of implant. J Indian Prosthodont Soc. 2020;20:180-5.\u003c/li\u003e\n\u003cli\u003eWang YS, Lee CT, Kandaswamy E, Theodorou K, Chien HH. Accuracy of mechanical torque-limiting devices for implant screw tightening: A systematic review and meta-analysis. J Prosthet Dent. 2024; 132:536-45.\u003c/li\u003e\n\u003cli\u003eKoroglu EN, Turker Kader İ, Albayrak B, Koksal M, Kurt M. Effect of mechanical aging and steam autoclaving on the accuracy of different mechanical torque limiting devices. The Journal of Prosthetic Dentistry. 2025;134: 1188.e1-e7.\u003c/li\u003e\n\u003cli\u003eAmroune S, Belaadi A, Zaoui M, Menaseri N, Mohamad B, Saada K, et al. Manufacturing of rapid prototypes of mechanical parts using reverse engineering and 3D printing. J Serbian Soc Comput Mech 2021; 15:1\u0026ndash;12.\u003c/li\u003e\n\u003cli\u003eGeng JPA, Tan KBC, Liu GR. Application of finite element analysis in implant dentistry: a review of the literature. J Prosthet Dent 2001; 85:585\u0026ndash;98.\u003c/li\u003e\n\u003cli\u003eJang Y, Choi WT, Johnson CT, Garc\u0026iacute;a AJ, Singh PM, Breedveld V, et al. Inhibition of bacterial adhesion on nanotextured stainless steel 316L by electrochemical etching. ACS Biomater Sci Eng 2018; 4:108\u0026ndash;16.\u003c/li\u003e\n\u003cli\u003eMohammad A, Aljamaan F, Shuqayr SB, Ahmed KM. Coordinate measuring machine performance verification using standard step gauges with new measurement model and modified uncertainty analysis. Measurement: Sensors 2025; 38:101658.\u003c/li\u003e\n\u003cli\u003eMcGlumphy EA, Mendel DA, Holloway JA. Implant screw mechanics. Dent Clin North Am 1998; 42:71\u0026ndash;90.\u003c/li\u003e\n\u003cli\u003eSammour SR, Maamoun El-Sheikh M, Aly El-Gendy A. Effect of implant abutment connection designs and implant diameters on screw loosening before and after cyclic loading: in vitro study. Dent Mater 2019;35: e265\u0026ndash;71.\u003c/li\u003e\n\u003cli\u003eSagheb K, G\u0026ouml;rgen C‑I, D\u0026ouml;ll S, Schmidtmann I, Wentaschek S. Preload and friction in an implant\u0026ndash;abutment\u0026ndash;screw complex including a carbon‑coated titanium alloy abutment screw. Int J Implant Dent. 2023; 9:8.\u003c/li\u003e\n\u003cli\u003eShiba H, Sato Y, Furuya J, Osawa T, Isobe A, Hayashi M, et al. Experimental study on the factors affecting torque of beam-type implant torque wrenches. BMC Oral Health 2021; 21:1\u0026ndash;10.\u003c/li\u003e\n\u003cli\u003eLi S, Xu J. Multiaxis force/torque sensor technologies: design principles and robotic force control applications: a review. IEEE Sens J 2025; 25:4055\u0026ndash;69.\u003c/li\u003e\n\u003c/ol\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":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9026603/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9026603/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eStatement of the Problem\u003c/b\u003e: Conventional vertical torque devices are difficult to use intraorally, especially in posterior regions, limiting accurate chairside assessment of implant abutment screw stability and underscoring the need for an intraoral-compatible torque measurement approach without loss of accuracy.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePurpose\u003c/b\u003e: This study aimed to develop and validate a customized horizontal torque arm intended to enable intraoral mechanical evaluation of abutment screw loosening, and to compare its performance with the original vertical torque device under laboratory conditions.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMaterials and Methods\u003c/b\u003e: A horizontal torque extension was designed using computer-aided design and fabricated from medical-grade stainless steel (316L) by 5-axis CNC milling. The device incorporated proximal and distal hexagonal interfaces to connect a digital torque gauge and a standard implant screwdriver, enabling torque transmission at a 90\u0026deg; orientation. Titanium implant\u0026ndash;abutment assemblies (n\u0026thinsp;=\u0026thinsp;17) were embedded in acrylic resin blocks, and abutment screws were tightened to 20 Ncm, and subjected to removal torque testing using both vertical (original) and horizontal (customized) configurations. The percentage of removal torque loss (%RTL) was calculated. Statistical analysis was performed using software released in 2020; data normality was assessed with the Shapiro\u0026ndash;Wilk test, and normally distributed variables were compared using the student\u0026rsquo;s t-test with a significance level of 0.05.\u003c/p\u003e \u003cp\u003e \u003cb\u003eResults\u003c/b\u003e: The vertical (original) device demonstrated a mean simulated removal torque loss (18.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.29%), while the customized horizontal arm showed a mean value (17.85\u0026thinsp;\u0026plusmn;\u0026thinsp;1.45%); the difference was not statistically significant (p\u0026thinsp;=\u0026thinsp;0.114), indicating comparable removal torque measurements between the two methods.\u003c/p\u003e \u003cp\u003e \u003cb\u003eConclusions\u003c/b\u003e: The customized horizontal torque arm showed accuracy comparable to the conventional vertical device and enables direct intraoral assessment of screw stability, particularly in posterior regions, making it a practical tool for both clinical and laboratory implant\u0026ndash;abutment evaluation.\u003c/p\u003e \u003cp\u003eClinical Implications\u003c/p\u003e \u003cp\u003eThe customized horizontal torque extension allows accurate intraoral evaluation of abutment screw stability in a clinically realistic orientation, particularly in posterior regions with limited access. Its comparable accuracy to conventional vertical devices supports its use for early detection of preload loss and screw loosening. This may help prevent mechanical complications and improve long-term maintenance of implant-supported restorations.\u003c/p\u003e","manuscriptTitle":"Novel Digitally Customized Horizontal Torque Extension for Mechanical Evaluation of Implant Abutment Screw","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-23 10:06:50","doi":"10.21203/rs.3.rs-9026603/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-05-12T12:35:29+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-12T07:33:22+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"327628641850295649776594834725550523597","date":"2026-04-21T07:46:07+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-19T01:38:40+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"30035698962698151610801843589333521555","date":"2026-04-15T23:44:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-15T07:13:11+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-04-08T08:01:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-23T13:37:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-11T07:28:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-03-11T05:10:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a2eead34-58cf-4eed-a183-cc0eabdd0eea","owner":[],"postedDate":"April 23rd, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Revision requested","date":"2026-05-12T12:35:29+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-12T07:33:22+00:00","index":47,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[{"id":66872525,"name":"Physical sciences/Engineering"},{"id":66872526,"name":"Health sciences/Health care"},{"id":66872527,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2026-05-12T13:15:32+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-23 10:06:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9026603","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9026603","identity":"rs-9026603","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}