Effect of fabrication technique on the fit of cobalt chromium frameworks in All-on-4 dental implant treatment (in vitro study)

Effect of fabrication technique on the fit of cobalt chromium frameworks in All-on-4 dental implant treatment (in vitro study) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effect of fabrication technique on the fit of cobalt chromium frameworks in All-on-4 dental implant treatment (in vitro study) Ahmed Mashaly, Ahmed M. Abdelhamid, Islam M.Abdelraheem This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9337823/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 16 You are reading this latest preprint version Abstract Background: The passivity of fit of cobalt chromium frameworks on All-on-4 implant concept is highly affected by the fabrication technique. Recently, additive manufacturing has become popular, however; its accuracy is questionable compared to the subtractive technique. Aim of this study: The aim of this in vitro study was to evaluate the effect of fabrication technique on the marginal fit of All-on-4 implant-supported cobalt chromium frameworks. Material and Methods: A master maxillary model was fabricated to simulate All-on-4 dental implant treatment, with two anterior parallel and angulated posterior dental implant analogs (17 degrees). Two straight multiunit abutments were tightened to the anterior implant analogs, and two 17 degrees angled multiunit abutments were tightened to the posterior angled implant analogs and torqued according to manufacturer’s recommendation. Abutment level Scan bodies were tightened to the abutments and scanned using a laboratory scanner. Ten scans were imported to a dental cad program to design the cobalt chromium frameworks. The frameworks were manufactured by subtractive technique (SM) (n=10) and additive technique (AM) (n=10). The marginal gap at each abutment-prosthesis interface were measured using a light microscope in 3 different conditions based on the number of screws tightening the prosthesis to the abutments: a prosthetic screw tightening the prosthesis on one posterior abutment simulating the Sheffield test, two prosthetic screws tightening the prosthesis on the posterior abutments, four prosthetic screws tightening the prosthesis on the posterior abutments. Results: The mean marginal gap for AM and SM when tightening left region (#26) were 108.01 and 79.56 µm respectively. The mean marginal gap for AM, SM when left region (#26) and right region (#16) were tightened were 103.47 and 67.17 µm respectively. The mean marginal gap for AM, SM when All MUA were tightened were 62.76 and 30.83 µm respectively. The marginal gaps between the groups were statistically significant in all conditions ( P <0.05). Conclusion: Within the limitations of this in vitro study, cobalt chromium frameworks that were fabricated using subtractive technique had better marginal fit than those fabricated by additive one. Fabrication Passivity Cobalt Chromium Implants All-on-4 Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 16 May, 2026 Reviews received at journal 16 May, 2026 Reviews received at journal 15 May, 2026 Reviews received at journal 13 May, 2026 Reviewers agreed at journal 07 May, 2026 Reviewers agreed at journal 07 May, 2026 Reviews received at journal 06 May, 2026 Reviewers agreed at journal 06 May, 2026 Reviewers agreed at journal 06 May, 2026 Reviewers agreed at journal 06 May, 2026 Reviewers agreed at journal 06 May, 2026 Reviewers invited by journal 06 May, 2026 Editor invited by journal 08 Apr, 2026 Editor assigned by journal 08 Apr, 2026 Submission checks completed at journal 08 Apr, 2026 First submitted to journal 06 Apr, 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. 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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-9337823","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":639423490,"identity":"d07b89e5-4e23-4575-8338-305d57351956","order_by":0,"name":"Ahmed Mashaly","email":"","orcid":"","institution":"Alexandria University","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Mashaly","suffix":""},{"id":639423492,"identity":"76ecb419-a11e-4e3f-a16c-725483f85d6a","order_by":1,"name":"Ahmed M. 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Recently, additive manufacturing has become popular, however; its accuracy is questionable compared to the subtractive technique.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAim of this study: \u003c/strong\u003eThe aim of this in vitro study was to evaluate the effect of fabrication technique on the marginal fit of All-on-4 implant-supported cobalt chromium frameworks.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterial and Methods: \u003c/strong\u003eA\u003cstrong\u003e \u003c/strong\u003emaster maxillary model was fabricated to simulate All-on-4 dental implant treatment, with two anterior parallel and angulated posterior dental implant analogs (17 degrees). Two straight multiunit abutments were tightened to the anterior implant analogs, and two 17 degrees angled multiunit abutments were tightened to the posterior angled implant analogs and torqued according to manufacturer’s recommendation. Abutment level Scan bodies were tightened to the abutments and scanned using a laboratory scanner. Ten scans were imported to a dental cad program to design the cobalt chromium frameworks. The frameworks were manufactured by subtractive technique (SM) (n=10) and additive technique (AM) (n=10). The marginal gap at each abutment-prosthesis interface were measured using a light microscope in 3 different conditions based on the number of screws tightening the prosthesis to the abutments: a prosthetic screw tightening the prosthesis on one posterior abutment simulating the Sheffield test, two prosthetic screws tightening the prosthesis on the posterior abutments, four prosthetic screws tightening the prosthesis on the posterior abutments.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The mean marginal gap for AM and SM when tightening left region (#26) were 108.01 and 79.56 µm respectively. The mean marginal gap for AM, SM when left region (#26) and right region (#16) were tightened were 103.47 and 67.17 µm respectively. The mean marginal gap for AM, SM when All MUA were tightened were 62.76 and 30.83 µm respectively. The marginal gaps between the groups were statistically significant in all conditions (\u003cem\u003eP\u003c/em\u003e\u0026lt;0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eWithin the limitations of this in vitro study, cobalt chromium frameworks that were fabricated using subtractive technique had better marginal fit than those fabricated by additive one.\u003c/p\u003e","manuscriptTitle":"Effect of fabrication technique on the fit of cobalt chromium frameworks in All-on-4 dental implant treatment (in vitro study)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-14 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