Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics: Vicker’s Hardness and Scanning Electron Microscope Evaluation

Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics: Vicker’s Hardness and Scanning Electron Microscope Evaluation | 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 Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics: Vicker’s Hardness and Scanning Electron Microscope Evaluation Anna Muryani, Dudi Aripin, Hendra Dian Adhita Dharsono, Satrio Wicaksono, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7369963/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Jan, 2026 Read the published version in BMC Oral Health → Version 1 posted 12 You are reading this latest preprint version Abstract Background Guided endodontic access uses a CBCT-derived template with a guide sleeve to direct the drill for precise canal location, particularly in calcified teeth. This technique is more conservative, time-efficient, and precise than conventional methods. Guide sleeves are fabricated from various materials (e.g., zirconia ceramic, cobalt-chromium alloy, titanium alloy, or 3D-printed resin), but their hardness and durability under drilling stress are not well characterized. However, guiding long, narrow drills through sleeves may generate excess heat through friction between surfaces, potentially causing tool wear. Studies in implant dentistry show significant drill wear with repeated use, but the effects of sleeve material and height on endodontic drill wear are also not well characterized. This study used scanning electron microscopy (SEM) to examine drill surface changes after guided Minimally Invasive Endodontic Access (MIEA) with different sleeve materials (resin, zirconia [Y-TZP], Ti-6Al-4V, CoCr alloy) and heights. This study evaluated Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics through Vickers Hardness Test and Scanning Electron Microscope. Methods In vitro, 30 guide sleeves (10 sizes: 3 mm, 5 mm, 7 mm; 4 different materials) fit a 1.5 mm carbide bur with limited clearance. Sleeve materials tested in the current study are dental photopolymer resin, Y-TZP, Co–Cr, and Ti-6Al-4V. Before and after drilling, the sleeve hardness was measured through Vickers Hardness Test (HV0.2). Hardness variations (ΔVHN) were determined. A one-way ANOVA was used to assess hardness among materials and sleeve heights, with significance at p < 0.05. Additionally, three teeth were drilled under irrigation by one-group standardized high-speed carbide drills per guide. Cleaning and imaging of drill tips and flutes were done using a 1000× SEM. Two examiners rated wear as Grade 0 (no wear), Grade 1 (minor blunting or edge rounding), or Grade 2 (severe chipping or edge loss). Five drills showing noticeable thermal discoloration (“burn marks”) were included in the analysis. This study is a pilot study or an early feasibility study. The data will be analyzed using a Descriptive approach. Results While zirconia sleeves had the highest hardness rating (mean ~ 1392 HV pre-drilling; ~1389 HV post-drilling), resin sleeves had the lowest (~ 6 to 7 HV both pre- and post-drilling), while CoCr and Ti-alloy sleeves had intermediate hardness (~ 315 and ~ 405 HV). ANOVA showed significant material differences (p 0.8). Due to modest hardness variations, drilling cycles do not strain-harden or soften the sleeve. Four drills (30%) exhibited Grade 1 wear. Six drills (70%) had Grade 2 wear. Medium and short resin sleeves showed Grade 1 wear, whereas Zirconia, Titanium, and CoCr had Grade 2. Short sleeves produced Grade 1 wear, while medium/long sleeves frequently caused Grade 2 wear. Five drills with burn marks corresponded to the Grade 2 group. Overall, Grade 2 wear was observed in 60% of drills, and Grade 1 in 40%. Conclusions Sleeve hardness was primarily determined by the material type, with sleeve height having no significant effect. Zirconia guide sleeves were harder than CoCr, Ti, and resin, and may also offer greater wear resistance and durability for guided endodontic template sleeves. All tested materials maintained their hardness after simulated guided access drilling. Guided minimally invasive endodontic access drill wear was considerable with static sleeves. The majority of the drills experienced heat burns and Grade 2 surface damage. Drill abrasion was notably increased when using resin, zirconia, and cobalt-chromium (CoCr) sleeves, attributed to their greater hardness, wear resistance, and sleeve height. While resin sleeves may help reduce wear during minimally invasive guided endodontics, the absence of an effective root canal irrigation system limits cooling efficiency. Clinicians must be aware that more rigid guides and sleeve systems may demand additional measures, such as optimized irrigation or intermittent drilling, to avoid thermal and mechanical damage. Proper selection of guide sleeves and implementation of effective cooling mechanisms are essential to the success of guided endodontic procedures. guided endodontics endodontic guide sleeve Vickers hardness drill wear scanning electron microscopy sleeve material sleeve height Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Jan, 2026 Read the published version in BMC Oral Health → Version 1 posted Editorial decision: Revision requested 09 Oct, 2025 Reviews received at journal 22 Sep, 2025 Reviews received at journal 20 Sep, 2025 Reviews received at journal 14 Sep, 2025 Reviewers agreed at journal 01 Sep, 2025 Reviewers agreed at journal 30 Aug, 2025 Reviewers agreed at journal 29 Aug, 2025 Reviewers agreed at journal 28 Aug, 2025 Reviewers invited by journal 28 Aug, 2025 Editor assigned by journal 27 Aug, 2025 Submission checks completed at journal 27 Aug, 2025 First submitted to journal 14 Aug, 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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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-7369963","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":508564501,"identity":"983a4228-b1d3-4018-9194-1c22d37f1b1d","order_by":0,"name":"Anna 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Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"guided endodontics, endodontic guide sleeve, Vickers hardness, drill wear, scanning electron microscopy, sleeve material, sleeve height","lastPublishedDoi":"10.21203/rs.3.rs-7369963/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7369963/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e\u003cp\u003eGuided endodontic access uses a CBCT-derived template with a guide sleeve to direct the drill for precise canal location, particularly in calcified teeth. This technique is more conservative, time-efficient, and precise than conventional methods. Guide sleeves are fabricated from various materials (e.g., zirconia ceramic, cobalt-chromium alloy, titanium alloy, or 3D-printed resin), but their hardness and durability under drilling stress are not well characterized. However, guiding long, narrow drills through sleeves may generate excess heat through friction between surfaces, potentially causing tool wear. Studies in implant dentistry show significant drill wear with repeated use, but the effects of sleeve material and height on endodontic drill wear are also not well characterized. This study used scanning electron microscopy (SEM) to examine drill surface changes after guided Minimally Invasive Endodontic Access (MIEA) with different sleeve materials (resin, zirconia [Y-TZP], Ti-6Al-4V, CoCr alloy) and heights. This study evaluated Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics through Vickers Hardness Test and Scanning Electron Microscope.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e\u003cp\u003eIn vitro, 30 guide sleeves (10 sizes: 3 mm, 5 mm, 7 mm; 4 different materials) fit a 1.5 mm carbide bur with limited clearance. Sleeve materials tested in the current study are dental photopolymer resin, Y-TZP, Co\u0026ndash;Cr, and Ti-6Al-4V. Before and after drilling, the sleeve hardness was measured through Vickers Hardness Test (HV0.2). Hardness variations (ΔVHN) were determined. A one-way ANOVA was used to assess hardness among materials and sleeve heights, with significance at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Additionally, three teeth were drilled under irrigation by one-group standardized high-speed carbide drills per guide. Cleaning and imaging of drill tips and flutes were done using a 1000\u0026times; SEM. Two examiners rated wear as Grade 0 (no wear), Grade 1 (minor blunting or edge rounding), or Grade 2 (severe chipping or edge loss). Five drills showing noticeable thermal discoloration (\u0026ldquo;burn marks\u0026rdquo;) were included in the analysis. This study is a pilot study or an early feasibility study. The data will be analyzed using a Descriptive approach.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWhile zirconia sleeves had the highest hardness rating (mean\u0026thinsp;~\u0026thinsp;1392 HV pre-drilling; ~1389 HV post-drilling), resin sleeves had the lowest (~\u0026thinsp;6 to 7 HV both pre- and post-drilling), while CoCr and Ti-alloy sleeves had intermediate hardness (~\u0026thinsp;315 and ~\u0026thinsp;405 HV). ANOVA showed significant material differences (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), but no significant effect of sleeve height on hardness (p\u0026thinsp;\u0026gt;\u0026thinsp;0.8). Due to modest hardness variations, drilling cycles do not strain-harden or soften the sleeve. Four drills (30%) exhibited Grade 1 wear. Six drills (70%) had Grade 2 wear. Medium and short resin sleeves showed Grade 1 wear, whereas Zirconia, Titanium, and CoCr had Grade 2. Short sleeves produced Grade 1 wear, while medium/long sleeves frequently caused Grade 2 wear. Five drills with burn marks corresponded to the Grade 2 group. Overall, Grade 2 wear was observed in 60% of drills, and Grade 1 in 40%.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions\u003c/b\u003e\u003c/p\u003e\u003cp\u003eSleeve hardness was primarily determined by the material type, with sleeve height having no significant effect. Zirconia guide sleeves were harder than CoCr, Ti, and resin, and may also offer greater wear resistance and durability for guided endodontic template sleeves. All tested materials maintained their hardness after simulated guided access drilling. Guided minimally invasive endodontic access drill wear was considerable with static sleeves. The majority of the drills experienced heat burns and Grade 2 surface damage. Drill abrasion was notably increased when using resin, zirconia, and cobalt-chromium (CoCr) sleeves, attributed to their greater hardness, wear resistance, and sleeve height. While resin sleeves may help reduce wear during minimally invasive guided endodontics, the absence of an effective root canal irrigation system limits cooling efficiency. Clinicians must be aware that more rigid guides and sleeve systems may demand additional measures, such as optimized irrigation or intermittent drilling, to avoid thermal and mechanical damage. Proper selection of guide sleeves and implementation of effective cooling mechanisms are essential to the success of guided endodontic procedures.\u003c/p\u003e","manuscriptTitle":"Sleeve Material, Height, and Drill Surface Changes in Guided Endodontics: Vicker’s Hardness and Scanning Electron Microscope Evaluation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-04 22:45:36","doi":"10.21203/rs.3.rs-7369963/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-09T09:29:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-22T14:41:43+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-20T19:49:29+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-14T12:27:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"255305784585418124780736357226791662594","date":"2025-09-01T13:03:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"293127533397247399554186942106049592178","date":"2025-08-30T14:43:14+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"180148575148007280954218767393686812744","date":"2025-08-29T08:10:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"301614646695564768785364211261858986987","date":"2025-08-28T21:11:51+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-28T14:22:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-27T06:50:05+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-27T06:49:05+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Oral Health","date":"2025-08-14T05:14:04+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-oral-health","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ohea","sideBox":"Learn more about [BMC Oral Health](http://bmcoralhealth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/ohea/default.aspx","title":"BMC Oral Health","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"821efb43-c87b-4c4a-993d-addd4f4017e5","owner":[],"postedDate":"September 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-01-12T16:06:59+00:00","versionOfRecord":{"articleIdentity":"rs-7369963","link":"https://doi.org/10.1186/s12903-025-07560-4","journal":{"identity":"bmc-oral-health","isVorOnly":false,"title":"BMC Oral Health"},"publishedOn":"2026-01-05 15:57:33","publishedOnDateReadable":"January 5th, 2026"},"versionCreatedAt":"2025-09-04 22:45:36","video":"","vorDoi":"10.1186/s12903-025-07560-4","vorDoiUrl":"https://doi.org/10.1186/s12903-025-07560-4","workflowStages":[]},"version":"v1","identity":"rs-7369963","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7369963","identity":"rs-7369963","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}