Precision Crown Lengthening with a Metal-Combined Guide: A Dental Technique

Precision Crown Lengthening with a Metal-Combined Guide: A Dental Technique | 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 Case Report Precision Crown Lengthening with a Metal-Combined Guide: A Dental Technique Xiaoying Qiu, Andi Shi, Siqi Luo, Huiqun Zhang, Ping Li, Jiangyong Huang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6062497/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract PURPOSE. This study presents a surgical technique for crown lengthening using a metal-combined guide, aimed at minimizing the gap between the bone surface and the guide to reduce visual and surgical errors. MATERIALS AND METHODS. The protocol includes: 1) Preoperative data acquisition through cone beam computed tomography (CBCT), intraoral scanning, and periodontal probing; 2) Creating a digital diagnostic wax-up to guide the design of the gingivectomy guide plate; 3) The elaboration of the alveolectomy guide plate and its combination structures, followed by the fabrication of the metal-combined guide; 4) Precisely placing the gingivectomy guide to assist in the gingivectomy procedure; 5) The subsequent removal of the gingivectomy guide, enabling the execution of alveolectomy and osteoplasty procedures; and 6) The provision of comprehensive post-operative care, encompassing temporary restoration, adjustment of adjacent contact points, final restoration, and scheduled follow-up visits. CONCLUSIONS. This technique utilizes digital technology to integrate various datasets for designing and fabricating a metal-combined guide, improving the precision of bone removal and leading to more predictable treatment outcomes. This approach is particularly beneficial for patients with maxillary overdevelopment and lingual tilt of the anterior teeth, or maxillary underdevelopment with lip tilt of the anterior teeth. Crown lengthening Alveolectomy Gap Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Surgical crown lengthening (SCL) is a periodontal procedure that exposes more tooth structure by removing gingiva and bone, facilitating restoration and enhancing gingival aesthetics while maintaining periodontal biological width [ 1 , 2 ] . The main surgical complications include gingival recession and tissue rebound influenced by the extent of alveolectomy and the positioning of the gingival flap [ 3 – 6 ] . SCL guides are recognized for their precision and stability, which help minimize aesthetic risks, decrease the need for secondary surgeries, and reduce intraoperative time [ 2 , 7 ] . In clinical practice, the commonly used one-piece guide often has a gap between the bone surface and the guide due to flap thickness following elevation. This gap is particularly pronounced in patients with maxillary overdevelopment and lingual tilt of the upper anterior teeth, or maxillary underdevelopment with labial tilt of the upper anterior teeth. In such cases, the space between the bone surface and the guide increases as the axial positioning of the teeth is adjusted to ensure proper placement. This misalignment can lead to errors and excessive bone removal (Fig. 1 ), potentially increasing the unpredictability of outcomes and negatively affecting the final aesthetic results [ 7 , 8 ] . The digital era has transformed clinical practice with the introduction of computer-aided design and manufacturing (CAD-CAM) technologies [ 9 ] . Digital guides reduce the dependence on surgeons' technical expertise, decrease operating time, enhance aesthetic predictability, and lower the need for follow-up surgeries [ 2 , 7 , 8 , 10 ] . Despite these advancements, the clinical outcomes of using a guide plate in crown lengthening surgeries remain controversially discussed. Comparatively, no significant differences can be observed in healing outcomes or gingival margin stability between surgeries using a one-piece guide plate and conventional methods [ 10 ] . This lack of clinical evidence can be attributed to the space between the bone surface and the guide plate, which potentially undermines the utility of the guide plate [ 8 ] . To address this issue, a 3D-printed guide has been developed to eliminate the gap, reduce human errors, and improve aesthetic predictability. The study involves a fully digital workflow to design, fabricate, and utilize a metal-combined guide. Unlike previous versions, the metal-combined guide is designed to fit without a gap and adjust the positioning direction to buccal-lingual. The use of metal makes the guide thin and durable, without obstructing the movement of the dental handpiece needle. any gap and change the direction of the position. The metal material makes it thin and tough and does not block the movement of the dental handpiece needle. Case report Figure 1 shows a schematic representation of different adhesion levels between the one-piece guide and the combined guide used for alveolectomy. A 28-year-old patient visited the outpatient department of the Department of Prosthodontics at Guangzhou Medical University, complaining of recurrent redness and swelling of the gums surrounding the bilateral maxillary central incisors and the left maxillary lateral incisor—teeth 11, 21, and 22 according to the FDI classification (fr. Federation Dentaire Internationale). The patient had previously received porcelain crown restoration at another hospital and is now requesting re-restoration. The patient was generally healthy, without systemic diseases and allergies. After a comprehensive evaluation through extraoral and intraoral examinations, as well as CBCT imaging, the treatment plan is to perform crown lengthening on teeth 11, 21, and 22, followed by crown restoration to restore periodontal health and anterior aesthetics. The participants signed an informed consent and the study was conducted following the declaration of Helsinki. At the initial visit, record preoperative images, including intraoral and extraoral photographs, as well as cone beam computed tomography (CBCT; NewTom VG; Quantitative Radiology) images (Fig. 2 ). Obtain the CBCT file in Digital Imaging and Communications in Medicine (DICOM) format and convert it to a standard tessellation language (STL) file. Capture digital scans after removing the defective prosthesis using an intraoral scanner (TRIOS 3; 3Shape), including arches and interocclusal records (Fig. 3 a). Save these files in STL format. Perform periodontal probing simultaneously to determine the patient's periodontal biotype. Design the gingivectomy guide plate. Extract the original bone margin data in STL format using specialized segmentation software (Mimics 20.0, Materialise). Transfer the intraoral scan files and extracted data to CAD software (3shape 2021) to design a digital diagnostic wax-up, indicating gingival limits and the proposed esthetic prosthesis (Fig. 3 b). After obtaining the patient's approval for the shape of the new teeth, gingival contour, and smile, use a best-fit algorithm to merge intraoral scan files with the diagnostic wax-up file (Fig. 3 c) to design the gingivectomy guide plate (Fig. 3 d). Using specialized software (Magic 22, Materialise), design two rectangular structures on the gingivectomy guide plate for stable connection with the subsequent alveolectomy plate. Design the alveolectomy guide plate and fabricate the metal combined guide. Import the extracted information into the bone resection guide plate design software (PlastyCAD 1.9). Use optimal algorithms to fit the extracted data with the diagnostic wax-up file to evaluate and establish a new bone margin, serving as the restrictive edge for the bone resection guide plate. Set the new bone boundary at 3 mm from the bone surface to the gingival margin to ensure supracrestal tissue attachment [ 1 ] . Design the overall shape of the alveolectomy guide (Fig. 4 a), which includes two square hollow structures to accommodate the raised square structures of the gingivectomy guide. Combine the guides for gingivectomy and alveolectomy using the snap-fit mechanism to create the final guide (Fig. 4 b), and fabricate it using selective laser melting technology (HBD-80; hb3dp) (Fig. 4 c, d). Place the gingivectomy guide and assess its adherence to the gingiva clinically (Fig. 5 a, b). Using a periodontal plastic blade, guided by the gingivectomy guide, make an incision to shape the gingiva into a thin, fan-like form (Fig. 5 c), preserving the gingival papillae. Remove the excess gingival flap to expose the new gingival margin (Fig. 5 d). After removing the gingivectomy guide, make an intrasulcular incision and elevate a full-thickness flap. Reapply the gingivectomy guide and connect it to the alveolectomy guide via the snap-fit mechanism (Fig. 6 a). The alveolectomy guide should fit securely against the alveolar bone, outlining the bone removal area and limiting bone resection. Perform the alveolectomy and osteoplasty procedures to remove excess bone through the guide windows (Fig. 6 b). Create a new, regular alveolar bone boundary that supports the supracrestal tissue attachment (Fig. 6 c). Reposition the flap and suture (Fig. 6 d). Manufacture a temporary fixed bridge using the intraoral scan data and temporarily bond it. Provide the patient with detailed postoperative instructions. Remove sutures 14 days post-surgery. Three weeks later, re-scan the abutments and intraoral conditions, as previously described. Design and 3D print a new temporary restoration based on the re-scanned data. Adjust the contact point coronally to allow for proper gingival papilla repositioning, and temporarily bond the new restoration [ 11 ] . Follow-up visits should be scheduled at 3 and 6 months. Once the soft tissue has matured and stabilized, with the gingival papillae filling the interproximal area and no signs of inflammation, proceed with the final restoration and capture postoperative images (Fig. 7 ). Discussion This CAD/CAM metal combined guide enhances the aesthetic predictability of SCL by preventing gaps between the bone surface and the alveolectomy guide. Such gaps can occur with one-piece guide plates that accommodate both the gingiva and the axial positioning of the teeth, which is necessary to ensure smooth placement of the guide. By providing a secure fit between the bone surface and the alveolectomy guide, this design minimizes angular deviations during bone removal, ensuring that the amount of bone removed is neither excessive nor insufficient. From a design perspective, the metal combined guide fits directly against the bone when the gingival flap is raised, leaving no space for the labial gingival flap. This eliminates the potential for gaps and reduces the risk of human error, improving the accuracy and predictability of the alveolectomy in SCL (Fig. 1 ). Compared to conventional one-piece guides, this approach more precisely confines the alveolectomy area, minimizing the risk of damaging the preserved bone [ 8 ] . The gingivectomy and alveolectomy guides are connected by two square snap-fit connections, ensuring stability. Additionally, the alveolectomy guide is designed to be placed in the labial and lingual directions, preventing errors caused by improper alignment along the axial direction of the tooth. To facilitate correct placement, the gingivectomy guide’s insertion path is aligned with the axial direction of the tooth rather than the bone. If the angle between the tooth’s axial direction and the labial bone surface is too large, excessive space may develop between the guide and the bone, leading to surgical errors. This is particularly evident in patients with maxillary overdevelopment and lingual tilt of the anterior teeth or maxillary underdevelopment and labial tilt. The two-piece design improves the precision and predictability of SCL, making it suitable for a broader range of patients. From a surgical perspective, as confirmed by previous studies, the guide allows adequate freedom of blade movement during gingivectomy, even near the gingival papillae [ 1 , 8 , 12 ] . There is no need for protruding structures to reinforce the guide, which also permits sufficient freedom of bur movement during alveolectomy, even in areas near the papillae. This flexibility is a result of the excellent material properties of the guide's metal construction. Moreover, it avoids residual plastic debris generated during bone removal when using a high-speed handpiece and helps reduce deviations caused by varying bur angles. The high hardness and flexural strength of the metal alloy lower the risk of deformation compared to 3D-printed plastic guides, which typically require additional protruding reinforcing structures [ 12 ] . However, further simplification of the technique is desirable. While the precision of this approach requires more initial design time and material costs compared to a one-piece resin guide, the investment may be justified by the enhanced predictability of aesthetic outcomes. Additionally, digital tools for periodontal analysis and quality control can further refine the technique by comparing predicted outcomes with actual results. 9 Piezosurgery equipment also offers the advantage of a clearer surgical field with minimal bleeding, preserving root surface integrity [ 13 ] . Limitations of this study include the small sample size and the lack of long-term follow-up to assess the clinical outcomes. Factors such as variations in printing materials, 3D printers, intraoral scanners, and software programs can affect the accuracy of SCL guides [ 1 , 14 , 15 ] . Therefore, further comparative clinical trials are necessary to validate the repeatability and predictability of this technique [ 16 , 17 ] . Conclusion This article introduces a digital, metal-based guide for crown lengthening that facilitates more precise bone removal and results in more predictable treatment outcomes. The fully digital workflow offers a promising alternative approach to the crown lengthening procedure. Declarations Author Contribution X.Q. and A. S. wrote the main manuscript text; S.L. collected image data; H.Z. designed the metal-combined guide; P.L. offered suggestions and polished the article; J.H. proposed the idea and completed the operation. All authors reviewed the manuscript. Acknowledgement The authors acknowledge the financial support from Key Clinical Technique of Guangzhou MunicipalHealth Commission (2023C-ZD07), Major Clinical Research Project of Guangzhou Medical University (GMUCR2024-02023). No conflicts of interest. Written informed consent was obtained from the participant(s) for the publication of their photographs. Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. References Liu X, Yu J, Zhou J, Tan J. A digitally guided dual technique for both gingival and bone resection during crown lengthening surgery. J Prosthet Dent. 2018;119:345-9. https://doi.org/DOI:10.1016/j.prosdent.2017.04.018. Ahmed WM, Hans A, Verhaeghe TV, Nguyen C. Managing Excessive Gingival Display Using a Digital Workflow. J Prosthodont. 2020;29:443-7. https://doi.org/DOI:10.1111/jopr.13181. Tatakis DN, Silva CO. 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Clin Oral Investig. 2020;24:3633-40. https://doi.org/DOI:10.1007/s00784-020-03239-y. Alazmi SO. Three Dimensional Digitally Designed Surgical Guides in Esthetic Crown Lengthening: A Clinical Case Report with 12 Months Follow Up. Clin Cosme Investig Dent. 2022;14:55-9. https://doi.org/DOI:10.2147/ccide.S338476. Li Y, Liu M, Zhou T, Lyu J, Tan J, Liu X. Accuracy of three types of digital guides for crown lengthening surgery: An in vitro study. J Dent Sci. 2024;19:39-45. https://doi.org/DOI:10.1016/j.jds.2023.06.007. Coachman C, Valavanis K, Silveira FC, Kahn S, Tavares AD, Mahn E et al. The crown lengthening double guide and the digital Perio analysis. J Esthet Restor Dent. 2023;35:215-21. https://doi.org/DOI:10.1111/jerd.12920. Borham E, Abuel-Ela HA, Mohamed IS, Fouad YA. Treatment of excessive gingival display using conventional esthetic crown lengthening versus computer guided esthetic crown lengthening: (a randomized clinical trial). BMC oral health. 2024;24:317. https://doi.org/DOI:10.1186/s12903-024-04080-5. Marzadori M, Stefanini M, Sangiorgi M, Mounssif I, Monaco C, Zucchelli G. Crown lengthening and restorative procedures in the esthetic zone. Periodontol 2000. 2018;77:84-92. https://doi.org/DOI:10.1111/prd.12208. Kim J, Lin YC, Danielak M, Van M, Lee DH, Kim H et al. Virtual Planning and Rapid 3D Prototyping Surgical Guide for Anterior Crown Lengthening Surgery: A Clinical Case Report. J Prosthodont. 2022;31:275-81. https://doi.org/DOI:10.1111/jopr.13471. Lavu V, Arumugam C, Venkatesan N, Sk B, Valandhan Vedha G. A Present Day Approach to Crown Lengthening - Piezosurgery. Cureus. 2019;11:e6241. https://doi.org/DOI:10.7759/cureus.6241. Passos L, Soares FP, Choi IGG, Cortes ARG. Full digital workflow for crown lengthening by using a single surgical guide. J Prosthet Dent. 2020;124:257-61. https://doi.org/DOI:10.1016/j.prosdent.2019.06.027. Tohme H, Revilla-León M, Semaan LB, Lawand G. Facially driven guided crown lengthening using a complete digital workflow: A dental technique. J Prosthet Dent. 2024. https://doi.org/DOI:10.1016/j.prosdent.2024.01.024. Mendoza-Azpur G, Cornejo H, Villanueva M, Alva R, Barbisan de Souza A. Periodontal plastic surgery for esthetic crown lengthening by using data merging and a CAD-CAM surgical guide. J Prosthet Dent. 2022;127:556-9. https://doi.org/DOI:10.1016/j.prosdent.2020.09.041. Coachman C, Bohner L, Jreige CS, Sesma N, Calamita M. Interdisciplinary guided dentistry, digital quality control, and the "copy-paste" concepts. J Esthet Restor Dent. 2021;33:982-91. https://doi.org/DOI:10.1111/jerd.12736. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-6062497","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":422160162,"identity":"503e62ef-561a-45e8-bf17-1e528272a66a","order_by":0,"name":"Xiaoying Qiu","email":"","orcid":"","institution":"Guangzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xiaoying","middleName":"","lastName":"Qiu","suffix":""},{"id":422160165,"identity":"af46c5c8-2df3-45a5-9ac8-f76f69439d9e","order_by":1,"name":"Andi Shi","email":"","orcid":"","institution":"Stomatology hospital, Guangzhou medical university","correspondingAuthor":false,"prefix":"","firstName":"Andi","middleName":"","lastName":"Shi","suffix":""},{"id":422160167,"identity":"cc05fcbb-8fc0-4ac9-967c-bf3b287fdf2c","order_by":2,"name":"Siqi Luo","email":"","orcid":"","institution":"Stomatology hospital, Guangzhou medical university","correspondingAuthor":false,"prefix":"","firstName":"Siqi","middleName":"","lastName":"Luo","suffix":""},{"id":422160168,"identity":"956b3b9b-f44f-4112-9594-e1bbf11878aa","order_by":3,"name":"Huiqun Zhang","email":"","orcid":"","institution":"KTJ Medical Technology Co., Ltd","correspondingAuthor":false,"prefix":"","firstName":"Huiqun","middleName":"","lastName":"Zhang","suffix":""},{"id":422160169,"identity":"3ed8867e-7f17-44f8-aed7-6e03074aaa2d","order_by":4,"name":"Ping Li","email":"","orcid":"","institution":"Guangzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ping","middleName":"","lastName":"Li","suffix":""},{"id":422160170,"identity":"02a46ce5-0bcd-43d8-9b1a-3240a110cb4c","order_by":5,"name":"Jiangyong Huang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYBAC9hk5BiBajoGBByzA2EBICyNUizEJWnrOgLUkNhCvpb3HTOLnjtr0+f5nj27mYbCR3XCA+dkDvFqa+b9J9p45nrvxwLm02zwMacYbDrCZG+DXwmMmwdt2LHdjY48ZUMvhxA0HeNgkCGmR/Nt2LN0QyABq+U9YiyBQpTRvW02CPBtYywHCWqSZeYytZdsOGG7g4TG7Occg2XjmYTYzvFr4mHkMb75tq5OX7z9jduNNhZ1s3/HmZ3i1QMFhBoMDIBoUVMxEqAeCOgb5BuJUjoJRMApGwQgEAHjGR0T2WfY8AAAAAElFTkSuQmCC","orcid":"","institution":"Guangzhou Medical University","correspondingAuthor":true,"prefix":"","firstName":"Jiangyong","middleName":"","lastName":"Huang","suffix":""}],"badges":[],"createdAt":"2025-02-19 09:08:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6062497/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6062497/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":78010096,"identity":"3680592b-c167-43a8-bd31-38fc78f66a2b","added_by":"auto","created_at":"2025-03-07 20:16:06","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":5333562,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic image of different adaptations of the alveolectomy guide between one-piece and combined guides.\u003c/p\u003e","description":"","filename":"Fig1.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/59f75ea5566349708675500a.jpg"},{"id":78009591,"identity":"bc55df9e-c355-4d7a-b244-371b3e45fb2d","added_by":"auto","created_at":"2025-03-07 20:08:04","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6039070,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative images. (A) Intraoral frontal view. (B) Intraoral lateral view. (C) CBCT images of teeth #11, 21, 22 (FDI World Dental Federation notation). CBCT, cone-beam computed tomography. (D) Extraoral lateral photograph.\u003c/p\u003e","description":"","filename":"Fig2.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/abd7e0993a2585ba1e3c277f.jpg"},{"id":78009593,"identity":"66e85f08-6a63-4928-bebc-0c049016fafd","added_by":"auto","created_at":"2025-03-07 20:08:05","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":5972590,"visible":true,"origin":"","legend":"\u003cp\u003eCAD-CAM gingivectomy guide. CAD-CAM, computer-aided design-computer-aided manufacture. (A)Intraoral scan after removal of the defective prosthesis. (B) Digital diagnostic wax-up merged with the initial intraoral scan. (C) Designed a gingivectomy guide on the digital model according to the digital diagnostic wax-up. (D) Frontal view of the designed gingivectomy guide on the digital model.\u003c/p\u003e","description":"","filename":"Fig3.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/a09b987508c61316efd0b499.jpg"},{"id":78009610,"identity":"cf40efea-2889-4742-81d4-a9799e19f5e9","added_by":"auto","created_at":"2025-03-07 20:08:06","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":6315329,"visible":true,"origin":"","legend":"\u003cp\u003eCAD-CAM alveolectomy guide. (A) Frontal view of the designed double guide on the digital model. (B) Lateral view of the designed double guide on the digital model. (C) Printed final guide (assembled). (D) Detached alveolectomy guide.\u003c/p\u003e","description":"","filename":"Fig4.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/c727e5b299b0f2aaabc91908.jpg"},{"id":78009590,"identity":"ef293da1-217c-4408-ad1c-9996bc3846b5","added_by":"auto","created_at":"2025-03-07 20:08:04","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":7995614,"visible":true,"origin":"","legend":"\u003cp\u003eGingivectomy of the metal combined guide for surgical crown lengthening. (A) Placement of the gingivectomy guide (Intraoral frontal view). (B) Placement of the gingivectomy guide (Intraoral occlusal view). (C) Gingival excision according to the gingivectomy guide. (D) Image after gingival resection.\u003c/p\u003e","description":"","filename":"Fig5.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/8f088c4b1578b1e3344fccd5.jpg"},{"id":78010092,"identity":"a64545a2-8eed-4b6d-8350-7940a525db87","added_by":"auto","created_at":"2025-03-07 20:16:05","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":6769269,"visible":true,"origin":"","legend":"\u003cp\u003eAlveolectomy of the metal combined guide for surgical crown lengthening. (A) Placement of the alveolectomy guide. (B) Grinding off excess alveolar bone according to the alveolectomy guide. (C) Image after alveoloplasty (about a 3-mm distance from the alveolar crest to the enamel cementum boundary was investigated). (D) Flap repositioned and sutured.\u003c/p\u003e","description":"","filename":"Fig6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/cc74c240c8b9bf6669c5a4a9.jpg"},{"id":78010097,"identity":"49f8e889-7a5f-4c8f-ab93-9bbc8ac9ae53","added_by":"auto","created_at":"2025-03-07 20:16:06","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":5894933,"visible":true,"origin":"","legend":"\u003cp\u003ePost-op 6 months with final prosthesis. (A) Intraoral frontal view. (B) Intraoral lateral view. (C) CBCT images of teeth 11, 21, and 22 (from left to right). CBCT, cone beam computed tomography. (D) Extraoral lateral photograph.\u003c/p\u003e","description":"","filename":"Fig7.tif.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/ff12c0446c53bc15aec9b9bf.jpg"},{"id":88273443,"identity":"434f16e1-01ba-48e0-8f89-2240399887e8","added_by":"auto","created_at":"2025-08-04 17:31:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":44659954,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6062497/v1/c1dd80b1-5b8e-4fa0-8cdd-7ba25162ed79.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Precision Crown Lengthening with a Metal-Combined Guide: A Dental Technique","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSurgical crown lengthening (SCL) is a periodontal procedure that exposes more tooth structure by removing gingiva and bone, facilitating restoration and enhancing gingival aesthetics while maintaining periodontal biological width \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. The main surgical complications include gingival recession and tissue rebound influenced by the extent of alveolectomy and the positioning of the gingival flap \u003csup\u003e[\u003cspan additionalcitationids=\"CR4 CR5\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. SCL guides are recognized for their precision and stability, which help minimize aesthetic risks, decrease the need for secondary surgeries, and reduce intraoperative time \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. In clinical practice, the commonly used one-piece guide often has a gap between the bone surface and the guide due to flap thickness following elevation. This gap is particularly pronounced in patients with maxillary overdevelopment and lingual tilt of the upper anterior teeth, or maxillary underdevelopment with labial tilt of the upper anterior teeth. In such cases, the space between the bone surface and the guide increases as the axial positioning of the teeth is adjusted to ensure proper placement. This misalignment can lead to errors and excessive bone removal (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), potentially increasing the unpredictability of outcomes and negatively affecting the final aesthetic results \u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe digital era has transformed clinical practice with the introduction of computer-aided design and manufacturing (CAD-CAM) technologies \u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. Digital guides reduce the dependence on surgeons' technical expertise, decrease operating time, enhance aesthetic predictability, and lower the need for follow-up surgeries \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. Despite these advancements, the clinical outcomes of using a guide plate in crown lengthening surgeries remain controversially discussed. Comparatively, no significant differences can be observed in healing outcomes or gingival margin stability between surgeries using a one-piece guide plate and conventional methods \u003csup\u003e[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. This lack of clinical evidence can be attributed to the space between the bone surface and the guide plate, which potentially undermines the utility of the guide plate \u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eTo address this issue, a 3D-printed guide has been developed to eliminate the gap, reduce human errors, and improve aesthetic predictability. The study involves a fully digital workflow to design, fabricate, and utilize a metal-combined guide. Unlike previous versions, the metal-combined guide is designed to fit without a gap and adjust the positioning direction to buccal-lingual. The use of metal makes the guide thin and durable, without obstructing the movement of the dental handpiece needle. any gap and change the direction of the position. The metal material makes it thin and tough and does not block the movement of the dental handpiece needle.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows a schematic representation of different adhesion levels between the one-piece guide and the combined guide used for alveolectomy.\u003c/p\u003e \u003cp\u003eA 28-year-old patient visited the outpatient department of the Department of Prosthodontics at Guangzhou Medical University, complaining of recurrent redness and swelling of the gums surrounding the bilateral maxillary central incisors and the left maxillary lateral incisor\u0026mdash;teeth 11, 21, and 22 according to\u003c/p\u003e \u003cp\u003ethe FDI classification (fr. Federation Dentaire Internationale). The patient had previously received porcelain crown restoration at another hospital and is now requesting re-restoration. The patient was generally healthy, without systemic diseases and allergies. After a comprehensive evaluation through extraoral and intraoral examinations, as well as CBCT imaging, the treatment plan is to perform crown lengthening on teeth 11, 21, and 22, followed by crown restoration to restore periodontal health and anterior aesthetics. The participants signed an informed consent and the study was conducted following the declaration of Helsinki.\u003c/p\u003e \u003cp\u003e \u003col\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAt the initial visit, record preoperative images, including intraoral and extraoral photographs, as well as cone beam computed tomography (CBCT; NewTom VG; Quantitative Radiology) images (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Obtain the CBCT file in Digital Imaging and Communications in Medicine (DICOM) format and convert it to a standard tessellation language (STL) file. Capture digital scans after removing the defective prosthesis using an intraoral scanner (TRIOS 3; 3Shape), including arches and interocclusal records (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). Save these files in STL format. Perform periodontal probing simultaneously to determine the patient's periodontal biotype.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eDesign the gingivectomy guide plate. Extract the original bone margin data in STL format using specialized segmentation software (Mimics 20.0, Materialise). Transfer the intraoral scan files and extracted data to CAD software (3shape 2021) to design a digital diagnostic wax-up, indicating gingival limits and the proposed esthetic prosthesis (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb). After obtaining the patient's approval for the shape of the new teeth, gingival contour, and smile, use a best-fit algorithm to merge intraoral scan files with the diagnostic wax-up file (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec) to design the gingivectomy guide plate (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed). Using specialized software (Magic 22, Materialise), design two rectangular structures on the gingivectomy guide plate for stable connection with the subsequent alveolectomy plate.\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eDesign the alveolectomy guide plate and fabricate the metal combined guide. Import the extracted information into the bone resection guide plate design software (PlastyCAD 1.9). Use optimal algorithms to fit the extracted data with the diagnostic wax-up file to evaluate and establish a new bone margin, serving as the restrictive edge for the bone resection guide plate. Set the new bone boundary at 3 mm from the bone surface to the gingival margin to ensure supracrestal tissue attachment \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Design the overall shape of the alveolectomy guide (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea), which includes two square hollow structures to accommodate the raised square structures of the gingivectomy guide. Combine the guides for gingivectomy and alveolectomy using the snap-fit mechanism to create the final guide (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb), and fabricate it using selective laser melting technology (HBD-80; hb3dp) (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec, d).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003ePlace the gingivectomy guide and assess its adherence to the gingiva clinically (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea, b). Using a periodontal plastic blade, guided by the gingivectomy guide, make an incision to shape the gingiva into a thin, fan-like form (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec), preserving the gingival papillae. Remove the excess gingival flap to expose the new gingival margin (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eAfter removing the gingivectomy guide, make an intrasulcular incision and elevate a full-thickness flap. Reapply the gingivectomy guide and connect it to the alveolectomy guide via the snap-fit mechanism (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea). The alveolectomy guide should fit securely against the alveolar bone, outlining the bone removal area and limiting bone resection. Perform the alveolectomy and osteoplasty procedures to remove excess bone through the guide windows (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb). Create a new, regular alveolar bone boundary that supports the supracrestal tissue attachment (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec). Reposition the flap and suture (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ed).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003cspan\u003e \u003cli\u003e \u003cp\u003eManufacture a temporary fixed bridge using the intraoral scan data and temporarily bond it. Provide the patient with detailed postoperative instructions. Remove sutures 14 days post-surgery. Three weeks later, re-scan the abutments and intraoral conditions, as previously described. Design and 3D print a new temporary restoration based on the re-scanned data. Adjust the contact point coronally to allow for proper gingival papilla repositioning, and temporarily bond the new restoration \u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Follow-up visits should be scheduled at 3 and 6 months. Once the soft tissue has matured and stabilized, with the gingival papillae filling the interproximal area and no signs of inflammation, proceed with the final restoration and capture postoperative images (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003c/li\u003e \u003c/span\u003e \u003c/ol\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis CAD/CAM metal combined guide enhances the aesthetic predictability of SCL by preventing gaps between the bone surface and the alveolectomy guide. Such gaps can occur with one-piece guide plates that accommodate both the gingiva and the axial positioning of the teeth, which is necessary to ensure smooth placement of the guide. By providing a secure fit between the bone surface and the alveolectomy guide, this design minimizes angular deviations during bone removal, ensuring that the amount of bone removed is neither excessive nor insufficient.\u003c/p\u003e \u003cp\u003eFrom a design perspective, the metal combined guide fits directly against the bone when the gingival flap is raised, leaving no space for the labial gingival flap. This eliminates the potential for gaps and reduces the risk of human error, improving the accuracy and predictability of the alveolectomy in SCL (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Compared to conventional one-piece guides, this approach more precisely confines the alveolectomy area, minimizing the risk of damaging the preserved bone \u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. The gingivectomy and alveolectomy guides are connected by two square snap-fit connections, ensuring stability. Additionally, the alveolectomy guide is designed to be placed in the labial and lingual directions, preventing errors caused by improper alignment along the axial direction of the tooth. To facilitate correct placement, the gingivectomy guide\u0026rsquo;s insertion path is aligned with the axial direction of the tooth rather than the bone. If the angle between the tooth\u0026rsquo;s axial direction and the labial bone surface is too large, excessive space may develop between the guide and the bone, leading to surgical errors. This is particularly evident in patients with maxillary overdevelopment and lingual tilt of the anterior teeth or maxillary underdevelopment and labial tilt. The two-piece design improves the precision and predictability of SCL, making it suitable for a broader range of patients.\u003c/p\u003e \u003cp\u003eFrom a surgical perspective, as confirmed by previous studies, the guide allows adequate freedom of blade movement during gingivectomy, even near the gingival papillae \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. There is no need for protruding structures to reinforce the guide, which also permits sufficient freedom of bur movement during alveolectomy, even in areas near the papillae. This flexibility is a result of the excellent material properties of the guide's metal construction. Moreover, it avoids residual plastic debris generated during bone removal when using a high-speed handpiece and helps reduce deviations caused by varying bur angles. The high hardness and flexural strength of the metal alloy lower the risk of deformation compared to 3D-printed plastic guides, which typically require additional protruding reinforcing structures \u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHowever, further simplification of the technique is desirable. While the precision of this approach requires more initial design time and material costs compared to a one-piece resin guide, the investment may be justified by the enhanced predictability of aesthetic outcomes. Additionally, digital tools for periodontal analysis and quality control can further refine the technique by comparing predicted outcomes with actual results.\u003csup\u003e9\u003c/sup\u003e Piezosurgery equipment also offers the advantage of a clearer surgical field with minimal bleeding, preserving root surface integrity \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. Limitations of this study include the small sample size and the lack of long-term follow-up to assess the clinical outcomes. Factors such as variations in printing materials, 3D printers, intraoral scanners, and software programs can affect the accuracy of SCL guides \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. Therefore, further comparative clinical trials are necessary to validate the repeatability and predictability of this technique \u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis article introduces a digital, metal-based guide for crown lengthening that facilitates more precise bone removal and results in more predictable treatment outcomes. The fully digital workflow offers a promising alternative approach to the crown lengthening procedure.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eX.Q. and A. S. wrote the main manuscript text; S.L. collected image data; H.Z. designed the metal-combined guide; P.L. offered suggestions and polished the article; J.H. proposed the idea and completed the operation. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors acknowledge the financial support from Key Clinical Technique of Guangzhou MunicipalHealth Commission (2023C-ZD07), Major Clinical Research Project of Guangzhou Medical University (GMUCR2024-02023).\u003c/p\u003e\u003cp\u003eNo conflicts of interest.\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the participant(s) for the publication of their photographs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLiu X, Yu J, Zhou J, Tan J. A digitally guided dual technique for both gingival and bone resection during crown lengthening surgery. J Prosthet Dent. 2018;119:345-9. https://doi.org/DOI:10.1016/j.prosdent.2017.04.018.\u003c/li\u003e\n\u003cli\u003eAhmed WM, Hans A, Verhaeghe TV, Nguyen C. Managing Excessive Gingival Display Using a Digital Workflow. J Prosthodont. 2020;29:443-7. https://doi.org/DOI:10.1111/jopr.13181.\u003c/li\u003e\n\u003cli\u003eTatakis DN, Silva CO. Contemporary treatment techniques for excessive gingival display caused by altered passive eruption or lip hypermobility. J Dent. 2023;138:104711. https://doi.org/DOI:10.1016/j.jdent.2023.104711.\u003c/li\u003e\n\u003cli\u003ePedrinaci I, Calatrava J, Flores J, Hamilton A, Gallucci GO, Sanz M. Multifunctional anatomical prototypes (MAPs): Treatment of excessive gingival display due to altered passive eruption. J Esthet Restor Dent. 2023;35:1058-67. https://doi.org/DOI:10.1111/jerd.13041.\u003c/li\u003e\n\u003cli\u003eAl-Sowygh ZH. Does Surgical Crown Lengthening Procedure Produce Stable Clinical Outcomes for Restorative Treatment? A Meta-Analysis. J Prosthodont. 2019;28:e103-e9. https://doi.org/DOI:10.1111/jopr.12909.\u003c/li\u003e\n\u003cli\u003eDom\u0026iacute;nguez E, Pascual-La Rocca A, Valles C, Carri\u0026oacute; N, Montagut L, Alemany AS et al. Stability of the gingival margin after an aesthetic crown lengthening procedure in the anterior region by means of a replaced flap and buccal osseous surgery: a prospective study. Clin Oral Investig. 2020;24:3633-40. https://doi.org/DOI:10.1007/s00784-020-03239-y.\u003c/li\u003e\n\u003cli\u003eAlazmi SO. Three Dimensional Digitally Designed Surgical Guides in Esthetic Crown Lengthening: A Clinical Case Report with 12 Months Follow Up. Clin Cosme Investig Dent. 2022;14:55-9. https://doi.org/DOI:10.2147/ccide.S338476.\u003c/li\u003e\n\u003cli\u003eLi Y, Liu M, Zhou T, Lyu J, Tan J, Liu X. Accuracy of three types of digital guides for crown lengthening surgery: An \u003cem\u003ein\u003c/em\u003e\u003cem\u003e \u003c/em\u003e\u003cem\u003evitro\u003c/em\u003e study. J Dent Sci. 2024;19:39-45. https://doi.org/DOI:10.1016/j.jds.2023.06.007.\u003c/li\u003e\n\u003cli\u003eCoachman C, Valavanis K, Silveira FC, Kahn S, Tavares AD, Mahn E et al. The crown lengthening double guide and the digital Perio analysis. J Esthet Restor Dent. 2023;35:215-21. https://doi.org/DOI:10.1111/jerd.12920.\u003c/li\u003e\n\u003cli\u003eBorham E, Abuel-Ela HA, Mohamed IS, Fouad YA. Treatment of excessive gingival display using conventional esthetic crown lengthening versus computer guided esthetic crown lengthening: (a randomized clinical trial). BMC oral health. 2024;24:317. https://doi.org/DOI:10.1186/s12903-024-04080-5.\u003c/li\u003e\n\u003cli\u003eMarzadori M, Stefanini M, Sangiorgi M, Mounssif I, Monaco C, Zucchelli G. Crown lengthening and restorative procedures in the esthetic zone. Periodontol 2000. 2018;77:84-92. https://doi.org/DOI:10.1111/prd.12208.\u003c/li\u003e\n\u003cli\u003eKim J, Lin YC, Danielak M, Van M, Lee DH, Kim H et al. Virtual Planning and Rapid 3D Prototyping Surgical Guide for Anterior Crown Lengthening Surgery: A Clinical Case Report. J Prosthodont. 2022;31:275-81. https://doi.org/DOI:10.1111/jopr.13471.\u003c/li\u003e\n\u003cli\u003eLavu V, Arumugam C, Venkatesan N, Sk B, Valandhan Vedha G. A Present Day Approach to Crown Lengthening - Piezosurgery. Cureus. 2019;11:e6241. https://doi.org/DOI:10.7759/cureus.6241.\u003c/li\u003e\n\u003cli\u003ePassos L, Soares FP, Choi IGG, Cortes ARG. Full digital workflow for crown lengthening by using a single surgical guide. J Prosthet Dent. 2020;124:257-61. https://doi.org/DOI:10.1016/j.prosdent.2019.06.027.\u003c/li\u003e\n\u003cli\u003eTohme H, Revilla-Le\u0026oacute;n M, Semaan LB, Lawand G. Facially driven guided crown lengthening using a complete digital workflow: A dental technique. J Prosthet Dent. 2024. https://doi.org/DOI:10.1016/j.prosdent.2024.01.024.\u003c/li\u003e\n\u003cli\u003eMendoza-Azpur G, Cornejo H, Villanueva M, Alva R, Barbisan de Souza A. Periodontal plastic surgery for esthetic crown lengthening by using data merging and a CAD-CAM surgical guide. J Prosthet Dent. 2022;127:556-9. https://doi.org/DOI:10.1016/j.prosdent.2020.09.041.\u003c/li\u003e\n\u003cli\u003eCoachman C, Bohner L, Jreige CS, Sesma N, Calamita M. Interdisciplinary guided dentistry, digital quality control, and the \u0026quot;copy-paste\u0026quot; concepts. J Esthet Restor Dent. 2021;33:982-91. https://doi.org/DOI:10.1111/jerd.12736.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Crown lengthening, Alveolectomy, Gap","lastPublishedDoi":"10.21203/rs.3.rs-6062497/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6062497/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePURPOSE. \u003c/strong\u003eThis study presents a surgical technique for crown lengthening using a metal-combined guide, aimed at minimizing the gap between the bone surface and the guide to reduce visual and surgical errors.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMATERIALS AND METHODS.\u003c/strong\u003e The protocol includes: 1) Preoperative data acquisition through cone beam computed tomography (CBCT), intraoral scanning, and periodontal probing; 2) Creating a digital diagnostic wax-up to guide the design of the gingivectomy guide plate; 3) The elaboration of the alveolectomy guide plate and its combination structures, followed by the fabrication of the metal-combined guide; 4) Precisely placing the gingivectomy guide to assist in the gingivectomy procedure; 5) The subsequent removal of the gingivectomy guide, enabling the execution of alveolectomy and osteoplasty procedures; and 6) The provision of comprehensive post-operative care, encompassing temporary restoration, adjustment of adjacent contact points, final restoration, and scheduled follow-up visits.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCONCLUSIONS. \u003c/strong\u003eThis technique utilizes digital technology to integrate various datasets for designing and fabricating a metal-combined guide, improving the precision of bone removal and leading to more predictable treatment outcomes. This approach is particularly beneficial for patients with maxillary overdevelopment and lingual tilt of the anterior teeth, or maxillary underdevelopment with lip tilt of the anterior teeth.\u003c/p\u003e","manuscriptTitle":"Precision Crown Lengthening with a Metal-Combined Guide: A Dental Technique","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-07 20:07:58","doi":"10.21203/rs.3.rs-6062497/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7953ac57-b626-4268-915d-d8b0063f89d8","owner":[],"postedDate":"March 7th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-04T17:23:27+00:00","versionOfRecord":[],"versionCreatedAt":"2025-03-07 20:07:58","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6062497","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6062497","identity":"rs-6062497","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}