Comparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses

Comparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses | 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 Comparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses Stalin This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9206898/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 Background Porcelain fracture or chipping in metal-ceramic fixed dental prostheses (FDPs) is a frequent clinical complication, necessitating reliable repair strategies. Direct intraoral and indirect laboratory-based repair systems represent the two principal approaches, yet their comparative performance remains incompletely characterized. Objectives To evaluate and compare shear bond strength, surface roughness, and time efficiency of direct intraoral and indirect porcelain repair systems in metal-ceramic FDPs under controlled in-vitro conditions. Materials and Methods Eighty-eight standardized nickel-chromium/porcelain disc specimens were fabricated and divided equally into two groups: Group I (Direct Intraoral Repair) and Group II (Indirect Porcelain Repair). A standardized 2 mm defect was introduced in each specimen. Shear bond strength was measured using a Universal Testing Machine (UNITEK 94100), surface roughness (Ra) was assessed with a profilometer, and procedure time was recorded with a stopwatch. Statistical analysis employed independent t-tests, one-way ANOVA, and the Mann-Whitney U test (α = 0.05). Results The indirect repair system demonstrated significantly higher mean shear bond strength (21.77 ± 1.38 MPa) compared to the direct system (18.49 ± 1.55 MPa) (p < 0.001). Surface roughness was comparable between groups (Direct: 0.801 µm; Indirect: 0.815 µm; p = 0.860). Direct repairs were substantially faster (mean: 13.41 min) than indirect repairs (mean: 50.11 min) (p < 0.001). All failures were adhesive in nature. Conclusion Indirect porcelain repair systems provide superior bond strength and are recommended for extensive or high-stress fractures. Direct intraoral systems offer a time-efficient, clinically viable alternative for minor fractures. The choice of technique should be guided by fracture extent, functional demands, and clinical circumstances. Dentistry Porcelain repair Metal-ceramic prosthesis Shear bond strength Surface roughness Time efficiency Fixed dental prostheses 1. INTRODUCTION Fixed dental prostheses (FDPs), particularly metal-ceramic (porcelain-fused-to-metal, PFM) restorations, have served as a cornerstone of prosthodontic rehabilitation for over six decades. Their sustained popularity is attributable to the complementary properties of the metal substructure — typically a cobalt-chromium or nickel-chromium alloy — providing structural rigidity and the overlying feldspathic porcelain veneer conferring natural tooth-like aesthetics and translucency [1,2]. Despite these advantages, porcelain fracture remains a clinically significant and frequently encountered complication, with reported incidence rates of 4–10% over a five- to ten-year service period [3,4]. Porcelain fracture in PFM restorations is multifactorial in origin, encompassing inadequate metal-ceramic bonding, improper occlusal design, thermal cycling fatigue, and mechanical overloading during mastication. When fracture occurs, the clinician is faced with a critical decision: complete prosthesis replacement — a costly, invasive, and time-consuming option — or in-situ repair using one of the available repair strategies [5,6]. Two principal repair philosophies exist: (i) direct intraoral repair systems, which employ resin composite materials applied chairside within the oral environment; and (ii) indirect repair systems, which involve fabrication of a repair component in the dental laboratory under controlled conditions, followed by adhesive bonding. Each approach carries distinct advantages and limitations with respect to bond strength, surface finish, procedural time, and long-term clinical durability [7,8]. Shear bond strength is the most widely adopted parameter for evaluating the mechanical efficacy of porcelain repair systems, as it reflects the ability of the repaired interface to resist delaminating forces comparable to masticatory loading. Surface roughness determines not only the aesthetic integration of the repair but also the susceptibility to plaque adhesion and secondary caries. Time efficiency is of practical importance in the clinical workflow, particularly for chairside repairs in a busy prosthodontic practice [9,10]. While previous investigations have examined individual aspects of porcelain repair, comprehensive in-vitro studies simultaneously evaluating shear bond strength, surface roughness, and time efficiency under controlled and standardized conditions remain limited. The present study was therefore designed to address this gap, providing an evidence-based comparative assessment of direct intraoral and indirect porcelain repair systems in metal-ceramic FDPs. 2. AIM AND OBJECTIVES 2.1 Aim To assess the shear bond strength, surface roughness, and time efficiency of direct intraoral and indirect porcelain repair systems in metal-ceramic fixed dental prostheses. 2.2 Primary Objectives 1. To evaluate the shear bond strength of the direct intraoral porcelain repair system using a Universal Testing Machine. 2. To evaluate the shear bond strength of the indirect porcelain repair system using a Universal Testing Machine. 3. To evaluate the surface roughness of the direct intraoral porcelain repair system using a profilometer. 4. To evaluate the surface roughness of the indirect porcelain repair system using a profilometer. 5. To evaluate and compare time efficiency between the two repair systems using a stopwatch. 2.3 Null Hypothesis There is no statistically significant difference between the direct intraoral and indirect porcelain repair systems in terms of shear bond strength, surface roughness, and time efficiency in metal-ceramic fixed dental prostheses. 3. MATERIALS AND METHODS 3.1 Study Design and Setting This in-vitro study was conducted at the Department of Prosthodontics and Crown & Bridge, Post Graduate Institute of Dental Sciences (PGIDS), Rohtak, India. Shear bond strength testing was performed at the University Institute of Engineering & Technology (UIET), Maharshi Dayanand University, Rohtak, and surface roughness was assessed at Deep Precision Pvt. Limited, IMT, Rohtak. 3.2 Sample Size Calculation Sample size was calculated using nMaster software version 2.0, based on estimation of difference between two means. Considering a standard deviation of 0.45 in Group I and 0.91 in Group II, an estimated mean difference of 0.3, and a 95% confidence level (α = 0.05), a minimum of 44 specimens per group was required. A total of 88 specimens were fabricated. 3.3 Specimen Fabrication Standardized metal-ceramic disc specimens were fabricated using nickel-chromium alloy pellets (Verabond II) and feldspathic porcelain (Noritake). A custom metal mold was fabricated using Direct Metal Laser Sintering (DMLS) technology in cobalt-chromium alloy, designed to produce wax patterns with precise dimensions (2 mm thickness, 1 mm radius). Molten blue inlay wax was poured into the mold cavity to create uniform wax patterns. The wax patterns were invested, subjected to controlled burnout, and cast using an induction casting machine. Cast metal discs were finished, sandblasted, and oxidized in a burnout furnace. Sequential porcelain layers — wash opaque, opaque, dentin, and enamel — were applied and fired at prescribed temperatures in a ceramic firing furnace. A final glaze firing was performed to achieve a smooth, clinically representative surface. All specimens were verified for dimensional accuracy using a digital Vernier caliper. 3.4 Defect Creation A standardized 2 mm-diameter defect was introduced into the porcelain surface of each specimen using a high-speed handpiece under water cooling. Defect margins were refined to simulate clinical fracture scenarios with clean, reproducible geometry. 3.5 Repair Protocols Group I — Direct Intraoral Porcelain Repair System (n = 44) : The defect surface was etched with 5% hydrofluoric acid for 90 seconds, rinsed, and dried. A silane coupling agent was applied and allowed to react for 60 seconds. Renew Universal bonding agent was applied and light-cured for 20 seconds. Flowable composite (Fusion Flo) was incrementally applied to fill the defect and light-cured for 40 seconds. Finishing and polishing were performed using a porcelain polishing kit. Group II — Indirect Porcelain Repair System (n = 44) : Following defect characterization and marginal preparation (chamfer/bevel design), an elastomeric impression (polyvinyl siloxane) was taken to record the defect dimensions. A working cast was poured and a porcelain veneer/disc was fabricated using porcelain layering technique in the laboratory. After trial fitting, the defect site and fabricated veneer were treated with hydrofluoric acid etching, silanization, and sandblasting. A bonding agent was applied followed by luting with resin cement. The restoration was light-cured and finished. 3.6 Testing Procedures Shear Bond Strength : Shear bond strength was measured using a Universal Testing Machine (UNITEK 94100) with a crosshead speed of 0.5 mm/min. The maximum force at failure (Newtons) was recorded and converted to MPa by dividing by the bonded area. All failure modes were classified as adhesive or cohesive upon visual and microscopic inspection. Surface Roughness : Surface roughness was measured using a contact profilometer. The Ra (arithmetic mean roughness), Rz (average maximum height), and Rq (root mean square roughness) parameters were recorded for each specimen across three scan lines, and mean values were calculated. Time Efficiency : The total duration of each repair procedure — encompassing defect preparation, surface treatment, material application, and finishing — was recorded using a calibrated digital stopwatch. Time was measured in minutes and seconds. 3.7 Statistical Analysis Data were compiled using MS Office Excel (v2019) and analyzed using SPSS v26.0 (IBM, Armonk, NY, USA). Normality was assessed using the Shapiro-Wilk test. As data were non-normally distributed, both parametric (independent t-test, one-way ANOVA) and non-parametric (Mann-Whitney U test, Chi-square test) analyses were applied. A p-value of < 0.05 was considered statistically significant. Pearson's r and Spearman's ρ were calculated to assess correlation strength. 4. RESULTS 4.1 Shear Bond Strength The mean shear bond strength for Group I (Direct Intraoral) was 18.49 MPa, while Group II (Indirect) yielded a significantly higher mean of 21.77 MPa. The independent t-test confirmed a statistically significant difference between the groups (t = − 9.412, p < 0.001), with a mean difference of − 3.277 MPa (95% CI: −3.970 to − 2.585). ANOVA corroborated this finding (F = 88.587, p < 0.001). The Mann-Whitney U test also demonstrated a significant intergroup difference (p = 0.000). Strong positive correlations between technique and bond strength were observed: Pearson's r = 0.712, Spearman's ρ = 0.707 (both p < 0.001). All failures were adhesive in nature, occurring at the repair material-porcelain interface; no cohesive failures were recorded. Table 1 Descriptive Statistics — Shear Bond Strength (MPa) Group Repair System Mean (MPa) SD p-value Group I Direct Intraoral 18.49 1.55 < 0.001* Group II Indirect 21.77 1.38 < 0.001* *Statistically significant (p < 0.05) 4.2 Surface Roughness Mean surface roughness (Ra) was 0.801 µm for Group I and 0.815 µm for Group II, representing a non-significant difference of 0.014 µm. The independent t-test (t = − 0.177, p = 0.860) and ANOVA (F = 0.031, p = 0.860) confirmed the absence of a statistically significant intergroup difference. The Chi-Square test (Pearson χ² = 84.000, p = 0.449) and symmetric measures (Pearson's r = 0.019; Spearman's ρ = 0.030; p > 0.05) further supported comparable surface roughness outcomes between the two systems. Table 2 Descriptive Statistics — Surface Roughness (µm) Group Repair System Mean Ra (µm) SD p-value Group I Direct Intraoral 0.801 0.380 0.860 (NS) Group II Indirect 0.815 0.375 0.860 (NS) NS = Not Significant 4.3 Time Efficiency Direct intraoral repairs required a mean procedure time of 13.41 minutes, compared to 50.11 minutes for indirect repairs — a difference of approximately 36.7 minutes. This difference was highly statistically significant (t = − 69.674, p < 0.001; 95% CI: −37.759 to − 35.650). ANOVA confirmed this finding (F = 4854.507, p < 0.001). The Chi-Square test (χ² = 88.000, p = 0.000) and high correlation coefficients (Pearson's r = 0.991; Spearman's ρ = 0.869; p = 0.000) demonstrated the strong relationship between technique choice and time requirements. Table 3 Descriptive Statistics — Time Efficiency (minutes) Group Repair System Mean Time (min) SD p-value Group I Direct Intraoral 13.41 2.10 < 0.001* Group II Indirect 50.11 3.85 < 0.001* *Statistically significant (p < 0.05) Table 4 Summary of Statistical Comparisons Parameter Group I (Direct) Group II (Indirect) t-value p-value Shear Bond Strength (MPa) 18.49 ± 1.55 21.77 ± 1.38 −9.412 < 0.001* Surface Roughness (µm) 0.801 ± 0.380 0.815 ± 0.375 −0.177 0.860 (NS) Time Efficiency (min) 13.41 ± 2.10 50.11 ± 3.85 −69.674 < 0.001* *Statistically significant; NS = Not Significant 5. DISCUSSION The present in-vitro study investigated the comparative performance of direct intraoral and indirect porcelain repair systems across three clinically relevant parameters: shear bond strength, surface roughness, and time efficiency. The findings provide a multidimensional perspective on the merits and limitations of each approach, informing evidence-based clinical decision-making. 5.1 Shear Bond Strength The indirect repair system demonstrated a statistically significantly higher mean shear bond strength (21.77 MPa) compared to the direct intraoral system (18.49 MPa) (p < 0.001). This finding aligns with the existing literature, where controlled laboratory sintering and optimized surface treatment in indirect methods consistently yield superior mechanical adhesion [16,18]. The t-statistic of − 9.412 and a mean difference of − 3.277 MPa, with a narrow confidence interval, underscore the robustness and clinical relevance of this difference. The superior bond strength of the indirect system can be attributed to several mechanistic factors. Laboratory conditions permit more thorough and controlled hydrofluoric acid etching, silanization, and adhesive application, free from the constraints of oral humidity, limited access, and temperature fluctuation that challenge direct intraoral procedures [19,21]. Furthermore, laboratory-fabricated porcelain allows precise adaptation to the defect margins, maximizing the bonded surface area and reducing stress concentrations. The direct intraoral system, although yielding a lower mean bond strength (18.49 MPa), still achieved values within the clinically acceptable range for minor restorative repairs, consistent with reports by Haselton et al. [19] and Yadav et al. [25], who reported direct repair bond strengths in the 15–22 MPa range depending on the system employed and the surface treatment protocol. All failures in the present study were adhesive in nature, occurring at the repair interface rather than within the porcelain bulk, indicating that both systems preserved the integrity of the underlying substrate. 5.2 Surface Roughness No statistically significant difference in surface roughness was observed between the direct and indirect repair systems (p = 0.860), with mean Ra values of 0.801 µm and 0.815 µm, respectively. This finding suggests that, under controlled conditions with meticulous polishing, both techniques are capable of achieving comparable surface finishes. The absence of a significant difference is consistent with previous studies reporting similar surface roughness outcomes for composite-based and laboratory-fabricated porcelain repairs [24,26]. While Ra values for both groups remained within the range reported for acceptable clinical surfaces (0.2–1.5 µm), the slightly higher variability in Group I may reflect operator-dependent irregularities inherent to intraoral polishing. Such surface inconsistencies, even if not statistically significant at the group level, could predispose to differential plaque accumulation over time, potentially affecting gingival health and restoration longevity [26]. This emphasizes the importance of meticulous finishing and polishing protocols regardless of the repair technique selected. 5.3 Time Efficiency The most clinically conspicuous difference between the two systems was procedural time. Direct intraoral repairs required a mean of 13.41 minutes, representing an 73.2% reduction in procedure time compared to indirect repairs (50.11 minutes; p < 0.001). The Pearson's correlation of 0.991 between technique type and time underscores the near-deterministic relationship between repair modality choice and procedural duration. The time advantage of direct intraoral repair is of considerable practical significance in busy clinical environments, particularly for managing minor porcelain chipping in emergency or single-appointment scenarios. Conversely, the extended time required for indirect repairs encompasses impression-taking, laboratory fabrication, and a subsequent cementation appointment — steps that, while adding procedural burden, confer the mechanical superiority documented above. The clinical utility of indirect repairs is thus greatest in scenarios where long-term durability outweighs time considerations, such as extensive fractures, posterior high-occlusal-load zones, or aesthetically critical anterior restorations. 5.4 Clinical Implications and Comparison with Literature The findings of this study extend the existing body of evidence on porcelain repair systems. Previous investigations have reported indirect laboratory-based repair to yield superior bond strength over direct systems [16,18], while time efficiency consistently favours direct approaches [5,7]. The comparable surface roughness findings in the present study add to this understanding, suggesting that surface finish should not be a primary discriminating factor between the two systems when appropriate polishing is performed. The null hypothesis — that no significant difference exists between the two repair systems in shear bond strength, surface roughness, and time efficiency — was partially rejected. Significant differences were confirmed for shear bond strength and time efficiency, while the null hypothesis was retained for surface roughness. The present study reinforces the paradigm that no single repair system is universally superior across all clinical parameters. Direct intraoral repair is the preferred option for time-critical, chairside management of minor porcelain fractures, while indirect repair is indicated for cases requiring maximal durability and longevity. Clinician expertise, patient preferences, prosthesis location, and occlusal demands must be integrated into the repair system selection process. 5.5 Limitations This study was conducted under controlled in-vitro conditions, which may not fully replicate the complex intraoral environment characterized by thermal cycling, occlusal fatigue, and salivary contamination. All specimens were prepared from standardized nickel-chromium/porcelain discs; clinical fractures may present with greater morphological variability. Additionally, operator variability was minimized in this controlled setting, whereas clinical outcomes may differ with operator experience. Further in-vivo and long-term clinical studies are recommended to validate and extend these findings. 6. CONCLUSION This in-vitro study provides a comprehensive comparative evaluation of direct intraoral and indirect porcelain repair systems in metal-ceramic fixed dental prostheses across three clinically relevant parameters. Based on the results, the following conclusions are drawn: 1. Shear Bond Strength: The indirect porcelain repair system demonstrated significantly superior shear bond strength (21.77 MPa) compared to the direct intraoral system (18.49 MPa) (p < 0.001), attributable to optimized laboratory processing conditions. 2. Surface Roughness: Both systems produced comparable surface roughness values (Direct: 0.801 µm; Indirect: 0.815 µm) with no statistically significant intergroup difference (p = 0.860), indicating equivalent surface finish quality when appropriate polishing is performed. 3. Time Efficiency: The direct intraoral repair system was substantially faster (13.41 min vs. 50.11 min; p < 0.001), making it the preferred choice for time-sensitive chairside applications. 4. All repair failures were adhesive in nature, affirming the structural integrity of both systems with respect to the underlying porcelain substrate. The selection of repair technique should be guided by the clinical scenario: direct intraoral repair is recommended for minor, low-stress fractures requiring rapid chairside management, whereas indirect repair is indicated for extensive fractures, high-load posterior zones, and situations where long-term mechanical performance is the primary consideration. Future research incorporating in-vivo conditions, thermal and mechanical aging, and diverse ceramic substrates will further refine clinical recommendations for porcelain repair. Declarations Conflict of Interest: The authors declare no conflict of interest. Funding: This study received no external funding. Ethical Approval: Not applicable (in-vitro study). References Kelly JR, Benetti P. Ceramic materials in dentistry: historical evolution and current practice. Aust Dent J. 2011;56(1):84–96. Özcan M. Fracture reasons in ceramic-fused-to-metal restorations. Dent Mater. 2003;19(6):595–603. Rosentritt M, Behr M, Van der Zel J. In vitro repair of all-ceramic crowns. J Dent. 2009;37(6):452–8. Burke FJT. Repair of minor defect in porcelain restorations. Dent Update. 2001;28(7):346–52. Fawzy AS, El-Askary FS. Effect of surface treatment and intermediate materials on shear bond strength of repaired ceramic. J Prosthodont. 2009;18(8):613–9. Kern M, Thompson VP. Bonding to glass-infiltrated alumina ceramic: adhesive methods and their durability. J Prosthet Dent. 1995;73(3):240–9. Hickel R, Brüshaver K. Guidelines for direct restorative materials. Clin Oral Investig. 2008;12(1):5–19. Pameijer CH. Adhesive solutions: materials, techniques, and clinical implications. Int J Dent. 2012;2012:951460. Ban S, Anusavice KJ. Influence of test method on failure stress of brittle dental materials. J Dent Res. 1990;69(12):1791–9. Roulet JF, Söderholm KJM. Adhesion: the silent revolution in dentistry. Quintessence Int. 2001;28(2):65–75. Amaral R, Özcan M, Bottino MA. Evaluation of silica coating and silanization on the bond strength of ceramics to resin cement. J Adhes Dent. 2008;10(6):431–8. Manicone PF, Rossi Iommetti P, Raffaelli L. An overview of zirconia ceramics: basic properties and clinical applications. J Dent. 2007;35(11):819–26. Tylka DF, Stewart GP. Comparison of acidulated phosphate fluoride gel and hydrofluoric acid etching of porcelain. J Prosthet Dent. 1994;72(2):121–7. Özcan M, Vallittu PK. Effect of surface conditioning methods on the bond strength of luting cement to ceramics. Dent Mater. 2003;19(8):725–31. Rosentritt M, Behr M, Bauer W. In-vitro repair of metal-ceramic fixed partial dentures. J Oral Rehabil. 2002;29(9):833–8. Dos Santos JG, Fonseca RG, Adabo GL, Dos Santos Cruz CA. Shear bond strength of metal-ceramic repair systems. J Prosthet Dent. 2006;96(3):165–73. Meshramkar R, Sajjan S. A comparative evaluation of shear bond strength of porcelain and composite using different bonding agents. J Indian Prosthodont Soc. 2010;10(3):160–6. Fahmy NZ, Mohsen CA. Assessment of an indirect metal ceramic repair system. J Prosthet Dent. 2008;100(4):292–9. Haselton DR, Diaz-Arnold AM, Dunne JT Jr. Shear bond strengths of two intraoral porcelain repair systems to porcelain or metal substrates. J Prosthet Dent. 2001;86(5):526–31. Kalra A, Mohan MS, Gowda EM. Comparison of shear bond strength of two porcelain repair systems after different surface treatments. J Conserv Dent. 2016;19(4):343–8. Ozcan M, Van Der Sleen JM, Kurunmaki H, Vallittu PK. Comparison of repair methods for ceramic-fused-to-metal crowns. Dent Mater. 2006;22(2):168–74. Sirageddin H, Erol F, Çelik MG. Shear bond strengths of five porcelain repair systems to zirconia infrastructures. J Prosthet Dent. 2022;128(2):311–8. Özcan M. Evaluation of alternative intra-oral repair techniques for fractured ceramic-fused-to-metal restorations. J Oral Rehabil. 2003;30(3):265–72. Siam R, Elnaggar G, Hassanien E. Effect of finishing protocol and zirconia content on surface roughness. Int J Appl Dent Sci. 2021;7(2):45–50. Yadav JS, Dabas N, Bhargava A, Malhotra P, Yadav B, Sehgal M. Comparing two intraoral porcelain repair systems for shear bond strength. J Indian Prosthodont Soc. 2019;19(4):301–8. Abdalla MM, Ali IAA, Khan K, et al. Surface roughening and polishing of ceramics: Their effect on surface roughness and biofilm adhesion. J Prosthodont. 2021;30(6):523–30. Additional Declarations The authors declare no competing interests. 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. 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-9206898","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":611097836,"identity":"cc4298a1-b11f-4224-bee9-09d484259337","order_by":0,"name":"Stalin","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIiWNgGAWjYHACxgMJDAwyDAzMB4AcCRnCGtgYGEBaeICsBJAWHuK0MIC18BgwQBgEgPz85gcHHu6w4+Gf3fP51Y0aCx4G9sNHN+DTYnCMzeBA4plkHok7Z7dZ5xwDOownLe0GXi1sDEAtbQd4GG7kbjPOYQNqkeAxw6tFvo39A1iL/I2cZ8Y5/4jQwnCMB2KLwY0c5se5bURoMTiWUwDUksxjeCPNjDm3T4KHjZBf5JuPb3z4s81OTu5G8uPPOd/q5PjZDx/D7zAkwCYBJolVDgLMH0hRPQpGwSgYBSMHAADhnEghX/iiMwAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0009-0005-0298-3762","institution":"POST GRADUATE INSTITUTE OF DENTAL SCIENCES","correspondingAuthor":true,"prefix":"","firstName":"","middleName":"","lastName":"Stalin","suffix":""}],"badges":[],"createdAt":"2026-03-24 05:20:31","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9206898/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9206898/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105565341,"identity":"076eb813-e368-4931-b314-50c53dabaee6","added_by":"auto","created_at":"2026-03-27 12:52:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":673762,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9206898/v1/f503a568-0c30-4d72-b9f4-854d8ad5fbf6.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eComparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eFixed dental prostheses (FDPs), particularly metal-ceramic (porcelain-fused-to-metal, PFM) restorations, have served as a cornerstone of prosthodontic rehabilitation for over six decades. Their sustained popularity is attributable to the complementary properties of the metal substructure \u0026mdash; typically a cobalt-chromium or nickel-chromium alloy \u0026mdash; providing structural rigidity and the overlying feldspathic porcelain veneer conferring natural tooth-like aesthetics and translucency [1,2]. Despite these advantages, porcelain fracture remains a clinically significant and frequently encountered complication, with reported incidence rates of 4\u0026ndash;10% over a five- to ten-year service period [3,4].\u003c/p\u003e \u003cp\u003ePorcelain fracture in PFM restorations is multifactorial in origin, encompassing inadequate metal-ceramic bonding, improper occlusal design, thermal cycling fatigue, and mechanical overloading during mastication. When fracture occurs, the clinician is faced with a critical decision: complete prosthesis replacement \u0026mdash; a costly, invasive, and time-consuming option \u0026mdash; or in-situ repair using one of the available repair strategies [5,6].\u003c/p\u003e \u003cp\u003eTwo principal repair philosophies exist: (i) direct intraoral repair systems, which employ resin composite materials applied chairside within the oral environment; and (ii) indirect repair systems, which involve fabrication of a repair component in the dental laboratory under controlled conditions, followed by adhesive bonding. Each approach carries distinct advantages and limitations with respect to bond strength, surface finish, procedural time, and long-term clinical durability [7,8].\u003c/p\u003e \u003cp\u003eShear bond strength is the most widely adopted parameter for evaluating the mechanical efficacy of porcelain repair systems, as it reflects the ability of the repaired interface to resist delaminating forces comparable to masticatory loading. Surface roughness determines not only the aesthetic integration of the repair but also the susceptibility to plaque adhesion and secondary caries. Time efficiency is of practical importance in the clinical workflow, particularly for chairside repairs in a busy prosthodontic practice [9,10].\u003c/p\u003e \u003cp\u003eWhile previous investigations have examined individual aspects of porcelain repair, comprehensive in-vitro studies simultaneously evaluating shear bond strength, surface roughness, and time efficiency under controlled and standardized conditions remain limited. The present study was therefore designed to address this gap, providing an evidence-based comparative assessment of direct intraoral and indirect porcelain repair systems in metal-ceramic FDPs.\u003c/p\u003e"},{"header":"2. AIM AND OBJECTIVES","content":"\u003cp\u003e\u003cstrong\u003e2.1 Aim\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo assess the shear bond strength, surface roughness, and time efficiency of direct intraoral and indirect porcelain repair systems in metal-ceramic fixed dental prostheses.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Primary Objectives\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1. To evaluate the shear bond strength of the direct intraoral porcelain repair system using a Universal Testing Machine.\u003c/p\u003e\n\u003cp\u003e2. To evaluate the shear bond strength of the indirect porcelain repair system using a Universal Testing Machine.\u003c/p\u003e\n\u003cp\u003e3. To evaluate the surface roughness of the direct intraoral porcelain repair system using a profilometer.\u003c/p\u003e\n\u003cp\u003e4. To evaluate the surface roughness of the indirect porcelain repair system using a profilometer.\u003c/p\u003e\n\u003cp\u003e5. To evaluate and compare time efficiency between the two repair systems using a stopwatch.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Null Hypothesis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no statistically significant difference between the direct intraoral and indirect porcelain repair systems in terms of shear bond strength, surface roughness, and time efficiency in metal-ceramic fixed dental prostheses.\u003c/p\u003e"},{"header":"3. MATERIALS AND METHODS","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Study Design and Setting\u003c/h2\u003e \u003cp\u003eThis in-vitro study was conducted at the Department of Prosthodontics and Crown \u0026amp; Bridge, Post Graduate Institute of Dental Sciences (PGIDS), Rohtak, India. Shear bond strength testing was performed at the University Institute of Engineering \u0026amp; Technology (UIET), Maharshi Dayanand University, Rohtak, and surface roughness was assessed at Deep Precision Pvt. Limited, IMT, Rohtak.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Sample Size Calculation\u003c/h2\u003e \u003cp\u003eSample size was calculated using nMaster software version 2.0, based on estimation of difference between two means. Considering a standard deviation of 0.45 in Group I and 0.91 in Group II, an estimated mean difference of 0.3, and a 95% confidence level (α\u0026thinsp;=\u0026thinsp;0.05), a minimum of 44 specimens per group was required. A total of 88 specimens were fabricated.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Specimen Fabrication\u003c/h2\u003e \u003cp\u003eStandardized metal-ceramic disc specimens were fabricated using nickel-chromium alloy pellets (Verabond II) and feldspathic porcelain (Noritake). A custom metal mold was fabricated using Direct Metal Laser Sintering (DMLS) technology in cobalt-chromium alloy, designed to produce wax patterns with precise dimensions (2 mm thickness, 1 mm radius).\u003c/p\u003e \u003cp\u003eMolten blue inlay wax was poured into the mold cavity to create uniform wax patterns. The wax patterns were invested, subjected to controlled burnout, and cast using an induction casting machine. Cast metal discs were finished, sandblasted, and oxidized in a burnout furnace. Sequential porcelain layers \u0026mdash; wash opaque, opaque, dentin, and enamel \u0026mdash; were applied and fired at prescribed temperatures in a ceramic firing furnace. A final glaze firing was performed to achieve a smooth, clinically representative surface. All specimens were verified for dimensional accuracy using a digital Vernier caliper.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Defect Creation\u003c/h2\u003e \u003cp\u003eA standardized 2 mm-diameter defect was introduced into the porcelain surface of each specimen using a high-speed handpiece under water cooling. Defect margins were refined to simulate clinical fracture scenarios with clean, reproducible geometry.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Repair Protocols\u003c/h2\u003e \u003cp\u003e \u003cem\u003eGroup I \u0026mdash; Direct Intraoral Porcelain Repair System (n\u0026thinsp;=\u0026thinsp;44)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eThe defect surface was etched with 5% hydrofluoric acid for 90 seconds, rinsed, and dried. A silane coupling agent was applied and allowed to react for 60 seconds. Renew Universal bonding agent was applied and light-cured for 20 seconds. Flowable composite (Fusion Flo) was incrementally applied to fill the defect and light-cured for 40 seconds. Finishing and polishing were performed using a porcelain polishing kit.\u003c/p\u003e \u003cp\u003e \u003cem\u003eGroup II \u0026mdash; Indirect Porcelain Repair System (n\u0026thinsp;=\u0026thinsp;44)\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eFollowing defect characterization and marginal preparation (chamfer/bevel design), an elastomeric impression (polyvinyl siloxane) was taken to record the defect dimensions. A working cast was poured and a porcelain veneer/disc was fabricated using porcelain layering technique in the laboratory. After trial fitting, the defect site and fabricated veneer were treated with hydrofluoric acid etching, silanization, and sandblasting. A bonding agent was applied followed by luting with resin cement. The restoration was light-cured and finished.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.6 Testing Procedures\u003c/h2\u003e \u003cp\u003e \u003cem\u003eShear Bond Strength\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eShear bond strength was measured using a Universal Testing Machine (UNITEK 94100) with a crosshead speed of 0.5 mm/min. The maximum force at failure (Newtons) was recorded and converted to MPa by dividing by the bonded area. All failure modes were classified as adhesive or cohesive upon visual and microscopic inspection.\u003c/p\u003e \u003cp\u003e \u003cem\u003eSurface Roughness\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eSurface roughness was measured using a contact profilometer. The Ra (arithmetic mean roughness), Rz (average maximum height), and Rq (root mean square roughness) parameters were recorded for each specimen across three scan lines, and mean values were calculated.\u003c/p\u003e \u003cp\u003e \u003cem\u003eTime Efficiency\u003c/em\u003e:\u003c/p\u003e \u003cp\u003eThe total duration of each repair procedure \u0026mdash; encompassing defect preparation, surface treatment, material application, and finishing \u0026mdash; was recorded using a calibrated digital stopwatch. Time was measured in minutes and seconds.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.7 Statistical Analysis\u003c/h2\u003e \u003cp\u003eData were compiled using MS Office Excel (v2019) and analyzed using SPSS v26.0 (IBM, Armonk, NY, USA). Normality was assessed using the Shapiro-Wilk test. As data were non-normally distributed, both parametric (independent t-test, one-way ANOVA) and non-parametric (Mann-Whitney U test, Chi-square test) analyses were applied. A p-value of \u0026lt;\u0026thinsp;0.05 was considered statistically significant. Pearson's r and Spearman's ρ were calculated to assess correlation strength.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. RESULTS","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003e4.1 Shear Bond Strength\u003c/h2\u003e \u003cp\u003eThe mean shear bond strength for Group I (Direct Intraoral) was 18.49 MPa, while Group II (Indirect) yielded a significantly higher mean of 21.77 MPa. The independent t-test confirmed a statistically significant difference between the groups (t\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;9.412, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with a mean difference of \u0026minus;\u0026thinsp;3.277 MPa (95% CI: \u0026minus;3.970 to \u0026minus;\u0026thinsp;2.585). ANOVA corroborated this finding (F\u0026thinsp;=\u0026thinsp;88.587, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The Mann-Whitney U test also demonstrated a significant intergroup difference (p\u0026thinsp;=\u0026thinsp;0.000). Strong positive correlations between technique and bond strength were observed: Pearson's r\u0026thinsp;=\u0026thinsp;0.712, Spearman's ρ\u0026thinsp;=\u0026thinsp;0.707 (both p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). All failures were adhesive in nature, occurring at the repair material-porcelain interface; no cohesive failures were recorded.\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\u003eDescriptive Statistics \u0026mdash; Shear Bond Strength (MPa)\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e Group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRepair System\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean (MPa)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDirect Intraoral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e18.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIndirect\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003e*Statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05)\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e4.2 Surface Roughness\u003c/h2\u003e \u003cp\u003eMean surface roughness (Ra) was 0.801 \u0026micro;m for Group I and 0.815 \u0026micro;m for Group II, representing a non-significant difference of 0.014 \u0026micro;m. The independent t-test (t\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;0.177, p\u0026thinsp;=\u0026thinsp;0.860) and ANOVA (F\u0026thinsp;=\u0026thinsp;0.031, p\u0026thinsp;=\u0026thinsp;0.860) confirmed the absence of a statistically significant intergroup difference. The Chi-Square test (Pearson χ\u0026sup2; = 84.000, p\u0026thinsp;=\u0026thinsp;0.449) and symmetric measures (Pearson's r\u0026thinsp;=\u0026thinsp;0.019; Spearman's ρ\u0026thinsp;=\u0026thinsp;0.030; p\u0026thinsp;\u0026gt;\u0026thinsp;0.05) further supported comparable surface roughness outcomes between the two systems.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescriptive Statistics \u0026mdash; Surface Roughness (\u0026micro;m)\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRepair System\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean Ra (\u0026micro;m)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDirect Intraoral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.801\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.380\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.860 (NS)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIndirect\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.815\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.375\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.860 (NS)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eNS\u0026thinsp;=\u0026thinsp;Not Significant\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e4.3 Time Efficiency\u003c/h2\u003e \u003cp\u003eDirect intraoral repairs required a mean procedure time of 13.41 minutes, compared to 50.11 minutes for indirect repairs \u0026mdash; a difference of approximately 36.7 minutes. This difference was highly statistically significant (t\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;69.674, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; 95% CI: \u0026minus;37.759 to \u0026minus;\u0026thinsp;35.650). ANOVA confirmed this finding (F\u0026thinsp;=\u0026thinsp;4854.507, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The Chi-Square test (χ\u0026sup2; = 88.000, p\u0026thinsp;=\u0026thinsp;0.000) and high correlation coefficients (Pearson's r\u0026thinsp;=\u0026thinsp;0.991; Spearman's ρ\u0026thinsp;=\u0026thinsp;0.869; p\u0026thinsp;=\u0026thinsp;0.000) demonstrated the strong relationship between technique choice and time requirements.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDescriptive Statistics \u0026mdash; Time Efficiency (minutes)\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=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRepair System\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMean Time (min)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDirect Intraoral\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e13.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eIndirect\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e50.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003e*Statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05)\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSummary of Statistical Comparisons\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=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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\u003eGroup I (Direct)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup II (Indirect)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eShear Bond Strength (MPa)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e18.49\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e21.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;9.412\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurface Roughness (\u0026micro;m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.801\u0026thinsp;\u0026plusmn;\u0026thinsp;0.380\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.815\u0026thinsp;\u0026plusmn;\u0026thinsp;0.375\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;0.177\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.860 (NS)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime Efficiency (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e13.41\u0026thinsp;\u0026plusmn;\u0026thinsp;2.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e50.11\u0026thinsp;\u0026plusmn;\u0026thinsp;3.85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026minus;69.674\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003e*Statistically significant; NS\u0026thinsp;=\u0026thinsp;Not Significant\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"5. DISCUSSION","content":"\u003cp\u003eThe present in-vitro study investigated the comparative performance of direct intraoral and indirect porcelain repair systems across three clinically relevant parameters: shear bond strength, surface roughness, and time efficiency. The findings provide a multidimensional perspective on the merits and limitations of each approach, informing evidence-based clinical decision-making.\u003c/p\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003e5.1 Shear Bond Strength\u003c/h2\u003e \u003cp\u003eThe indirect repair system demonstrated a statistically significantly higher mean shear bond strength (21.77 MPa) compared to the direct intraoral system (18.49 MPa) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This finding aligns with the existing literature, where controlled laboratory sintering and optimized surface treatment in indirect methods consistently yield superior mechanical adhesion [16,18]. The t-statistic of \u0026minus;\u0026thinsp;9.412 and a mean difference of \u0026minus;\u0026thinsp;3.277 MPa, with a narrow confidence interval, underscore the robustness and clinical relevance of this difference.\u003c/p\u003e \u003cp\u003eThe superior bond strength of the indirect system can be attributed to several mechanistic factors. Laboratory conditions permit more thorough and controlled hydrofluoric acid etching, silanization, and adhesive application, free from the constraints of oral humidity, limited access, and temperature fluctuation that challenge direct intraoral procedures [19,21]. Furthermore, laboratory-fabricated porcelain allows precise adaptation to the defect margins, maximizing the bonded surface area and reducing stress concentrations.\u003c/p\u003e \u003cp\u003eThe direct intraoral system, although yielding a lower mean bond strength (18.49 MPa), still achieved values within the clinically acceptable range for minor restorative repairs, consistent with reports by Haselton et al. [19] and Yadav et al. [25], who reported direct repair bond strengths in the 15\u0026ndash;22 MPa range depending on the system employed and the surface treatment protocol. All failures in the present study were adhesive in nature, occurring at the repair interface rather than within the porcelain bulk, indicating that both systems preserved the integrity of the underlying substrate.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e5.2 Surface Roughness\u003c/h2\u003e \u003cp\u003eNo statistically significant difference in surface roughness was observed between the direct and indirect repair systems (p\u0026thinsp;=\u0026thinsp;0.860), with mean Ra values of 0.801 \u0026micro;m and 0.815 \u0026micro;m, respectively. This finding suggests that, under controlled conditions with meticulous polishing, both techniques are capable of achieving comparable surface finishes. The absence of a significant difference is consistent with previous studies reporting similar surface roughness outcomes for composite-based and laboratory-fabricated porcelain repairs [24,26].\u003c/p\u003e \u003cp\u003eWhile Ra values for both groups remained within the range reported for acceptable clinical surfaces (0.2\u0026ndash;1.5 \u0026micro;m), the slightly higher variability in Group I may reflect operator-dependent irregularities inherent to intraoral polishing. Such surface inconsistencies, even if not statistically significant at the group level, could predispose to differential plaque accumulation over time, potentially affecting gingival health and restoration longevity [26]. This emphasizes the importance of meticulous finishing and polishing protocols regardless of the repair technique selected.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003e5.3 Time Efficiency\u003c/h2\u003e \u003cp\u003eThe most clinically conspicuous difference between the two systems was procedural time. Direct intraoral repairs required a mean of 13.41 minutes, representing an 73.2% reduction in procedure time compared to indirect repairs (50.11 minutes; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The Pearson's correlation of 0.991 between technique type and time underscores the near-deterministic relationship between repair modality choice and procedural duration.\u003c/p\u003e \u003cp\u003eThe time advantage of direct intraoral repair is of considerable practical significance in busy clinical environments, particularly for managing minor porcelain chipping in emergency or single-appointment scenarios. Conversely, the extended time required for indirect repairs encompasses impression-taking, laboratory fabrication, and a subsequent cementation appointment \u0026mdash; steps that, while adding procedural burden, confer the mechanical superiority documented above. The clinical utility of indirect repairs is thus greatest in scenarios where long-term durability outweighs time considerations, such as extensive fractures, posterior high-occlusal-load zones, or aesthetically critical anterior restorations.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003e5.4 Clinical Implications and Comparison with Literature\u003c/h2\u003e \u003cp\u003eThe findings of this study extend the existing body of evidence on porcelain repair systems. Previous investigations have reported indirect laboratory-based repair to yield superior bond strength over direct systems [16,18], while time efficiency consistently favours direct approaches [5,7]. The comparable surface roughness findings in the present study add to this understanding, suggesting that surface finish should not be a primary discriminating factor between the two systems when appropriate polishing is performed.\u003c/p\u003e \u003cp\u003eThe null hypothesis \u0026mdash; that no significant difference exists between the two repair systems in shear bond strength, surface roughness, and time efficiency \u0026mdash; was partially rejected. Significant differences were confirmed for shear bond strength and time efficiency, while the null hypothesis was retained for surface roughness.\u003c/p\u003e \u003cp\u003eThe present study reinforces the paradigm that no single repair system is universally superior across all clinical parameters. Direct intraoral repair is the preferred option for time-critical, chairside management of minor porcelain fractures, while indirect repair is indicated for cases requiring maximal durability and longevity. Clinician expertise, patient preferences, prosthesis location, and occlusal demands must be integrated into the repair system selection process.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003e5.5 Limitations\u003c/h2\u003e \u003cp\u003eThis study was conducted under controlled in-vitro conditions, which may not fully replicate the complex intraoral environment characterized by thermal cycling, occlusal fatigue, and salivary contamination. All specimens were prepared from standardized nickel-chromium/porcelain discs; clinical fractures may present with greater morphological variability. Additionally, operator variability was minimized in this controlled setting, whereas clinical outcomes may differ with operator experience. Further in-vivo and long-term clinical studies are recommended to validate and extend these findings.\u003c/p\u003e \u003c/div\u003e"},{"header":"6. CONCLUSION","content":"\u003cp\u003eThis in-vitro study provides a comprehensive comparative evaluation of direct intraoral and indirect porcelain repair systems in metal-ceramic fixed dental prostheses across three clinically relevant parameters. Based on the results, the following conclusions are drawn:\u003c/p\u003e\n\u003cp\u003e1. Shear Bond Strength: The indirect porcelain repair system demonstrated significantly superior shear bond strength (21.77 MPa) compared to the direct intraoral system (18.49 MPa) (p \u0026lt; 0.001), attributable to optimized laboratory processing conditions.\u003c/p\u003e\n\u003cp\u003e2. Surface Roughness: Both systems produced comparable surface roughness values (Direct: 0.801 µm; Indirect: 0.815 µm) with no statistically significant intergroup difference (p = 0.860), indicating equivalent surface finish quality when appropriate polishing is performed.\u003c/p\u003e\n\u003cp\u003e3. Time Efficiency: The direct intraoral repair system was substantially faster (13.41 min vs. 50.11 min; p \u0026lt; 0.001), making it the preferred choice for time-sensitive chairside applications.\u003c/p\u003e\n\u003cp\u003e4. All repair failures were adhesive in nature, affirming the structural integrity of both systems with respect to the underlying porcelain substrate.\u003c/p\u003e\n\u003cp\u003eThe selection of repair technique should be guided by the clinical scenario: direct intraoral repair is recommended for minor, low-stress fractures requiring rapid chairside management, whereas indirect repair is indicated for extensive fractures, high-load posterior zones, and situations where long-term mechanical performance is the primary consideration. Future research incorporating in-vivo conditions, thermal and mechanical aging, and diverse ceramic substrates will further refine clinical recommendations for porcelain repair.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u0026nbsp;\u003c/strong\u003eThe authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThis study received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval:\u0026nbsp;\u003c/strong\u003eNot applicable (in-vitro study).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKelly JR, Benetti P. Ceramic materials in dentistry: historical evolution and current practice. Aust Dent J. 2011;56(1):84\u0026ndash;96.\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zcan M. Fracture reasons in ceramic-fused-to-metal restorations. Dent Mater. 2003;19(6):595\u0026ndash;603.\u003c/li\u003e\n\u003cli\u003eRosentritt M, Behr M, Van der Zel J. In vitro repair of all-ceramic crowns. J Dent. 2009;37(6):452\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eBurke FJT. Repair of minor defect in porcelain restorations. Dent Update. 2001;28(7):346\u0026ndash;52.\u003c/li\u003e\n\u003cli\u003eFawzy AS, El-Askary FS. Effect of surface treatment and intermediate materials on shear bond strength of repaired ceramic. J Prosthodont. 2009;18(8):613\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eKern M, Thompson VP. Bonding to glass-infiltrated alumina ceramic: adhesive methods and their durability. J Prosthet Dent. 1995;73(3):240\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eHickel R, Br\u0026uuml;shaver K. Guidelines for direct restorative materials. Clin Oral Investig. 2008;12(1):5\u0026ndash;19.\u003c/li\u003e\n\u003cli\u003ePameijer CH. Adhesive solutions: materials, techniques, and clinical implications. Int J Dent. 2012;2012:951460.\u003c/li\u003e\n\u003cli\u003eBan S, Anusavice KJ. Influence of test method on failure stress of brittle dental materials. J Dent Res. 1990;69(12):1791\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eRoulet JF, S\u0026ouml;derholm KJM. Adhesion: the silent revolution in dentistry. Quintessence Int. 2001;28(2):65\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eAmaral R, \u0026Ouml;zcan M, Bottino MA. Evaluation of silica coating and silanization on the bond strength of ceramics to resin cement. J Adhes Dent. 2008;10(6):431\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eManicone PF, Rossi Iommetti P, Raffaelli L. An overview of zirconia ceramics: basic properties and clinical applications. J Dent. 2007;35(11):819\u0026ndash;26.\u003c/li\u003e\n\u003cli\u003eTylka DF, Stewart GP. Comparison of acidulated phosphate fluoride gel and hydrofluoric acid etching of porcelain. J Prosthet Dent. 1994;72(2):121\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zcan M, Vallittu PK. Effect of surface conditioning methods on the bond strength of luting cement to ceramics. Dent Mater. 2003;19(8):725\u0026ndash;31.\u003c/li\u003e\n\u003cli\u003eRosentritt M, Behr M, Bauer W. In-vitro repair of metal-ceramic fixed partial dentures. J Oral Rehabil. 2002;29(9):833\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eDos Santos JG, Fonseca RG, Adabo GL, Dos Santos Cruz CA. Shear bond strength of metal-ceramic repair systems. J Prosthet Dent. 2006;96(3):165\u0026ndash;73.\u003c/li\u003e\n\u003cli\u003eMeshramkar R, Sajjan S. A comparative evaluation of shear bond strength of porcelain and composite using different bonding agents. J Indian Prosthodont Soc. 2010;10(3):160\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eFahmy NZ, Mohsen CA. Assessment of an indirect metal ceramic repair system. J Prosthet Dent. 2008;100(4):292\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eHaselton DR, Diaz-Arnold AM, Dunne JT Jr. Shear bond strengths of two intraoral porcelain repair systems to porcelain or metal substrates. J Prosthet Dent. 2001;86(5):526\u0026ndash;31.\u003c/li\u003e\n\u003cli\u003eKalra A, Mohan MS, Gowda EM. Comparison of shear bond strength of two porcelain repair systems after different surface treatments. J Conserv Dent. 2016;19(4):343\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eOzcan M, Van Der Sleen JM, Kurunmaki H, Vallittu PK. Comparison of repair methods for ceramic-fused-to-metal crowns. Dent Mater. 2006;22(2):168\u0026ndash;74.\u003c/li\u003e\n\u003cli\u003eSirageddin H, Erol F, \u0026Ccedil;elik MG. Shear bond strengths of five porcelain repair systems to zirconia infrastructures. J Prosthet Dent. 2022;128(2):311\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003e\u0026Ouml;zcan M. Evaluation of alternative intra-oral repair techniques for fractured ceramic-fused-to-metal restorations. J Oral Rehabil. 2003;30(3):265\u0026ndash;72.\u003c/li\u003e\n\u003cli\u003eSiam R, Elnaggar G, Hassanien E. Effect of finishing protocol and zirconia content on surface roughness. Int J Appl Dent Sci. 2021;7(2):45\u0026ndash;50.\u003c/li\u003e\n\u003cli\u003eYadav JS, Dabas N, Bhargava A, Malhotra P, Yadav B, Sehgal M. Comparing two intraoral porcelain repair systems for shear bond strength. J Indian Prosthodont Soc. 2019;19(4):301\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eAbdalla MM, Ali IAA, Khan K, et al. Surface roughening and polishing of ceramics: Their effect on surface roughness and biofilm adhesion. J Prosthodont. 2021;30(6):523\u0026ndash;30.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Pandit Bhagwat Dayal Sharma University of Health Sciences","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":"Porcelain repair, Metal-ceramic prosthesis, Shear bond strength, Surface roughness, Time efficiency, Fixed dental prostheses","lastPublishedDoi":"10.21203/rs.3.rs-9206898/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9206898/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003ePorcelain fracture or chipping in metal-ceramic fixed dental prostheses (FDPs) is a frequent clinical complication, necessitating reliable repair strategies. Direct intraoral and indirect laboratory-based repair systems represent the two principal approaches, yet their comparative performance remains incompletely characterized.\u003c/p\u003e\u003ch2\u003eObjectives\u003c/h2\u003e \u003cp\u003eTo evaluate and compare shear bond strength, surface roughness, and time efficiency of direct intraoral and indirect porcelain repair systems in metal-ceramic FDPs under controlled in-vitro conditions.\u003c/p\u003e\u003ch2\u003eMaterials and Methods\u003c/h2\u003e \u003cp\u003eEighty-eight standardized nickel-chromium/porcelain disc specimens were fabricated and divided equally into two groups: Group I (Direct Intraoral Repair) and Group II (Indirect Porcelain Repair). A standardized 2 mm defect was introduced in each specimen. Shear bond strength was measured using a Universal Testing Machine (UNITEK 94100), surface roughness (Ra) was assessed with a profilometer, and procedure time was recorded with a stopwatch. Statistical analysis employed independent t-tests, one-way ANOVA, and the Mann-Whitney U test (α\u0026thinsp;=\u0026thinsp;0.05).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe indirect repair system demonstrated significantly higher mean shear bond strength (21.77\u0026thinsp;\u0026plusmn;\u0026thinsp;1.38 MPa) compared to the direct system (18.49\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55 MPa) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Surface roughness was comparable between groups (Direct: 0.801 \u0026micro;m; Indirect: 0.815 \u0026micro;m; p\u0026thinsp;=\u0026thinsp;0.860). Direct repairs were substantially faster (mean: 13.41 min) than indirect repairs (mean: 50.11 min) (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). All failures were adhesive in nature.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIndirect porcelain repair systems provide superior bond strength and are recommended for extensive or high-stress fractures. Direct intraoral systems offer a time-efficient, clinically viable alternative for minor fractures. The choice of technique should be guided by fracture extent, functional demands, and clinical circumstances.\u003c/p\u003e","manuscriptTitle":"Comparative Assessment of Shear Bond Strength, Surface Roughness, and Time Efficiency of Direct Intraoral and Indirect Porcelain Repair Systems in Metal-Ceramic Fixed Dental Prostheses","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-25 11:16:46","doi":"10.21203/rs.3.rs-9206898/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":"5af718bb-fc14-46e3-a3de-871324b40569","owner":[],"postedDate":"March 25th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":65019101,"name":"Dentistry"}],"tags":[],"updatedAt":"2026-03-25T11:16:46+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-25 11:16:46","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9206898","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9206898","identity":"rs-9206898","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}