Next Article in Journal
Application of Molecular Diagnostics in Periprosthetic Joint Infection Microorganism Identification Following Screening Colonoscopy: A Case Report and Review of the Literature
Previous Article in Journal
The Stress Distribution and Deformation of Maxillary Bilateral Distal-Extension Removable Partial Dentures with U-Shaped Palatal Major Connectors Fabricated from Different Materials: A Finite Element Analysis
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Prosthesis
Volume 7
Issue 6
10.3390/prosthesis7060151
prosthesis-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Mechanochemical Optimization of Composite–Substrate Interfaces for Durable Repair Adhesion to Metal and Zirconia: An In Vitro Study

by
Bryar Abdulqadir Sharif
* and
Hawzhen Masoud Mohammed Saeed
Department of Operative Dentistry and Endodontics, College of Dentistry, University of Sulaimani, Sulaimaniyah 46001, Iraq
*
Author to whom correspondence should be addressed.
Prosthesis 2025, 7(6), 151; https://doi.org/10.3390/prosthesis7060151
Submission received: 22 October 2025 / Revised: 7 November 2025 / Accepted: 10 November 2025 / Published: 21 November 2025
Browse Figures
Versions Notes

Abstract

Background/Objectives: Achieving durable intraoral repairs of fractured metal and zirconia restorations requires optimal adhesion. This in vitro study evaluated the effects of mechanical surface treatments and commercial repair systems on the shear bond strength (SBS) of composite resin to nickel–chromium (Ni-Cr) alloy and zirconia, including the influence of thermocycling aging. Methods: In this study, 144 Ni-Cr and zirconia discs (12 × 12 × 2 mm) were randomly assigned to three surface treatments: untreated control, airborne particle abrasion (50 µm Al2O3), and medium grit diamond bur grinding. Each group was further subdivided to assess two intraoral repair kits (GC Corp (Tokyo, Japan). and Bisco Inc. (Schaumburg, IL, USA)). Composite resin cylinders were bonded following the manufacturer’s instructions. Half of the specimens (n = 12/subgroup) underwent 5000 thermocycles (5–55 °C). Micro-shear bond strength testing was performed, and failure modes were analyzed. Data were analyzed using three-way ANOVA and post hoc tests (p < 0.05). Results: Air abrasion significantly increased SBS compared to control and bur grinding for metal (p < 0.001). For zirconia, both air abrasion and bur grinding yielded similarly improved SBS over the control (p < 0.001). The GC repair kit demonstrated significantly superior bond stability after thermocycling across both substrates. Aging significantly reduced SBS in all groups (p < 0.001), with the most substantial reductions observed in untreated controls and groups repaired with the Bisco system. Conclusions: Airborne particle abrasion combined with a HEMA-free, 10-MDP-containing universal adhesive achieved the strongest and most durable resin bonds to both metal and zirconia, supporting its clinical use for the intraoral repair of ceramic and metal restorations.

1. Introduction

Ceramics were initially used with metal substructures to reinforce the more brittle ceramic materials. These combinations, known as porcelain-fused-to-metal (PFM) restorations, have long been considered the gold standard for fixed partial restorations due to their ability to fulfill both functional and esthetic demands. However, several disadvantages have been associated with PFMs, including reduced light transmission, gingival discoloration around abutment teeth, allergic reactions, and the release of metallic ions into gingival tissues. As a result, the growing demand for highly esthetic restorations has led to the development of metal-free all-ceramic restorations, using different resin-based adhesive systems, which provide superior esthetic outcomes [1,2].
Dental ceramics are commonly classified based on their composition into glass-based ceramics, resin-matrix ceramics, and polycrystalline ceramics [3,4]. Glass ceramics, such as lithium disilicate and leucite-reinforced ceramics, consist primarily of a silica-based matrix that provides excellent polish ability and esthetic characteristics. The crystalline phase enhances mechanical strength and fracture resistance [3,5]. Resin-matrix ceramics are composed of a ceramic network infiltrated with a polymer resin; combining the esthetics and wear resistance of ceramics with the resilience, ease of milling, and repairability of composite resins [6]. In contrast, polycrystalline ceramics are composed entirely of densely packed crystals with no glassy phase. Among them, zirconia is notable for its superior mechanical properties, and compared with metal frameworks, it provides satisfactory esthetic outcomes [3,7].
Despite ongoing advances in ceramic materials, including efforts to improve the translucency of monolithic zirconia, this material remains relatively opaque. Therefore, zirconia is often used as a core structure, veneered with feldspathic porcelain or lithium disilicate powder, to achieve optimal esthetic outcomes [8,9].
All commercially available ceramic materials used for indirect restorations are prone to fracture during clinical service. Such failures may arise from fatigue, traumatic events, or parafunctional habits, as well as laboratory-related factors such as inadequate slow cooling, improper framework-to-veneer ratios, and inadequate firing procedures, etc. [1,10,11].
Due to the inherent characteristics of ceramic processing, new porcelain cannot be added to an existing restoration intraorally. Consequently, intraoral repair represents a practical and often emergency approach for managing localized fractures. Direct repairs performed with resin-based composites in a single appointment offer several advantages, including reduced treatment time and lower costs for the patient. Moreover, this approach minimizes the need for further interventions or additional tooth preparation, which could compromise pulp vitality and weaken tooth structure, thereby enabling a more conservative and efficient restorative treatment [3,10,12].
The repair of fractured ceramic restorations serves as a conservative method to restore both function and esthetics through the implementation of intraoral repair system components. This process needs mechanical surface preparation and chemical bonding agents to achieve strong composite resin adhesion with the ceramic surfaces [2,13,14].
Researchers have developed multiple repair protocols over the past years to enhance the bond strength, durability, and esthetic results of ceramic restorations. The most effective repair system remains unclear because various elements determine the results. The success of ceramic repair depends on multiple factors, which include ceramic material selection, surface preparation methods, environmental exposure conditions, and the choice of repair materials [15,16].
Surface treatment is crucial in repairing fractured ceramic surfaces. It involves mechanically increasing the surface area, reducing tension, and creating a fine surface roughness. Chemically, it selectively dissolves the glassy matrix, promoting resin adhesion. Surface treatment alters the roughness of dental materials’ surfaces, which is essential for indirect restorations. Enhancing surface roughness improves mechanical interlocking with adhesive materials, ensuring long-lasting and stable restorations in challenging oral environments [17,18].
This in vitro study aims to assess the effect of mechanical surface treatments, along with two different intra-oral repair kits, on the shear bond strength between composite resin and two types of indirect restorative materials: metal (nickel–chromium alloy) and zirconia. The null hypotheses were as follows: (1) that applying different surface treatment methods to the indirect restorative materials would not result in a statistically significant difference in shear bond strength; (2) that there would be no significant difference in shear bond strength among the different types of restorative materials, regardless of the repair protocol used.

2. Materials and Methods

2.1. Study Design

A schematic representation of the study design and experimental workflow of this in vitro study is shown in Figure 1.

2.2. Sample Preparation

The sample size was calculated using G*Power software (version 3.1.9.2; University of Kiel, Kiel, Germany) to ensure adequate statistical power for detecting significant differences among groups. The calculation was performed with 80% power, an alpha level of 0.05, and an effect size of 0.80. A total of 144 samples was deemed sufficient to achieve statistical significance. For each material, 72 square-shaped specimens (12 × 12 × 2 mm) were fabricated by a single operator following the manufacturer’s instructions.
Nickel–Chromium Alloy: Nickel–chromium samples (Realoy-N+, German Special Alloys GmbH, Carl-Friedrich-Benz-Str. 1b, 47877 Willich, Germany) were fabricated using selective laser melting technology following the alloy’s fabrication guidelines.
Zirconia: Zirconia blocks (CaroZir®, Carol Zircolite Pvt. Ltd., Bad Säckingen, Germany) were milled from pre-sintered blanks using a CAD/CAM system and sintered at 1530 °C for 10 h, as per the manufacturer’s instructions. The materials used in this study are presented in Table 1.
All samples were embedded in cold-cured acrylic resin (Veracril, New Stetics, Colombia), leaving only one surface exposed for subsequent treatments (Figure 2). The exposed surfaces were sequentially polished with 600-, 800-, 1000-, and 1200-grit silicon carbide abrasive papers under water cooling. This was followed by ultrasonic cleaning in distilled water for 5 min and drying with oil-free compressed air.

2.3. Sample Grouping and Surface Treatments

Specimens were numbered, thoroughly mixed, and then randomly allocated to the experimental groups in equal numbers using a simple random allocation method to minimize potential selection bias. Each material group (n = 72) was then randomly divided into three surface treatment subgroups (n = 24 each):
Group 1: (Control) Received no surface treatment.
Group 2: (Airborne Particle Abrasion) Performed using an air abrasion unit (Foshan Asin Dental Equipment Co., Foshan, China) mounted on a dental surveyor for standardization. Surfaces were treated with 50 µm aluminum oxide particles at a pressure of 2.5 bar through a nozzle with a 0.5 mm internal diameter, positioned perpendicular (90°) to the specimen surface, and maintained at a constant distance of 10 mm in a circular motion for 10 s. The samples were then rinsed and air-dried [19].
Group 3: (Diamond Bur grinding) Surfaces were roughened with a medium-grit (approx. 100 µm) diamond bur (Jota, Rüthi, Switzerland) mounted in a dental surveyor. The bur was applied in a standardized back-and-forth motion (10 passes) at 200,000 RPM under water cooling; burs were replaced every five specimens [20].

2.4. Surface Roughness Measurement

To assess surface roughness and topography of the specimens after surface treatment, two additional specimens were fabricated in each group, as explained earlier. They were analyzed using an atomic force microscope (AFM Workshop Model TT-2, Hilton Head Island, SC, USA). A silicon nitride tip with a 50 nm radius and 45° apex angle was used. Surfaces were scanned at 80 µm/s across a 50 × 50 µm area at 312 × 271-pixel resolution. AFM scans were taken from three randomly selected central areas on each sample, avoiding the edges to prevent measurement bias. The arithmetic mean height (Sa) value was calculated from these three readings to obtain a representative value for each surface. High-resolution 3D AFM images were used to illustrate surface morphology more clearly. Images were analyzed using MountainsSPIP® software (Expert version 8.2.10392) [21].

2.5. Bonding Procedures and Composite Resin Application

Each surface-treated group was further subdivided into two subgroups (n = 12) based on the adhesive system used. Adhesives were applied according to the manufacturer’s instructions. To ensure uniform adhesive thickness, all applications were performed by the same operator using a new microbrush every five specimens. The adhesive was gently air-dried for 5 s at a constant air pressure and 10 cm distance before light curing, resulting in a thin and consistent adhesive layer.
Intraoral Repair Kit Group:
Z-Prime plus: One layer of Z-prime plus (Bisco, USA) was applied to each treated sample using a microbrush and dried with an air spray for 5 s. Porcelain Bonding Resin (Bisco, USA): A thin layer of porcelain bonding resin was applied to the treated samples, and the solvent was evaporated using air-drying followed by light curing for 10 s.
GC Repair Kit Group:
G-Multi Primer (GC Corporation, Tokyo, Japan): One layer of G-Multi Primer was applied onto the all-treated sample, then it was air-dried. G-Premio Bond Universal Adhesive (GC Corporation, Japan): A single layer was applied, followed by a 10 s wait. The adhesive was then dried for 5 s under a strong stream of air and finally light-cured for 10 s.
Three polyethylene microtubules (2 mm internal diameter, 3 mm height) were placed over each surface and filled with Tokuyama Palfique LX5 composite resin (A2 shade, Japan) in three increments. Each increment was light-cured for 20 s using a curing unit (Foshan Coxo Medical Instrument Co., Ltd.) at an intensity of 1200 mW/cm2. Subsequently, after the removal of the microtubule, the entire restoration received an additional 20 s of light curing [22].
All bonding and testing procedures were carried out in a controlled laboratory environment at 23 ± 2 °C and 50 ± 10% relative humidity, consistent with the ISO guideline for dental material testing.

2.6. Storage and Thermocycling

Specimens were stored in distilled water at 37 °C for 15 h. Half of the specimens were thermocycled for 5000 cycles between 5 °C and 55 °C with a 30 s dwell time. Afterward, they were again stored in distilled water at 37 °C for 15 h before testing [23].

2.7. Micro-Shear Bond Strength (μSBS) Testing

Specimens were mounted in a universal testing machine (MultiTest 1 d, Mecmesin, Slinfold, UK) equipped with an AFG 500 N digital force gauge. The machine was calibrated before testing using a certified reference load cell, following the manufacturer’s standard procedure to ensure measurement accuracy and consistency. A shear force was applied to the bonded composite interface at a crosshead speed of 1.0 mm/min using a knife-edge blade until failure occurred (Figure 3). The maximum load at failure (N) was recorded for each sample. Bond strength values, expressed in megapascals (MPa), were calculated using the formula: Bond Strength (MPa) = Failure Load (N)/Bonding Area (mm2) [9].

2.8. Failure Mode Analysis

Failure modes were examined visually under a stereomicroscope (AmScope, Irvine, CA, USA) at ×20 magnification. Single calibrated examiners categorized based on predefined criteria as:
  • Adhesive failure (A): at the adhesive–substrate interface.
  • Cohesive failure (C): within the composite resin.
  • Mixed failure (M): a combination of adhesive and cohesive failures.
The percentage of each failure mode was calculated from the number of samples per category relative to the total in each group. No software was used. Representative failure modes were photographed for illustration.

2.9. Statistical Analysis

Data were analyzed with IBM SPSS Statistics software (Version 27). The Shapiro–Wilk test confirmed that all data points followed a normal distribution pattern. One-way ANOVA was used for surface roughness analysis. Three-way ANOVA was applied to assess the main effects and interactions of surface treatment, adhesive system, and aging on μSBS. Tukey HSD tests were conducted for pairwise comparisons, with a p-value threshold of 0.05 to determine statistical significance.

3. Results

3.1. Surface Roughness Results and Topography

The surface roughness values increased substantially when using more intense treatment methods for both substrate materials. The surface roughness measurements of metal samples increased to 0.293 µm after air abrasion and 0.618 µm after bur grinding when compared to the control value of 0.037 µm. The zirconia samples showed matching surface roughness trend patterns with measurements of 0.145 µm, 0.190 µm, and 0.318 µm, respectively. The treatment pairs showed highly significant differences (p < 0.001) with small standard deviations and non-overlapping 95% CIs, which supports the reliability of measurement results (Table 2).
The nanoscale surface patterns observed by atomic force microscopy (AFM) explained the quantitative variations that were observed. The untreated surfaces of both materials maintained their typical smooth and uniform appearance. The surface treatment methods generated different patterns, where air abrasion produced matching crater and pit structures on both metal and zirconia materials at (87.2 nm and 105 nm maximum surface height (Sz) values), respectively. The bur grinding process created surfaces with deep, sharp grooves, producing the highest peak-to-valley measurements for metal at (Sz = 117.4 nm) and zirconia at (Sz = 109 nm) (Figure 4).

3.2. Result of Shear Bond Strength Testing

Overall, surface treatment and adhesive system significantly influenced the composite’s shear bond strength of the metal and zirconia substrates. Airborne particle abrasion yielded the highest bond strength for both materials, followed by diamond bur grinding and no treatment. The GC system showed a superior bond stability after thermocycling, while aging generally decreased SBS in all groups.

3.2.1. SBS (Metal)

Air particle abrasion yielded the highest initial µSBS for metal, particularly with Bisco (40.45 ± 1.39 MPa vs. the control at 24.97 ± 3.65 MPa). However, aging reduced bond strength across all groups, most notably in the air abrasion–Bisco (−11.1 MPa). By contrast, air abrasion–GC showed the greatest stability (34.55 ± 2.74 to 32.26 ± 4.03 MPa; ~7% loss), as shown in Table 3.
Three-way ANOVA confirmed significant main effects of surface treatment, repair kit, and aging on SBS (R2 = 0.780, adjusted R2 = 0.740) (Table 4). The type of repair kit also influenced SBS (p < 0.001), and aging caused a marked reduction (p < 0.001).
Significant surface treatment × repair kit interactions revealed that GC outperformed Bisco in control and diamond bur groups, but Bisco slightly exceeded GC after air abrasion; a three-way interaction confirmed that repair kit performance after aging depended on surface pretreatment (Figure 5A).
Air abrasion produced significantly higher SBS than control (p < 0.001, Δ = +8.29 MPa) and bur grinding (p < 0.001, Δ = +7.99 MPa), whereas no difference emerged between control and bur grinding (p = 0.960) (Table 5).

3.2.2. SBS (Zirconia)

For zirconia, the highest initial µSBS values occurred in air abrasion–Bisco (36.75 ± 5.72 MPa) and diamond bur–Bisco (36.60 ± 6.78 MPa), while aging produced the greatest loss in control–Bisco (~50%) and the best retention in air abrasion–GC (~20% loss) (Table 3).
Three-way ANOVA confirmed significant effects of surface treatment, repair kit, and aging on SBS (R2 = 0.850, adjusted R2 = 0.823) (Table 6). GC generally produced higher SBS than Bisco (p = 0.001), and aging caused the largest reduction across all groups (p < 0.001).
Both air abrasion (+6.33 MPa, p < 0.001) and diamond bur (+4.80 MPa, p < 0.001) significantly increased SBS versus control, with no difference between them (p = 0.253) (Table 7).
Significant interactions indicated that GC outperformed Bisco in control groups, but both kits performed similarly after mechanical pretreatment; surface treatment × aging interaction further showed treatment-dependent bond degradation (Figure 5B).
Failure Mode
Failure mode analysis revealed no cohesive failures in any of the groups. For metal specimens, the GC kit decreased adhesive failures from 80% (control) to 40% after air abrasion and bur grinding, while mixed failures increased to 60%. With the BISCO kit, adhesive failures decreased from 100% in controls to 60% after air abrasion and to 80% after bur grinding, with mixed failures rising correspondingly. A similar trend was observed with zirconia: the GC kit reduced adhesive failures from 60% to 40%, and the BISCO kit from 100% to 60%, with mixed failures increasing in both cases. This shift from predominantly adhesive to mixed failures reflects improved interfacial integrity and micromechanical interlocking after surface modification (Figure 6). Representative images of these failure modes are shown in Figure 7.

4. Discussion

4.1. Surface Treatment Effects on Bond Strength

Mechanical surface treatments are fundamental to enhancing resin adhesion by increasing surface roughness and surface free energy, thereby facilitating micromechanical interlocking and chemical bonding [24,25]. In the current study, diamond bur roughening produced the maximum quantitative surface roughness (Sa) values for both metal and zirconia, yet this was not consistently associated with the strongest bond strength, particularly in metal substrates, where air abrasion yielded superior SBS results. This discrepancy can be attributed to the nature and quality of surface irregularities induced, as reported by Jain et al. (2013), diamond burs create deeper and more irregular grooves, which may introduce microcracks or stress concentration points detrimental to adhesive durability. This explains that excessive mechanical roughening can weaken substrate integrity and reduce long-term bond strength [2]. Conversely, airborne particle abrasion with 50 µm aluminum oxide particles effectively increased surface roughness and energy by producing a uniformly frosted surface with shallow, interconnected furrows that facilitate capillary infiltration of primers and adhesives, resulting in pronounced improvements in SBS for metal substrates [2,26]. This observation aligns with multiple studies, SBS improvements following Al2O3 air abrasion on substrate surfaces, emphasizing its ability to clean and activate the surface by generating microporosities favorable for resin infiltration and retention [27].
For zirconia, both mechanical treatments produced statistically similar SBS increases relative to control groups, confirming the substrate’s responsiveness to varied surface modifications due to its polycrystalline structure that exposes fresh zirconia grains upon abrasion. This aligns with the work of Yeğin (2018), who concluded that both grinding and sandblasting are equally effective chairside treatments for enhancing the bond strength of resin cement to Y-TZP ceramics [28]. Valizadeh et al. (2020) and Dieckmann et al. (2020) found aluminum oxide sandblasting and bur abrasion to be equally effective for repairing composite restorations [29,30]. (Chatterjee and Ghosh 2022) corroborated these findings, noting comparable bond strength improvements with air abrasion and bur grinding methods on zirconia ceramics [31]. These consistent findings across different materials underscore that the critical mechanism is the creation of surface roughness and mechanical retention, which can be achieved equally well by either abrasion method However, some studies (e.g., Fathpour et al., 2022) (Libecki et al. 2017) argue that the clinical superiority of air abrasion combined with chemical primers may ultimately yield more durable bonds due to synergistic mechanical and chemical effects [8,32]. Therefore, while surface roughness is necessary, it is insufficient alone, and careful selection of accompanying adhesive chemistry is paramount.

4.2. Impact of Adhesive Systems on Repair Performance

The adhesive repair system used also significantly affected bond strength and its longevity after thermocycling; a decrease in bond strength was potentially due to hydrolysis at the interface by water absorption [33,34]. The superior post-aging stability of GC repair systems can be attributed to the adhesive composition. Both G-Multi Primer and G-Primeo Bond contain Methacryloyloxydecyl dihydrogen phosphate (10-MDP), a hydrophobic functional monomer that creates ionic bonds with metal and zirconia oxide and covalently links to the resin composite, resulting in hydrolytically stable adhesion [35]. Klaisiri et al. (2021) demonstrated that universal adhesives rich in phosphate monomers better preserve bond strength under long-term simulated oral aging than some traditional bonding systems [36]. Furthermore, a silica filler in G-Primeo bond renders it less sensitive to water absorption, contributing to the adhesive’s resistance against hydrolytic breakdown [34,37].
In contrast, Bisco’s Z-Prime Plus is formulated with Hydroxyethyl methacrylate (HEMA), a hydrophilic monomer prone to water absorption and hydrolysis, which compromises bond stability over time [38]. The presence of Bisphenol A-glycidyl methacrylate (Bis-GMA) in both Z-Prime Plus and Porcelain Bonding Resin may further decrease durability because of the hydroxyl group, which facilitates water uptake and degradation of the adhesive interface [39]. Additionally, Triethylene Glycol Dimethacrylate (TEGDMA) in the Porcelain Bonding Resin raises polymerization shrinkage and water absorption, further undermining bond integrity [40]. These compositional differences probably explain why the GC kit shows better bond durability in this study, aligning with the previous reports that show MDP-based adhesives have better hydrolytic stability than those with higher levels of HEMA and Bis-GMA.
The interaction between the surface treatment and the adhesive system effectiveness highlights that optimal intra-oral repair requires both mechanical and chemical preparation. For metal substrates, GC outperformed Bisco in control and diamond bur groups, but both were similar after air abrasion, indicating that strong mechanical preparation reduces reliance on adhesive type. On zirconia, GC showed higher bond strength in controls, while both adhesives were comparable after mechanical treatment, emphasizing the key role of primer chemistry when roughening is limited.

4.3. Effect of Aging on Bond Durability

Simulated aging through thermocycling significantly diminished bond strength across all experimental groups, reflecting the deteriorative effects of fluctuating thermal and moisture stresses commonly endured intraorally [41]. The most substantial SBS reductions were observed in control groups without mechanical surface treatment, especially when repaired with the Bisco adhesive, corroborating extensive literature demonstrating the vulnerability of unprepared surfaces and inadequate chemical adhesive systems to hydrolytic degradation and resin–substrate debonding.
These findings align with Mokeem et al. (2023), who noted that unprepared surfaces and inadequate primer (or adhesive) treatment are especially vulnerable to hydrolytic degradation, leading to adhesive failures in dental composites [42]. Similarly, pronounced bond strength losses post-thermocycling were observed in zirconia repairs without mechanical roughening or robust primers. These collective findings highlight the necessity of surface modification and appropriate adhesive monomers to withstand the challenging oral environment [43].
Importantly, sandblasted surfaces treated with the GC repair kit retained approximately 80% of their initial bond strength after aging, indicating the synergistic benefits of mechanical interlocking combined with chemical durability in maintaining restoration integrity [44]. Klaisiri et al. (2022) demonstrated that composite repairs employing sandblasting plus 10-MDP-containing primers exhibited significantly enhanced resistance to thermal and mechanical fatigue compared to other protocols [45,46].

4.4. Clinical Implications

This resilience is essential clinically, as insufficiently durable repairs can lead to premature restoration failure, increased patient costs, and additional invasive procedures. Accordingly, our results advocate for repair approaches combining airborne particle abrasion with chemically stable universal adhesives to optimize repair longevity and clinical outcomes. The present findings support that airborne particle abrasion combined with the MDP-containing universal adhesive (GC repair kit) shows superior and durable intraoral repair performance for fractured metal and zirconia restorations, offering a conservative and cost-effective alternative to full replacement.
However, as an in vitro study, the findings are limited by the inability to fully replicate the complex oral environment, including masticatory fatigue, chemical degradation from pH variation, and biofilm colonization. The results are also specific to the two materials and repair systems tested.
Future works should incorporate extended aging, mechanical fatigue testing, and randomized clinical trials, as well as newer substrates and adhesives, to validate and broaden these results.

5. Conclusions

Within the limitations of this study, both surface treatment and adhesive systems significantly influenced the bond strength of composite resin to metal and zirconia substrates. Airborne particle abrasion, followed by a universal adhesive system, showed the most predictable and superior performance. Compared to the untreated controls, airborne particle abrasion increased shear bond strength by approximately 80–90% for metal and 70–85% for zirconia, depending on the repair system. The GC repair kit consistently provided slightly higher bond strength than the Bisco system in both aging and non-aging conditions, attributed to its MDP-based adhesive and filler reinforcement. This mechanochemical synergy between surface roughening and chemical coupling agents is critical for durable composite repair bonding. These findings improve the understanding of the interfacial bonding mechanisms and guide clinicians in selecting effective minimally invasive repair protocols. Optimized repair strategies can extend the clinical longevity of restorations. They also reduce treatment time and cost and improve patient outcomes.

Author Contributions

Conceptualization, H.M.M.S. and B.A.S.; methodology, B.A.S.; validation, H.M.M.S. and B.A.S.; formal analysis, B.A.S.; investigation, B.A.S.; resources, B.A.S.; data curation, B.A.S.; writing—original draft preparation, B.A.S.; writing—review and editing, H.M.M.S. and B.A.S.; visualization, B.A.S.; supervision, H.M.M.S.; project administration, H.M.M.S. All authors have read and agreed to the published version of the manuscript.

Funding

This study received no external funding.

Institutional Review Board Statement

This research was approved by the Ethics Committee of the College of Dentistry—University of Sulaimani, Code No.: (COD-EC-24-0026) issued on 16 December 2024.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data supporting the results of this research are available from the corresponding author on reasonable request.

Acknowledgments

The author would like to express their sincere gratitude to the dental laboratory for the invaluable technical assistance and material support in the fabrication of samples. We are also deeply grateful to Abdulsalam Al Zahawi, Aras Jalal, Sewara J. Mohammed, and Rand Saman for the valuable guidance and continuous support throughout the course of this research.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

Abbreviations

SBSShear bond strength
SDStandard deviation
SaArithmetic mean height
SzMaximum surface height
MDPMethacryloyloxydecyl dihydrogen phosphate
MDTPMethacryloyloxydecyl dihydrogen thiophosphate
HEMAHydroxyethyl methacrylate
γ-MPTSGamma-methacryloxypropyl trimethoxy silane
4-MET4-methacryloxyethyl trimellitic acid
Bis-GMABisphenol A-glycidyl methacrylate
TEGDMATriethylene Glycol Dimethacrylate
UDMAUrethane dimethacrylate

References

  1. Arshad, M.; Gordan, R.; Farrokhi, P.; Habibzadeh, S. Composite Resin Bond Strength to Zirconia and Base Metal Alloys Using Two Types of Intraoral Porcelain Repair Systems. Front. Dent. 2023, 20, 43. [Google Scholar] [CrossRef]
  2. Jain, S.; Parkash, H.; Gupta, S.; Bhargava, A. To Evaluate the Effect of Various Surface Treatments on the Shear Bond Strength of Three Different Intraoral Ceramic Repair Systems: An In Vitro Study. J. Indian Prosthodont. Soc. 2013, 13, 315–320. [Google Scholar] [CrossRef]
  3. da Rosa, L.S.; Pilecco, R.O.; Soares, P.M.; Rippe, M.P.; Pereira, G.K.R.; Valandro, L.F.; Kleverlaan, C.J.; Feilzer, A.J.; Tribst, J.P.M. Repair Protocols for Indirect Monolithic Restorations: A Literature Review. PeerJ 2024, 12, e16942. [Google Scholar] [CrossRef] [PubMed]
  4. Kelly, J.R. Dental Ceramics: What Is This Stuff Anyway? J. Am. Dent. Assoc. 2008, 139 (Suppl. S4), 4S–7S. [Google Scholar] [CrossRef]
  5. Zhang, Y.; Kelly, J.R. Dental Ceramics for Restoration and Metal Veneering. Dent. Clin. N. Am. 2017, 61, 797–819. [Google Scholar] [CrossRef]
  6. Alves De Lucena, M.; Relvas, A.; Lefrançois, M.; Venício Azevedo, M.; Sotelo, P.; Sotelo, L. Resin Matrix Ceramics—Mechanical, Aesthetic and Biological Properties. RGO—Rev. Gaúcha Odontol. 2021, 69, e20210018. [Google Scholar] [CrossRef]
  7. Blatz, M.B.; Vonderheide, M.; Conejo, J. The Effect of Resin Bonding on Long-Term Success of High-Strength Ceramics. J. Dent. Res. 2018, 97, 132–139. [Google Scholar] [CrossRef]
  8. Fathpour, K.; Nili Ahmadabadi, M.; Atash, R.; Fathi, A.H. Effect of Different Surface Treatment Methods on the Shear Bond Strength of Resin Composite/Zirconia for Intra-oral Repair of Zirconia Restorations. Eur. J. Dent. 2023, 17, 809–817. [Google Scholar] [CrossRef] [PubMed]
  9. Tokar, E.; Polat, S.; Ozturk, C. Repair Bond Strength of Composite to Er,Cr:YSGG Laser Irradiated Zirconia and Porcelain Surfaces. Biomed. J. 2019, 42, 193–199. [Google Scholar] [CrossRef] [PubMed]
  10. Güngör, M.B.; Nemli, S.K.; Bal, B.T.; Ünver, S.; Doğan, A. Effect of Surface Treatments on Shear Bond Strength of Resin Composite Bonded to CAD/CAM Resin-Ceramic Hybrid Materials. J. Adv. Prosthodont. 2016, 8, 259–266. [Google Scholar] [CrossRef]
  11. Mahgoli, H.; Arshad, M.; Rasouli, K.; Sobati, A.A.; Shamshiri, A.R. Repair Bond Strength of Composite to Zirconia Ceramic Using Two Types of Zirconia Primers. Front. Dent. 2019, 16, 342–350. [Google Scholar] [CrossRef]
  12. Loomans, B.; Özcan, M. Intraoral Repair of Direct and Indirect Restorations: Procedures and Guidelines. Oper. Dent. 2016, 41, S68–S78. [Google Scholar] [CrossRef]
  13. Turunç-Oğuzman, R.; Şişmanoğlu, S. Influence of Surface Treatments and Adhesive Protocols on Repair Bond Strength of Glass-Matrix and Resin-Matrix CAD/CAM Ceramics. J. Esthet. Restor. Dent. 2023, 35, 1322–1331. [Google Scholar] [CrossRef]
  14. Köse, M.; Çölgeçen, Ö. Enhancing Dental Porcelain Repair Strength: The Impact of Chairside Plasma Surface Treatment—An In Vitro Study. BMC Oral Health 2025, 25, 1180. [Google Scholar] [CrossRef]
  15. Elsaka, S.E. Repair Bond Strength of Resin Composite to a Novel CAD/CAM Hybrid Ceramic Using Different Repair Systems. Dent. Mater. J. 2015, 34, 161–167. [Google Scholar] [CrossRef]
  16. Dikici, B.; Türkeş Başaran, E.; Şirinsükan, N.; Can, E. Repair Bond Strength and Surface Roughness Evaluation of CAD/CAM Materials After Various Surface Pretreatments. Coatings 2025, 15, 432. [Google Scholar] [CrossRef]
  17. Inagati, C.M.; Rodrigues, J.V.M.; Grangeiro, M.T.V.; Rossi, N.R.; Anami, L.C.; Saavedra, G.D.S.F.A.; Souza, R.O.D.A.E.; Marinho, R.M.D.M. Effect of Surface Treatments on the Repair of a Hybrid Ceramic through the Microtensile Test. Cerâmica 2025, 71, eVAAB7281. [Google Scholar] [CrossRef]
  18. Naderi, N.; Majidinia, S.; Moghaddas, M.J.; Shooshtari, Z.; Hoseinzadeh, M. Surface Modification Effect on the Repair Bond Strength of Hybrid and Non-Hybrid Ceramics. BMC Oral Health 2025, 25, 1131. [Google Scholar] [CrossRef] [PubMed]
  19. Taokhampu, N.; Lekatana, H.; Palasuk, J. Bond Strength of Aged Provisional 3D-Printed Methacrylate Resin with Different Surface Treatments and Repair Materials. BMC Oral Health 2025, 25, 789. [Google Scholar] [CrossRef] [PubMed]
  20. Jadid, R.S.; Al-Zahawi, A.R. In Vitro Comparison of Monolithic Zirconia Crowns: Marginal/Internal Adaptation and 3D-Quantified Preparation Defects Using Air-Driven, Electric-Driven, and Piezoelectric Ultrasonic Handpieces. Prosthesis 2025, 7, 75. [Google Scholar] [CrossRef]
  21. Flores-Ferreyra, B.I.; Scougall-Vilchis, R.J.; Velazquez-Enriquez, U.; Garcia-Contreras, R.; Aguillon-Sol, L.; Olea-Mejia, O.F. Effect of Airborne-Particle Abrasion and, Acid and Alkaline Treatments on Shear Bond Strength of Dental Zirconia. Dent. Mater. J. 2019, 38, 182–188. [Google Scholar] [CrossRef]
  22. Wahsh, M.M.; Ghallab, O.H. Influence of Different Surface Treatments on Microshear Bond Strength of Repair Resin Composite to Two CAD/CAM Esthetic Restorative Materials. Tanta Dent. J. 2015, 12, 178–184. [Google Scholar] [CrossRef]
  23. Binhasan, M.; Althobaiti, F.; Alyami, R.; Aljabri, K.; Alabbas, T.; Barakah, H. Effect of Surface Treatments on Repair Bond Strength of Aged Bulk-Fill Resin Composites. Polymers 2025, 17, 2326. [Google Scholar] [CrossRef]
  24. Bourgi, R.; Etienne, O.; Holiel, A.A.; Cuevas-Suárez, C.E.; Hardan, L.; Roman, T.; Flores-Ledesma, A.; Qaddomi, M.; Haikel, Y.; Kharouf, N. Effectiveness of Surface Treatments on the Bond Strength to 3D-Printed Resins: A Systematic Review and Meta-Analysis. Prosthesis 2025, 7, 56. [Google Scholar] [CrossRef]
  25. Fahmi, M. Effect of Surface Treatments on the Bond Strength of 3D-Printed Composite Resin to Feldspathic Ceramic. Coatings 2025, 15, 998. [Google Scholar] [CrossRef]
  26. Coskun, M.E.; Akar, T.; Tugut, F. Airborne-Particle Abrasion; Searching the Right Parameter. J. Dent. Sci. 2018, 13, 293–300. [Google Scholar] [CrossRef]
  27. Ghada o Alrabeah, A. Effect of Surface Textures and Fabrication Methods on Shear Bond Strength Between Titanium Framework and Auto-Polymerizing Acrylic Repair Resin. Cureus 2023, 15, e48883. [Google Scholar] [CrossRef]
  28. Yeğin, E. Effects of Various Chairside Surface Treatments on Zirconia-Resin Cement Bond Strength. J. Dent. Mater. Tech. 2019, 8, 12–18. [Google Scholar] [CrossRef]
  29. Dieckmann, P.; Baur, A.; Dalvai, V.; Wiedemeier, D.B.; Attin, T.; Tauböck, T.T. Effect of Composite Age on the Repair Bond Strength after Different Mechanical Surface Pretreatments. J. Adhes. Dent. 2020, 22, 365–372. [Google Scholar] [CrossRef] [PubMed]
  30. Hoorizad Ganjkar, M.; Nasoohi, N.; Lesani, M.; Sanaee, N. Effect of Aging and Different Surface Treatments on the Repair Microshear Bond Strength of a Nanohybrid Composite Resin. Front. Dent. 2025, 22, 6. [Google Scholar] [CrossRef]
  31. Chatterjee, N.; Ghosh, A. Current Scenario on Adhesion to Zirconia; Surface Pretreatments and Resin Cements: A Systematic Review. J. Indian Prosthodont. Soc. 2022, 22, 13–20. [Google Scholar] [CrossRef]
  32. Libecki, W.; Elsayed, A.; Lehmann, F.; Kern, M. Efficacy of Different Surface Treatments for Intraoral Repair of Veneered Zirconia Frameworks. J. Adhes. Dent. 2017, 19, 323–329. [Google Scholar] [CrossRef]
  33. Irmak, O.; Celiksoz, O.; Yilmaz, B.; Yaman, B.C. Adhesive System Affects Repair Bond Strength of Resin Composite. J. Istanb. Univ. Fac. Dent. 2017, 51, 25–31. [Google Scholar] [CrossRef]
  34. Uğur, M.; Kavut, İ.; Tanrıkut, Ö.O.; Cengiz, Ö. Effect of Ceramic Primers with Different Chemical Contents on the Shear Bond Strength of CAD/CAM Ceramics with Resin Cement After Thermal Ageing. BMC Oral Health 2023, 23, 210. [Google Scholar] [CrossRef]
  35. Carrilho, E.; Cardoso, M.; Marques Ferreira, M.; Marto, C.M.; Paula, A.; Coelho, A.S. 10-MDP Based Dental Adhesives: Adhesive Interface Characterization and Adhesive Stability—A Systematic Review. Materials 2019, 12, 790. [Google Scholar] [CrossRef] [PubMed]
  36. Klaisiri, A.; Krajangta, N.; Thamrongananskul, N. The Durability of Zirconia/Resin Composite Shear Bond Strength using Different Functional Monomer of Universal Adhesives. Eur. J. Dent. 2021, 16, 756–760. [Google Scholar] [CrossRef] [PubMed]
  37. Tang, C.; Mercelis, B.; Zhang, F.; Mocquot, C.; Nakanishi, K.; Yoshihara, K.; Peumans, M.; Van Meerbeek, B. Filler Mixed into Adhesives Does Not Necessarily Improve Their Mechanical Properties. Oper. Dent. 2024, 49, 311–324. [Google Scholar] [CrossRef] [PubMed]
  38. Abdelkhalek, E.; Hamama, H.H.; Mahmoud, S.H. HEMA-Free Versus HEMA-Containing Adhesive Systems: A Systematic Review. Syst. Rev. 2025, 14, 17. [Google Scholar] [CrossRef]
  39. Pratap, B.; Gupta, R.K.; Bhardwaj, B.; Nag, M. Resin Based Restorative Dental Materials: Characteristics and Future Perspectives. Jpn. Dent. Sci. Rev. 2019, 55, 126–138. [Google Scholar] [CrossRef]
  40. Barszczewska-Rybarek, I.M.; Chrószcz, M.W.; Chladek, G. Novel Urethane-Dimethacrylate Monomers and Compositions for Use as Matrices in Dental Restorative Materials. Int. J. Mol. Sci. 2020, 21, 2644. [Google Scholar] [CrossRef]
  41. Unalan Degirmenci, B.; Degirmenci, A.; Seyfioglu Polat, Z. The Influence of Thermocycling and Ultraviolet Aging on Surface Characteristics and the Repair Bond Strength of CAD/CAM Resin Nanoceramics. J. Funct. Biomater. 2025, 16, 156. [Google Scholar] [CrossRef] [PubMed]
  42. Mokeem, L.S.; Garcia, I.M.; Melo, M.A. Degradation and Failure Phenomena at the Dentin Bonding Interface. Biomedicines 2023, 11, 1256. [Google Scholar] [CrossRef] [PubMed]
  43. Janson, M.; Bassier, V.; Liebermann, A.; Schoppmeier, C.M.; Gregorio-Schininà, M.D. Composite Repair on Zirconia: Influence of Different Sandblasting Pretreatments and Various Universal Adhesives on Shear Bond Strength. J. Adhes. Dent. 2025, 27, 53–64. [Google Scholar] [CrossRef] [PubMed]
  44. Yang, X.; Liu, Y. Influence of Different Surface Treatments on Zirconia/Resin Shear Bond Strength Using One-Bottle Universal Adhesive. Adv. Appl. Ceram. 2019, 118, 70–77. [Google Scholar] [CrossRef]
  45. Klaisiri, A.; Maneenacarith, A.; Jirathawornkul, N.; Suthamprajak, P.; Sriamporn, T.; Thamrongananskul, N. The Effect of Multiple Applications of Phosphate-Containing Primer on Shear Bond Strength between Zirconia and Resin Composite. Polymers 2022, 14, 4174. [Google Scholar] [CrossRef]
  46. Lechte, C.; Hohmann, E.; Wiegand, A.; Kanzow, P. Effect of Different Working Settings of Sandblasting on Resin Composite Repair Bond Strength. Materials 2025, 18, 313. [Google Scholar] [CrossRef]
Prosthesis 07 00151 g001
Figure 1. Flow chart illustrating the experimental design and grouping of specimens.
Figure 1. Flow chart illustrating the experimental design and grouping of specimens.
Prosthesis 07 00151 g001
Prosthesis 07 00151 g002
Figure 2. Metal alloy and zirconia samples used in this study.
Figure 2. Metal alloy and zirconia samples used in this study.
Prosthesis 07 00151 g002
Prosthesis 07 00151 g003
Figure 3. Illustrating shear bond strength testing.
Figure 3. Illustrating shear bond strength testing.
Prosthesis 07 00151 g003
Prosthesis 07 00151 g004aProsthesis 07 00151 g004b
Figure 4. Atomic Force Microscopy (AFM) images of Metal and Zirconia surfaces after different surface treatments. The Sz (mamum height) values were: Metal–Control = 25 nm, Abrasion = 87 nm, Bur grinding = 117 nm; Zirconia–Control = 52 nm, Abrasion = 105 nm, Bur grinding = 109 nm.
Figure 4. Atomic Force Microscopy (AFM) images of Metal and Zirconia surfaces after different surface treatments. The Sz (mamum height) values were: Metal–Control = 25 nm, Abrasion = 87 nm, Bur grinding = 117 nm; Zirconia–Control = 52 nm, Abrasion = 105 nm, Bur grinding = 109 nm.
Prosthesis 07 00151 g004aProsthesis 07 00151 g004b
Prosthesis 07 00151 g005
Figure 5. Estimated marginal means (±SE) of shear bond strength (MPa) from the two-way ANOVA model, showing the interaction between surface treatment and repair kit for (A) metal and (B) zirconia.
Figure 5. Estimated marginal means (±SE) of shear bond strength (MPa) from the two-way ANOVA model, showing the interaction between surface treatment and repair kit for (A) metal and (B) zirconia.
Prosthesis 07 00151 g005
Prosthesis 07 00151 g006
Figure 6. Failure mode distribution across surface treatments and repair kit.
Figure 6. Failure mode distribution across surface treatments and repair kit.
Prosthesis 07 00151 g006
Prosthesis 07 00151 g007
Figure 7. Stereo microscope images (A) adhesive failure and (B) mixed failure in zirconia, (C) adhesive failure and (D) mixed failure in metal.
Figure 7. Stereo microscope images (A) adhesive failure and (B) mixed failure in zirconia, (C) adhesive failure and (D) mixed failure in metal.
Prosthesis 07 00151 g007
Table 1. Description of materials and their compositions and manufacturers.
Table 1. Description of materials and their compositions and manufacturers.
MaterialManufacturerComposition
Carozir Zirconia CADCarol Zircolite Private LimitedBad Säckingen, Germany95% ZrO2, 5% Y2O3. Small amounts of other oxides like hafnium dioxide (HfO2) or aluminum oxide (Al2O3)
Realoy-N+ (nickel–chromium base metal alloyGerman Special Alloys GmbH, Worms, GermanyNi (Nickel): 62.4%, Cr (Chromium): 25.0%, Mo (Molybdenum): 11.0%, Si (Silicon): 1.6%, Nb, Mn, and Fe: <1%
G-Multi primerGC, Tokyo, JapanEthanol 80–100% w/w, γ-MPTS, 10-MDP, MDTP
G-Premio Bond Universal AdhesiveGC, Tokyo, JapanAcetone, 10-MDP, 4-MET, MDPT, Silica, water, Photo-initiator
Z-Prime plusBISCO, Schaumburg, IL, USAEthanol 75–85%, Bis-GMA, HEMA, MDP, carboxylic acid resin monomer
Porcelain Bonding ResinBISCO, Schaumburg, IL, USAEthanol, Bis-GMA, UDMA, TEGDMA, Water, Initiator
MDP: Methacryloyloxydecyl dihydrogen phosphate, 4-MET: 4-methacryloxyethyl trimellitic acid, MDTP: Methacryloyloxydecyl dihydrogen thiophosphate, HEMA: Hydroxyethyl methacrylate, Bis-GMA: Bisphenol A-glycidyl methacrylate, TEGDMA: Triethylene Glycol Dimethacrylate, γ-MPTS: Gamma-methacryloxypropyl trimethoxy silane, UDMA: Urethane dimethacrylate.
Table 2. Mean and SD of the Sa values and Tukey multiple comparison.
Table 2. Mean and SD of the Sa values and Tukey multiple comparison.
MaterialSurface TreatmentMean (µm)SD (µm)95% CI Lower Bound95% CI Upper BoundComparisonp-Value
MetalControl0.0370.00220.034970.03966Control vs. Air abrasion<0.001
Air abrasion0.2930.01550.276800.30937Control vs. Diamond bur<0.001
Bur grinding0.6180.03450.582310.65486Air abrasion vs. Diamond bur<0.001
ZirconiaControl0.145000.00960.134870.15513Control vs. Air abrasion<0.001
Air abrasion0.189570.01140.177550.20158Control vs. Diamond bur<0.001
Bur grinding0.317970.01540.301760.33418Air abrasion vs. Diamond bur<0.001
Table 3. Mean and SD values of shear bond strength of all experimental groups.
Table 3. Mean and SD values of shear bond strength of all experimental groups.
MaterialSurface TreatmentRepair KitµSBS No Aging (Mean ± SD)µSBS Aging (Mean ± SD)
MetalControlBisco24.97 ± 3.6520.27 ± 7.18
ControlGC34.93 ± 1.5923.27 ± 4.51
Air abrasionBisco40.45 ± 1.3929.35 ± 1.34
Air abrasionGC34.55 ± 2.7432.26 ± 4.03
Bur grindingBisco20.64 ± 1.6520.38 ± 5.84
Bur grindingGC36.21 ± 2.0927.42 ± 4.79
ZirconiaControlBisco28.09 ± 2.5914.05 ± 2.16
ControlGC35.13 ± 2.0321.63 ± 3.14
Air abrasionBisco36.75 ± 5.7225.23 ± 2.33
Air abrasionGC34.56 ± 1.2627.68 ± 2.51
Bur grindingBisco36.60 ± 6.7821.64 ± 1.65
Bur grindingGC36.45 ± 1.7223.42 ± 2.73
Table 4. Three-way ANOVA results for the effects of surface treatment, repair kit, and aging on the shear bond strength of metal substrate.
Table 4. Three-way ANOVA results for the effects of surface treatment, repair kit, and aging on the shear bond strength of metal substrate.
SourcedfFp-ValuePartial η2
Surface Treatment235.520<0.0010.542
Repair Kit135.502<0.0010.372
Aging150.362<0.0010.456
Surface Treatment × Repair Kit216.781<0.0010.359
Surface Treatment × Aging21.3600.2640.043
Repair Kit × Aging11.4870.2270.024
Surface Treatment × Repair Kit × Aging29.246<0.0010.236
Error60
R2 = 0.780, Adjusted R2 = 0.740.
Table 5. Tukey HSD multiple comparisons of shear bond strength between surface treatments (Metal).
Table 5. Tukey HSD multiple comparisons of shear bond strength between surface treatments (Metal).
ComparisonMean Difference ± SEp-Value95% CI (Lower–Upper)
Control vs. Air abrasion−8.29 ± 1.12 *<0.001−10.98 to −5.61
Control vs. Diamond Bur−0.30 ± 1.120.960−2.98 to 2.38
Air abrasion vs. Diamond Bur7.99 ± 1.12 *<0.0015.31 to 10.67
* Mean difference is significant at p < 0.05. Error term: MS (Error) = 14.946.
Table 6. Three-way ANOVA results for the effects of surface treatment, repair kit, and aging on shear bond strength of zirconia substrate.
Table 6. Three-way ANOVA results for the effects of surface treatment, repair kit, and aging on shear bond strength of zirconia substrate.
SourcedfFp-ValuePartial η2
Surface Treatment224.084<0.0010.445
Repair Kit112.544<0.0010.173
Aging1251.321<0.0010.807
Surface Treatment × Repair Kit28.656<0.0010.224
Surface Treatment × Aging24.0440.0230.119
Repair Kit × Aging12.3240.1330.037
Surface Treatment × Repair Kit × Aging20.5990.5530.020
Error60
R2 = 0.850 (Adjusted R2 = 0.823).
Table 7. Tukey HSD multiple comparisons of shear bond strength between surface treatments (zirconia).
Table 7. Tukey HSD multiple comparisons of shear bond strength between surface treatments (zirconia).
ComparisonMean Difference ± SEp-Value95% CI (Lower–Upper)
Control vs. Air abrasion−6.33 ± 0.95 *<0.001−8.62 to −4.04
Control vs. Diamond Bur−4.80 ± 0.95 *<0.001−7.09 to −2.52
Air abrasion vs. Diamond Bur1.52 ± 0.95.253−0.76 to 3.81
* Mean difference is significant at p < 0.05. Error term: MS (Error) = 10.871.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Sharif, B.A.; Mohammed Saeed, H.M. Mechanochemical Optimization of Composite–Substrate Interfaces for Durable Repair Adhesion to Metal and Zirconia: An In Vitro Study. Prosthesis 2025, 7, 151. https://doi.org/10.3390/prosthesis7060151

AMA Style

Sharif BA, Mohammed Saeed HM. Mechanochemical Optimization of Composite–Substrate Interfaces for Durable Repair Adhesion to Metal and Zirconia: An In Vitro Study. Prosthesis. 2025; 7(6):151. https://doi.org/10.3390/prosthesis7060151

Chicago/Turabian Style

Sharif, Bryar Abdulqadir, and Hawzhen Masoud Mohammed Saeed. 2025. "Mechanochemical Optimization of Composite–Substrate Interfaces for Durable Repair Adhesion to Metal and Zirconia: An In Vitro Study" Prosthesis 7, no. 6: 151. https://doi.org/10.3390/prosthesis7060151

APA Style

Sharif, B. A., & Mohammed Saeed, H. M. (2025). Mechanochemical Optimization of Composite–Substrate Interfaces for Durable Repair Adhesion to Metal and Zirconia: An In Vitro Study. Prosthesis, 7(6), 151. https://doi.org/10.3390/prosthesis7060151

Article Metrics

Article metric data becomes available approximately 24 hours after publication online.
Back to TopTop