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Comparison of microleakage under orthodontic brackets bonded with five different adhesive systems - in vitro study

MetadataDetails
Publication Date2023-09-05
JournalBMC Oral Health
AuthorsNela Masarykova, Emil Tkadlec, Zdeněk Chlup, Jan Vrbský, Alena Brysova
InstitutionsPalacký University Olomouc, St. Anne’s University Hospital Brno
Citations6
AnalysisFull AI Review Included

Technical Documentation & Analysis: MPCVD Diamond for High-Precision Interface Studies

Section titled “Technical Documentation & Analysis: MPCVD Diamond for High-Precision Interface Studies”

Research Paper Analyzed: Masarykova et al. (2023). Comparison of microleakage under orthodontic brackets bonded with five different adhesive systems: in vitro study. BMC Oral Health.


This documentation analyzes an in vitro study evaluating the integrity of adhesive interfaces in orthodontics, focusing on the high-precision material science techniques required for replication and extension of this research.

  • Core Problem: Microleakage at the enamel-adhesive interface leads to enamel demineralization and caries under orthodontic brackets.
  • Methodology: 100 extracted premolars were bonded with stainless steel brackets using five different adhesive systems, followed by rigorous thermal cycling (600 cycles, 2.5 °C to 56 °C).
  • Analysis Technique: Microleakage was quantified by 2% methylene blue dye penetration, requiring precision sectioning via a low-speed diamond saw and high-magnification digital microscopy (60×).
  • Key Finding (Adhesives): Composite materials (GC Ortho Connect, Transbond XT, Light Bond) demonstrated superior performance, exhibiting the lowest proportional dye penetration (PDP).
  • Key Finding (Location): Microleakage was statistically higher at the enamel-adhesive interface compared to the adhesive-bracket interface (p < 0.001).
  • 6CCVD Relevance: The study relies heavily on ultra-precision material preparation (diamond cutting) and high-resolution surface analysis, areas where 6CCVD’s MPCVD diamond materials and processing capabilities offer significant advantages for next-generation biomedical testing platforms.

The following hard data points were extracted from the research paper detailing the experimental setup and key results.

ParameterValueUnitContext
Sample Size (Teeth)100PremolarsDivided into 5 groups (20 teeth each)
Bracket MaterialStainless SteelN/ALegend Medium metal brackets
Thermal Cycling Range2.5 to 56°CSimulating oral thermal stress
Total Thermal Cycles600CyclesTotal duration: 145 hours (6 days)
Staining Tracer2%Methylene blue aqueous solution
Sectioning ToolIsometLow-speed diamond sawUsed for longitudinal cuts
Microscopy Magnification60×Olympus DSX 1000 Digital Microscope
Total Bracket Length3mmUsed to normalize Proportional Dye Penetration (PDP)
Lowest PDP (GCO)0.208PDPGC Ortho Connect (Composite)
Highest PDP (GCF)0.733PDPGC Fuji Ortho LC (Resin-reinforced GIC)
Lowest Microleakage Length0.624mmGC Ortho Connect (Composite)
Highest Microleakage Length2.199mmGC Fuji Ortho LC (Resin-reinforced GIC)

The experiment utilized a sequence of high-precision steps involving material preparation, controlled thermal stress, and microscopic analysis of the resulting interfaces.

  1. Sample Preparation: Extracted premolars were cleaned (0.5% chloramine T) and stored in physiological solutions.
  2. Bracket Bonding: Stainless steel brackets were bonded using five distinct adhesive systems (GCF, LB, TB, TL, GCO) via the direct bonding method.
  3. Curing: Adhesives were photopolymerized using an LED Ortholux™ Luminous Curing Light.
  4. Thermal Cycling (Thermocycling): Specimens were subjected to 600 cycles, alternating between 2.5 °C (5 min) and 56 °C (2 min 15 s) baths to simulate thermal expansion and contraction stress on the adhesive interfaces.
  5. Staining: Samples were coated in nail varnish (leaving a 1 mm margin) and immersed in 2% methylene blue solution to trace microleakage paths.
  6. Precision Sectioning: Samples were embedded in resin blocks and sectioned longitudinally using a low-speed diamond saw (Isomet) to expose the enamel-adhesive and adhesive-bracket interfaces.
  7. Measurement: Microleakage extent (Proportional Dye Penetration, PDP) was measured using a digital microscope at 60× magnification and analyzed statistically using generalized linear mixed models (GLMM).

The research highlights the critical need for materials science expertise in analyzing high-stress interfaces and preparing ultra-smooth surfaces for microscopic evaluation. 6CCVD specializes in providing the MPCVD diamond materials and precision processing services necessary to replicate, control, and extend such demanding in vitro studies into advanced engineering applications.

While the study used standard dental materials, 6CCVD provides the ultimate substrates and components for high-resolution analysis and extreme environment testing, crucial for validating next-generation adhesives and biomedical devices.

  • Optical Grade Single Crystal Diamond (SCD):
    • Application: Ideal for high-transparency windows or anvils in high-pressure/high-temperature testing rigs, allowing in situ optical monitoring of adhesive interfaces under extreme thermal or mechanical stress, extending the thermal cycling analysis performed in this paper.
    • Thickness: Available from 0.1Âľm up to 500Âľm.
  • Polycrystalline Diamond (PCD):
    • Application: Used as ultra-hard, chemically inert platforms for mechanical wear testing or as large-area substrates for complex bonding experiments where chemical resistance is paramount.
    • Dimensions: Available in plates/wafers up to 125mm in diameter.

The paper relied on a low-speed diamond saw and 60× microscopy. 6CCVD offers superior precision capabilities essential for true nanoscale interface analysis (e.g., SEM, AFM).

6CCVD CapabilityTechnical Advantage over Standard MethodsRelevance to Interface Research
Ultra-Low Roughness PolishingGuaranteed Ra < 1nm (SCD) and Ra < 5nm (Inch-size PCD).Essential for preparing cross-sections for high-resolution imaging (e.g., SEM, AFM) far beyond the 60× magnification used in this study, enabling precise measurement of sub-micron leakage paths.
Custom Dimensions & Laser CuttingPlates/wafers up to 125mm; custom laser cutting services.Allows researchers to define precise geometries for test coupons or substrates, ensuring highly reproducible sample preparation for mechanical or thermal testing rigs.
In-House MetalizationInternal capability for Au, Pt, Pd, Ti, W, Cu layers.Critical for enhancing contrast or creating conductive paths for advanced interface characterization techniques (e.g., SEM/EDS analysis of adhesive-bracket interfaces).
Boron-Doped Diamond (BDD)Custom BDD films available.Provides conductive, electrochemically stable diamond surfaces for potential use in advanced electrochemical sensing or sterilization applications related to dental plaque and bacteria mentioned in the paper’s background.

6CCVD’s in-house PhD team can assist with material selection for similar Biomedical Interface Integrity projects, particularly those involving extreme thermal cycling, chemical exposure, or high-precision mechanical analysis. We ensure that the diamond material specifications (purity, orientation, surface finish) meet the rigorous demands of advanced scientific research.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Abstract Background Orthodontic treatment is associated with numerous adverse side effects, such as enamel discoloration, demineralization or even caries. The presence of microleakage between the enamel and the adhesive and between the adhesive and the base of the orthodontic bracket allows penetration of the bacteria, molecules, and liquids into the enamel and can lead to unpleasant “white spot lesions” or secondary caries beneath and around the brackets. The aim of this in vitro study was to evaluate microleakage in five adhesive systems commonly used in orthodontic practice for bonding brackets. Methods One hundred extracted premolars were divided into five groups of twenty teeth. Stainless steel Legend medium metal brackets were bonded to teeth using five adhesive systems: resin-reinforced glass ionomer cement GC Fuji Ortho LC (GCF) and composite materials Light Bond (LB), Transbond XT (TB), Trulock™ Light Activated Adhesive (TL), and GC Ortho Connect (GCO). The specimens were subjected to thermal cycling, stained with 2% methylene blue, sectioned with low-speed diamond saw Isomet and evaluated under a digital microscope. Microleakage was detected at the enamel-adhesive and adhesive-bracket interfaces from occlusal and gingival margins. Statistical analysis was performed using generalized linear mixed models with beta error distribution. Results Microleakage was observed in all materials, with GCF showing the highest amount of microleakage. Composite materials GCO, TB, and LB exhibited the lowest amount of microleakage with no statistical difference between them, while TL showed a statistically significantly higher amount of microleakage (p < 0.001). The enamel-adhesive interface had more microleakage in all composite materials (GCO, LB, TB, and TL) than the adhesive bracket-interface (p < 0.001). The highest amount of microleakage occurred in the gingival region in all materials. Conclusion Composite materials showed better adhesive properties than a resin-reinforced glass ionomer cement. The presence of microleakage at the enamel-adhesive interface facilitates the penetration of various substances into enamel surfaces, causing enamel demineralization and the development of dental caries.