Standardized Protocol to Evaluate the Effect of Surface Treatments, Luting Cements, and Thermocycling on PEEK–Composite Bond Strength
June 9th, 2026
This protocol aims to evaluate the effects of surface treatment protocols, luting cement selection, and thermocycling on the shear bond strength between PEEK and an indirect composite resin.
This study presents a standardized protocol to evaluate the effects of surface treatment, cement type, and thermocycling on PEEK composite bone strength. The protocol facilitates consistent evaluation of bonding approaches that may improve the long-term performance of PEEK restorations. To begin, obtain polyether ether ketone, or PEEK, disk specimens.
Surface-treat them according to the designated protocols. Prepare standardized indirect composite resin disks for bonding to the treated PEEK surfaces using different luting cements. Divide each surface treatment group into zinc oxide non-eugenol cement and self-adhesive resin cement groups.
For the zinc oxide non-eugenol cement, dispense equal lengths of the base and catalyst pastes onto a mixing pad. Mix for approximately 20 seconds until a homogeneous consistency is achieved. Using a spatula, apply the mixed cement to the treated PEEK surface with gentle pressure to minimize air entrapment.
For the self-adhesive resin cement, attach an automixed tip to the syringe and dispense a small initial amount to ensure proper mixing. Then, apply the cement directly to the treated PEEK surface while keeping the tip in contact to maintain continuous flow and reduce air entrapment. Cover the entire bonding area with a uniform layer.
Position the composite disk centrally on either of the cement-covered PEEK surfaces. Next, apply a constant vertical load of 500 grams for 10 seconds to standardize cement thickness and ensure uniform adaptation. Remove excess cement from the margins using a microbrush.
For the zinc oxide non-eugenol cement, allow a setting time of six minutes under the applied load. For the self-adhesive resin cement, polymerize with a light curing device from all directions for a total of 80 seconds at a distance of five millimeters. Thermo-cycle the designated specimens between five and 55 degrees Celsius for a total of 5, 500 cycles under standardized conditions.
Then, mount the embedded specimen in a universal testing machine and perform the shear bond strength test. Self-adhesive resin cement showed higher shear bond strength values than zinc oxide non-eugenol cement across all surface treatment groups. The specimens luted with temporary cement after thermocycling showed the lowest shear bond strength values compared to other groups.
Thermocycling reduced the shear bond strength values for both cement types. The sandblasted specimens luted with resin cement without thermocycling showed the highest shear bond strength values. The sulfuric acid etched and laser-treated specimens demonstrated intermediate shear bond strength values.
The untreated PEEK surfaces luted with temporary cement showed shear bond strength values comparable to or higher than the treated surfaces. This protocol can be used to measure the durability of PEEK composite adhesion under simulated clinical conditions. Safe handling of sulfuric acid and laser equipment is essential to ensure operator safety and procedural consistency.
Future studies can evaluate additional surface treatments, different cements, composites, and thermocycling conditions to optimize PEEK bonding.
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Overview
This study addresses the challenge of achieving durable adhesion between polyetheretherketone (PEEK), a chemically inert biomaterial used in prosthodontics, and veneering composite materials. The authors present a standardized and reproducible protocol to evaluate the shear bond strength (SBS) of PEEK to an indirect composite resin under various surface treatments, luting cements, and thermocycling conditions.
Key Study Components
Area of Science
- Dental materials science
- Prosthodontics
- Biomaterials engineering
Background
- PEEK is increasingly used in dental prosthodontics due to its favorable properties.
- Its chemically inert structure makes bonding to composite resins difficult.
- Surface treatments and cement selection are critical for improving adhesion.
- Standardized testing protocols are needed for reproducible evaluation of bond strength.
Purpose of Study
- To develop and validate a standardized protocol for assessing SBS between PEEK and composite resin.
- To compare the effects of different surface treatments and luting cements on bond strength.
- To evaluate the impact of thermocycling on bonding durability.
Methods Used
- Preparation of 240 PEEK discs divided into four surface treatment groups: no treatment, sandblasting, sulfuric acid etching, and laser irradiation.
- Surface morphology analysis using atomic force microscopy.
- Subdivision by luting cement: zinc oxide non-eugenol or self-adhesive resin cement.
- Further subdivision into thermocycled and non-thermocycled groups.
- Measurement of SBS using a universal testing machine.
- Failure mode analysis under a stereomicroscope.
Main Results
- Self-adhesive resin cement without thermocycling yielded the highest SBS values (25.134 ± 1.665 MPa).
- Zinc oxide non-eugenol cement with thermocycling resulted in the lowest SBS values (1.958 ± 0.345 MPa).
- Self-adhesive resin cement significantly outperformed zinc oxide non-eugenol cement in all surface treatment groups (p < 0.001).
- Thermocycling significantly reduced SBS values across all groups (p < 0.001).
Conclusions
- Surface treatment and cement type are critical factors influencing PEEK–composite bonding.
- Thermocycling negatively impacts bond durability.
- The presented protocol offers a reproducible framework for evaluating and optimizing PEEK–composite adhesion in dental applications.
Frequently Asked Questions
Executive Industry Relevance
Standardized evaluation of PEEK–composite bond strength addresses a critical challenge in biomaterials engineering, enabling more predictive assessment of adhesion durability under clinically relevant conditions. This protocol supports early-stage material selection and de-risking for dental and medical device development pipelines. Reliable, reproducible workflows for surface treatment and cement selection inform portfolio decisions and translational continuity in prosthetic innovation.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables systematic interrogation of adhesion mechanisms between inert biomaterials and composites.
- Supports functional validation of surface modification strategies for improved bonding.
- Facilitates predictive confidence in material selection for downstream device development.
Screening & Assay Development
- Provides a reproducible framework for quantitative shear bond strength measurement.
- Standardizes assessment of surface treatments and cement types for assay comparability.
- Enables scalable screening of new biomaterial formulations and adhesives.
Translational & Preclinical Research
- Aligns laboratory testing with clinically relevant durability endpoints via thermocycling.
- Supports risk-adjusted advancement of candidate materials based on quantitative failure analysis.
- Facilitates continuity from bench validation to preclinical device evaluation.
Pipeline & Workflow Integration
This protocol integrates into the discovery-to-preclinical continuum for dental and medical device R&D, bridging early material screening with translational durability assessment.
- Discovery Biology: Clarifies the impact of surface chemistry and treatment on adhesion mechanisms.
- Screening: Delivers standardized, quantitative outputs for cross-comparison of bonding strategies.
- Analytics: Provides robust shear bond strength data and failure mode analysis for decision-making.
- Translational Research: Incorporates thermocycling to simulate clinical aging and inform preclinical risk assessment.
- Enterprise Reuse: Establishes a validated workflow adaptable to new biomaterial and adhesive candidates.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in adhesion performance and material compatibility.
- Operational Value: Enhances reproducibility and standardization across R&D teams and sites.
- Strategic Value: Informs go/no-go decisions for material advancement and reduces late-stage failure risk.
- Portfolio Impact: Supports risk-adjusted prioritization of biomaterial and adhesive combinations.
Implementation Considerations
- Requires expertise in biomaterials handling and quantitative mechanical testing.
- Needs access to atomic force microscopy and universal testing instrumentation.
- Demands cross-team standardization of surface treatment and cement protocols.
- Adaptable to various biomaterial–adhesive systems with protocol modifications.
- Thermocycling introduces practical considerations for simulating clinical aging.
