PEEK, carbon or titanium: what is the future for dental osseointegration?

PEEK optimization in implantology: towards surpassing the titanium gold standard?

Although titanium is the reference for its biocompatibility, its high elastic modulus induces a stress-shielding effect linked to bone resorption, with complications documented in approximately 20% of patients over 10 years. Polyetheretherketone (PEEK) constitutes a serious alternative thanks to an elastic modulus (3-4 GPa) close to that of cortical bone, although its bioinert and hydrophobic nature limits initial osseointegration. The objective of this systematic review of 35 studies (PRISMA) is to compare the mechanical, biological, and clinical performances of titanium against pure PEEK and its modified variants, specifically titanium-coated (Ti-coated) PEEK and carbon fiber-reinforced PEEK (CFR-PEEK).

The authors test the hypothesis that titanium-coated PEEK allows for combining the osteoconductivity of the metal with the mechanical flexibility of the polymer to promote direct bonding with bone tissue. In parallel, CFR-PEEK is evaluated for its ability to offer increased structural resistance and more homogeneous stress distribution than pure titanium, thereby aiming to reduce the risks of biomechanical complications while preserving the integrity of the surrounding bone.

Systematic review methodology

This study was conducted according to the PRISMA 2020 recommendations to analyze the performance of polyetheretherketone (PEEK) as an alternative to titanium. The authors conducted a literature search on the PubMed, Scopus, and Web of Science databases, covering publications released between 2020 and 2025.

The selection of articles was structured around the PCC (Population-Concept-Context) framework:

• Population: Original studies including in silico, in vitro, in vivo investigations, and clinical trials on dental implants.
• Concept: Comparative analysis of mechanical, physical, chemical, biological, and clinical properties.
• Context: Evaluation of osseointegration, fixation stability, and interactions with hard and soft tissues.

Of all the results identified, 35 studies strictly meeting the eligibility criteria were included in the qualitative synthesis. The analysis focused on four categories of materials: pure (unmodified) PEEK, titanium (standard control), titanium-coated PEEK (Ti-coated PEEK), and carbon fiber-reinforced PEEK (CFR-PEEK). The evaluation focused on the optimization of surface bioactivity and the reduction of the elastic modulus to approach the properties of cortical bone.

The evolution of materials: beyond titanium

Although titanium remains the standard in implantology thanks to its biocompatibility, its clinical limitations are documented: an elastic modulus higher than that of cortical bone inducing a stress-shielding effect, rare allergic reactions (~0.6%), and aesthetic challenges in cases of mucosal recession. Faced with a complication rate affecting approximately 20% of patients over 5 to 10 years, this systematic review of 35 studies (PRISMA) analyzes the potential of Polyetheretherketone (PEEK) and its modified variants (titanium coating and carbon reinforcement) as biomimetic alternatives.

Performance analysis: pure PEEK vs. modified PEEK

The authors of this review report that pure PEEK, despite an ideal elastic modulus of 3 to 4 GPa close to bone, suffers from bioinertness limiting osseointegration. The synthesis of the data shows that surface modifications radically transform these biological and mechanical properties.

Compiled data indicate that Ti-coated PEEK combines the mechanical flexibility of the polymer with the osteoconductivity of the metal. Meanwhile, carbon fiber-reinforced PEEK (CFR-PEEK) offers superior structural rigidity while maintaining more physiological load transfer than pure titanium (Haseeb et al. 2022).

Compared biological and mechanical results

According to the included studies, several surface modification strategies stand out:

• Osteogenic differentiation: The authors cite Qiu et al. (2023) showing that CPP coatings improve osteoblast adhesion and mineralization.
• Antibacterial activity: Plasma (N2) or graphene oxide-modified PEEK exhibits enhanced antibacterial activity compared to conventional PEEK (Liu et al. 2021, Guo et al. 2021).
• Biomechanics: Reported finite element analysis (FEA) (Mondragon et al. 2023) confirms that CFR-PEEK reduces critical stress at the peri-implant bone level.

The synthesis shows that Ti-coated PEEK is currently the most promising candidate for osteoconduction, although the authors highlight the need for large-scale clinical trials to validate long-term safety.

Conclusion

Modified PEEK is no longer a mere theoretical alternative but a viable technical solution that outperforms native PEEK and equals, or even exceeds, titanium in certain biomechanical parameters.

Titanium vs PEEK: the rise of hybrid implants

This systematic review of 35 studies (PRISMA) evaluates PEEK and its variants (titanium coating, carbon reinforcement) as alternatives to titanium, whose high modulus of elasticity and rare allergic risks (~0.6%) limit its ideal use. The objective is to analyze these materials at the mechanical and biological levels to determine their clinical viability in implantology.

The balance between biomechanics and bioactivity

The compiled results highlight that native PEEK, although biomechanically biomimetic with a modulus of elasticity of 3–4 GPa, remains limited by its bioinert and hydrophobic nature. The major contribution of this synthesis lies in the demonstrated superiority of modified forms. Titanium-coated PEEK stands out particularly by combining the structural flexibility of the polymer with the osteoconductive properties of the metal, thus promoting surface bioactivity and apatite formation. Furthermore, carbon-fiber reinforcement (CFR-PEEK) allows approaching the strength of titanium while offering a stress distribution closer to cortical bone, which theoretically reduces the risk of stress-shielding and associated bone resorption.

Nevertheless, the scope of these conclusions faces a structural limitation of current literature: the predominance of experimental data. While numerical simulations are encouraging, human clinical validation remains marginal in this body of studies. For the implantologist, the major challenge remains the durability of the interface between the coating and the polymer substrate under real occlusal load, a critical parameter that in vitro models cannot fully guarantee.

Concretely, for the practitioner:

• Anticipate stress-shielding: Prefer materials with a low modulus of elasticity such as PEEK (3–4 GPa) for a more homogeneous stress distribution than titanium, particularly in areas at risk of resorption.
• Choose CFR-PEEK for strength: If you are looking for a compromise between bone flexibility and mechanical rigidity, carbon-fiber-reinforced PEEK is the most structurally stable variant.
• Monitor Ti-coated PEEK: Although this is the most promising modification for direct osseointegration, wait for large-scale human clinical trials before systematic adoption as a replacement for standard titanium.

Technical glossary of the study

Polyetheretherketone (PEEK): High-performance polymer exhibiting high chemical and thermal stability. In the implant context, it is distinguished by a modulus of elasticity of 3–4 GPa, close to that of cortical bone, reducing the risks of bone atrophy compared to metals.

Stress-shielding: Phenomenon of peri-implant bone resorption linked to the use of excessively rigid materials (such as titanium). The implant absorbs the majority of mechanical stress, depriving the surrounding bone of the stimuli necessary for its healthy remodeling.

CFR-PEEK (Carbon-Fiber-Reinforced PEEK): PEEK reinforced with carbon fibers (short or continuous). This structural modification aims to increase the mechanical strength and rigidity of the material while maintaining mechanical biocompatibility with bone tissue.

Titanium-coated PEEK: Surface modification consisting of applying a titanium coating to the PEEK substrate. The goal is to combine the mechanical flexibility of the polymer with the osteoconductive properties and surface bioactivity of titanium.

Bioinertness: Biological property of pure PEEK which, although non-toxic, limits the formation of direct bonds with bone cells in vivo, thus restricting spontaneous osseointegration without surface modification.

In Silico Analysis (FEA): Research method using numerical simulation via Finite Element Analysis. It allows for the predictive evaluation of stress distribution and biomechanical performance of implant materials under various loads.

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