To avoid exceeding the adaptive limits of the bone and maintain the proper stimulation of mechanical stress that will keep the bone vital, PEEK components seem a viable alternative to obtaining a similar modulus to that of cortical bone. In this way, bone could be stimulated, favouring remodelling without overload. It would concentrate the load by absorbing and distributing the same. Its capacity of load absorption has led some authors to recommend its use in patients with severe bruxism.

Finite element analysis suggests that maximum contact pressure at the bone-titanium implant interface can be significantly reduced by using a PEEK crown rather than a ceramic crown.

In addition to PEEK, new coatings based on PMMA or composite materials (Anaxblent®Anaxdent®, Nexco®Ivoclar®, Solidex®Shofu®, Novo.lign®Bredent®, etc.) which incorporate ceramic fillings have been developed. Due to their molecular structure, these materials have excellent density and homogeneity. The micro filling integrated into the polymer matrix increases abrasion resistance, at the same time as providing optimal elasticity which resembles the natural structure of a tooth. Although these restorations show good colour stability and a long-lasting shine, texture and brightness, they differ substantially from ceramic coatings which have excellent optical properties that enable them to achieve better long-term aesthetic results.

None of the authors have any competing interests in the manuscript. All authors have performed important contribution and have read and approved the final version to be published.

Zirconia implants with PEEK restorations can be considered a good alternative for replacing natural teeth. Their biocompatibility and biostability make them a promising material for those patients who suffer from allergies and sensitivity to metal alloys.

PEEK restorations are a valid and alternative recommendation when using zirconia implants because of their cushioning effect and elastic modulus, which absorb occlusal forces and wear like a natural tooth, which could optimise and preserve osseointegration with time.

Within the limitations of this study, we recommend the combined use of zirconia implants, PEEK structures and PMMA coatings in patients with intolerance to or rejection of metal alloys.