Allergic reaction of poly‐ether‐ether‐ketone versus titanium implants: A posttest‐only control group design experimental study using a rabbit model

Purpose The aim of this study was to determine clinically and genetically the allergic effects of titanium and poly‐ether‐ether‐ketone (PEEK) implants following loading in rabbit tibias. Materials and methods This study included 18 white New Zealand male rabbits (n = 18) divided evenly into three groups: control, titanium (Ti), and PEEK (P). Clinically, the allergenic effect of titanium and PEEK was investigated by detecting the effect on lymph nodes. Furthermore, RT‐PCR and ELISA were used to detect the expression of certain genes IL‐6, TNF‐α, OPG, RANKL, and RUNX‐2 through both types of implants. Results Our findings demonstrated that titanium implants induced enlarged lymph nodes, which PEEK did not. Overall, RT‐PCR and ELISA techniques revealed that Ti implants had higher expression of the inflammatory genes IL‐6 and TNF‐α. Ti had the highest expression in OPG findings, while PEEK had the lowest. RANKL expression was highest in the control group and lowest in the PEEK group. RUNX‐2 is the highest for the control group and the lowest for the titanium group. Conclusion Although titanium implants elicited greater allergy responses than PEEK implants, titanium has the highest expression of bone formation genes and the lowest expression of bone resorption genes, making it preferable to PEEK.