Influence of fused deposition modeling parameters on the mechanical and thermal properties of 3D-printed PEEK dental endosseous implants.

Objectives: This study aims to explore the application of Fused Deposition Modeling (FDM) as a 3D printing technique for developing endosseous Polyetheretherketone (PEEK) dental implants. Specifically, the primary aim of the study is to systematically investigate the effects of key FDM processing parameters, including thermal conditions, print speed, layer height, build orientation, and post-processing heat treatments, on the mechanical and thermal properties of PEEK implants. By conducting an in-depth analysis, this study aims to establish optimized processing guidelines for the reliable manufacturing of high-performance, clinically viable PEEK dental implants.

Methods: PEEK dental implants were fabricated using FDM with variations in thermal conditions (nozzle, bedplate, and chamber temperatures), print speed, layer height, build orientation, and post-print heat treatments. Mechanical testing (compression and fatigue), detailed thermal characterization using Differential Scanning Calorimetry (DSC), and fractographic analysis were performed. Finite Element Analysis (FEA) was also conducted to understand the implant's load-bearing performance.

Results: Nozzle temperature dictates implant resolution, while chamber temperature is a key determinant of implant crystallinity. Interestingly, for PEEK dental implants, all the FDM thermal processing conditions play a crucial role in influencing the part's thermal properties. Moreover, print speed plays an essential role in developing dimensionally accurate high-strength implants. Notably, the fractographic analysis of the failed implants revealed interesting multimodal fracture behavior specific to 3D-printed threaded implants. FEA demonstrates that the implants tend to buckle under load and break at the implant-abutment interface, consistent with experimental results. Furthermore, fatigue testing reveals that PEEK implants, fabricated at a specific build orientation with respect to the bedplate, suffice the Food and Drug Administration durability requirements.

Significance: These findings underscore the clinical potential of FDM-developed PEEK as a customizable, lightweight, and durable alternative to conventional metallic implants, paving the way for next-generation patient-specific lightweight dental implant solutions.