Background/Aim. In implant prosthetics, there is an increasing use of materials which, with their mechanical characteristics, can alleviate the negative consequences of implant stress. The aim of this research was to conduct a comparative analysis of stress distribution and deformation of implant supported telescopic systems and surrounding structures, made of different materials, using the finite element method. Methods. 3D finite element models were prepared using (SolidWorks 2018, Concord, MA, USA). Two models of telescopic crowns with the characteristics of polyetheretherketone (PEEK) polymer and cobaltchrome( Co-Cr) alloy faceted with feldspat ceramics were used. The models are loaded with an axial force of 150 N in the region of the central fossa. The analysis of stress and strain distribution was performed by the finite element method in the Ansis software (ANSYS Workbench 16; Ansys Inc., Pittsburg, PA, USA).Results. Implant-supported telescopic crowns made of PEEK polymer significantly reduce stress in the implant and abutment neck area compared to a conventional cobalt-chrome (Co-Cr) crown veneered ceramic. At the level of bone structure, both models showed a concentration of stress at the level of the cortical bone, while the trabecular bone was significantly less exposed to stress. Under the same conditions, the degree of deformation of the secondary telescopic crown was more pronounced in models with PEEK polymer characteristics. Conclusion. Owing to their mechanical characteristics, PEEK polymers can be the materials of choice in the fabrication of superstructures on implants. Given that this in vitro study is accompanied by limitations, further research is needed to confirm the superior role of PEEK material in implant prosthetics.

Background: The aim of this ex vivo study was to compare the resistance to lateral wall failure during sequential implant site preparation using osseodensification (OD) burs and conventional rotary drills in a standardized narrow ridge model. The primary outcome was the drill diameter at first lateral wall perforation. Secondary outcomes included paired perforation occurrence at a clinically relevant diameter (4.0 mm) and perforation morphology (length and width). Methods: Twenty standardized trabecular bone blocks were prepared in a paired within-specimen design, with each block receiving two osteotomies: one prepared using conventional rotary drills and the other using OD burs. Osteotomy diameter was sequentially increased according to the manufacturers’ protocols until lateral wall perforation occurred. The drill diameter at first perforation was recorded. Perforation morphology (length and width) was quantified using high-resolution extraoral digital scanning and software-based measurements. Statistical analysis was performed using paired non-parametric tests (α = 0.05). Results: OD burs significantly delayed lateral wall perforation compared with conventional drills (median 4.30 vs. 4.00 mm; p = 0.0000171). At the 4.0 mm drill step, perforation occurred in 16/20 (80%) conventional versus 2/20 (10%) OD preparations (p = 0.0013). Perforation length was significantly greater with conventional drilling (p = 0.000681), while no significant difference was observed for perforation width (p = 0.073). Conclusions: Within the limits of this decorticated trabecular ex vivo model, OD increased resistance to lateral wall failure, delayed perforation onset, and reduced perforation length compared with conventional drilling.