The effect of 3D printing technology combined with Morse taper and platform switching design on microleakage...

This study aims to investigate the effects of a Morse taper connection combined with platform switching design and hydroxyapatite (HA) coating on the mechanical properties, bacterial leakage, bioactivity, and osteogenic properties of dental implants. Four groups of models (platform switching of 0 and 0.6 mm; Morse taper of 0° and 10°) were determined through three-dimensional finite element analysis and labeled as TI, P, T, and PT groups. The dental implants were fabricated using selective laser melting and then surface-modified with sandblasting, acid etching, and HA coating. The physicochemical properties of the implants were measured using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), and profilometry. Bacterial leakage was detected by colony counting. Finally, the biocompatibility, bioactivity, and osteogenic capacity of the implants were assessed through cell culture, immunohistochemistry, and Western blot. Significant differences were observed between the PT and Ti groups in terms of morphology, mechanical properties, and bacterial leakage. HA coating significantly enhanced the bioactivity of the implants. Implants modified by sandblasting, acid etching, and HA coating exhibited better biocompatibility, bioactivity, and osteogenic capacity compared to unmodified implants. Additionally, the PT group showed a significant improvement in reducing bacterial leakage. The Morse taper connection combined with platform switching design places less stress on the implant system than conventional platform-docked implants. The narrowing of the abutment neck is more favorable for the attachment of osteoblast-associated cells.