Porous Tantalum vs. Titanium Implants: Enhanced Mineralized Matrix Formation after Stem Cells Proliferation and Differentiation

Abstract

Titanium dental implants are used routinely, with surgical procedure, to replace missing teeth. Even though they lead to satisfactory results, novel developments with implant materials can still improve implant treatment outcomes. The aim of this study was to investigate the efficiency of porous tantalum (Ta) dental implants for osseointegration, in comparison to classical titanium (Ti). Mesenchymal stem cells from the dental pulp (DPSC) were incubated on Ta, smooth titanium (STi), and rough titanium (RTi) to assess their adhesion, proliferation, osteodifferentiation, and mineralized matrix production. Cell proliferation was measured at 4 h, 24 h, 48 h with MTT test. Early osteogenic differentiation was followed after 4, 8, 12 days by alkaline phosphatase (ALP) quantification. Cells organization and matrix microstructure were studied with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Collagen production and matrix mineralization were evaluated by immunostaining and histological staining. MTT test showed significantly higher proliferation of DPSC on Ta at 24 h and 48 h. However, APL quantification after 8 and 12 days was significantly lower for Ta, revealing a delayed differentiation, where cells were proliferating the more. After 3 weeks, collagen immunostaining showed an efficient production of collagen on all samples. However, Red Alizarin staining clearly revealed a higher calcification on Ta. The overall results tend to demonstrate that DPSC differentiation is delayed on Ta surface, due to a longer proliferation period until cells cover the 3D porous Ta structure. However, after 3 weeks, a more abundant mineralized matrix is produced on and inside Ta implants. Cell populations on porous Ta proliferate greater and faster, leading to the production of more calcium phosphate deposits than cells on roughened and smooth titanium surfaces, revealing a potential enhanced capacity for osseointegration.

Porous tantalum structure integrated on Ti6Al4V base by Laser Powder Bed Fusion for enhanced bony-ingrowth implants: In vitro and in vivo validation

“…Osteointegration is another crucial criterion for orthopedic scaffolds [ 45 ]. A large amount of evidence derived from clinical and laboratory studies has proved the outstanding osteointegration performance of Ta [ 13 , 46 ], which was also demonstrated to be superior to Ti via ample studies [ 17 , 47 ]. Two canonical detection approaches, ALP and mineralized nodule production, were chosen to evaluate the osteogenesis performance of the newly developed scaffolds in the present study.…”

Tantalum Particles Induced Cytotoxic and Inflammatory Effects in Human Monocytes

“…With the progress in implant surface research and considering the limitations of porous tantalum in the application of orthopedic prosthesis surfaces, researchers have reconsidered whether Ta can be used as an implant coating material. More evidence has shown porous tantalum has potential advantages as dental implant coating material comparing with conventional Ti [ 16 , 22 , 28 ]. However, little research has been conducted on the biological safety of Ta as a dental implant coating.…”

“…Comparing with conventional titanium surfaces, porous tantalum structures have more porosity and structural irregularities. Thus, greater surface areas in porous tantalum structures are available for cell attachment and proliferation [ 22 ]. However, the research on the biological safety of Ta particles is limited and needs further exploration.…”

The Clinical Application of Porous Tantalum and Its New Development for Bone Tissue Engineering

“…Reprinted from ref. [ 36 ]. Abundant bone ingrowth can be found in the pores of porous Ta implant ( c ).…”

“…Meanwhile, the high porosity of porous Ta ensures desirable permeability for vascularization and nutrient flow, which can guarantee rapid osteointegration at an early stage [ 35 ]. Combined with the inherent high wettability and surface energy, porous Ta can further facilitate the adhesion, differentiation and spread of stem cells [ 36 ], osteoblasts [ 37 , 38 ] and chondrocytes [ 39 ], as well as vascularized fibrous tissues [ 40 ] and tendon [ 41 ]. Furthermore, bone ingrowth can be found within the pores of porous Ta as early as 4 weeks after implantation [ 38 ] ( Figure 2 ).…”