Assessing the Efficacy of Whole-Body Titanium Dental Implant Surface Modifications in Inducing Adhesion, Proliferation, and Osteogenesis in Human Adipose Tissue Stem Cells

Abstract

Background: Although the influence of titanium implants’ micro-surface properties on titanium discs has been extensively investigated, the research has not taken into consideration their whole-body effect, which may be considered possible using a combinatorial approach. Methods: Five titanium dental implants with a similar moderate roughness and different surface textures were thoroughly characterized. The cell adhesion and proliferation were assessed after adipose-tissue-derived stem cells (ADSCs) were seeded on whole-body implants. The implants’ inductive properties were assessed by evaluating the osteoblastic gene expression. Results: The surface micro-topography was analyzed, showing that hydroxyapatite (HA)-blasted and bland acid etching implants had the highest roughness and a lower number of surface particles. Cell adhesion was observed after 24 h on all the implants, with the highest score registered for the HA-blasted and bland acid etching implants. Cell proliferation was observed only on the laser-treated and double-acid-etched surfaces. The ADSCs expressed collagen type I, osteonectin, and alkaline phosphatase on all the implant surfaces, with high levels on the HA-treated surfaces, which also triggered osteocalcin expression on day seven. Conclusions: The findings of this study show that the morphology and treatment of whole titanium dental implants, primarily HA-treated and bland acid etching implants, impact the adherence and activity of ADSCs in osteogenic differentiation in the absence of specific osteo-inductive signals.

Considering the Value of 3D Cultures for Enhancing the Understanding of Adhesion, Proliferation, and Osteogenesis on Titanium Dental Implants

“…A bland detaching solution, namely CTC (collagenase 20 U/mL, trypsin 0.75 mg/mL, 2% heat-inactivated dialyzed chicken serum (Gibco) in calcium, and magnesium Hank's balanced salt solution (HBSS)), was used to detach ADSCs. Cells between passages 1 and 6 (P1 and P6) were used in the experiments [24,26].…”

“…Five different titanium dental implants, 1: sandblasted with aluminum oxide and acid etched (Al Blast, N = 9); 2: laser-sintered (Laser Sint, N = 9); 3: sandblasted with titanium dioxide spheres and fluoride treatment (Ti Blast, N = 9); 4: laser-machined (Laser Mach, N = 9); 5: sandblasted with corundum and different acid etchings (Cor Blast, N = 9), have been tested and compared throughout this study. The implants had a tronco-conical shape with dimensions ranging from 3.6 to 4 mm in diameter and 8 to 9 mm in length and were chosen for their wider market representation, which could be attributed to their higher difference in roughness degree and surface texture compared to our previous research [24]. The surface of Al Blast, which is made of grade 4 titanium, has a uniform finish due to a temperature-controlled process of large-grit sandblasting with aluminum oxide (Al 2 O 3 , around 0.5 mm) and acid etching.…”

“…Although initially created for different purposes and highlighting the measurement uncertainty and noise that can be caused by errors induced by this method and by the roughness estimation process itself [28][29][30], the plugin SurfCharJ was used for approximately determining the roughness parameters from the SEM microphotographs [20]. Therefore, roughness was assessed according to ISO 4287/2000, measuring the following parameters: Ra (arithmetical mean deviation), Rq (root mean square deviation), Rsk (skewness of the assessed profile), and Rku (kurtosis of the assessed profile) using SEM photomicrographs and the SurfCharJ plugin [20,24]. Ra and Rq specifically describe the topological events' height and amplitude (peaks and valleys).…”

“…On the downside, the impact of titanium dental implants on cells varies significantly because of the different surface textures and coatings [5,6,10,[19][20][21][22][23]. Nevertheless, several previous studies examining the effects of coating and surface roughness on whole-body titanium dental implants established the approach's feasibility by demonstrating a significant advantage from testing stem cells in 3D in terms of adhesion and differentiation [24,25]. In fact, stem cells grown on implants display an improved differentiation compared to the same cells maintained in 2D because 3D cell cultures better resemble the physiological cell environment [25].…”

Surface Modification and Functionalities for Titanium Dental Implants

“…The success rate of Ti dental implant surgery can reach over 90%, but there are still about 10% failures . The key that determines the success of Ti implants is the effective osseointegration. − In addition, improving the antibacterial properties of the implant and suppressing peri-implant inflammation are also important factors for the success of the surgery. − Osteogenesis requires osteoblasts to adhere and grow on the surface of the implant. − And the occurrence of inflammation is mostly related to bacterial adsorption and biofilm formation on the surface of implants. − All of the above processes are closely related to the surface conditions of Ti implants. However, during the Ti implant manufacturing process, if the overall material is changed to achieve good surface conditions, the overall performance of the implant may be seriously affected.…”