Titanium Substratum Roughness as a Determinant of Human Gingival Fibroblast Fibronectin and α-Smooth Muscle Actin Expression

Platelet-rich fibrin stimulates the proliferation and expression of proteins related to survival, adhesion, and angiogenesis in gingival fibroblasts cultured on a titanium nano-hydroxyapatite-treated surface

OBJECTIVES

This in vitro study aimed to evaluate the cell viability and expression of proteins related to angiogenesis, adhesion, and cell survival (vascular endothelial growth factor, paxillin, vinculin, fibronectin, and protein kinase B) in gingival fibroblasts that were cultured on titanium discs treated with or without nanohydroxyapatite and exposed to platelet-rich fibrin (PRF)-conditioned medium.

METHODS

To obtain the conditioned medium, the PRF membranes were prepared and incubated for 48 h in a culture medium without fetal bovine serum. Analyses were performed at 24 and 48 h for the cells cultured on machined-titanium discs or surfaces treated with nanohydroxyapatite in a control medium or PRF-conditioned medium, resulting in four experimental groups (CT-TI, CT-NANO, PRF-TI, and PRF-NANO).

RESULTS

A decrease in the viability of the gingival fibroblasts was not observed in any of the experimental groups. The PRF-NANO group showed significantly higher immunoexpression of paxillin and AKT at 24 and 48 h (p < 0.01). The same result was observed for vinculin expression at 24 h (p < 0.001). The expression of fibronectin at 48 h and VEGF at 24 and 48 h was significantly higher when the cells were exposed to the PRF-conditioned medium, regardless of the disc surface (p < 0.05).

CONCLUSION

Gingival fibroblasts cultured on a nanohydroxyapatite-treated surface and in a PRF-conditioned medium showed a greater expression of proteins modulating adhesion, angiogenesis, and cell survival. Our results may contribute to the understanding of the mechanisms related to peri-implant soft tissue sealing.

Effect of calcium hydrothermal treatment of zirconia abutments on human gingival fibroblasts

Zirconia materials have been increasingly used in implant rehabilitation due to their excellent physical and esthetic properties. Stable peri-implant epithelial tissue adhesion to the transmucosal implant abutment may significantly enhance the efficacy of implant long-term stability. However, it is difficult to form stable chemical or biological bindings with peri-implant epithelial tissue due to the strong biological inertia of zirconia materials. In the present study, we investigated whether calcium hydrothermal treatment of zirconia promotes sealing of peri-implant epithelial tissue. In vitro experiments were performed to analyze the effects of calcium hydrothermal treatment on zirconia surface morphology and composition by scanning electron microscopy and energy dispersive spectrometry. Immunofluorescence staining of adherent proteins, namely, F-actin and integrin β1, in human gingival fibroblast line (HGF-l) cells was performed. In the calcium hydrothermal treatment group, there was higher expression of these adherent proteins and increased HGF-l cell proliferation. An in vivo study was conducted by extracting the maxillary right first molars of rats and replacing them with mini-zirconia abutment implants. The calcium hydrothermal treatment group showed better attachment at the zirconia abutment surface, which inhibited horseradish peroxidase penetration at 2 weeks post-implantation. These results demonstrated that calcium hydrothermal treatment of zirconia improves the seal between the implant abutment and surrounding epithelial tissues, potentially increasing the long-term stability of the implant.

Direct-Writing Electrospun Functionalized Scaffolds for Periodontal Regeneration: In Vitro Studies

Multiphasic scaffolds that combine different architectural, physical, and biological properties are the best option for the regeneration of complex tissues such as the periodontium. Current developed scaffolds generally lack architectural accuracy and rely on multistep manufacturing, which is difficult to implement for clinical applications. In this context, direct-writing electrospinning (DWE) represents a promising and rapid technique for developing thin 3D scaffolds with controlled architecture. The current study aimed to elaborate a biphasic scaffold using DWE based on two polycaprolactone solutions with interesting properties for bone and cement regeneration. One of the two scaffold parts contained hydroxyapatite nanoparticles (HAP) and the other contained the cementum protein 1 (CEMP1). After morphological characterizations, the elaborated scaffolds were assessed regarding periodontal ligament (PDL) cells in terms of cell proliferation, colonization, and mineralization ability. The results demonstrated that both HAP- and CEMP1-functionalized scaffolds were colonized by PDL cells and enhanced mineralization ability compared to unfunctionalized scaffolds, as revealed by alizarin red staining and OPN protein fluorescent expression. Taken together, the current data highlighted the potential of functional and organized scaffolds to stimulate bone and cementum regeneration. Moreover, DWE could be used to develop smart scaffolds with the ability to spatially control cellular orientation with suitable cellular activity at the micrometer scale, thereby enhancing periodontal and other complex tissue regeneration.

Dual-catalytic CuTPP/TiO2 nanoparticles for surface catalysis engineering of cardiovascular materials

Endowing materials with catalytic activities analogous to those of the natural endothelium to thus enhance their biological performance has become an option for constructing advanced blood-contact materials. The electron transfer between Cu2+ and Cu+ in the porphyrin center can catalyze the reaction of GSH and GSNO to generate NO, and this electron transfer can also catalyze the decomposition of ROS. Based on this, we created a dual-catalytic surface possessing NO-generating and ROS-scavenging activities to better mimic the versatile catalytic abilities of the endothelium. Copper tetraphenylporphyrin/titanium dioxide nanoparticles (CuTPP/TiO2-NPs) exhibiting excellent NO-generating and ROS-scavenging activities were synthesized and immobilized on the material surface to form a dual-catalytic film (CuTPP/TiO2-film) with the help of the catechol chemistry technique. Unlike most single catalytic surfaces, the dual-catalytic CuTPP/TiO2-film effectively regulated the microenvironment surrounding the implanted device by releasing NO signaling molecules and scavenging harmful ROS. This dual-catalytic film exhibited excellent biosafety and biocompatibility with anti-thrombosis, vascular wall cells (ECs and SMCs) modulation, and anti-inflammatory properties. We envision that this dual-catalytic endothelial bionic strategy may provide a promising solution to the clinical problems plaguing blood-contact devices and provide a novel basis for the further development of surface catalytic-engineered biomaterials.

Effect of addition of Ca2+ to titanium by a hydrothermal method on soft tissue sealing

The long-term stability of implants requires good peri-implant soft tissue sealing. Calcium ion (Ca²⁺ ) was loaded onto titanium surface by a hydrothermal method. In vitro, the morphology and composition of titanium surfaces were determined by scanning electron microscopy and energy-dispersive spectroscopy; proliferation of hGF-1 cells was measured by the CCK-8 assay; immunofluorescence staining was done to detect adherent proteins on titanium surface. In vivo, the degree of attachment between the implant and the surrounding soft tissue was measured by horseradish peroxidase (HRP). The percentage of hGF-1 cells adhering in the Ca group was significantly higher (p < .01); the fluorescence of integrin-β1 and F-actin in the Ca group was stronger; Ca group had the shorter length of HRP (p < .01). Ca²⁺ can be added to the surface of titanium by a hydrothermal method and it will be more beneficial for soft tissue early sealing.