Initial attachment, subsequent cell proliferation/viability and gene expression of epithelial cells related to attachment and wound healing in response to different titanium surfaces

Enhancement of Biocompatibility of High-Transparency Zirconia Abutments with Human Gingival Fibroblasts via Cold Atmospheric Plasma Treatment: An In Vitro Study

The objective of this study was to explore the effects of cold atmospheric plasma (CAP) treatment on the biological behavior of human gingival fibroblasts (HGFs) cultured on the surface of high-transparency zirconia. Two types of zirconia, 3Y-ZTP and 4Y-PSZ, were subjected to a CAP treatment for various treatment durations. Analyses of the physical and chemical properties of 3Y-ZTP and 4Y-PSZ were conducted using scanning electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy, both before and after CAP treatment. The biological responses of HGFs on both surfaces were assessed using CCK-8 assay, confocal laser scanning microscopy, and real-time PCR. Initially, the oxygen and hydroxyl contents on the surface of 4Y-PSZ exceeded those on 3Y-ZTP. CAP treatment enhanced the surface hydrophilicity and the reactive oxygen species (ROS) content of 4Y-PSZ, while not altering the surface morphology. After CAP treatment, HGFs' adhesion on 4Y-PSZ was superior, with more pronounced effects compared to 3Y-ZTP. Notably, HGFs counts and the expression of adhesion-related genes on 4Y-PSZ peaked following the CAP exposures for 30 s and 60 s. Consequently, this study demonstrates that, following identical CAP treatments, 4Y-PSZ is more effective in promoting HGFs adhesion compared to traditional 3Y-ZTP zirconia.

Influence of surface nanotopography and wettability on early phases of peri-implant soft tissue healing: an in-vivo study in dogs

BACKGROUND

It is well established that nanotopography and wettability of implant surfaces contribute to osseointegration and long-term implant success. However, the effects of a hydrogenated surface with nanotubular and superhydrophilic properties on peri-implant soft tissue remain unclear. This study was designed to study the impact of a modified abutment surface on early soft tissue integration compared with a machined surface.

METHODS

Thirty-six implants were placed at the bone level in the bilateral mandible of six beagles, followed by healing abutments belonging to the standard machined Ti-6Al-4V alloy abutments (TC4-M), anodized abutments with nanotubes (TC4-Nano), and hydrogenated abutments (TC4-H/Nano) groups, which were randomly screwed to the implants. After two and four weeks of wound healing, the animals were euthanized for histological evaluation.

RESULTS

A superhydrophilic nanotubular surface developed on the hydrogenated abutment. Histological and histometric analyses revealed similar peri-implant soft tissue healing and dimensions for the three types of abutments at two and four weeks. Connective tissue (CT) length was longer around TC4-H/Nano abutments compared with standard abutments; however, the differences were not statistically significant. Moreover, collagen fibers in the TC4-H/Nano group extended and were attached perpendicularly to the superhydrophilic surface.

CONCLUSIONS

Our results revealed that the soft tissue interface adjacent to the hydrogenated abutment is comparable to that of the machined abutment. A tendency of increased CT length and perpendicular collagen fibers was observed around the modified abutment. This study suggests that nanotubular/superhydrophilic surfaces could be a promising modification to enhance soft tissue sealing. However, comprehensive studies should be conducted to evaluate the peri-implant soft tissue around the modified abutment immunohistochemically, histopathologically, and clinically.

SEM Evaluation of Thermal Effects Produced by a 445 nm Laser on Implant Surfaces

The aim of this in vitro study was to evaluate thermal effects on implant surfaces using a 445 nm diode laser (Eltech K-Laser Srl, Treviso, Italy) with different power settings and irradiation modalities. Fifteen new implants (Straumann, Basel, Switzerland) were irradiated to evaluate surface alteration. Each implant was divided into two zones: the anterior and posterior areas. The anterior coronal areas were irradiated with a distance of 1 mm between the optical fiber and the implant; the anterior apical ones were irradiated with the fiber in contact with the implant. Instead, the posterior surfaces of all of the implants were not irradiated and used as control surfaces. The protocol comprised two cycles of laser irradiation, lasting 30 s each, with a one-minute pause between them. Different power settings were tested: a 0.5 W pulsed beam (T-on 25 ms; T-off 25 ms), a 2 W continuous beam and a 3 W continuous beam. Lastly, through a scanning electron microscopy (SEM) analysis, dental implants' surfaces were evaluated to investigate surface alterations. No surface alterations were detected using a 0.5 W laser beam with a pulsed mode at a distance of 1 mm. Using powers of irradiation of 2 W and 3 W with a continuous mode at 1 mm from the implant caused damage on the titanium surfaces. After the irradiation protocol was changed to using the fiber in contact with the implant, the surface alterations increased highly compared to the non-contact irradiation modality. The SEM results suggest that a power of irradiation of 0.5 W with a pulsed laser light emission mode, using an inactivated optical fiber placed 1 mm away from the implant, could be used in the treatment of peri-implantitis, since no implant surface alterations were detected.

The burden of diabetes on the soft tissue seal surrounding the dental implants

Soft tissue seal around implant prostheses is considered the primary barrier against adverse external stimuli and is a critical factor in maintaining dental implants' stability. Soft tissue seal is formed mainly by the adhesion of epithelial tissue and fibrous connective tissue to the transmembrane portion of the implant. Type 2 diabetes mellitus (T2DM) is one of the risk factors for peri-implant inflammation, and peri-implant disease may be triggered by dysfunction of the soft tissue barrier around dental implants. This is increasingly considered a promising target for disease treatment and management. However, many studies have demonstrated that pathogenic bacterial infestation, gingival immune inflammation, overactive matrix metalloproteinases (MMPs), impaired wound healing processes and excessive oxidative stress may trigger poor peri-implant soft tissue sealing, which may be more severe in the T2DM state. This article reviews the structure of peri-implant soft tissue seal, peri-implant disease and treatment, and moderating mechanisms of impaired soft tissue seal around implants due to T2DM to inform the development of treatment strategies for dental implants in patients with dental defects.

Chitosan Oligosaccharide Inhibits the Synthesis of Milk Fat in Bovine Mammary Epithelial Cells through AMPK-Mediated Downstream Signaling Pathway

Simple Summary

In order to study the effect of chitosan oligosaccharides on milk fat synthesis of bovine mammary epithelial cells (BMECs), we did a series of related experiments. The results showed that chitosan oligosaccharide (COS) could inhibit the fatty acid synthesis and promote milk fat decomposition and oxidation through AMPK/SREBP1/SCD1, AMPK/HSL and AMPK/PPARα signaling pathways to reduce the milk fat content in bovine mammary epithelial cells. We elucidated the important role of COS in BMECs lipid metabolism. COS may be the potential small-molecule component in milk cow molecular breeding to regulate milk fat synthesis and metabolism. These findings will help us to further understand the mechanism of COS on milk fat metabolism.

Abstract

Chitosan oligosaccharide (COS) is a variety of oligosaccharides, and it is also the only abundant basic amino oligosaccharide in natural polysaccharides. Chitosan oligosaccharide is a low molecular weight product of chitosan after enzymatic degradation. It has many biological effects, such as lipid-lowering, antioxidant and immune regulation. Previous studies have shown that chitosan oligosaccharide has a certain effect on fat synthesis, but the effect of chitosan oligosaccharide on milk fat synthesis of bovine mammary epithelial cells (BMECs) has not been studied. Therefore, this study aimed to investigate chitosan oligosaccharide’s effect on milk fat synthesis in bovine mammary epithelial cells and explore the underlying mechanism. We treated bovine mammary epithelial cells with different concentrations of chitosan oligosaccharide (0, 100, 150, 200, 400 and 800 μg/mL) for 24 h, 36 h and 48 h respectively. To assess the effect of chitosan oligosaccharide on bovine mammary epithelial cells and determine the concentration and time for chitosan oligosaccharide treatment on cells, several in vitro cellular experiments, including on cell viability, cycle and proliferation were carried out. The results highlighted that chitosan oligosaccharide (100, 150 μg/mL) significantly promoted cell viability, cycle and proliferation, increased intracellular cholesterol content, and reduced intracellular triglyceride and non-esterified fatty acids content. Under the stimulation of chitosan oligosaccharide, the expression of genes downstream of Phosphorylated AMP-activated protein kinase (P-AMPK) and AMP-activated protein kinase (AMPK) signaling pathway changed, increasing the expression of peroxisome proliferator-activated receptor alpha (PPARα) and hormone-sensitive lipase (HSL), but the expression of sterol regulatory element-binding protein 1c (SREBP1) and its downstream target gene stearoyl-CoA desaturase (SCD1) decreased. In conclusion, these results suggest that chitosan oligosaccharide may inhibit milk fat synthesis in bovine mammary epithelial cells by activating the AMP-activated protein kinase signaling pathway, promoting the oxidative decomposition of fatty acids and inhibiting fatty acid synthesis.

The Potential Role of a Surface-Modified Additive-Manufactured Healing Abutment on the Expression of Integrins α2, β1, αv, and β6 in the Peri-Implant Mucosa: A Preliminary Human Study

The stability of peri-implant soft tissues is essential for long-term success. Integrins play a vital role in biological processes through developing and maintaining cell interactions; however, few studies have evaluated the effects of modifications to abutment surfaces on cell adhesion across integrin expression. Therefore, this pilot study assessed the influence of different surface topographies of titanium healing abutments prepared by additive manufacturing (AM) on the gene expression levels of the integrin subunits α2, β1, αv, and β6 in the human peri-implant mucosa. Thirteen healthy adults were included. Depending on the number of required implants, the subjects were distributed in different groups as a function of healing abutment topography: group 1 (fully rough surface); group 2 (upper machined + lower rough); group 3 (rough upper surface + lower machined); group 4 (fully machined). A total of 40 samples (n = 10/group) of the peri-implant mucosa around the abutments were collected 30 days after implant placement, and subsequently, the gene expression levels were evaluated using real-time PCR. The levels of gene expression of β1-subunit integrin were upregulated for individuals receiving fully rough surface abutments compared with the other surface topographies (p < 0.05). However, the healing abutment topography did not affect the gene expression levels of the α2, αv, and β6 integrin subunits in the human peri-implant mucosa (p > 0.05). This preliminary study suggested that controlled modifications of the surface topography of titanium healing abutments produced by AM may influence the quality of the peri-implant mucosa in the early stages of the soft tissue healing process.

Physicochemical Characteristics of Chitosan-Based Hydrogels Containing Albumin Particles and Aloe vera Juice as Transdermal Systems Functionalized in the Viewpoint of Potential Biomedical Applications

In recent years, many investigations on the development of innovative dressing materials with potential applications, e.g., for cytostatics delivery, have been performed. One of the most promising carriers is albumin, which tends to accumulate near cancer cells. Here, chitosan-based hydrogels containing albumin spheres and Aloe vera juice, designed for the treatment of skin cancers or burn wounds resulting from radiotherapy, were developed. The presence of albumin in hydrogel matrices was confirmed via Fourier transform infrared (FT-IR) and Raman spectroscopy. Albumin spheres were clearly visible in microscopic images. It was proved that the introduction of albumin into hydrogels resulted in their increased resistance to the tensile load, i.e., approximately 30% more force was needed to break such materials. Modified hydrogels showed approximately 10% more swelling ability. All hydrogels were characterized by hydrophilicity (contact angles were <90°) which may support the regeneration of epithelial cells and non-cytotoxicity towards murine fibroblasts L929 and released Aloe vera juice more effectively in an acidic environment than in a neutral one wherein spheres introduced into the hydrogel matrix extended the release time. Thus, the developed materials, due to their chemical composition and physicochemical properties, constitute promising materials with great application potential for biomedical purposes.

Effect of Plasma Treatment on Titanium Surface on the Tissue Surrounding Implant Material

Early osseointegration is important to achieve initial stability after implant placement. We have previously reported that atmospheric-pressure plasma treatment confers superhydrophilicity to titanium. Herein, we examined the effects of titanium implant material, which was conferred superhydrophilicity by atmospheric-pressure plasma treatment, on the surrounding tissue in rat femur. Control and experimental groups included untreated screws and those irradiated with atmospheric-pressure plasma using piezobrush, respectively. The femurs of 8-week-old male Sprague-Dawley rats were used for in vivo experiments. Various data prepared from the Micro-CT analysis showed results showing that more new bone was formed in the test group than in the control group. Similar results were shown in histological analysis. Thus, titanium screw, treated with atmospheric-pressure plasma, could induce high hard tissue differentiation even at the in vivo level. This method may be useful to achieve initial stability after implant placement.

Influence of bisphosphonates on oral implantology: Sodium alendronate and zoledronic acid enhance the synthesis and activity of matrix metalloproteinases by gingival fibroblasts seeded on titanium

OBJECTIVE

This study aimed to assess the influence of the bisphosphonates zoledronic acid and sodium alendronate on MMP-2 and MMP-9 synthesis and activity by gingival fibroblasts seeded onto titanium substrate.

DESIGN

Titanium discs were placed in 24-well cell culture plates and gingival fibroblasts were seeded (1 × 10⁵ cells/discs) on them using Dulbecco's Modified Eagle's Medium (DMEM) + 10 % fetal bovine serum (FBS) for 24 h. After this period, a fresh serum-free DMEM containing zoledronic acid or sodium alendronate at 0.5 μM, 1 μM or 5 μM was applied on the cells for an additional of 24 h. Serum-free DMEM and tumor necrosis factor alpha (TNF-α) were used as negative and positive controls, respectively. MMP-2 and MMP-9 synthesis and activity were determined by ELISA (Enzyme-Linked Immunosorbent Assay) and conventional/in situ zymography. Quantitative data were analyzed by one-way ANOVA and Tukey's tests (α = 0.05). The in situ zymography data were qualitatively described.

RESULTS

Despite both bisphosphonates increased the MMPs synthesis, this effect was significant higher in zoledronic acid groups. MMPs activity resembled by gelatinolytic activity was also enhanced by sodium alendronate and zoledronic acid in a similar pattern.

CONCLUSIONS

Zoledronic acid and sodium alendronate increased in a dose-dependent manner MMP-2 and MMP-9 synthesis by gingival fibroblasts seeded on titanium. MMP-2 activity was up-regulated by zoledronic acid treatment.

Covalent immobilization of the phytic acid-magnesium layer on titanium improves the osteogenic and antibacterial properties

In order to improve early osseointegration and long-term survival rate of implants, a multifunctional titanium surface that promotes osteogenesis and antibacterial properties is expected. Incorporation of bioactive trace elements such as magnesium ions was proved a promising method to improve osseointegration of titanium. Phytic acid has strong chelating ability with multivalent cations, which has been used in surface modification. Moreover, phytic acid was proved antibacterial potential. Herein, to improve the osteogenic and antibacterial properties, a phytic acid-magnesium (PA-Mg) layer was introduced on titanium using phytic acid as a cross-linker molecule. No obvious changes of the surface characterization were observed by scanning electron microscopy and atomic force microscopy. X-ray photoelectron spectroscopy confirmed that the PA-Mg layer covalently bond to the Ti surface, and the thickness of the PA-Mg layer was about 150 nm. Besides, improved hydrophilic and more protein adsorption were observed on Ti-PA-Mg. Notably, a relatively controlled magnesium release was also observed on Ti-PA-Mg. Human bone mesenchymal stem cells showed better adhesion, proliferation, and osteogenic differentiation on Ti-PA-Mg samples, indicating improved biocompatibility and osteoinductivity. Moreover, Ti-PA-Mg had better antibacterial properties against porphyromonas gingivalis than Ti. Overall, the PA-Mg layer on Ti surface improved the osteogenic and antibacterial properties, which may have promise for use in dental implantation.

Photobiomodulation using LLLT and LED of cells involved in osseointegration and peri-implant soft tissue healing

This study evaluated the influence of photobiomodulation (PBM) using low-level laser therapy (PBM/LLLT) or light-emitting diode (PBM/LED) therapy on peri-implant tissue healing. A laboratory model was used to assess the adhesion and metabolism of osteoblasts (SaOs-2), human gingival fibroblasts (HGF), and normal oral keratinocytes (NOK) seeded on a titanium (Ti) surface. After seeding the cells on disks of Ti placed in wells of 24-well plates, three irradiations were performed every 24 h at energy density of 3 J/cm². For PBM/LLLT, a LaserTABLE device was used with a wavelength of 780 nm and 25 mW, while for PBM/LED irradiation, a LEDTABLE device was used at 810 nm, 20 mW, at a density of 3 J/cm². After irradiations, the number of cells (NC) attached and spread on the Ti surface, cell viability (CV), total protein (TP), and collagen (Col) synthesis were assessed. Alkaline phosphate activity (ALP) was evaluated only for SaOs-2. Data were submitted to ANOVA complemented by Turkey statistical tests at a 5% significance level. PBM significantly increased adherence of NOK to the Ti surface, while no significant effect was observed for SaOs-2 and HGF. PBM positively affected CV, as well as Col and TP synthesis, in distinct patterns according to the cell line. Increased ALP activity was observed only in those cells exposed to PBM/LLLT. Considering cell specificity, this investigation reports that photobiomodulation with low-power laser and LED at determined parameters enhances cellular functions related to peri-implant tissue healing in a laboratory model.

Orchestrating soft tissue integration at the transmucosal region of titanium implants

Osseointegration at the bone-implant interface and soft tissue integration (STI) at the trans-mucosal region are crucial for the long-term success of dental implants, especially in compromised patient conditions. The STI quality of conventional smooth and bio-inert titanium-based implants is inferior to that of natural tissue (i.e. teeth), and hence various surface modifications have been suggested. This review article compares and contrasts the various modification strategies (physical, chemical and biological) utilized to enhance STI of Ti implants. It also details the STI challenges associated with conventional Ti-based implants, current surface modification strategies and cutting-edge nano-engineering solutions. The topographical, biological and therapeutic advances achievable via electrochemically anodized Ti implants with TiO₂ nanotubes/nanopores are highlighted. Finally, the status and future directions of such nano-engineered implants is discussed, with emphasis on bridging the gap between research and clinical translation.

Race to invade: Understanding soft tissue integration at the transmucosal region of titanium dental implants

OBJECTIVES

The success of a dental implant system not only depends on appropriate osseointegration at the bone-implant interface, but also on robust soft-tissue integration (STI)/muco-integration at the transmucosal region. However, numerous studies have reported that the STI quality of conventional smooth and bio-inert titanium-based transmucosal components is significantly inferior to that of natural teeth, which may compromise the long-term success of implant restorations. In this review article, we discuss the structural and histological characteristics of peri-implant tissues; compare the roles of various cells residing in the transmucosal region and explore the material-based challenges that must be addressed to achieve early establishment and long-term maintenance of STI.

METHODS

This extensive review article critically compares and contrasts the findings from articles published in the domain of 'soft-tissue integration around Ti dental implants'.

RESULTS

Histological characteristics, including poorer epithelial attachment and absence of direct collagen-implant/abutment integration, are responsible for the inferior STI strength around dental implants/abutments. Furthermore, various cellular functions during STI establishment and maturation at the abutment-mucosa interface must be modulated to achieve early STI. Moreover, we discuss and detail the challenges of achieving robust STI, including the presence of oral bacterial milieu, as well as material and corrosion related issues. Finally, research challenges towards achieving and maintaining robust STI are discussed, targeting the future directions to enhance the long-term survival of implant restorations.

SIGNIFICANCE

Based on its histological characteristics, STI on current implant/abutment surfaces is suboptimal compared to the periodontal attachment found at teeth, making implants potentially more susceptible to disease initiation and progression. To obtain stable STI at the trasmucosal region, it is essential for future studies to design customized implant systems, with enhanced surface bioactivity and tailorable therapeutic capacity, which can improve the long-term success of implant restorations, especially in compromised conditions.

Niobium-oxynitride coatings for biomedical applications: Its antibacterial effects and in-vitro cytotoxicity

316L Stainless Steel (SS) has been widely used in many medical applications, such as orthopedic prostheses and cardiovascular implants due to its good mechanical properties and resistance to corrosion. Despite its superior features, SS has bio-functionality problems. In this study, niobium oxynitride coatings were deposited onto 316L SS substrates to improve their biocompatibility using a reactive radio frequency (RF) magnetron sputtering technique. The nitrogen flow was fixed, and the nitrogen to oxygen flow ratio was set to 2, 5 and 10 to investigate the effect of oxygen concentration on biocompatibility and the antibacterial behavior of the oxynitride films. The microstructure, morphology and wettability properties of the coatings were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and an optical tensiometer. The antibacterial activities of coated and uncoated 316L substrates were tested against S. aureus and E. coli bacterial strains. The cytotoxic effects of NbO_xN_y-coated and uncoated substrates were evaluated on human fibroblast cells. The results showed that niobium oxynitride coatings were not cytotoxic and exhibited more antibacterial activity in comparison to the uncoated ones.

The impact of surface alteration on epithelial tissue attachment after the mechanical cleaning of titanium or zirconia surface

OBJECTIVE

Mechanical plaque removal may alter the surface morphology of the gingival penetration part of the implant. We applied an air-powered abrasive system (AP), titanium curette (TC), stainless curette (SC), ultrasound scaler (US), and titanium brush (TB) which are commonly used to remove plaque, to titanium or zirconia and the changes in surface morphology and the epithelial attach against substrata.

MATERIALS AND METHODS

(a) The morphological changes of titanium and zirconia after mechanical cleaning were assessed by scanning electron microscopy and a roughness analyser. (b) Oral epithelial cells of rats were inoculated on the surface of the materials after mechanical cleaning, and the adherence of epithelial cells was observed. (c) The maxillary first molars were extracted from the rats and replaced by experimental titanium or zirconia implants. The length of the immunoreactive laminin-332 band was observed at the implant-peri-implant epithelium interface.

RESULTS

(a) The surface roughness increased in experimental groups except the AP group. (b) Among the experimental groups, the AP group showed the highest number of attached cells. (c) The length of the immunoreactive laminin-332 band was longer in the control group than those in all five experimental groups. Among the experimental groups, the AP group showed the longest band.

CONCLUSION

All mechanical cleaning methods increased the surface roughness of the materials except AP. AP did not cause distinct implant surface alterations. Surface alteration caused by mechanical cleaning may evoke inferior for epithelial attachment and reduce resistance against foreign infiltration.

Effect of Calcium Chloride Hydrothermal Treatment of Titanium on Protein, Cellular, and Bacterial Adhesion Properties

Topographical modification of the dental implant surface is one of the main topics for the improvement of the material, however, the roughened surface has some risks for peri-implantitis. A hydrothermal treatment (HT) of titanium with calcium chloride solution was reported to improve osseointegration and soft tissue sealing without changing the surface topography; however, its mechanism is unclear. We herewith investigated the interaction between extracellular matrix (ECM) protein and HT titanium. Furthermore, we also clarified the bacterial interaction. We employed two kinds of HT, HT with water (DW-HT) and HT with calcium chloride solution (Ca-HT). As a result, the adsorptions of both laminin-332 and osteopontin onto the Ca-HT surface were enhanced. In contrast, the adsorption of albumin, which was reported to have no cell adhesion capacity, was not influenced by Ca-HT. Osteoblast adhesion onto Ca-HT was also enhanced. Although Ca-HT was reported to enhance both epithelial cell attachment strength and in vivo peri-implant epithelial bonding, the number of epithelial cell attachment was not increased even after HT. Ca-HT had no impact in the adhesion of Streptococcus gordonii. These results suggest that Ca-HT enhances cell adhesion onto titanium without increasing bacterial adhesion, and the improvement of ECM protein adsorption is supposed to contribute to cell adhesion.

In vitro effects of photobiomodulation applied to gingival fibroblasts cultured on titanium and zirconia surfaces and exposed to LPS from Escherichia coli

Photobiomodulation (PBM) therapy is used to stimulate cell proliferation and metabolism, as well as reduce inflammatory cytokine synthesis, which plays a main role in the long-term stability of implants. This study assessed the response of gingival fibroblasts cultured on titanium (Ti) and zirconia (ZrO₂), submitted to PBM and exposed to lipopolysaccharide (LPS). Cells seeded on Ti and ZrO₂ were irradiated (InGaAsP; 780 nm, 25 mW) 3 times, using 0.5, 1.5, and 3.0 J/cm² doses, and exposed to Escherichia coli LPS (1 μg/mL). After 24 h, cell viability (alamarBlue, n = 8), interleukin 6 (IL-6) and 8 (IL-8) synthesis (ELISA, n = 6), and IL-6 and vascular endothelial growth factor (VEGF) gene expression (qPCR, n = 5) were assessed and statistically analyzed (one-way ANOVA, α = 0.05). Cell morphology was evaluated by fluorescence microscopy. Increased cell viability occurred in all groups cultured on Ti compared with that of the control, except for cells exposed to LPS. Fibroblasts cultured on ZrO₂ and LPS-exposed exhibited reduced viability. PBM at 3.0 J/cm² and 1.5 J/cm² downregulated the IL-6 synthesis by fibroblasts seeded on Ti and ZrO₂, as well as IL-8 synthesis by cells seeded on ZrO₂. Fibroblasts seeded on both surfaces and LPS-exposed showed increased IL-6 gene expression; however, this activity was downregulated when fibroblasts were irradiated at 3.0 J/cm². Enhanced VEGF gene expression by cells seeded on Ti and laser-irradiated (3.0 J/cm²). Distinct patterns of cytoskeleton occurred in laser-irradiated cells exposed to LPS. Specific parameters of PBM can biomodulate the inflammatory response of fibroblasts seeded on Ti or ZrO₂ and exposed to LPS.

Zirconia implants with improved attachment to the gingival tissue

BACKGROUND

Gingival tissue attachment is known to be important for long-term prognosis of implants. This in vitro study evaluated the gingival attachment to zirconia implants and zirconia implants modified with sol-gel derived TiO₂ coatings.

METHODS

Zirconia endodontic posts (n = 23) were used to function as implants that were inserted into the center of full-thickness porcine gingival explants (n = 31). The tissue/implant specimens were then individually placed at an air/liquid interface on a stainless-steel grid in cell culture wells containing a nutrient solution. The tissue cultures were incubated at 37°C in a 5% CO₂ environment and at days 7 and 14, the specimens were harvested and analyzed by dynamic mechanical analysis (DMA) measurements under dynamic loading conditions mimicking natural mastication. Specimens were also analyzed by immunohistochemical staining identifying the laminin (Ln) γ2 chain specific for Ln-332, which is known to be a crucial molecule for the proper attachment of epithelium to tooth/implant surface.

RESULTS

Tissue attachment to TiO₂ -coated zirconia demonstrated higher dynamic modulus of elasticity and higher creep modulus, meaning that the attachment is stronger and more resistant to damage during function over time. Laminin γ2 was identified in the attachment of epithelium to TiO₂ -coated zirconia.

CONCLUSIONS

Both DMA and histological analysis support each other, so the gingival tissue is more strongly attached to sol-gel derived TiO₂ -coated zirconia than uncoated zirconia. Immunohistochemical staining showed that TiO₂ coating may enhance the synthesis and deposition of Ln-332 in the epithelial attachment to the implant surface.

Preparation, Microstructure, Mechanical Properties and Biocompatibility of Ta-Coated 3Y-TZP Ceramic Deposited by a Plasma Surface Alloying Technique

A Ta coating has been successfully fabricated on the surface of zirconia polycrystals ceramic (3 mol% yttria, 3Y-TZP) by a plasma surface alloying technique. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that a α-Ta coating with a continuous and compact surface morphology which consisted of a deposited layer with a thickness of 390 nm and a diffusion layer with a thickness of 200 nm covered the 3Y-TZP. Due to the effect of inhabitation the t→m transformation by the deposited Ta coating, the biaxial flexural strength caused by the phase transformation during hydrothermal aging is reduced e.g. p < 0.05 after 20 h and/or 100 h. In addition, the Ta coating shows non-cytotoxicity and improved proliferation ability of osteoblasts.

Visible-Light-Induced Photocatalytic and Antibacterial Activity of TiO2 Codoped with Nitrogen and Bismuth: New Perspectives to Control Implant-Biofilm-Related Diseases

Biofilm-associated diseases are one of the main causes of implant failure. Currently, the development of implant surface treatment goes beyond the osseointegration process and focuses on the creation of surfaces with antimicrobial action and with the possibility to be re-activated (i.e., light source activation). Titanium dioxide (TiO₂), an excellent photocatalyst used for photocatalytic antibacterial applications, could be a great alternative, but its efficiency is limited to the ultraviolet (UV) range of the electromagnetic spectrum. Since UV radiation has carcinogenic potential, we created a functional TiO₂ coating codoped with nitrogen and bismuth via the plasma electrolytic oxidation (PEO) of titanium to achieve an antibacterial effect under visible light with re-activation potential. A complex surface topography was demonstrated by scanning electron microscopy and three-dimensional confocal laser scanning microscopy. Additionally, PEO-treated surfaces showed greater hydrophilicity and albumin adsorption compared to control, untreated titanium. Bismuth incorporation shifted the band gap of TiO₂ to the visible region and facilitated higher degradation of methyl orange (MO) in the dark, with a greater reduction in the concentration of MO after visible-light irradiation even after 72 h of aging. These results were consistent with the in vitro antibacterial effect, where samples with nitrogen and bismuth in their composition showed the greatest bacterial reduction after 24 h of dual-species biofilm formation ( Streptococcus sanguinis and Actinomyces naeslundii) in darkness with a superior effect at 30 min of visible-light irradiation. In addition, such a coating presents reusable photocatalytic potential and good biocompatibility by presenting a noncytotoxicity effect on human gingival fibroblast cells. Therefore, nitrogen and bismuth incorporation into TiO₂ via PEO can be considered a promising alternative for dental implant application with antibacterial properties in darkness, with a stronger effect after visible-light application.

Chitosan oligosaccharide-mediated attenuation of LPS-induced inflammation in IPEC-J2 cells is related to the TLR4/NF-κB signaling pathway

The protective mechanism of chitosan oligosaccharide (COS) against lipopolysaccharides (LPS) -induced inflammatory responses in IPEC-J2 and in mice with DSS dextran sulfate sodium (DSS) -induced colitis is reported. Upon exposure to LPS, the proliferation rate of IPEC-J2 cells markedly decreased, and epithelial cell integrity was compromised. However, COS pretreatment significantly reduced these changes. Low-concentration (200 μg/mL) COS up-regulated Toll-like receptor 4 (TLR4) and nuclear p65 expression, but inhibited LPS-induced expression of nuclear p65, IL-6, and IL-8. Addition of the TLR4 inhibitor reduced nuclear p65, IL-6, and IL-8 expression in IPEC-J2 cells exposed to COS or LPS alone, and a slight up-regulation in nuclear p65 was observed in COS and LPS co-treated cells. Medium-dose COS (600 mg/kg/d) protected against DSS-induced colitis, in which TLR4 and nuclear p65 expression levels were decreased. We postulate that the prevention of both LPS- and DSS -induced inflammatory responses in IPEC-J2 cells and mice by COS are related to the inhibition of the TLR4/NF-κB signaling pathway.

What is the Best Micro and Macro Dental Implant Topography?

Implant surface micro and macro topography plays a key role in early osseointegration. The physicochemical features of the implant surface (ie, chemical composition, hydrophobicity/hydrophilicity and roughness) influence the deposition of extracellular matrix proteins, the precipitation of bone mineral, and the stimulation of cells. Modification of the implant topography provides better primary stability and faster osseointegration, allowing for immediate placement or immediate loading. Randomized clinical trials are warranted to compare the response of osseointegration with various implant micro and macro surface topographies in people with various local or systemic risk factors.

Characterization of titanium surface coated with epidermal growth factor and its effect on human gingival fibroblasts

OBJECTIVES

Different strategies, such as modifications on the implant abutments surface have been proposed to accelerate and improve the formation of the biological seal (BS). The aim of this study was to characterize a titanium (Ti) surface impregnated with epidermal growth factor (EGF) and to assess its influence on the metabolism and adhesion of oral mucosal cells.

DESIGN

Ti discs were coated with EGF (100 nM) conjugated with a fluorophore and analyzed by fluorescence microscopy. The surface roughness analysis (Ra) of the EGF-coated Ti was performed by confocal microscopy. The EGF released in the wet environment was determined at 0, 24, 48 and 72 h by fluorimetric quantification. For assessment of the biological effects of EGF-coated Ti, gingival fibroblasts were seeded (5 × 10⁴ cells) onto the substrate coated or not with this growth factor. After 24 h, cell adhesion and viability were evaluated by ANOVA and Tukey tests, α = .05.

RESULTS

Immediate release of EGF as well as its incorporation by fibroblasts within 1 h after cells were seeded was observed. EGF-coated Ti discs presented significantly enhance surface roughness. Increased cell viability was observed on the EGF-coated discs.

CONCLUSION

EGF applied to Ti discs stimulated the adhesion and metabolism of gingival fibroblasts and could be considered as an interesting alternative for improving the BS.

Gingipains impair attachment of epithelial cell to dental titanium abutment surfaces

The study investigated in vitro the effect of Porphyromonas gingivalis and its cysteine proteases (gingipains) on epithelial cell adhesion to titanium-zirconium alloy surfaces. Titanium-zirconium discs with a standard machined (M) or chemically modified hydrophilic surface (modM) were coated with lamin-5 and incubated with telomerase-inactivated gingival keratinocytes (TIGK). Three P. gingivalis strains or gingipains were either added simultaneously with TIGK or after TIGK cells were already attached to the disks. Adhered TIGK cells were counted at 24 h. All P. gingivalis strains clearly inhibited adhesion of TIGK cells to M and modM surfaces. Compared with bacteria/gingipain-free TIGK cell cultures, the number of attached TIGK cells was reduced by about 80% and 60% when P. gingivalis was added simultaneously or after TIGK cells were already attached to the disks (each p < 0.01), respectively. Counts of attached cells were similarly reduced when only gingipains were used. Adhesion molecules of TIGK cells, in particular E-cadherin, were cleaved by P. gingivalis. In conclusion, P. gingivalis and gingipains interfere with the adhesion of epithelial cells to titanium-zirconium alloy surfaces by cleaving adhesion molecules, while a chemically modified hydrophilic titanium-zirconium alloy surface did not yield any protection. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2549-2556, 2019.

The Effects of Non-Thermal Atmospheric Pressure Plasma treated Titanium Surface on Behaviors of Oral Soft Tissue Cells

Here, we investigated the possible use of the technology known as non-thermal atmospheric pressure plasma on integration and control of cytokine release of soft tissue on titanium surface. After NTAPP was applied to titanium samples, changes of surface characteristics were measured as topographical features, contact angle, surface tension, and with X-ray photoelectron spectroscopy (XPS). Protein absorption was evaluated using a bovine serum albumin absorption assay. The attachment, viability, morphology, proliferation, and cytokine release of soft tissue on titanium were assessed. No change in topographical features was observed between control and NTAPP-treated groups. However, NTAPP treatment resulted in significant lowering of the contact angle for polar and non-polar liquids and increase of surface tension. Protein absorption was significantly enhanced on the NTAPP-treated samples. Normal soft tissue attachment was improved on the NTAPP-treated groups with good viability. Cellular morphology was improved in NTAPP-treated groups whereas cellular proliferation was not enhanced. There was a significant reduction in the amounts of cytokine release for inflamed IHOK and hTERT-hNOF on the NTAPP-treated groups; except for IL-8 for IHOKs. This study demonstrates that surface functional consequences by NTAPP exposure enhanced behavior of oral soft tissue cells without topographical change.

Micro-/nano-topography of selective laser melting titanium enhances adhesion and proliferation and regulates adhesion-related gene expressions of human gingival fibroblasts and human gingival epithelial cells

Background

Selective laser melting (SLM) titanium is an ideal option to manufacture customized implants with suitable surface modification to improve its bioactivity. The peri-implant soft tissues form a protective tissue barrier for the underlying osseointegration. Therefore, original microrough SLM surfaces should be treated for favorable attachment of surrounding soft tissues.

Material and methods

In this study, anodic oxidation (AO) was applied on the microrough SLM titanium substrate to form TiO₂ nanotube arrays. After that, calcium phosphate (CaP) nanoparticles were embedded into the nanotubes or the interval of nanotubes by electrochemical deposition (AOC). These two samples were compared to untreated (SLM) samples and accepted mechanically polished (MP) SLM titanium samples. Scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, surface roughness, and water contact angle measurements were used for surface characterization. The primary human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs) were cultured for cell assays to determine adhesion, proliferation, and adhesion-related gene expressions.

Results

For HGECs, AOC samples showed significantly higher adhesion, proliferation, and adhesion-related gene expressions than AO and SLM samples (P<0.05) and similar exceptional ability in above aspects to MP samples. At the same time, AOC samples showed the highest adhesion, proliferation, and adhesion-related gene expressions for HGFs (P<0.05).

Conclusion

By comparison between each sample, we could confirm that both anodic oxidation and CaP nanoparticles had improved bioactivity, and their combined utilization may likely be superior to mechanical polishing, which is most commonly used and widely accepted. Our results indicated that creating appropriate micro-/nano-topographies can be an effective method to affect cell behavior and increase the stability of the peri-implant mucosal barrier on SLM titanium surfaces, which contributes to its application in dental and other biomedical implants.

Dopamine self-polymerized along with hydroxyapatite onto the preactivated titanium percutaneous implants surface to promote human gingival fibroblast behavior and antimicrobial activity for biological sealing

The clinical success of dental implants requires not only the optimum osseointegration but also the integration of implant surface with soft tissues to form biological sealing. In this study, alkali-heat treatment was applied to modify the pure titanium surface constructing a unique micro-and nano-structure. Then, poly(dopamine), along and with the additional incorporation of hydroxyapatite and carboxymethyl chitosan have been successfully infiltrated into the preactivated Ti surface during dopamine self-polymerization proceeding. Here, the effects of poly(dopamine)-modified surface coating on the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens have been systematically studied, which was critical for the early peri-implant soft tissue integration. The results showed that the poly(dopamine)-modified alkali-heat-titanium surface was a superior substrate for human gingival fibroblast adhesion, spread and proliferation. Moreover, further enhancements on cytoskeleton organization, collagen secretion and fibronectin adsorption were generally observed through the additional incorporation of hydroxyapatite. The addition of carboxymethyl chitosan exerted a positive modulation effect on antibacterial activity. Overall, our study demonstrated that combined superior soft tissue integration and antibacterial activity can be achieved by using poly(dopamine)-modified titanium implant, which has great potential in the optimal design of dental implant.

Influence on proliferation and adhesion of human gingival fibroblasts from different titanium surface decontamination treatments: An in vitro study

OBJECTIVES

To investigate the effects of different decontamination treatments on microstructure of titanium (Ti) surface as well as proliferation and adhesion of human gingival fibroblasts (HGFs).

MATERIAL AND METHODS

Ti discs with machined (M) and sand blasted, acid etched (SAE) surfaces were treated with five different decontamination treatments: (1) stainless steel curette (SSC), ultrasonic system with (2) straight carbon fiber tip (UCF) or (3) metal tip (UM), (4) rotating Ti brush (RTB), and (5) Er:YAG laser (30 mJ/pulse at 30 Hz). Surface roughness was analyzed under optical interferometry. HGFs were cultured on each disc. Proliferation and adhesive strength were analyzed. qRT-PCR and ELISA were performed to detect the RNA and protein expression of FAK, ITGB1, COL1A1, and FN1 respectively from different Ti surfaces.

RESULTS

Surface roughness increased on M surface. Proliferation, adhesive strength and gene expression were higher on M surface than SAE surface. Decontamination treatments affected surface parameters significantly (P < 0.001), making M surface less smooth while SAE surface became less rough. SSC, UCF, UM and RTB decreased proliferation on M surfaces significantly (P < 0.05). UCF, RTB and laser increased proliferation on SAE surface significantly (P < 0.05). UM decreased adhesive strength on M surface significantly and laser increased adhesive strength on SAE surface significantly (P < 0.05). Gene expression increased with time and was altered by decontamination treatments significantly (P < 0.001).

CONCLUSIONS

Decontamination treatments influence surface roughness and cell behavior of HGFs. Laser might be an optimal decontamination treatment which has the least negative effect on M surface and the most positive effect on SAE surface.

Various Surface Treatments to Implant Provisional Restorations and Their Effect on Epithelial Cell Adhesion: A Comparative In Vitro Study

PURPOSE AND OBJECTIVE

The aim of this in vitro study was to investigate the ability of epithelial cells to attach to or proliferate on various mechanical or chemical surface treatments of an implant provisional material.

MATERIALS AND METHODS

Polyethyl methacrylate discs 10 mm in diameter and ∼0.2 to 0.75 mm in width were used in the study. Experimental discs were treated with either a mechanical (pumice, varnish for shine, or high polishing) or a chemical agent (alcohol, chlorhexidine, or steam) to provide cleaning and/or polishing. Using primary human epidermal keratinocytes, experiments were performed to test the adhesion or proliferation of cells on the discs with various surface treatments.

RESULTS

Scanning electron microscope analysis, rhodamine staining, and cell counting using a hemocytometer corroborated all findings and illustrated that the highest cell adhesion was found to be in the smooth surface treatment groups and the poorest adhesion was found to be in the rough surface groups and chemical treatment group.

CONCLUSION

Within the limitations of this study, the following clinical protocol is recommended for finishing, polishing, and disinfecting implant provisional restorations: coarse, medium, fine pumice → high polishing (if desired) → steam. It is recommended to avoid applying varnish in the perimucosal area near the epithelium. This study could establish the most appropriate way to handle provisional restorations in the peri-implant sulcus for improved soft tissue health, esthetics, and long-term stability.

Influence of bisphosphonates on the adherence and metabolism of epithelial cells and gingival fibroblasts to titanium surfaces

OBJECTIVES

To evaluate the effects of sodium alendronate (SA) and zoledronic acid (ZA), on the adhesion and metabolism of epithelial cells and gingival fibroblasts to titanium surfaces considering cell functions related to an effective mucosal barrier around the implant.

MATERIALS AND METHODS

Cells were seeded onto titanium discs and incubated for 24 h. Then, serum-free DMEM containing selected bisphosphonates (0, 0.5, 1, or 5 μM) was added for 24 and 48 h. Factors related to the achievement of an effective mechanical and immunological barrier-cell adhesion, viability, collagen epidermal growth factor, and immunoglobulin synthesis-were evaluated. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests as well as by ANOVA and Tukey's tests, (α = 0.05).

RESULTS

The presence of bisphosphonates culminated in lower cell adhesion to the titanium discs, particularly for SA at 5 μM (40%) and ZA at all concentrations (from 30 to 50%, according to increased concentrations). Reduced cell viability occurred after exposing these cells to ZA (40%); however, only 5 μM SA-treated cells had decreased viability (30%). Reduced synthesis of growth factors and collagen was observed when cells were reated with ZA (20 and 40%, respectively), while about 70% of IgG synthesis was enhanced.

CONCLUSION

Bisphosphonates negatively affected the adhesion and metabolism of oral mucosal cells, and this effect was related to the type of bisphosphonate as well as to concentration and period of treatment.

CLINICAL RELEVANCE

The negative effects of bisphosphonates on oral mucosal cells can hamper the formation of an effective biological seal in osseointegrated implants.

Biomaterial surface proteomic signature determines interaction with epithelial cells

Cells interact with biomaterials indirectly through extracellular matrix (ECM) proteins adsorbed onto their surface. Accordingly, it could be hypothesized that the surface proteomic signature of a biomaterial might determine its interaction with cells. Here, we present a surface proteomic approach to test this hypothesis in the specific case of biomaterial-epithelial cell interactions. In particular, we determined the surface proteomic signature of different biomaterials exposed to the ECM of epithelial cells (basal lamina). We revealed that the biomaterial surface chemistry determines the surface proteomic profile, and subsequently the interaction with epithelial cells. In addition, we found that biomaterials with surface chemistries closer to that of percutaneous tissues, such as aminated PMMA and aminated PDLLA, promoted higher selective adsorption of key basal lamina proteins (laminins, nidogen-1) and subsequently improved their interactions with epithelial cells. These findings suggest that mimicking the surface chemistry of natural percutaneous tissues can improve biomaterial-epithelial integration, and thus provide a rationale for the design of improved biomaterial surfaces for skin regeneration and percutaneous medical devices.

STATEMENT OF SIGNIFICANCE

Failure of most biomaterials originates from the inability to predict and control the influence of their surface properties on biological phenomena, particularly protein adsorption, and cellular behaviour, which subsequently results in unfavourable host response. Here, we introduce a surface-proteomic screening approach using a label-free mass spectrometry technique to decipher the adsorption profile of extracellular matrix (ECM) proteins on different biomaterials, and correlate it with cellular behaviour. We demonstrated that the way a biomaterial selectively interacts with specific ECM proteins of a given tissue seems to determine the interactions between the cells of that tissue and biomaterials. Accordingly, this approach can potentially revolutionize the screening methods for investigating the protein-cell-biomaterial interactions and pave the way for deeper understanding of these interactions.

Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials with Human Gingival Keratinocytes (HGKs)

OBJECTIVE

Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials, a new class of CAD-CAM composites, is poorly explored in the literature, in particular, no data are available regarding Human Gingival Keratinocytes (HGK). The first objective of this study was to evaluate the in vitro biocompatibility of PICNs with HGKs in comparison with other materials typically used for implant prostheses. The second objective was to correlate results with PICN monomer release and indirect cytotoxicity.

METHODS

HGK attachment, proliferation and spreading on PICN, grade V titanium (Ti), yttrium zirconia (Zi), lithium disilicate glass-ceramic (eM) and polytetrafluoroethylene (negative control) discs were evaluated using a specific insert-based culture system. For PICN and eM samples, monomer release in the culture medium was quantified by high performance liquid chromatography and indirect cytotoxicity tests were performed.

RESULTS

Ti and Zi exhibited the best results regarding HGK viability, number and coverage. eM showed inferior results while PICN showed statistically similar results to eM but also to Ti regarding cell number and to Ti and Zi regarding cell viability. No monomer release from PICN discs was found, nor indirect cytotoxicity, as for eM.

SIGNIFICANCE

The results confirmed the excellent behavior of Ti and Zi with gingival cells. Even if polymer based, PICN materials exhibited intermediate results between Ti-Zi and eM. These promising results could notably be explained by PICN high temperature-high pressure (HT-HP) innovative polymerization mode, as confirmed by the absence of monomer release and indirect cytotoxicity.

Functional Differences In Gingival Fibroblasts Obtained from Young and Elderly Individuals

Abstract Fibroblasts participate in the wound repair process through proliferation and migration as well as the synthesis of factors growth and extracellular matrix molecules. However, cell aging and the individual himself can lead to reduction of cell functions and consequently, the ability of tissue repair. This study evaluated the activity of gingival fibroblasts from young (Y) and elderly (Y) patients and their responsiveness to tumor necrosis factor alpha (TNF-a). Gingival fibroblasts were isolated from six patients (3Y; and 3E) and seeded in complete culture medium (DMEM). For cell viability analysis, total protein production and collagen synthesis, fibroblasts were cultured in 96-well plates for 24, 48 or 72 h (n=36). Cell responses to TNF-a, was evaluated by application of this cytokine to cultured cells (100 ng/mL) for 24 h, followed by evaluation of reactive oxygen species (ROS), nitric oxide (NO) and CCL5 production (n=36). Data were analyzed by Kruskal-Wallis and the Mann-Whitney U tests (a = 0.05). Viability of E fibroblasts was higher than Y fibroblasts for 24 and 48 h, but these cells showed gradual reduction of viability over the course of time. For Y cells, reduced collagen synthesis was observed at 48 h. No difference was observed in ROS production for both cells after TNF-a exposure. However, both cultures showed increased production of NO and CCL5 in the presence of TNF-a. Functional differences and distinct responsiveness to TNF-a were observed according to patient's age.

Topographic characterisation of dental implants for commercial use

BACKGROUND

To characterize the surface topography of several dental implants for commercial use.

MATERIAL AND METHODS

Dental implants analyzed were Certain (Biomet 3i), Tissue Level (Straumann), Interna (BTI), MG-InHex (MozoGrau), SPI (Alphabio) and Hikelt (Bioner). Surface topography was ascertained using a confocal microscope with white light. Roughness parameters obtained were: Ra, Rq, Rv, Rp, Rt, Rsk and Rku. The results were analysed using single-factor ANOVA and Student-Neuman-Keuls (p<0.05) tests.

RESULTS

Certain and Hikelt obtained the highest Ra and Rq scores, followed by Tissue Level. Interna and SPI obtained lower scores, and MG-InHex obtained the lowest score. Rv scores followed the same trend. Certain obtained the highest Rp score, followed by SPI and Hikelt, then Interna and Tissue Level. MG-InHex obtained the lowest scores. Certain obtained the highest Rt score, followed by Interna and Hikelt, then SPI and Tissue Level. The lowest scores were for MG-InHex. Rsk was negative (punctured surface) in the MG-InHex, SPI and Tissue Level systems, and positive (pointed surface) in the other systems. Rku was higher than 3 (Leptokurtic) in Tissue Level, Interna, MG-InHex and SPI, and lower than 3 (Platykurtic) in Certain and Hikelt.

CONCLUSIONS

The type of implant determines surface topography, and there are differences in the roughness parameters of the various makes of implants for clinical use.

Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials with Human Gingival Fibroblasts (HGFs)

OBJECTIVES

Polymer-infiltrated-ceramic-network (PICN) materials constitute an innovative class of CAD-CAM materials offering promising perspectives in prosthodontics, but no data are available in the literature regarding their biological properties. The objective of the present study was to evaluate the in vitro biocompatibility of PICNs with human gingival fibroblasts (HGFs) in comparison with materials typically used for implant prostheses and abutments.

METHODS

HGF attachment, proliferation and spreading on discs made of PICN, grade V titanium (Ti), yttrium zirconia (Zi), lithium disilicate glass-ceramic (eM) and polytetrafluoroethylene (negative control), were evaluated using a specific insert-based culture system (IBS-R). Sample surface properties were characterized by XPS, contact angle measurement, profilometry and SEM.

RESULTS

Ti and Zi gave the best results regarding HGF viability, morphology, number and coverage increase with time in comparison with the negative control, while PICN and eM gave intermediate results, cell spreading being comparable for PICN, Ti, Zi and eM. Despite the presence of polymers and their related hydrophobicity, PICN exhibited comparable results to glass-ceramic materials, which could be explained by the mode of polymerization of the monomers.

SIGNIFICANCE

The results of the present study confirm that the currently employed materials, i.e. Ti and Zi, can be considered to be the gold standard of materials in terms of HGF behavior, while PICN gave intermediate results comparable to eM. The impact of the present in vitro results needs to be further investigated clinically, particularly in the view of the utilization of PICNs for prostheses on bone-level implants.

Enhanced Biological Behavior of In Vitro Human Gingival Fibroblasts on Cold Plasma-Treated Zirconia

Objective

To evaluate whether atmospheric-pressure dielectric-barrier-discharge plasma treatment of zirconia enhances its biocompatibility with human gingival fibroblasts.

Materials and Methods

The zirconia disks were divided into four groups and treated using helium atmospheric-pressure dielectric-barrier-discharge plasmas for 30, 60 or 90 s or left untreated. The surface morphology, wettability and chemical elements were analyzed. Fibroblasts density, morphology, morphometry and attachment-related genes expression were measured at different time points from 3 to 72 h.

Results

After plasma treatment, the surface morphology and roughness remained the same, while the contact angle decreased from 78.31° to 43.71°, and the surface C/O ratio decreased from 3.17 to 0.89. The surficial areas and perimeters of HGFs were increased two-fold in the treated groups at 3 h. Fibroblasts density increased on treated disks at all time points, especially the ones treated for 60 s. Attachment-related genes in the groups treated for 30 and 60 s were significantly higher at 3 and 24 h.

Conclusion

The helium atmospheric-pressure dielectric-barrier-discharge plasma treatment enhances the biological behavior of fibroblasts on zirconia by increasing the expression of attachment-related genes within 24 h and promoting the cell density during longer culture times. Wettability of zirconia, an important physicochemical property, has a vital influence on the cell behaviors.

Effect of laser-dimpled titanium surfaces on attachment of epithelial-like cells and fibroblasts

PURPOSE

The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti.

MATERIALS AND METHODS

Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-µm dimples at 10-µm intervals, and SM30 (n=16) had 5-µm dimples at 25-µm intervals in a 2 × 4 mm(2) area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences.

RESULTS

The adhesion strength of epithelial cells was higher on Ti surfaces with 5-µm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins.

CONCLUSION

These findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.

Behavior of osteoblasts on TI surface with two different coating designed for orthodontic devices

In the present study we coated Ti surfaces with polytetrafluorethylene (PTFE) and titanium nitride (TiN) and investigated in vitro the behavior of osteoblasts on these surfaces. MG-63 osteoblasts were cultured on titanium discs with different surface treatment: uncoated Ti6Al4V, TiN-coated, PTFE-coated. Cell viability/proliferation was detected by MTT assay. Gene-expression levels of alkaline phosphatase (ALP), osteocalcin (OC), type I collagen, receptor activator of nuclear factor-kappa-B ligand (RANKL), and osteoprotegerin (OPG) were determined by qPCR. Cell behavior on different surfaces was observed by time-lapse microscopy. Cells grown on PTFE-coated Ti surface exhibited delayed surface attachment and decreased proliferation after 48 h. However, after 168 h of culture cells grown on PTFE-coated surface exhibited higher viability/proliferation, higher expression levels of ALP and OC, and higher OPG/RANKL ratio compared to uncoated surface. No effect of TiN-coating on any investigated parameter was found. Our results shows that PTFE coating exhibits no toxic effect on MG-63 cells and slightly stimulates expression of several genes associated with osteogenesis. We propose that PTFE coating could be considered as a possible choice for a surface treatment of temporary skeletal anchorage devices in orthodontics.

Enhanced bioactivity of polyvinylidene chloride films using argon ion bombardment for guided bone regeneration

Polyvinylidene chloride (PVDC) is a long chain carbon synthetic polymer. The objective of this study was to improve the bioactivity of PVDC films through surface modification using argon (Ar) ion bombardment to create Ar-modified PVDC films (Ar-PVDC) to address the clinical problems of guided bone regeneration (GBR), which is technique-sensitive, and low bone regenerative ability. First, the effects of Ar ion bombardment, a low temperature plasma etching technique widely used in industry, on PVDC film wettability, surface chemistry, and morphology were confirmed. Next, fibroblast-like and osteoblast-like cell attachment and proliferation on Ar-PVDC were assessed. As a preclinical in vivo study, Ar-PVDC was used to cover a critical-sized bone defect on rat calvaria and osteoconductivity was evaluated by micro-computed tomography analysis and histological examinations. We found that the contact angle of PVDC film decreased by 50° because of the production of -OH groups on the PVDC film surface, though surface morphological was unchanged at 30 min after Ar ion bombardment. We demonstrated that cell attachment increased by about 40% and proliferation by more than 140% because of increased wettability, and 2.4 times greater bone regeneration was observed at week 3 with Ar-PVDC compared with untreated PVDC films. These results suggest that Ar ion bombardment modification of PVDC surfaces improves osteoconductivity, indicating its potential to increase bone deposition during GBR.

A review on the wettability of dental implant surfaces II: Biological and clinical aspects

Dental and orthopedic implants have been under continuous advancement to improve their interactions with bone and ensure a successful outcome for patients. Surface characteristics such as surface topography and surface chemistry can serve as design tools to enhance the biological response around the implant, with in vitro, in vivo and clinical studies confirming their effects. However, the comprehensive design of implants to promote early and long-term osseointegration requires a better understanding of the role of surface wettability and the mechanisms by which it affects the surrounding biological environment. This review provides a general overview of the available information about the contact angle values of experimental and of marketed implant surfaces, some of the techniques used to modify surface wettability of implants, and results from in vitro and clinical studies. We aim to expand the current understanding on the role of wettability of metallic implants at their interface with blood and the biological milieu, as well as with bacteria, and hard and soft tissues.