Numerous studies have investigated the surface treatment of implants using various types of plasma, including atmospheric pressure plasma and vacuum plasma, to remove impurities and increase surface energy, thereby enhancing osseointegration. Most previous studies have focused on generating plasma directly on the implant surface by using the implant as an electrode for plasma discharge. However, plasmas generated under atmospheric and moderate vacuum conditions often have a limited plasma volume, meaning the shape of the electrodes significantly influences the local electric field characteristics, which in turn affects plasma behavior. Consequently, to ensure consistent performance across implants of different sizes and shapes, it is essential to develop a plasma source with discharge characteristics that are unaffected by the treatment target, ensuring uniform exposure. To address this challenge, we developed a novel plasma source, termed “vortex plasma”, which generates uniform plasma using a magnetic field within a controlled space. We then compared the surface treatment efficiency of the vortex plasma to that of conventional direct plasma discharge by evaluating hydrophilicity, surface chemistry, and surface morphology. In addition, to assess the biological outcomes, we examined osteoblast cell activity on both the vortex and direct plasma-treated surfaces. Our results demonstrate that vortex plasma improved hydrophilicity, reduced carbon content, and enhanced osteoblast adhesion and activity to a level comparable to direct plasma, all while maintaining the physical surface structure and morphology.

Nonthermal plasma has been extensively utilized in various biomedical fields, including surface engineering of medical implants to enhance their biocompatibility and osseointegration. To ensure robustness and cost effectiveness for commercial viability, stable and effective plasma is required, which can be achieved by reducing gas pressure in a controlled volume. Here, we explored the impact of reduced gas pressure on plasma properties, surface characteristics of plasma-treated implants, and subsequent biological outcomes. Implant materials were treated with plasmas under varying discharge conditions, with pre-pumping times of 10 s and 20 s, thereby modulating the pressure during plasma treatments. Through optical emission spectroscopy, we demonstrated that the 5 Torr operational condition, achieved by 20-s pre-pumping, generated a greater density of excited nitrogen species and provided more stable plasma compared to the 16 Torr condition, achieved by 10-s prepumping. We then assessed the surface hydrophilicity, chemical composition, protein adsorption, and osteoblast activities on plasma-treated implants compared with those of untreated controls. Our results reveal that the 5 Torr condition significantly enhances removal of carbon-based impurities and increased protein adsorption, leading to improved cell adhesion, proliferation, and differentiation. In particular, implants treated under the 5 Torr condition showed significantly higher carbon-based impurity reduction and osteoblast differentiation performance compared to those treated under the 16 Torr condition. These findings suggest that optimizing gas pressure in plasma devices is critical for effectively controlling excited nitrogen radicals, which improves plasma surface modification and enhances the biocompatibility of implant surfaces.

Recent studies have explored surface treatments, such as increasing the hydrophilicity of implant fixtures, to enhance the osseointegration of implants. This prospective clinical study aimed to assess the clinical stability and efficacy of plasma treatment applied to implants with sandblast−acid etching (SLA) surfaces before placement. Twenty-eight patients requiring implant placement provided consent and were assigned randomly to either the SLA group without plasma treatment or the SLA/plasma group with plasma treatment. Recall checks were conducted one and three months after the first-stage surgery, followed by a second surgery at four months. Although no significant differences in buccal bone defects or implant stability were observed between the groups, the SLA/plasma group showed significant increases in marginal bone changes on the mesial and distal sides, as assessed using periapical radiographs. This study underscores the potential of pre-implantation plasma treatment to enhance bone regeneration around implants.

PURPOSE. This study was conducted to evaluate the effects of plasma treatment of sandblasted and acid-etched (SLA) titanium implants on surface cleansing and osseointegration in a beagle model. 

MATERIALS AND METHODS. For morphological analysis and XPS analysis, scanning electron microscope and x-ray photoelectron spectroscopy were used to analyze the surface topography and chemical compositions of implant before and after plasma treatment. For this animal experiment, twelve SLA titanium implants were divided into two groups: a control group (untreated implants) and a plasma group (implants treated with plasma). Each group was randomly located in the mandibular bone of the beagle dog (n = 6). After 8 weeks, the beagle dogs were sacrificed, and volumetric analysis and histometric analysis were performed within the region of interest.

RESULTS. In morphological analysis, plasma treatment did not alter the implant surface topography or cause any physical damage. In XPS analysis, the atomic percentage of carbon at the inspection point before the plasma treatment was 34.09%. After the plasma treatment, it was reduced to 18.74%, indicating a 45% reduction in carbon. In volumetric analysis and histometric analysis, the plasma group exhibited relatively higher mean values for new bone volume (NBV), bone to implant contact (BIC), and inter-thread bone density (ITBD) compared to the control group. However, there was no significant difference between the two groups (P > .05). 

CONCLUSION. Within the limits of this study, plasma treatment effectively eliminated hydrocarbons without changing the implant surface. [J Adv Prosthodont 2024;16:189-99]

Efforts are ongoing to enhance the functionality of human acellular dermal matrices (hADMs), which are extensively utilized in reconstructive surgeries. Among these efforts, plasma treatments, particularly vacuum plasma treatments, have recently emerged in the medical field. This study aims to investigate the efficacy of a vacuum plasma treatment in enhancing the biocompatibility and biointegration of hADMs. Utilizing a plasma activator (ACTILINK reborn, Plasmapp Co., Ltd., Daejeon, Republic of Korea), hADMs were treated and evaluated through in vitro and in vivo analyses. Hydrophilicity changes were gauged by the blood absorption times, while SEM imaging was used to analyze physical surface deformation. Protein adsorption was measured with fluorescently labeled bovine serum albumin and fibronectin. For the in vivo study, mice were implanted with plasma-treated and untreated hADMs, and the post-implantation effects were analyzed through histological and immunofluorescence microscopy. The plasma-treated hADMs demonstrated a significantly enhanced hydrophilicity compared to the untreated samples. SEM imaging confirmed the maintenance of the microroughness after the treatment. The treated hADMs showed a significant reduction in fibronectin adsorption, a critical factor for cellular adhesion. In vivo, the plasma-treated hADMs exhibited reduced capsule formation and enhanced fibroblast infiltration, indicating improved biocompatibility and integration. These findings highlight the potential of a plasma treatment to enhance the performance of hADMs in clinical settings, offering a promising avenue for improving reconstructive surgery outcomes.

This study was conducted to compare the effects of an innovative plasma surface treatment device that does not need a gas supply for titanium disks with two different surface topographies: the prototypical machined surface (MAC) and one of the most diffused roughened ones (SL) obtained through grit blasting and acid etching. A total of 200-MAC and 200-SL titanium disks were used. Each group of disks was divided into four sub-groups of 40 samples each that were subjected to five different tests. Among these, 150-MAC and 150-SL were considered the test group, and they were treated with plasma for 15, 30, and 60 s after being removed from the sterile packaging. On the other hand, 50-MAC and 50-SL were considered the control group, and they were only removed from sterile plastic vials. The samples were analyzed to evaluate the capability of the plasma treatment in influencing protein adsorption, cell adhesion, proliferation, and microbial growth on the test group disks when compared to the untreated disks. Protein adsorption was significantly enhanced after 20 min of plasma treatment for 15 and 30 s on the MAC and SL disks. Plasma treatment for 15 and 30 s significantly increased the level of adhesion in both treated samples after 30 min. Furthermore, the MAC samples showed a significant increase in cell adhesion 4 h after plasma treatment for 15 s. The SEM analysis highlighted that, on the treated samples (especially on the MAC disks), the cells with a polygonal and flat shape prevailed, while the fusiform- and globular-shaped cells were rare. The encouraging results obtained further confirm the effectiveness of plasma treatments on cell adhesion and fibroblast activity.

Recent technological advancements led to the development of various plasma-based technologies for post-packaging modifications. The purpose of the present preclinical in vivo study was to assess the safety and efficacy of a novel chairside nonthermal gas plasma treatment for enhancing osseointegration of titanium implants. Six male mixed foxhounds underwent extraction of mandibular premolars and first molars, and the sockets healed for 42 days. Canine mandibles were randomized to receive either plasma-treated (test) or non-plasma-treated (control) dental implants. A total of 36 implants were placed in six animals, and they were sacrificed at 2 weeks (two animals), 4 weeks (two animals), and 6 weeks (two animals) after the implant surgery. When the radiographic analysis was performed, the changes in bone level were not statistically significant between the two groups at 2 weeks and 4 weeks. The difference became significant at 6 weeks (p = 0.016), indicating more bone loss from baseline to 6 weeks for the control group. The bone-to-implant contact (BIC) appeared to be higher for the test groups at all time points, and the BIC was significantly higher for the test group at 4 weeks (p = 0.046). In conclusion, this study underscored the potential of nonthermal plasma treatment in enhancing implant osseointegration. 

In this study, we propose a vacuum plasma device for surface treatment of dental implants. This plasma device was designed to allow direct installation of sealed implant packaging containing the dental implant. In this manner, the dental implant could be treated with plasma under a moderate vacuum environment while remaining in a sterile condition. To assess the osseointegration efficiency, in vitro experiments using sandblasted, large grit, acid etching (SLA), calcium coated-SLA (CaSLA), and calcium coated-SLA with plasma treatment (PCaSLA) were performed. The implant surface was observed with scanning electron microscope (SEM) before and after plasma treatment. Thereafter, protein adsorption, cell adhesion, proliferation, and differentiation efficiency were investigated on the surface of each implant type using saos-2, an osteoblast. Plasma treatment significantly improved protein adsorption, cell adhesion, and cell proliferation efficiency compared to both CaSLA and SLA without damaging the calcium coating. According to the findings, the proposed vacuum plasma device has shown the potential to improve osseointegration efficiency. We believe that this plasma technology can be an innovative chairside solution that can be easily handled in the clinical field with superb usability.

A novel plasma treatment source for generating cylindrical plasma on the surface of titanium dental implants is developed herein. Using the titanium implant as an electrode and the packaging wall as a dielectric barrier, a dielectric barrier discharge (DBD) plasma was generated, allowing the implant to remain sterile. Numerical and experimental investigations were conducted to determine the optimal discharge conditions for eliminating hydrocarbon impurities, which are known to degrade the bioactivity of the implant. XPS measurement confirmed that plasma treatment reduced the amount of carbon impurities on the implant surface by approximately 60%. Additionally, in vitro experiments demonstrated that the surface treatment significantly improved cell adhesion, proliferation, and differentiation. Collectively, we proposed a plasma treatment source for dental implants that successfully removes carbon impurities and facilitate the osseointegration of SLA implants.

A novel impermeable sterile pouch is developed to allow the forced convective heating mechanism for improving the sterilization cycle. The heating process is parametrically investigated to obtain an optimized condition in which a sterilization load is heated from 20 to 45℃ within 2 min, and the forced convection is experimentally and numerically analyzed to find that the convection coefficient is dramatically increased to 450 W/㎡ K when compared with the conventional natural convection coefficient of 80 W/㎡ K. The optimized heating process is applied to a sterilization cycle using the impermeable pouch, and the overall sterilization cycle is found to be completed within 7.5 min whose performance is validated by using a process challenge device.