Dental Abutment Screw Research Articles

Mechanical, antibacterial and cytotoxic characteristics of nanolayered TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings

Titanium and titanium alloy materials are often made as medical implants. Surface properties of titanium medical implants play decisive roles for antibacterial and biological response and tissue biocompatibility. In this study, cathode arc evaporation (CAE) technology was used to deposit TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings with nanostructures on the Ti–6Al–4V dental abutment screws. The deposited coatings were then oxidized at high temperature to produce different oxides on the surface of the coatings. The mechanical properties, antibacterial properties and biocompatibilities of the coatings were analyzed. The effect of coatings on the abutment screw loosening and removal torque between the abutment screw and the pure titanium implant fixture was studied by removal torque measurement. In addition, Staphylococcus aureus (S. aureus) was used for evaluating the antibacterial properties of coatings, and mouse fibroblasts (L929) were used for ISO 10993-5 cytotoxicity analyses to determine whether it had good biocompatibility.Nanolayered structures and multiphases of polycrystalline TiNb–Zr–Ta were obtained by co-deposition of Ta, Zr and TiNb. When small content of N was introduced, the TiNb–Zr–Ta(N) showed a polycrystalline TiNb–Zr–Ta where N atoms entered the metallic lattice at interstitial sites. After oxidation, oxide phases of Ta2O5, TiO2, Nb2O5 and ZrO2 were formed on the surface of TiNb–Zr–Ta and TiNb–Zr–Ta(N). Ta2O5 was obtained on the surface of the coating prior to other oxides such as TiO2, Nb2O5 and ZrO2. The deposited TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had high contact angle and exhibited a hydrophobic feature, while the annealed TiNb–Zr–Ta–O and TiNb–Zr–Ta(N)–O showed hydrophilicity. The deposited TiNb–Zr–Ta had similar hardness and Young's modulus values to that of the uncoated Ti–6Al–4V. When N was doped, the TiNb–Zr–Ta(N) had the highest hardness and Young's modulus. The hardness of the annealed TiNb–Zr–Ta(N) coating only decreased slightly due to the small oxide layer of ∼140 nm. Compared with the uncoated Ti–6Al–4V, TiNb–Zr–Ta serial coatings deposited on abutment screws had higher removal torques, which prevented the abutment screw of dental implant from loosening after long-term use. The biocompatibility of TiNb–Zr–Ta serial coatings was similar to that of the uncoated Ti–6Al–4V. In addition, the oxidized TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had excellent antibacterial properties. It is speculated that the resulting Ta2O5 of both coatings may inhibit bacterial growth and improve the antibacterial effect. Based on the above advantages, the TiNb–Zr–Ta serial coatings are expected to have the potential to be applied to biomedical implants.

The dental abutment screw and new methods to remove fractured abutment screw from jawbone: A review

Dental implants are becoming increasingly popular due to their ease of use, effectiveness, and reliability as prosthodontics treatment options, as well as an alternative to bridges and traditional dentures. However, complications related with implants have also been reported. Abutment screw fractures are serious endodontic issues because the fragment that remains inside the implant can cause the implant to malfunction. It is extremely difficult to remove screw particles from the screw hole if the abutment screw is cracked where the thread and shank meet. At the same time, the implant will not serve effectively as an anchor, if the screw is cracked at this point. There are numerous risks associated with the use of the rotary device, which could damage the implant's internal threads, due to the small area between the engraving surface of the implant and the broken abutment screw. This review article discusses the modified technique explained in various literature-based articles for removing the abutment screw.

A technique for identifying implant abutment screw heads and corresponding implant drivers by using colored polytetrafluorethylene tape

This technical report presents a color-coded classification system for identifying a dental abutment screw head design to its corresponding implant driver system with polytetrafluorethylene (PTFE) tape. This proposed standardization should simplify the restoration and retrieval of implant components.

Detorque Evaluation of Dental Abutment Screws after Immersion in a Fluoridated Artificial Saliva Solution

Implant-abutment connections still present failures in the oral cavity due to the loosening of mechanical integrity by detorque and corrosion of the abutment screws. The objective of this study was to evaluate the detorque of dental abutment screws before and after immersion in fluoridated solutions. Five commercial implant-abutment assemblies were assessed in this investigation: (C) Conexão®, (E) Emfils®, (I) INP®, (S) SIN®, and (T) Titanium Fix®. The implants were embedded in an acrylic resin and then placed in a holding device. The abutments were first connected to the implants and torqued to 20 Ncm using a handheld torque meter. The detorque values of the abutments were evaluated after 10 minutes. After applying a second torque of 20 Ncm, implant-abutment assemblies were withdrawn every 3 hours for 12 hours in a fluoridated solution over a period of 90 days. After that period, detorque of the abutments was examined. Scanning electronic microscopy (SEM) associated to energy dispersive spectroscopy (EDS) was applied to inspect the surfaces of abutments. Detorque values of systems C, E, and I immersed in the fluoridated solution were significantly higher than those of the initial detorque. ANOVA demonstrated no significant differences in detorque values between designs S and T. Signs of localized corrosion could not be detected by SEM although chemical analysis by EDS showed the presence of elements involved in corrosive processes. An increase of detorque values recorded on abutments after immersion in fluoridated artificial saliva solutions was noticed in this study. Regarding chemical analysis, such an increase of detorque can result from a corrosion layer formed between metallic surfaces at static contact in the implant-abutment joint during immersion in the fluoridated solutions.

AC Impedance Behaviors of TiN and ZrN Coated Dental Abutment Screw Using Arc-ion Plating Method

AC Impedance Behaviors of TiN and ZrN Coated Dental Abutment Screw Using Arc-ion Plating Method

TiN 및 WC코팅된 치과용 어버트먼트 나사의 안정성

Dental implant system is composed of abutment, abutment screw and implant fixture connected with screw. The problems of loosening/tightening and stability of abutment screw depend on surface characteristics, like a surface roughness, coating materials and friction resistance and so on. For this reason, surface treatment of abutment screw has been remained research problem in prosthodontics. The purpose of this study was to investigate the stability of TiN and WC coated dental abutment screw, abutment screw was used, respectively, for experiment. For improving the surface characteristics, TiN and WC film coating was carried out on the abutment screw using EB-PVD and sputtering, respectively. In order to observe the coating surface of abutment screw, surfaces of specimens were characterized, using field emission scanning electron microscope(FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The stability of TiN and WC coated abutment screw was evaluated by potentiodynamic, and cyclic potentiodynamic polarization method in 0.9% NaCl solution at . The corrosion potential of TiN coated specimen was higher than those of WC coated and non-coated abutment screw. Whereas, corrosion current density of TiN coated screws was lower than those of WC coated and non-coated abutment screw. The stability of screw decreased as following order; TiN coating, WC coating and non-coated screw. The pitting potentials of TiN and WC coated specimens were higher than that of non-coated abutment screw, but repassivation potential of WC coated specimen was lower than those of TiN coated and non-coated abutment screws due to breakdown of coated film. The degree of local ion dissolution on the surface increased in the order of TiN coated, non-coated and WC coated screws.

Deformation of Dental Abutment Screw after Tightening and Loosening

To evaluate the mechanical deformation phenomena of dental abutment screw after tightening and loosening, five species of abutments were selected (3i-three, Avana- two) respectively by two pieces. The abutment screws were repeatedly tightened and removed 20 times with a digital controller. Field emission scanning electron microscope (FE-SEM) was used to observe changes of each part caused by repeatedly tightening and loosening experiment. As the number of tightening and loosening was increased, the wear or distortion of hexed or squared slot that contacted with the driver tip was more severely progressed. Wear or distortion of hexed slot was more severe than that of squared slot and it was more remarkable in the titanium screw than in the gold screw. All the tested screws showed that the width in the crest of their screw thread decreased gradually as the test was proceeded.

Effect of surface coating on the screw loosening of dental abutment screws

Regardless of the type of performed restoration, in most cases, a screw connection is employed between the abutment and implant. For this reason, implant screw loosening has remained a problem in restorative practices. The purpose of this study was to compare the surface of coated/plated screws with titanium and gold alloy screws and to evaluate the physical properties of coated/plated material after scratch tests via FE-SEM (field emission scanning electron microscopy) investigation. GoldTite, titanium screws provided by 3i (Implant Innovation, USA) and TorqTite, titanium screws by Steri-Oss (Nobel Biocare, USA) and gold screws and titanium screws by AVANA (Osstem Implant, Korea) were selected for this study. The surface, crest, and root of the abutment screws were observed by FE-SEM. A micro-diamond needle was also prepared for the scratch test. Each abutment screw was fixed, and a scratch on the surface of the head region was made at constant load and thereafter the fine trace was observed with FE-SEM. The surface of GoldTite was smoother than that of other screws and it also had abundant ductility and malleability compared with titanium and gold screws. The scratch tests also revealed that teflon particles were exfoliated easily in the screw coated with teflon. The titanium screw had rough surface and low ductility. The clinical use of gold-plated screws is recommended as a means of preventing screw loosening.

Comparative sporicidal effect of liquid chemical germicides on three medical devices contaminated with spores of Bacillus subtilis

Background: The relatively limited variety of surfaces and geometries challenged in current sporicidal testing reduces the predictive value of these analyses when extrapolated to the wide variety of medical devices. The unknown spore load being challenged and the qualitative nature (growth/no growth) of those tests further prevent precise comparison among liquid chemical disinfectants. Hence, the relative activity of different chemical substances has not been clearly established, hindering selection of the best agent for each clinical situation. Methods: A micromethod was developed to assess sporicidal activity against Bacillus subtilis spores deposited on three different medical devices: carbon-steel dental burs silicone-rubber medical catheters, and titanium-alloy dental abutment screws. The spore load on each device and the recovery after three analytical steps were quantitatively assessed with spores radiolabeled with carbon 14 menthionine. Results: The killing of 2 to 7 × 10 6 spores loaded on three different devices and exposed to glutaraldehyde, fomaldehyde, copper ascorbate, hydrogen peroxide, peracetic acid, sodium hypochlorite, or phenol for 30 minutes at 20° C ranged from a 10 3-fold decrease for 10% hydrogen peroxide to zero decrease for 5% phenol. Our results suggest that the nature of the surface being challenged may affect the sporicidal activity of some chemical agents. Conclusion: The quantitative data presented allow comparison of the sporicidal effect of different liquid chemical agents. These findings may help prevent an overestimation of sporicidal activity and possible transmission of pathogens from the surface of improperly decontaminated medical devices.