KR100540345B1 - Method for Manufacturing of Surface Coating on the Screw Release of Dental Implant Screw - Google Patents

Abstract

The present invention in the implant abutment screw for use in dentistry,

In the dental implant, characterized in that the surface of the abutment screw by selecting any one of ZrN and TiN to enhance the wear resistance by the ion plating, and to improve the anti-loosening function by giving strength to the surface of the screw The present invention provides a method of manufacturing abutment screws with improved loosening prevention function. The present invention further enhances abrasion resistance by ion plating ZrN and TiN on the abutment screw surface for implants, and provides a loosening prevention function by imparting strength to the surface of the screw. It is a very useful invention that can significantly improve.

Dental, implant, anti-loosening, abutment, screw

Description

 Method for Manufacturing of Surface Coating on the Screw Release of Dental Implant Screw}             

FIG. 1-SEM photograph of the surface coated with TiN and ZrN in a titanium screw according to the present invention.

Figure 2-SEM photograph of the surface of the screw of 3i implant innovation uncoated nothing.

Figure 3-In the present invention using a Vickers hardness tester after measuring the hardness of the titanium screw of 3i photographed indentation with an optical microscope.

Figure 4-In the present invention after measuring the hardness of the gold screw of the AVANA using a Vickers hardness tester photograph of the indentation with an optical microscope.

5-After the wear test on the titanium screw surface of TiN and ZrN-coated 3i titanium in the present invention, the wear surface photograph using a SEM.

Figure 6-After the wear test of the gold screw surface of the TiANA and ZrN-coated AVANA in the present invention, the wear surface photographed by SEM.

FIG. 7 is a graph showing surface roughness before abrasion test of titanium screw of 3i implant innovation using a surface roughness gauge to determine surface roughness before and after abrasion test in the present invention. FIG.

8-A graph showing surface roughness after abrasion testing of titanium screws of 3i implantinnovation after abrasion testing of specimens in the present invention.

FIG. 9 is a graph showing surface roughness before abrasion testing of gold screws of AVANA using a surface roughness measuring instrument in order to find out surface roughness before and after abrasion testing in the present invention. FIG.

10-A graph showing the surface roughness after the abrasion test of the gold screw of AVANA after the abrasion test of the specimen in the present invention.

Figure 11-Photograph of the Ti screw of 3i subjected to a scratch test with a surface scratch tester using a diamond tip to test the adhesion of the coating film on the surface in the present invention.

12-Photograph of Steri-Oss Ti subjected to a scratch test with a surface scratch tester using a diamond tip to test the adhesion of the coating film on the surface in the present invention.

Figure 13-A scratch photograph of AVANA's gold screw subjected to a scratch test with a surface scratch tester using a diamond tip to test the adhesion of the coating film on the surface in the present invention.

Figure 14-Scratching photograph of the Ti screw of AVANA subjected to a scratch test with a surface scratch tester using a diamond tip to test the adhesion of the coating film on the surface in the present invention.

Figure 15-Scratching photograph of the TorqTite and 3i GoldTite screw of Steri-Oss, which was subjected to a scratch test with a surface scratch tester using a diamond tip to test the adhesion of the coating film on the surface in the present invention.

The present invention relates to a method for manufacturing abutment screw in a dental implant, and more particularly, to manufacture abutment screw to improve the anti-loosening function by ion plating ZrN and TiN on the abutment screw used in the dental implant procedure. It is about a method.

Since the development of dental implants, most research has focused mainly on the biocompatibility of Ti fixtures and bone. However, after completing the actual prosthesis, the abutment screw (hereinafter referred to as screw) for the implant plays an important role in fixing the fixture and the prosthesis and causes a big problem such as loosening of the screw in clinical use. Should pay attention to In clinical practice, there are actually many problems associated with the use of screws, the most frequent of which is the loosening of screws. These screw loosening often appears to occur most frequently in single tooth implant restorations, but has been reported to occur in many cases in the case of multiple tooth restorations, and in the case of posterior restorations, it is more difficult to maintain tight tightening.

When the screw is tightened, an initial preload of tension is generated on the screw, which in turn acts as a compressive force between the implant and the crown, thereby securing the artificial crown to the implant. Therefore, the greater the load, the less the loosening of the screw. In Burgutte et al., The coefficient of friction, geometry, and material properties of a screw affect the correlation between the torque applied to the screw and the preload. Hardness, surface finish, quantity and properties of lubricant, speed of screw tightening, geometrical factors include thread radius, thread form, and physical properties of modulus of elasticity, fabric Many factors are involved, including the Poisson's ratio and yield stress.

Therefore, one of the most important factors that determine screw tightening characteristics is the screw material, and many manufacturers have made many changes in this regard. The force that holds the screw tight is the friction force between the thread, between the head and the abutment of the bolt, and between the implant and the abutment, which prevents the screw from being tightened by friction in these areas when the screw is tight. The magnitude of the frictional force depends on the charge as well as on the degree of intermetallic combination, surface texture, contamination or lubrication. At the micro level, friction is the interlocking and welding of a fine peak called the asperity of the surface on the opposing face. If a movement appears parallel to the friction plane, this roughness of the surface is scraped off and wear occurs between the two surfaces. About 90% of the torque initially applied when tightening the screw is used to overcome friction and only 10% causes charge. Therefore, in order to achieve joint stability, it is important to maximize the charge and minimize the loss of torque applied by friction, i.e. to reduce the friction when tightening the screw.

To this end, various attempts have been made to coat chemically stable, abrasion-resistant bio-friendly materials on screws, among which nitride coating or epoxy coating are used to enhance the surface properties of dental abutment screws. do. However, the coating (coating) is required properties vary depending on the site or purpose, and it may be advantageous for the purpose of use to change the properties strongly or weakly according to each purpose.

Larry et al. Reported that gold thread screws had less loosening screws than titanium thread screws in the use of abutment screws, and Millere and Haack et al. Also found that gold screws have a greater amount of charge than titanium screws. This is because the coefficient of friction of Ti-Ti is 0.5, and the coefficient of friction of Ti-Au is 0.5, which is more effective in the case of titanium screws because of the higher frictional resistance (μ = 0.15) in close contact with titanium fixtures or abutments. Because it can be tightened, 800N charge charge, which is about twice as large as that of titanium screws, can be obtained, and gold can be further tightened because the yield strength is higher than that of titanium. In addition, titanium screws have the properties of galling and seizing, so the coefficient of friction increases due to repeated locking and unlocking, making it difficult to give proper charge weight. Recently, lubricants have been applied in an effort to reduce such friction coefficients. Among them, goldtite of 3i and Torqtite of Steri-oss are the most widely used. Goldtite plated the gold alloy with 0.76 micrometers of pure gold, using pure gold as a dry lubricant, and manufacturers said that the charge weight increased 24 percent and the vertical locking force increased 75 percent. Torqtite is a titanium lubricant coated with Teflon, a solid lubricant. The manufacturer says it reduces the coefficient of friction by 60 percent and has twice the locking force of conventional titanium screws. Will et al. Found that GoldTite and TorqTite help to lower the coefficient of friction, resulting in higher charge weights than conventional gold and titanium screws. Among the coating properties of implant abutment screw, 3i gold coated screw was used to reduce surface properties and to prevent loosening of abutment screw using its modified properties. In addition, the low coefficient of friction of pure gold allows for a little more rotation in tightening the abutment screw, thus increasing the initial torque. In this way, the problem of loosening and tightening was solved. In particular, these coating materials have low abrasion resistance and shear strength, which increases the frictional resistance by increasing the frictional resistance by roughening the surface when metal ions or worn particles freed from the implant fixture screw surface and the abutment screw surface are repeatedly loosened and tightened. It appears to be.

Their research shows that the treatment of screw surfaces has an important effect on preventing screw loosening. However, Gold-coated GoldTite and Teflon-coated TorqTite are worn and damaged repeatedly when tightening and loosening, and the effects of TiN and ZrN coating are required to improve the effects of repeated tightening and loosening. In addition, there is a need for a coating method that can impart strength to the surface at the same time by minimizing frictional resistance.

Recently, studies have been attempted to solve foreign body reactions and physical weaknesses of Ti materials by coating bioinert nitrides such as TiN and ZrN on the surface of Ti implants, but there are no examples of abutment screws. Currently widely used coating methods include sputtering, ion plating, and laser ablation, and these physical vapor deposition methods minimize physical strength and surface roughness due to the physical bonding between the base material and the coating layer. Among them, ion plating has been rapidly used as the surface hardening of general alloy steel since it was first reported by Berghaus, and the development of nitriding equipment and the easy control of plasma have been made. Unlike the hardening by carburization performed at a high temperature, this method enables a low temperature process using plasma in the case of ion nitriding, thereby obtaining surface hardening while minimizing material deformation. The surface reaction by plasma is sputtering phenomenon that is accelerated by the ionization of nitrogen ions ionized by the voltage difference acting on the anode. Firstly, unlike gas nitriding, nitrogen ion and Ar ions are continuously connected to the nitride object by sputtering phenomenon. It is a phenomenon in which the surface oxide film is destroyed and removed by transfer, and the added Ar gas facilitates the adsorption and diffusion of the nitride object to the nitrogen atom by the plasma phenomenon. Second, Zr or Ti element is sputtered by accelerated nitrogen ion and then combined with nitrogen ion to form ZrN or TiN.

Therefore, in order to improve the surface properties of the abutment screw for implants, ZrN and TiN are ion-plated on the abutment screw surface to further enhance wear resistance and to impart strength to the surface of the screw to improve the anti-loosening function. will be.

In order to achieve the above object, the present inventors first need a method for lowering the surface friction coefficient of the abutment screw to further apply an initial torque in order to increase the anti-loosening effect of the abutment screw. It was noted that a material with low modulus should be coated on the abutment screw surface.

To this end, the present inventors coated various coating materials on the surface of the abutment screw and tested the results. Among them, TiN and ZrN were determined to be the most preferable coating materials because of excellent stability and strength in the oral corrosive environment.

As described above, there is no research to reduce the frictional resistance by coating TiN and ZrN on the surface of the abutment screw, and the present invention also allows the TiN and ZrN to be coated on the surface of the abutment screw by using an ion plating method.

Since the ion plating method used is first reported by Berghaus, hardware development of the nitriding equipment and easy control of plasma have been rapidly developed, and are already used for the surface hardening of low alloy steel. Unlike the hardening by carburizing, which is performed in the case of ion nitriding, since the low temperature process using plasma is possible, surface hardening can be obtained while minimizing material deformation.

The film of TiN and ZrN plated abutment screw coated by the ion plating method was photographed using a three-dimensional photograph. As a result, TiN showed a gold color, and the typical TiN coating film was formed. It was made and shown to be uniform. In particular, the results of the scanning electron microscopy showed a very smooth shape compared to the case where the abutment screw was not coated. ZrN has a uniform coating as compared to TiN, and even when observed at high magnification, the particles appear very small and the plating is uniform on the surface. It was found that the density of the coating film was high.

The ion plating of TiN and ZrN shows a difference according to the material of the screw. When observing the surface of the screw made of gold alloy and the alloy made of Ti, the surface of the screw made of gold is well processed and the surface roughness is lower than that of Ti. And it was found. However, when TiN and ZrN were coated, the surface roughness was greatly reduced. In particular, the coating of ZrN minimized the surface roughness. Even in the same material, the surface defects appearing during processing in AVANA are so severe that even the coating remains large.

The hardness of the coating film was measured by using the vickers hardness tester on the head of the screw. The hardness value of the coating film was about 100 VHS to 200 VHS higher than that of TiN and ZrN. In particular, when the coating was not coated, the hardness of gold was lower than that of Ti, and the hardness was greatly increased by coating TiN and ZrN, but the coating was also lower than that of Ti even if gold was also coated. It can be seen that the hardness of the matrix also affects the coating. When the coating is made of Teflon, 391 shows the lowest hardness value, indicating that the hardness varies depending on the coating material.

Hardness is reported to be 2000 kg / mm2 and ZrN 2500 kg / mm2 when coated on the alloy steel.26) It is generally found that the ZrN film is more stable and has better surface characteristics than TiN.

The wear resistance test was performed by selecting the head portion of the abutment column of the implant, and the TiN and ZrN coated screw surfaces were tested for wear resistance and adhesion to the coating film of the screw coated with TiN and ZrN. Excellent Therefore, by minimizing the plastic deformation of the screw portion generated during tightening and loosening of the screw it will be able to easily contact the screw surface of the fixture with a small tightening force.

The wear surface properties of the TiN and ZrN ion-plated screws showed a ductile surface for gold, but showed a brittle wear surface for Ti. However, the wear surface on the TiN or ZrN-coated surface showed a largely unworn form, indicating a large coating effect. The resistance of abrasion can also be seen in reports that ZrN has a coefficient of friction less than 0.6, but TiN has a coefficient of friction higher than 0.6. In addition, ZrN is 45N, TiN is 55N, and TiN is excellent in adhesion. However, in this study, ZrN and TiN were slightly different depending on the base. When TiN is coated on Ti, ZrN is coated on gold. Each case is shown to be excellent. This is because TiN is coated on Ti base having a body-centered cubic crystal structure (bcc), which results in a good structural match with the base, which increases adhesion and ZrN is well structured in terms of atoms. I think it is because. These results have been confirmed in the scratch test and wear test.

  Based on these results, the problem of tightening and loosening the abutment screw and the fixture is that the abutment screw due to deformation during repeated tightening and loosening can be maintained if the friction coefficient is somewhat low and the strength of the screw can be maintained permanently. To maximize the anti-loosening effect.

The present invention will be described in more detail by way of examples.

Example

The abutment screw samples used in this example were 3T GoldTite, titanium screw (Implant Innovation, USA) and Steri-Oss TorqTite, titanium screw (Nobel Biocare, USA) and AVANA gold screw, titanium screw (Osstem Implant, Korea ) 3 pieces each.

Plasma-arc ion plating equipment was used for the ion plating experiment. After mounting the specimen, the vacuum chamber was evacuated to 3.0 x 10-5 torr and Ar gas was reduced to 10-20 m torr using a mass flow controller. Supplied.

After generating Ar plasma with a power of 900 W, DC was applied to the sample stage to remove contaminants on the surface of the specimen including the oxide layer for about 10 minutes, and then the vacuum chamber was evacuated again to 3.0 × 10 −5 torr. For ion plating, nitrogen gas was supplied at 10-20 m torr for TiN coating and 9-10 m torr for ZrN and the plating thickness was 2.0-2.5 μm with a plating time of 60 min. The rotational speed of the specimen was 0.5 RPM, so that the coating was uniformly applied to all parts of the thread. The temperature was 350-380 ° C to increase the adhesion.

In order to confirm the results, the coating surface irradiation was analyzed by using field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDX) to investigate the change of the surface structure of the plating after ion plating. The surface hardness test was averaged by measuring the hardness of the coated surface five times per specimen using a Vickers hardness tester (Model: HMV-2, Shimadzu, Japan).

In the surface scratch test, a diamond tip was used to test the scratch at a speed of 100 mm / min with a load of 100 gr / mm2 using a surface scratch tester.

The wear test was performed using a pin on disk type abrasion tester. The ball was a 3mm diameter ruby ball and the disk was a plated abutment screw for each test condition. At this time, 50 g of test load was applied and the rotational linear velocity was maintained at 28 mm per second. The wear characteristics were compared from the wear trace and the weight loss after rubbing a certain friction distance (about 35m). Weighing was compared with the difference between the weight before and after abrasion using a microbalance. Continued relative friction between the plate and the ball leaves a so-called wear track contacted by the ball on the contacting plate surface. The wear traces of these wear areas were widened with increasing test time and test load. In this experiment, the area of the wear traces was observed by SEM to compare the degree of wear.

In the surface roughness test, the surface roughness was measured by obtaining Ra and Rmax values using a roughness meter (Model: DSF-1000, Kosaka, Japan).

Test results FIG. 1 is a SEM photograph of the test specimen of the present invention, ie, TiN and ZrN ion-coated surfaces on a titanium screw of 3i company, a is a specimen in which TiN is ion-plated, and b is a specimen in which ZrN is ion-plated. . The specimens were much smoother than the surface of the screw of 3i implant innovation shown in FIG. Looking at the EDX curve, Ti, Zr, and N were detected, indicating that the coating was well formed.

Figure 3 is a Vickers hardness tester after measuring the hardness of the titanium screw of the 3i and the indentation was taken with an optical microscope, (a) Non coated, (b) TiN coated, (c) is the indentation marks of ZrN coated screw to be. Indentation marks (b) and (c) coated with TiN and ZrN appeared somewhat smaller than the uncoated (a) but the hardness was increased.

Figure 4 is a Vickers hardness tester measured the hardness of the gold screw of the AVANA and the indentation was taken with an optical microscope, (a) Non coated, (b) TiN coated, (c) the indentation marks of ZrN coated screw to be. As shown in the case of coating on Ti, the indentation marks are small, indicating that the hardness is increased.

Table 1 above summarizes the hardness values of all specimens. The measured surface hardness of each screw shows about 100 to 200 times higher than uncoated. Especially, ZrN plating is higher than TiN plating. Showed hardness.

FIG. 5 is a photograph of the wear surface of the TiN and ZrN-coated 3i titanium screw after the abrasion test was performed using a pin on disk type abrasion tester. coated (b) shows TiN coated and (c) shows wear surface of ZrN coated screws. It can be seen that the coated case is narrower than the uncoated width of the wear. In particular, TiN-coated (b) shows less depth or width than (c), indicating that the TiN coating film has excellent adhesion to Ti screws.

Figure 6 is a photograph of the wear surface observed by using a SEM after the wear test using a pin on disk type abrasion tester to investigate the wear resistance of the gold screw surface of TiN and ZrN-coated AVANA coated (b) shows TiN coated and (c) shows wear surface of ZrN coated screws. The gold screw has a small abrasion width and depth of the ZrN film, indicating strong adhesion.

Table 2 shows the results of weighing before and after the abrasion test for all specimens. The amount of abrasion is significantly reduced when ZrN is coated rather than TiN, especially when TiN is coated on Ti and ZrN is coated on Gold. The case showed a significant decrease in the amount of wear.

Figure 7 shows the surface roughness before the wear test of the titanium screw of the 3i implant innovation using a surface roughness meter to determine the surface roughness before and after the wear test. (a) is Non coated, (b) TiN coated, (c) is coated with the surface roughness of the ZrN coated screw, it can be seen that the surface roughness is uniform and smooth surface is obtained.

FIG. 8 shows the surface roughness after abrasion testing of titanium screws of 3i implantinnovation after abrasion testing of the FIG. 7 specimen. (a) is non coated, (b) is TiN coated, and (c) is the surface roughness of ZrN coated screw. Able to know. Particularly, when TiN is coated on the Ti screw, (b) shows that the roughness is greatly reduced compared to (c) coated with ZrN.

Fig. 9 shows the surface roughness before the abrasion test of the gold screw of AVANA using a surface roughness measuring instrument to find out the surface roughness before and after the abrasion test. (a) is non coated, (b) is TiN coated, (c) is coated with the surface roughness of the ZrN coated screw, it can be seen that the surface roughness is uniform and smooth surface is obtained.

FIG. 10 shows the surface roughness after the wear test of the gold screw of AVANA after the wear test of the FIG. 9 specimen. (a) is non coated, (b) is TiN coated, and (c) is surface roughness of ZrN coated screw. After the abrasion test, overall surface roughness is greatly increased compared to before abrasion test. It can be seen that decreases. Particularly, when the gold screw is coated with ZrN, (c) shows that the roughness shows the same roughness as before the abrasion test compared to TiN-coated (b).

Table 3 shows the roughness average value Ra and the maximum roughness value Rmax for all specimens. Here, it can be seen that the Ra value of the gold screw is superior to the titanium screw, so that the surface roughness is small due to the excellent millability. However, the abrasion test increases overall and the Ti screw of AVANA also shows the effect of scratches that existed in the past, showing a high Ra value of 0.38㎛. In the case of TiN and ZrN coating, Ra was greatly reduced.

FIG. 11 is a scratch photograph of a Ti screw of 3i subjected to a scratch test at a load of 100 gr / mm 2 and a speed of 100 mm / min using a diamond tip to test the adhesion of the coating film on the surface. (a) is Non coated, (b) is TiN coated, and (c) is ZrN coated. Uncoated (a) shows deep and wide scratches, but TiN coated (b) shows no deep traces. However, (c), which is a case where ZrN is coated, shows a narrow trace and shows excellent adhesion of TiN to Ti base. Looking at Figure 12, the case of the company's other Steri-Oss Ti, it can be seen clearly that TiN has excellent adhesion.

Figure 13 is a scratched photograph of the gold screw of AVANA (a) is non coated, (b) is TiN coated, (c) is ZrN coated photo. In the case of no coating, the ductility characteristic of gold and the width of traces are widely seen. In the case of TiN coating of (b), the trace is narrow but deep, and the coating of ZrN of (c) shows the same trace pattern of the specimen coated with TiN on Ti.

Fig. 14 is a photograph of AVANA's Ti screw scratch test. In the case of TiN coating, the boundary of the scratch marks appeared without the ductility property, but ZrN showed the ductility marks. It can be seen that low.

Figure 15 shows the traces after the scratch test of the Steri-Oss TorqTite and 3i GoldTite screw. Epoxy coating shows delamination on the surface, and gold shows ductility.

As such, the present invention is a result of coating TiN and ZrN on the surface of the abutment screw to improve the suitability of the interface between the implant and the abutment screw and the characteristics of loosening and tightening. As a result of observing ZrN and TiN ion-plated on the screw with a scanning electron microscope Compared with the abutment screw not coated (Ra: 0.15∼0.24㎛), it showed a very smooth shape (Ra: 0.07∼0.04㎛), and ZrN had a more uniform coating and a higher density of the coating film than TiN.

In addition, the surface of the screw made of gold has a lower roughness than Ti depending on the material of the screw, but when TiN and ZrN are coated, the surface roughness is greatly reduced, and the coating of ZrN minimizes the surface roughness. , ZrN coated with a high hardness of about 100 VHS or more than 200 VHS compared to the uncoated. In the case of no coating, the hardness of gold was lower than that of Ti, and the hardness was greatly increased by coating TiN and ZrN, but it was lower than that of Ti even if gold was also coated.

In addition, the wear resistance test results show that the TiN, ZrN coated screw surface has excellent wear resistance. In the case of gold, the surface showed ductile properties in the case of gold, but in the case of Ti, the wear surface showed brittleness. In the case of Tir coated with Ti, TiN was coated with Ti. Were found to be superior to each other.

As described above, the present invention is a very useful invention that can further improve the wear resistance by ion-plating ZrN and TiN on the surface of the implant abutment screw, and remarkably improve the anti-loosening function by imparting strength to the surface of the screw.

Claims (2)

In the abutment screw for implants used in dentistry, Anti-loosening in dental implants characterized in that the abrasion resistance is enhanced by selecting one of ZrN and TiN on the surface of the abutment screw and ion plating to significantly improve the anti-loosening function by imparting strength to the surface. Method of making abutment screws with improved functionality. The method of claim 1, wherein the ion plating is a plasma arc ion plating method is used in the preparation of abutment screw with improved anti-loosening function in the dental implant.

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