• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.25 no.5
• /
• pp.433-438
• /
• 2012

This paper is the second paper among two papers which constitute the paper about the structural design of a dental implant. This paper completed the test drafting for the structural model of the new dental implant whose structural performance was confirmed and verified through the comparative structural analysis carried out in the first paper. This paper finished the structural design of a dental implant by manufacturing the dental implant using CNC machines and so forth on the basis of the completed draft and finally by evaluating the machining condition of the dental implant. The drafting work was performed using MDT(Mechanical Desk Top). The manufacturing work was carried out using CNC machines, general purpose milling machine, and Wire EDM. The manufactured surface condition of the dental implant was evaluated and confirmed finally using an electron microscope. As a result of evaluation, a testing dental implant with very good condition was designed and manufactured.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.22-22
• /
• 2018

의료기기는 사용목적과 사용 시 인체에 미치는 잠재적 위해성의 정도에 따라 4개의 등급으로 분류하며, 두 가지 이상의 등급에 해당되는 제품의 경우에는 가장 높은 등급으로 분류하게 된다. 의료기기 품목허가를 위해서는 기술문서를 작성하여야 하며, 이를 위해서는 기술문서 심사를 신청하는 절차를 이해하여야 한다. 의료기기 기술문서란 의료기기의 성능과 안전성 등 품질에 관한 자료로서 해당 품목의 원자재, 구조, 사용목적, 사용방법, 작용원리, 사용 시 주의사항, 시험규격 등이 포함되는 문서를 말하며, '의료기기 허가 신청서'와 '첨부자료(임상시험자료 포함)'로 구성되어 있다. 의료기기 품목허가 시 제출되는 기술문서를 통하여 해당 의료기기의 안전성 및 성능이 충분히 입증되어야 하며, 인체 삽입되는 표면처리 임플란트를 포함한 인체 접촉 의료기기의 안전성의 경우 '의료기기의 생물학적 안전에 관한 공통 기준규격'에 따라 평가 후 제조 수입품목 허가를 진행해야 한다. 또한 성능의 경우는 해당 규격 또는 자사의 기준 및 시험방법에 따른 성능에 관한 자료, 물리 화학적 특성에 관한 자료를 통하여 평가되어야 하며, 기허가 인증된 제품에 한 번도 사용되지 않은 원재료 또는 적용부위 및 적용방법이 달라 안전성 및 유효성 확인이 필요한 경우 임상시험에 관한 자료가 요구될 수 있다. 본 발표에서는 이러한 인체 삽입용 표면처리 임플란트의 전반적인 인허가 절차에 대해서 안내하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.3
• /
• pp.259-267
• /
• 2014

Fatigue tests were performed in various simulated body environments reflecting various factors (such as body fluids, artificial saliva) relevant within a living body. First, the fatigue limit under a simulated body environment (artificial saliva) was evaluated and the governing factors of implant fatigue strength were looked into by observing the fracture mode. The fatigue life of an implant decreased in the artificial saliva environment compared with that in the ringer environment. Furthermore, in the artificial saliva environment, the implant fracture mode was fatigue failure of fixture as opposed to the abutment screw mode in the ringer environment. In the fatigue test, corrosion products were observed on the implant in the simulated body environment. A larger amount of corrosion products were generated on the artificial saliva specimen than on the ringer specimen. It is thought that the stronger corrosion activity on the artificial saliva specimen as compared with that on the ringer specimen led to an overall decrease of fatigue life of the former specimen. In the case of the implant with a nitrided abutment screw eliminated hardened layer (TixN), a several times increase in fatigue life is achieved in comparison with tungsten carbide-coated implants.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.9
• /
• pp.418-424
• /
• 2017

Magnesium has a higher specific strength than other metals and is widely used industry wide due to its excellent vibration absorption ability and electromagnetic wave shielding property.For example, it is used for automobile parts such as car seat frames and cylinder heads, and is widely used in electronic products such as notebook cases and mobile phone cases. In addition, it is in the spotlight as a bone-implant material used to assist in the treatment of damaged bones when the bones are cracked or broken. Currently, Ti alloy, stainless steel and Co-Cr-Mo alloy are used as the implant material, and the Mg alloy remains in research stage. The current problem with bone implant implants is that the patients must undergo reoperation to remove the implants after joint surgery. Magnesium, however, can achieve sufficient strength compared to current materials. In addition, since it is self-decomposed after the recovery, reoperation is not necessary. In this paper, Mg alloys were designed by adding harmless Ca and Zn to the human body. In order to improve the strength and corrosion resistance, the final alloy was designed by adding a small amount of Sr as a grain refiner. The radioactive elements of Sr are harmful to the human body, but other naturally occurring Sr elements are harmless. Microstructure analysis of the alloys was performed by optical microscopy and scanning electron microscopy. The mechanical properties and corrosion characteristics were evaluated by tensile test, potentiodynamic test and immersion test.

• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.4
• /
• pp.424-434
• /
• 2009

Statement of problem: Problems such as loosening and fractures of retained screws and fracture of implant fixture have been frequently reported in implant prosthesis. Purpose: Implant has weak mechanical properties against lateral loading compared to vertical occlusal loading, and therefore, stress analysis of implant fixture depending on its material and geometric features is needed. Material and methods: Total 28 of external hexed implants were divided into 7 of 4 groups; Group A (3i, FULL $OSSEOTITE^{(R)}$Implant), Group B (Nobelbiocare, $Br{\aa}nemark$ $System^{(R)}$Mk III Groovy RP), Group C (Neobiotec, $SinusQuick^{TM}$ EB), Group D (Osstem, US-II). The type III gold alloy prostheses were fabricated using adequate UCLA gold abutments. Fixture, abutment screw, and abutment were connected and cross-sectioned vertically. Hardness test was conducted using MXT-$\alpha$. For fatigue fracture test, with MTS 810, the specimens were loaded to the extent of 60-600 N until fracture occurred. The fracture pattern of abutment screw and fixture was observed under scanning electron microscope. A comparative study of stress distribution and fracture area of abutment screw and fixture was carried out through finite element analysis Results: 1. In Vicker's hardness test of abutment screw, the highest value was measured in group A and lowest value was measured in group D. 2. In all implant groups, implant fixture fractures occurred mainly at the 3-4th fixture thread valley where tensile stress was concentrated. When the fatigue life was compared, significant difference was found between the group A, B, C and D (P<.05). 3. The fracture patterns of group B and group D showed complex failure type, a fracture behavior including transverse and longitudinal failure patterns in both fixture and abutment screw. In Group A and C, however, the transverse failure of fixture was only observed. 4. The finite element analysis infers that a fatigue crack started at the fixture surface. Conclusion: The maximum tensile stress was found in the implant fixture at the level of cortical bone. The fatigue fracture occurred when the dead space of implant fixture coincides with jig surface where the maximum tensile stress was generated. To increase implant durability, prevention of surrounding bone resorption is important. However, if the bone resorption progresses to the level of dead space, the frequency of implant fracture would increase. Thus, proper management is needed.