• 대한치과교정학회지
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• 제47권4호
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• pp.229-237
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• 2017

Objective: The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. Methods: Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, and $40^{\circ}$. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. Results: There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was $56.88{\pm}6.72%$. Conclusions: Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

• 대한기계학회논문집B
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• 제40권5호
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• pp.305-311
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• 2016

유도가열은 유도전류를 이용하여 도체에 열을 가하는 방식이다. 유도가열은 열을 가하고자 하는 물체 내부에서 열이 발생하고, 비접촉이며 안전하기 때문에 산업이나 의료분야에서 광범위하게 사용되고 있다. 최근에 형상기억합금을 사용하여 열에 의해 인공치아가 임플란트에서 쉽게 빠질 수 있게 하는 임플란트 시스템이 개발되었다. 본 논문에서는 새로운 임플란트 시스템에서 인공치아를 쉽게 제거할 수 있는 유도가열 장치를 개발하였다. 먼저 전자장-열 구조 유한요소 연성 해석을 통해 다양한 입력 전류와 코일 형상에 대해 온도를 시뮬레이션 상으로 확인해보았다. 해석 결과를 토대로 유도가열장치 시작품을 제작하여 실험을 통해 86초에 인공 치아가 분리됨을 확인하였다.

• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.41-57
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• 2001

It is well known that the apposition of bone at implant surface would be influenced by the microstructure of titanium implants. The purpose of this study was to compare bone healing around the screw-shaped titanium implant with three different surface topographies in the canine mandibles by histological and biomechanical evaluation. All mandibular premolars of six mongrel dogs were extracted and implants were placed one month later. The pure titanium implants had different surface topographies: smooth and machined ($Steri-OSS^{(R)}$: Group II); sandblasted and acid-etched ($ITI^{(R)}$, SLA: Group III) surface. The fluorescent dyes were injected on the 2nd (calcein), 4th (oxytetracycline HCI) and 12th (alizarin red) weeks of healing. Dogs were sacrificed at 4 and 12 weeks after implantation. The decalcified and undecalcified specimens were prepared for histological and histo-metrical evaluation of implant-bone contact. Some specimens at 12 weeks after implantation were used for removal torque testing. Histologically, direct bone apposition to implant surface was found in all of the treated groups. More mature and dense bone was observed at the implant-bone interface at 12 weeks than that at 4 weeks after implantation. Under the fluorescent microscope, thick regular green fluorescent lines which mean early bone apposition were observed at the implant-bone interface in Group III, while yellow and red fluorescent areas were found at the implant-bone interface in Group I and II. The average implant-bone contact ratios at 4 weeks of healing were 54.3% in Group I, 57.7% in Group II and 66.2% in Group III. In Group I, implant-bone contact ratio was significantly lower than Group II and III(p<0.05). The average implant-to-bone contact ratios at 12 weeks after implantation were 64.3% in Group I, 66.7% in Group II and 71.2% in Group III. There was no significant difference among the three groups. In Group I and II, the implant-bone contact ratio at 12 weeks increased significantly in comparison to ratio at 4 weeks(p<0.05). The removal torque values at 12 weeks after implantation were 90.9 Ncm in Group I, 81.6 Ncm in Group II and 77.1 Ncm in Group III, which were significantly different(p<0.05). These results suggest that bone healing begin earlier and be better around the surface-treated implants compared to the smooth surface implants. The sandblasted and acid-etched implants showed the most favorable bone response among the three groups during the early healing stage and could reduce the waiting period prior to implant loading.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.309-320
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• 2007

Purpose: This study was to evaluate the removal effect on artificial plaque from RBM treated implant surfaces that are exposed due to peri-implantitis. Materials and methods: Artificial plaque with Streptococcus mutans and acquired pellicle adhered to RBM treated implant discs. Study materials divided into one control and six test groups. In test groups, physical and chemical methods used to remove plaques. Prophyflex, Professional Mechanical Tooth Cleaning (PMTC) and interdental brush as mechanical treatments and 0.1% Chlorhexidine, Citric acid, HCl tetracycline as a chemical treatment were used. To analyses the study, disc weight was measured for remaining plaque quantities and SEM(Scanning Electronic Microscope) findings was taken for evaluation of surfaces. Results: 1. In weight changes, there was significant difference between each treatment group and the control group (p<0.05). Therefore all treatment methods using this study have good ability for remove plaques. 2. In weight changes, there was no significant difference between mechanical and chemical group, and there were no significant differences between each groups (p>0.05). 3. SEM findings after mechanical treatment disclosed as follows; Prophyflex group looked like sound implant surface, and there were some paste on implant surface at PMTC group, and there were some artificial plaque at interdental brush group. 4. SEM findings after chemical treatment disclosed as follows; there were some dark lesions which were supposed as the product from Streptococcus mutans at Chlorhexidine, Citric acid and HCl tetracycline groups. Conclusion: All six methods using in this study have good ability to remove artificial plaque on RBM treated implant. According to SEM findings, prophyflex is a superior method for removing of dental plaque among test groups.

• 대한치과교정학회지
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• 제36권4호
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• pp.275-283
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• 2006

작은 크기의 교정용 미니임플랜트는 교정적 고정원으로 널리 이용되고 있다. 그러나 빈번히 탈락하는 단점이 있어 이를 개선하기 위해 안정성을 향상시키기 위한 다양한 연구가 시도되어 왔다. 이 연구의 목적은 이중 피치와 직경에 관련하여 미니임플랜트의 안정성에 대한 기계적 성질을 비교 분석하는 것이다. 미니임플랜트의 길이는 8 mm였으며, 피치는 단일 피치형과 이중 피치형, 직경은 1.4 mm와 1.6 mm로 단일 피치형 1.4 mm, 단일 피치형 1.6 mm, 이중 피치형 1.4 mm, 이중 피치형 1.6 mm 등 총 4군으로 구성되었다. 각 군은 20개의 미니임플랜트로 구성되었고, 균일한 밀도의 polyurethane foam에 삽입 후 제거하였다. 시간에 따른 삽입 및 제거 토크의 변화와 각각의 최대 토크 등을 측정하여 기계적 성질을 비교 분석하였다. 이중 피치형은 단일 피치형보다 유의성 있게 더 낮은 최대 삽입 토크와 더 큰 최대 제거 토크를 보여주었다. 직경 1.6 mm는 1.4 mm보다 유의성 있게 더 큰 최대 삽입 토크와 최대 제거 토크를 보여주었다. 이중 피치형 1.4 mm군은 삽입 시에는 유의성 있게 가장 낮은 최대 삽입 토크를 보여주었으며 제거 시에는 단일 피치형 1.6 mm군보다 높거나 비슷한 최대 제거 토크를 보여주었다. 특히, 이중 피치형군은 최대 제거 토크 후 지속적으로 높은 제거 토크를 보여주었다. 미니임플랜트의 기계적 안정성은 이중 피치에 의해 향상될 수 있으며, 상부의 미세 나사산은 작은 직경에서도 풀림 토크에 저항하는 기계적 안정성을 향상시킬 수 있을 것으로 보인다.

• 대한구강악안면임플란트학회지
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• 제22권4호
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• pp.242-254
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• 2018

The aim of the current study was to evaluate the results of horizontal guided bone regeneration (GBR) with xenograf t (deproteinized bovine bone mineral, DBBM), allograf t (irradiated allogenic cancellous bone and marrow), titanium membrane, resorbable collagen membrane, and advanced platelet-rich fibrin (A-PRF) in the anterior maxilla. The titanium membrane was used in this study has a three-dimensional (3D) shape that can cover ridge defects. Case 1. A 32-year-old female patient presented with discomfort due to mobility and pus discharge on tooth #11. Three months after extracting tooth #11, diagnostic software (R2 GATE diagnostic software, Megagen, Daegu, Korea) was used to establish the treatment plan for implant placement. At the first stage of implant surgery, GBR for horizontal augmentation was performed with DBBM ($Bio-Oss^{(R)}$, Geistlich, Wolhusen, Switzerland), irradiated allogenic cancellous bone and marrow (ICB $cancellous^{(R)}$, Rocky Mountain Tissue Bank, Denver, USA), 3D-titanium membrane ($i-Gen^{(R)}$, Megagen, Daegu, Korea), resorbable collagen membrane (Collagen $membrane^{(R)}$, Genoss, Suwon, Korea), and A-PRF because there was approximately 4 mm labial dehiscence after implant placement. Five months after placing the implant, the second stage of implant surgery was performed, and healing abutment was connected after removal of the 3D-titanium membrane. Five months after the second stage of implant surgery was done, the final prosthesis was then delivered. Case 2. A 35-year-old female patient presented with discomfort due to pain and mobility of implant #21. Removal of implant #21 fixture was planned simultaneously with placement of the new implant fixture. At the first stage of implant surgery, GBR for horizontal augmentation was performed with DBBM ($Bio-Oss^{(R)}$), irradiated allogenic cancellous bone and marrow (ICB $cancellous^{(R)}$), 3D-titanium membrane ($i-Gen^{(R)}$), resorbable collagen membrane (Ossix $plus^{(R)}$, Datum, Telrad, Israel), and A-PRF because there was approximately 7 mm labial dehiscence after implant placement. At the second stage of implant surgery six months after implant placement, healing abutment was connected after removing the 3D-titanium membrane. Nine months after the second stage of implant surgery was done, the final prosthesis was then delivered. In these two clinical cases, wound healing of the operation sites was uneventful. All implants were clinically stable without inflammation or additional bone loss, and there was no discomfort to the patient. With the non-resorbable titanium membrane, the ability of bone formation in the space was stably maintained in three dimensions, and A-PRF might influence soft tissue healing. This limited study suggests that aesthetic results can be achieved with GBR using 3D-titanium membrane and A-PRF in the anterior maxilla. However, long-term follow-up evaluation should be performed.

• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.209-231
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• 1999

Even though titanium(Ti) and its alloys are the most used dental implant materials, there are some problems that Ti wears easily and interferes normal osteogenesis due to the metal ions. Ti coated with bioactive ceramics such as hydroxyapatite has also such problems as the exfoliation or resorption of the coated layer, Recent studies on implant materials have been proceeding to improve physical properties of the implant substrate and biocompatibility of the implant surfaces. The purpose of the present study was to examine the physical property and bone tissue compatibility of bioinert nitrides ion plated Ti, Button type specimens(14mm in diameter, 2.32rrun in height) for the abrasion test and cytotoxicity test and thread type implants(3.75mm in diameter, 6mm in length) for the animal experiments were made from Ti(grade 2) and 316LVM stainless steel. Ti specimens were ion plated with TiN, ZrN by the low temperature arc vapor deposition, and the depth profile of the TiN/Ti, ZrN/Ti ion plated surface was examined by Auger Electron Spectroscopy. Three kind of button type specimens .of TiN/Ti, ZrN/Ti and Ti were used for abrasion test, and HEPAlClC7 cells and CCD cells were cultivated for 4 days with the specimens for cytotoxicity test. Thread type implants of TiN/Ti, ZrN/Ti, Ti, 316LVM were implanted on the femur of 6 adult dogs weighing 10kg-13kg. Two dogs were sacrified for histological examination after 45 days and 90 days, and four dogs were sacrified for the removal torque test of the implant') after 90 days. The removal torque force was measured by Autograph (Shimadzu Co., AGS-1000D series, Japan). Abrasion resistance of TiN/Ti was the highest, and that of ZrN/Ti and Ti were followed. The bioinert nitride ion plated Ti had much better abrasion resistance, compared with Ti, In the cytotoxicity test, the number of both cells were increased in all specimens, and there were no significant difference in cytotoxic reaction among all groups (p>0.1), In histological examination, 316LVM showed the soft tissue engagement in interface between the implant and bone, but the other materials after 45 days noted immature new bone formation in the medullary portion along the implant surface, and those after 90 days showed implant support by new bone formation in both the cortical and the medullary portion, The removal torque force of Tilv/Ti showed significantly higher than that of Ti(p(O,05). The difference in removal torque force between TiN/Ti and ZrN/Ti was not significant(p>0.05), and that of 316LVM was lowest among all groups(p<0.05). These results suggest that bioinert nitrides ion plated Ti can resolve the existing problems of Ti and bioactive ceramics, and it may be clinically applicable to human.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.177-193
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• 2004

Several experimental studies showed that the application of small amounts of electric current to bone stimulated osteogenesis at the site of the cathode and suggested that electrical currents promote osseointegration around dental implants. The purpose of this study was to determine the effect of direct microcurrent to endosseous titanium implants placed in bone defects. The right and left 2nd, 3rd and 4th mandibular premolars in ten mongrel dogs (15Kg of weight) were extracted. One monthe later, Ti-machined screw type implants(3.8 mm diameter x 8.5 mm length, $AVANA^{(R)}$, Ostem) were placed in surgically created circumferential defect area(width 5mm, depth 4mm). The implants were divided into three groups according to the treatment modalities: Control group- implants without electrical stimulation; Experimental group I- implants with allogenic demineralized freeze dried bone grafting; and Experimental group II-implants allogenic demineralized freeze dried bone grafting and electric stimulation. The animals were sacrificed in the 4th and 8th week after implant placement and un-decalcified specimens were prepared for histological and histometrical evaluation of bone-implant contact ratio (BIC) and bone formation area ratio (BFA) in defect area. Some specimens at 8 weeks after implantation were used for removal torque testing. Histologically, there was connective tissue infiltration in the coronal part of defect area in control and the experimental group I, whereas direct bone contact was found in the experimental group II without connective tissue invasion. Average BIC ratios at 4 weeks of healing were 60.1% in the experimental group II, 47.4% in the experimental group I and 42.7% in the control. Average BIC ratios at 8 weeks after implantation were 67.6% in the experimental group II, 55.9% in the experimental group I and 54.6% in the control. The average BFA ratio was 84.0% in the experimental group II, 71.8% in the experimental group I and 58.8% in the control at 4 weeks, and the BFA ratios were 89.6% in the experimental group II, 81.4% in the experimental group I and 70.5% in the control at 8 weeks after implantation. The experimental group II showed also significantly greater BIC and BFA ratios compared to the control and the experimental group I (p<0.05). The removal torque values at 8 weeks after implantation were 56 Ncm in the experimental group II, 49 Ncm in the experimental group I and 43 Ncm in the control. There was a statistically significant difference among 3 groups (p<0.05). These results suggest that electrical stimulation improve and accelerate bone healing around endosseous titanium implants in bone defect.

• 대한치과보철학회지
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• 제44권4호
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• pp.432-442
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• 2006

Statement of problem: One of common problems associated with dental implant is the loosening of abutment screws that retain the implants. Purpose : This study was performed to investigate the influence of abutment screw length and repeated tightening on screw loosening in dental implant. Material and method: Forty nine Hexplants (13mm length, 4.3mm diameter, Ti grade IV, Warantec. Co. Ltd. Seongnam, Korea) and cementation type abutments(straight abutment) and abutment screws (0.4mm/pitch) were divided into 7 groups, depending on abutment screw length. Each implant and abutment was tightened to 30Ncm by torque controller(MGT50, MARK-10 Inc., USA) and the removal torque values were measured during 10 consecutive closure/opening trials. Results and Conclusion: The results of comparing the removal torque value are as follows : 1. There is no significant difference in the removal torque value between groups in 10 consecutive closure/opening trials (p = 0.97). 2. If the fractured abutment screw is engaged in longer than 2.425 thread length, there is no significant difference in the preload between the fractured abutment screw and the new abutment screw when both are equally tightened to 30 Ncm. 3. The removal torque value in the 1st trial(24.510 Ncm) was lower than that in the 2nd, 3rd, 4th, 5th, 6th, 7th trials and the removal torque value in the 2nd trials(25.551 Ncm) was maximum and was decreased in 1311owing trials. The removal torque value in the 1st trial was significantly lower than that in the 2nd, 3rd, 4th trials and was significantly higher than that in the 8th, 9th, l0th trials(p<0.05). 4. In the 2nd, 3rd, 4th, 5th, 6th, 7th trials, the abutment screw was mainly influenced by settling effect and the higher preload was obtained In the 8th, 9th, l0th trials, the abutment screw was mainly influenced by adhesive wear and the progressively lower preload was obtained.

• 구강회복응용과학지
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• 제30권3호
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• pp.253-258
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• 2014

본 증례는 상악 구치부에서 실패한 임플란트 제거 후 깊은 나사선을 갖는 직경이 큰 임플란트를 식립 후 조기하중을 가한 증례이다. 1년 경과 후, 임플란트 안정성 지수에서 안정적인 결과를 보였다. 본 임상증례는 상악 구치부에서 깊은 나사선을 갖는 임플란트를 이용한 조기하중의 가능성을 보여준다.