• The korean journal of orthodontics
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• v.35 no.1 s.108
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• pp.35-42
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• 2005

There is lack of data for the amount of vertical bone in the midpalatal region for miniscrew implantation. The purpose of this study was to measure the structure of the midpalatal suture area using CT image and V-works 4.0 program (Cybermed Inc, Seoul, Korea). CT images of 14 male and 14 female adults were reconstructed. In detail, it was 1) to measure the length of maxilla on the midsagittal plane 2) to measure vertical bone height in the midpalatal area 3) to establish the zone of safety for miniscrew implantation. The following results were obtained. The mean length of ANS-PNS was 51.08mm in males and 47.34mm in females. There was a statistically significant difference between males and females (p<0.05). The vertical bone height of the midpalatal suture area was above 0mm except for 6mm posterior from the central Point of ANS-PNS in males The zone of safety was located 19.43mm posterior from the ANS in males while it was 17.62mm in females along the palatal plane. These results support that the safety zone of the midpalatal area is suitable for screw implantation. Midpalatal miniscrew implantation is a powerful tool in modern orthodontics Through many applications. it can expand the modern orthodontic field.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.811-822
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• 2001

최근 임플란트를 원하고, 필요로 하는 환자가 증가하면서 술전의 정확한 진단이 보다 중요해졌고 다양한 진단방법이 소개되고 이용되어져 왔다. 그 중 보편적으로 가장 널리 사용되어지는 방법이 방사선 촬영법이고 그 중에서도 파노라마방사선사진이다. 하지만 파노라마방사선사진의 용이함과 간편성에도 불구하고 그 방법 자체가 가지고 있는 한계점 때문에 CT/MPR(Computer Tomography/Multiplanar Reformatting)이 일부 환자에서는 반드시 필요하다는 주장이 대다수이다. 본 연구의 목적은 하악 구치부에 임플란트 시술을 받은 환자를 대상으로 파노라마방사선사진의 확대율을 알아보고 파노라마방사선사진과 CT/MPR에서 치조정-하악관간 거리가 실제 어느 정도 차이를 보이는지, 그리고 CT/MPR에 대한 파노라마방사선사진의 확대율에 환자의 하악골의 경사도와 하악관의 해부학적 위치가 어떤 영향을 미치는지를 알아보는 것이다. 본 연구는 서울대학 치과병원 치주과를 내원하여 하악구치부에 Dental Implant 시술을 받은 15명의 환자, 32개 부위를 대상으로, 임플란트 시술을 위한 술전 파노라마방사선사진과 CT/MPR, 술후의 파노라마방사선사진, CT/MPR상을 자료로, 임플란트가 식립될 위치에서 치조정에서 하악관의 길이, 하악골의 협설폭경, 하악골의 설측면에서 하악관의 수평길이, 임플란트 매식체의 설측에서 하악관까지의 수평거리를 계측하였고 이 해부학적 계측치들이 CT/MPR에 대한 파노라마방사선사진의 확대율과 어떤 상관관계에 있는지 Pearson's correlation coefficient test를 이용해 살펴보았다. 1. CT/MPR에 대한 파노라마방사선사진의 확대율은 CT/MPR상에서 하악골 단면의 협설폭경(Pearson test에서의 상관관계 분석시, 상관계수 r=-0.604), 임플란트 매식체의 설측에서 하악관까지의 수평거리(r=-0.515), 하악골의 설측면에서 하악관까지의 수평거리(r=-0.640)와 뚜렷한 음적 선형관계가 있었다. 2. CT/MPR에 대한 파노라마방사선사진의 확대율은 CT/MPR상에서 하악골의 장축의 각도와는 뚜렷한 양적 선형관계(Pearson test에서의 상관관계 분석시, 상관계수 r=-0.446)가 있었다. 3. 여러 요소중 CT/MPR에 대한 파노라마방사선사진의 확대율과 가장 유의성있는 연관성을 보이는 것은 CT/MPR상에서 하악골의 설측면에서 하악관까지의 수평거리였다(r=-0.640) 4. CT/MPR에 대한 파노라마방사선사진의 확대율은 일반적으로 생각되어지는 파노라마방사선사진의 확대율 125%보다 큰, 약 135%로 나왔다. 이상의 결과로 볼 때, 하악골의 설측면에서 하악관까지의 수평거리가 CT/MPR에 대한 파노라마방사선사진의 확대율에 가장 영향을 미치는 요소로 추정되며 확대율은 125%보다 높은 것으로 나타났다.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.59-68
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• 2010

Recently, dental implants extensively inserted on edentulous area show highly clinical success rate. However, clinicians cannot exclude the possibility of failure and it often unexpectively occures. Many possible factors associated with failure of dental implants have been reported but controversy exists over the extent to them. In this study, we collected 212 patients who had been inserted 358 dental implants on mandibular premolar and molar area from 2005 to 2006. The survival rate of fixtures was recorded according to age of patients, implantation site, implant system, diameter and length of fixtures. Multi-variable analysis using SPSS chi-square test was operated to verify relation of each factors and survival rates. Accumulative survival rate was 98.3% for 3 years. Only diameter of fixtures was related to the implant survival rate. This may be thought that wider fixtures had been chosen to rescue implants or used in sites of poor bone quality. Further continuous study will be needed for direct guidance associated with survival rate of implants.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.246-252
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• 2016

Double crown prostheses can be used in patients who have a few remaining teeth and poor periodontal condition because of secondary splinting of abutments, vertical loading, decrease of the length of lever arm due to fulcrum line located on margin of inner and outer crown. Successful results of treatments using double crown prostheses for the partially edentulous patients who have a few remaining teeth and implant overdenture using a small number of implants have been reported. In this case, there were a few remaining teeth with a very poor periodontal condition in maxilla, and there were a failed implant with severe alveolar bone resorption and shrinkage in the mandible. The main objective of this report is to introduce our case because a double crown partial denture showed satisfactory results in functional and esthetical aspects during more than one-year follow-up period.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.239.2-239.2
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• 2011

치과재료의 개발은 치과 치료 기술에 있어서 가장 중요한 요소이며, 현재 일반화되고 있는 치과 치료 기술 중 하나가 임플란트 시술이다. 임플란트의 기술 개발은 주로 임플란트 나사의 표면개질을 통한 기능개선에 초점을 ��추어 진행되어지고 있다. 본 연구에서는 Ti 임플란트 표면상에 양극산화법을 적용하여 다양한 지름 및 기공 크기를 갖는 $TiO_2$ 나노튜브를 제조하여 전자빔 조사를 통한 표면개질시 그 특성에 관한 연구를 수행하였다. 특히 전자빔 조사가 Ti/$TiO_2$ 나노튜브 표면상에 존재 가능한 조골세포의 성장 특성에 미치는 영향을 연구하였다. 양극산화법을 이용한 Ti/$TiO_2$ 나노튜브는 전해질로서 HF와 $NH_4F$를 사용하였으며, 20-80 V의 인가 전압하에서 내경 약 80 nm, 외경 약 124 nm 및 길이 약 280 nm-14 ${\mu}m$의 비교적 균질한 지름 및 분포를 갖는 Ti/$TiO_2$ 나노튜브를 제조하였다. 전자빔 조사는 EB-Tech (대전, 한국)의 electron-beam accelerator(Model ELV-4)를 이용하였으며, 1.0 MeV의 빔 에너지로 총 흡수선량이 50 kGy, 500 kGy 및 5,000 kGy로 조사하였다. 전자빔을 조사하기 전 후 Ti/$TiO_2$ 나노튜브 표면상에 조골세포주(Osteoblast cell)의 배양시간의 변화에 따른 효과를 연구한 결과 배양 전 후 전자빔 조사선량의 증가에 따라 조골세포의 흡착률이 증가함을 확인할 수 있었다. 특히 HF전해질을 이용한 $TiO_2$ 나노튜브의 경우 5,000 kGy 조사선량의 전자빔을 조사한 후 조골세포 흡착률이 약 160% 증가하는 결과를 얻을 수 있었다. 전자빔 조사 전 후 조골세포 흡착률의 변화원인은 전자빔 조사 유무에 따른 $Ti^{3+}$와 $Ti^{4+}$의 변화에 기인함을 규명하였다. 이러한 결과는 향후 임플란트용 Ti/$TiO_2$ 나노튜브의 표면 개질시 전자빔의 유용성을 제시한다고 할 수 있다.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.34-41
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• 2014

Purpose: In this study, the diameter of each implant driver was measured and compared to find out the compatibility of implant drivers. Materials and methods: Drivers from 12 implant systems being used in Dankook University Dental Hospital were included in this study. The shapes of the implant drivers were segregated, and the effective length and the diameter of upper, middle, lower part of driver tips were measured (n=10). The measured data were mathematically analyzed for its compatibility. Results: A driver with the smallest diameter (1.17 mm) had the highest compatibility at the upper part of driver tip. This driver could be used for a bigger driver up to 1.35 mm in diameter. There were several driver groups which had the same diameter so as to be interchangeable each other. In the middle part, the smallest diameter measured was 1.2 mm and this was able to replace a driver up to 1.40 mm diameter. Since the diameter generally became thicker from upper part (the tip of driver) to the lower part (the shank of driver), some drivers with bigger diameter at the upper part so which was failed to show any compatibility became compatible with a driver which had smaller diameter at the upper part but wider in the middle part. The compatibility of torx shape drivers were affected by the inner diameter of the drivers not only by the outer diameter. Furthermore, the inner diameter of torx drivers decided the compatibility between torx and hex drivers. Conclusion: From the study it was found that compatibility in drivers existed among certain implant systems and to check its compatibility the diameter at a certain effective length should be measured. However, there has been not enough studies about long-term use of compatible drivers, so effects of using compatible drivers on drivers and implants are unknown. Therefore, usage in inevitable cases only is recommended and further study is needed.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.289-295
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• 2020

Improving implant esthetics is very difficult, especially in cases where unaesthetic problems are related to implants in the maxillary anterior dentition. A 69-year old male patient was referred by a prosthodontist for periodic pus discharge and an unaesthetic implant prosthesis (maxillary right lateral incisor). The implant was placed too deeply and showed soft tissue volume deficiency and a long clinical crown. After a clinical and radiographic examination, implant submergence and alveolar ridge augmentation were performed to enhance the aesthetics instead of an explantation. The treatment plan was as follows: extraction the adjacent teeth with tooth mobility, secondary caries, and poor prognosis; placement an additional dental implant with hard and soft tissue grafting; fabrication a fixed bridge using implant abutments. A fixed esthetic prosthesis using implants was fabricated, and the patient was satisfied with the prosthesis. A ridge augmentation with implant submergence may be an alternative for solving the problems of unaesthetic implant restorations in the esthetic zone.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.279-286
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• 2014

Purpose: The aim of this study was to investigate the effect of implant thread profile on the marginal bone stresses which develop during implant insertion. Materials and methods: Four experimental implants were created by placing four different thread systems on the body ($4.1mm{\times}10mm$) of the ITI standard implant. The thread types studied in this study included the buttress, v-shape, reverse buttress, and square shape threads. In order to examine the insertion stress generation, 3D dynamic finite element analysis was performed which simulated the insertion process of implants into a 1.2 mm thick cortical bone plate (containing 3.5 mm pilot hole) using a PC-based DEFORM 3D (ver 6.1, SFTC, Columbus, OH, USA) program. Results: Insertion stresses higher than human cortical bone developed around the implants. The level of insertion stresses was much different depending on the thread. Stress level was lowest near the v-shape thread, and highest near the square shaped thread. Difference in the interfacial bone stress level was more noticeable near the valley than the tip of the threads. Conclusion: Among the four threads, the v-shape thread was turned out to minimize the insertion stress level and thereby create better conditions for implant osseointegration.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.266-272
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• 2010

Purpose: The purpose of this study was to investigate the effects of the surface morphology of the implant neck on marginal bone stress measured by using finite element analysis in six implant models. Materials and methods: The submerged type rescue implant system (Dentis co., Daegu, Korea) was selected as an experimental model. The implants were divided into six groups whose implant necks were differently designed in terms of height (h, 0.4 and 1.0 mm) and width (platform width, w = 3.34 + 2b [b, 0.2, 0.3 and 0.4 mm]). Finite element models of implant/bone complex were created using an axisymmetric scheme. A load of 100 N was applied to the central node on the top of crown in parallel with the implant axis. The maximum compression stress was calculated and compared. Results: Stress concentration commonly observed around dental implants did not occur in the marginal bone around all six test implant models. Marginal bone stress varied according to the implant neck bevel which had different width and height. The stress was affected more markedly by the difference in height than in width. Conclusion: This result indicates that the implant neck bevel may play an important role in improving stress distribution in the marginal bone area.

• 대한치과보철학회:학술대회논문집
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• 1995.12a
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• pp.26-26
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• 1995