• 구강회복응용과학지
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• 제24권1호
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• pp.41-56
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• 2008

상용 임플란트의 표면을 개질하기 위해 물리적, 화학적 방법을 이용한 새로운 표면이 증가하고 있으며 이에 대한 골반응도 다를 것으로 예상할 수 있지만 대부분의 연구는 단순히 기계절삭형 임플란트와의 비교만을 하고 있다. 본 연구에서는 4종의 다른 개질된 표면을 가진 상용 임플란트를 가토의 경골에 식립한 후 생역학적, 조직형태학적으로 비교하였다. 연구 결과, 모든 임플란트는 6주 후 안정적인 골유착을 이루고 있었으며 4종의 표면개질의 차이에 의한 공진주파수 및 조직형태학적 골반응의 차이는 없었으며 표면개질을 비교하기 위해 피질골 하방으로 증식한 골을 비교하는 것이 유용하였다. 생역학적, 조직형태학적 골반응에 비해 미세단층촬영(micro-CT)를 이용하는 비교법은 유용성과 정확도가 낮은 것으로 나타났다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제19권1호
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• pp.35-44
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• 1997

The most critical factor in determining which type of implant to be used would be the available bone of the patient. Usually a minimum of 5mm in the bone width and 8mm in the bone height is necessary to ensure primary implant stability and maintain the integrity of bone contact surface. Placement of implant is limited by the several anatomic strutures such as maxillary sinus, floor of the nose, inferior alveolar neurovascular bundle and nasopalatine foramen, etc. When severe resorption of alveolar ridge is encountered, implant placement would be a problematic procedure. A number of techniques to improve the poor anatomic situations have been proposed. This article reports 4 cases of patients using surgical procedures such as blade implant technique, cortical split technique in the anterior maxillary area, sinus lifting and lateral repositioning of inferior alveolar nerve, We treated dental implant candidates with unfavorable alveolar ridge utilizing various surgical techniques, resulted in successful rehabilitation of edentulous ridge.

• Journal of Periodontal and Implant Science
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• 제33권4호
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• pp.651-671
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• 2003

The influence of calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated two types of titanium implants, i.e. as -machined ,as -machined with Ca-P coating, were prepared. The Ca-P coating produced by OCT Inc technique. These implants were inserted into the left and right femur of beagle dog, After implantation periods of 3 days, 1weeks, weeks, 4weeks, 8weeks, 12weeks. 24weeks, the bone-implant interface was evaluated histologically, histomorphometrically , and removal torque. Histological evaluation revealed no new bone formation around different implant materials after 2weeks of implantation. After 4 weeks, Ca-P coated implants showed a higher amount of bone contact than either of the non coated implants. After 12weeks, bone healing was almost completed. And implant were removed by reverse torque rotation with torque-measuring device. Mean torque values for 4weeks control were 2.375Kgf.cm and experimental were 2.725Kgf.cm. And mean torque values for 8weeks control were 1.25Kgf.cm and experimental were 1.0Kgf.cm On the basis of these findings, we concluded that deposition of a Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase. Besides implant surface conditions the bone response is also determined by local implant site condition.

• 대한치과보철학회지
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• 제41권2호
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• pp.169-181
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• 2003

Statement of problem : The survival rate of wide diameter implants was lower than of 3.75-mm implants in some clinical researches. Purpose : The purpose of this study was to investigate the influence of implant diameter on the osseointegration of implants in the rabbit femoral condyle and tibial metaphyses by means of removal torque measurements and histomorphometric analysis. Material and Method : Ten adult New Zealand White rabbits were used in this study Two 3.75-mm diameter implants were inserted through one cortical layer in the tibial metaphyses and one 3.75-mm diameter implant was inserted in the femoral condyle. 5.0-mm diameter implants were inserted in the other leg in the same manner. A total of 60 implants (3.75-mm diameter implants:30 : 5.0-mm diameter implants:30) were installed. After a healing time of 4 and 12 weeks, the peak removal torque values required to shear off the implants were recorded. From the removal torque values (Ncm) obtained, the mean shear stress ($N/mm^2$) was calculated. And the percentage of direct bone-to-implant contact and the percentage of bone area inside the thread were measured by Kappa Image Base-metreo. The Student's t-test was undertaken for statistical analysis (p<0.05). Results : The removal torque value of 5.0-mm diameter implants was higher than of 3.75-mm diameter implants (p<0.05). The difference of shear stress value between 3.75-mm and 5.0-mm diameter implants was not statistically significant (p>0.05). The percentage direct bone-to-implant contact had no statistical difference between two groups (p>0.05). The percentage of bone area inside the thread had no statistical difference between two groups (p>0.05). Conclusion It is concluded that the quality f osseointegration is not influenced by increasing implant diameter.

• 구강회복응용과학지
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• 제23권1호
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• pp.21-30
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• 2007

Despite of the successful clinical performance of implants, it is still lacking of the knowledge of changes in implant occlusion. The purpose of this study was to evaluate the changes of infraocclusal contact after clinical occlusal function of implant. Twenty patients(38 implants) were recalled during 10 months after placement of implant prosthesis. Occlusion changes were investigated at placement, placement 1 months, 4 months and 10 months serially with silicone bite material and T-Scan II sensor. Bony changes were also evaluated with periapical radiographs. The changes of silicone thickness and T-Scan II sensored areas were statistically analyzed with repeated measured ANOVA and the Scheffe's post-hoc test at the 95% significance level. The following results have been made based on this study: 1. Alveolar bone loss was within 0.20mm and it was generally concluded within physiologic level. 2. There were no statistically significant differences in the thickness changes of silicone material at 1 month and 4 months of occlusal function. However, there was statistically significant difference at 10 months of occlusal function (p<0.05). 3. There was no statistically significant difference in changes of occlusal contact area in T-Scan II at 1 month and 4 months of occlusal function, but there was statistically significant difference at 10 months of occlusal function (p<0.05). Conclusively, as time goes by, implant occlusion to be formed infraocclusion was to be far close and increased occlusal contact. However, it was not observed destructive bone resorption in periapical radiographs and any other side effects.

• 대한치과보철학회지
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• 제29권3호
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• pp.55-74
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• 1991

The purpose of this study was to investigate the influence of early functional load around osseointegrated titanium implants. 24 titanium plasma spray coated implants (ITI HS-type) were placed into the previously extracted site in the mandible of six adult dogs. The implants were divided into three groups : the control group was the implants without abutment during the experimental period; the experimental group I was loaded by connecting the contoured abutment after 6 weeks of healing; the experimental group II was loaded after 12 weeks of healing: and the mandibular second premolar and surrounding tissues were selected for natural tooth group to compare the implanted group. All dogs were injected intravenously tetracycline, alizarin red S, and calcein for bone labeling. After the experimental period of 18 weeks, the dogs were sacrificed and longitudinal sections of the bone-implant interface were cut and observed using light microscope, scanning electron microscope, and fluorescence microscope. The results of the study were as follows: 1. Light and scanning electron microscopically, all implant surfaces were well contact with bone tissue at the cortical layer, but some areas of cancellous bone were not contact directly. 2. Fluorescence microscopically, number and size of the new secondary osteons around the implant were increased than those of the natural tooth. 3. Fluorescence microscopically, linear and concentrical fluorescence was observed at or near the surface of all implants, and the bone formation and remodeling of the implants loaded after 6 week of healing were great, and unloaded implants were worst. 4. Fluorescence microscopically, endosteal bone formation was greater than periosteal bone formation at or near the implants. 5. Fluorescence microscopically, number and size of linear and concentric fluorescence was increased at the lingual side than the buccal side of the loaded implants. The result of the study indicate the possibility of the early load to the implant via a prosthesis.

• Journal of Korean Dental Science
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• 제4권2호
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• pp.67-72
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• 2011

Purpose: This study sought to evaluate the effects of bone graft wedging on the initial stability of implants in bone sites of unfavorable quality. Materials and Methods: Three male beagle dogs were used in this study. Osteotomies were performed with parallel drills (${\O}4.1{\times}10mm$), and fixtures (${\O}3.3{\times}8mm$) were placed. The control group was given implants without bone graft. Experiment group A was given implants with minimal initial stability using autobone grafts, whereas experiment group B was given xenografts. Groups were also divided by healing times at 4, 8, and 12 weeks. Results: All implants in the control group failed to osseointegrate. On the other hand, all implants in the experiment groups were clinically well-maintained during the entire experiment period. After 4, 8, and 12 weeks, bone-to-implant contact (BIC) ratio and implant stability quotient (ISQ) increased in the experiment groups. The differences between experiment groups A and B were not statistically significant, however. Conclusion: In unfavorable bone regions for dental implants, bone graft packing into the osteotomy prior to implant placement secured minimal initial stability and showed reasonable BIC ratios and ISQ values throughout the study period.

• Journal of Periodontal and Implant Science
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• 제46권5호
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• pp.291-302
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• 2016

Purpose: The aim of the present study was to evaluate the effectiveness of using a mineralized bone cortical allograft (MBCA), with or without a resorbable collagenous membrane derived from bovine pericardium, on alveolar bone remodeling after immediate implant placement in a dog model. Methods: Six mongrel dogs were included. The test and control sites were randomly selected. Four biradicular premolars were extracted from the mandible. In control sites, implants without an allograft or membrane were placed immediately in the fresh extraction sockets. In the test sites, an MBCA was placed to fill the gap between the bone socket wall and implant, with or without a resorbable collagenous membrane. Specimens were collected after 1 and 3 months. The amount of residual particles and new bone quality were evaluated by histomorphometry. Results: Few residual graft particles were observed to be closely embedded in the new bone without any contact with the implant surface. The allograft combined with a resorbable collagen membrane limited the resorption of the buccal wall in height and width. The histological quality of the new bone was equivalent to that of the original bone. The MBCA improved the quality of new bone formation, with few residual particles observed at 3 months. Conclusions: The preliminary results of this animal study indicate a real benefit in obtaining new bone as well as in enhancing osseointegration due to the high resorbability of cortical allograft particles, in comparison to the results of xenografts or other biomaterials (mineralized or demineralized cancellous allografts) that have been presented in the literature. Furthermore, the use of an MBCA combined with a collagen membrane in extraction and immediate implant placement limited the extent of post-extraction resorption.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권6호
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• pp.481-491
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• 2005

Purpose: The aim of the present study is to evaluate the effect of autogenous bone and allograft material coverd with a bioresorbable membrane on bone regeneration after a simultaneous installation of implant. Materials and methods: Twelve healthy rabbits, weighing about $3{\sim}4$ kg, were used in this experiment. Following impalnt(with 3.25 mm diameter and 8 mm length) site preparation by surgical protocol of $Oraltronics^{(R)}$, artificial bony defect, 5mm sized in height and depth, was created on femoral condyle using trephine drill(with 5 mm diameter and 5 mm length). Then implant was inserted. In the experimental group A, the bony defect was filled with autogenous particulated bone and coverd with $Lyoplant^{(R)}$ resorbable membrane. In the experimental group B, the bony defect was filled with allograft material(Orthoblast $II^{(R)}$) containing demineralized bone matrix and covered with $Lyoplant^{(R)}$. In the control group, without any graft materials, the bony defect was covered with $Lyoplant^{(R)}$. The experimental group A and B were divided into each 9 cases and control group into 3 cases. The experimental animals were sacrificed at 3, 6 and 8 weeks after surgery and block specimens were obtained. With histologic and histomorphometric analysis, we observed the histologic changes of the cells and bone formation after H-E staining and then, measured BIC and bone density with KAPPA Image $Base^{(R)}$ system. Results: As a result of this experiment, bone formation and active remodeling process were examined in all experimental groups and the control. But, the ability of bone formation of the experimental group A was somewhat better than any other groups. Especially bone to-implant contact fraction ranged from 12.7% to 43.45% in the autogenous bone group and from 9.02% to 29.83% in DBM group, at 3 and 8 weeks. But, bone density ranged from 15.67% to 23.17% in the autogenous bone group and from 25.95% to 46.06% in DBM group at 3 and 6 weeks, respectively. Although the bone density of DBM group was better than that of autogenous bone group at 3 and 6weeks, the latter was better than the former at 8 weeks, 54.3% and 45.1%, respectively. Therefore these results showed that DBM enhanced the density of newly formed bone at least initially.

• 대한의용생체공학회:의공학회지
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• 제21권3호
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• pp.295-301
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• 2000

뼈의 성장에 미치는 많은 요소들 중에서 implant의 상대적인 미세운동(relative micromotion)은 뼈의 implant와의 접합을 방해하는 것으로 알려져 왔다. 그런데 이러한 상대적인 운동 및 spinal stability에 직접적으로 영향을 주는 하중조건, spinal material의 물성치, spinal geometry 및 뼈와 implant의 접촉면에서의 마찰계수를 고려하기 위하여, 하나의 titanium interbody cage 가 삽입된 human lumbar segments (L4-L5)의 유한요소 모델이 개발되었다. 이러한 유한요소 모델의 해석을 통하여 상대적인 미세운동, Posterior의 수직적인 변위, von Mises 응력 및 마찰력이 예측되었다. Cancellous bone. annulus fibers 및 ligaments의 기계적인 물성치의 감소 또는 접촉면에서의 마찰계수의 감소는 상대적인 미세운동 (relative micromotion or slip distance)을 증가 시켰다. 접촉면에서의 normal force는 뼈의 밀도 (cancellous bone density) 가 감소하거나 접촉마찰계수가 증가하면 감소했다. 특히 하중조건에 있어서, compressive preload에 대한 torsion의 추가는 접촉면의 anterior부위에서 상대적인 미세운동을 증가 시켰다. 하지만 디스크면적이 증가할수록 상대적인 미세운동은 감소했다. 결론적으로, 접촉면의 기계공학적 거동 (Relative micromotion, stress response, posterior axial displacement and contact normal force)은 접촉면의 마찰계수 뼈의 밀도, 하중조건 및 노화에 따른 형상/물성의 변화에 매우 민감함을 보이고있다.