• 대한치과보철학회지
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• 제56권2호
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• pp.114-119
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• 2018

목적: 원광대학교 치과대학병원 임플란트 센터에서 임플란트를 식립한 후 1주일 내에 임시보철물을 수복한 다음, 즉시 하중을 가한 환자들을 대상으로 골 흡수량을 측정하고자 하였다. 이러한 후향적 분석을 통하여 임플란트에 대한 즉시 하중의 임상적 근거를 보강하고 주의해야 할 사항 등을 파악하고자 하였다. 대상 및 방법: 2005년 1월 1일부터 2016년 6월 31일 사이에 원광대학교 치과대학병원 임플란트 센터에서 임플란트를 식립한 후 1주일 내에 임시보철물을 수복한 환자들을 대상으로 하여 진료기록부와 방사선 사진을 조사하였다. 총 임플란트의 수는 70개였으며, 임플란트의 제조회사, 길이, 직경, 체결 방식에 따른 변연골의 흡수량을 측정하였다. 변연골의 흡수량을 측정하기 위해 임플란트 식립 직후와 6개월 이후의 치근단 방사선 사진을 비교 분석하였다. 통계 프로그램인 SPSS 22.0을 이용하여 Mann-whitney U test와 Kruskal-wallis test를 시행하였다. 결과: 즉시 하중 임플란트 군에서 임플란트와 지대주의 연결 구조에 따른 변연골 흡수량을 비교한 결과 내부 육각 연결 구조 임플란트에서의 변연골 흡수량은 평균 $1.24{\pm}0.72mm$, 외부 육각 연결 구조 임플란트에서 $1.73{\pm}1.27mm$로 나타났으며 통계적으로 유의한 차이를 보였다. 임플란트 제조회사, 길이, 직경에 따른 변연골 흡수량의 차이는 통계적으로 유의한 차이를 보이지 않았다. 결론: 즉시 하중 임플란트에서 내부 육각 연결 구조 임플란트에서의 변연골 흡수량은 외부 육각 연결 구조 임플란트에서의 변연골 흡수량보다 적게 나타났으며, 임플란트의 다른 조건들에서는 변연골 흡수량에 차이를 보이지 않았다.

• 대한치과보철학회지
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• 제42권4호
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• pp.397-411
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• 2004

Purpose: The purpose of this study was to determine the effect of anchorage systems and palatal coverage of denture base on load transfer in maxillary implant-supported overdenture. Material and methods: Maxillary implant -supported overdentures in which 4 implants were placed in the anterior region of edentulous maxilla were fabricated, and stress distribution patterns in implant supporting bone in the case of unilateral vertical loading on maxillary right first molar were compared with each other depending on various types of anchorage system and palatal coverage extent of denture base using three-dimensional photoelastic stress analysis. Two photoelastic overdenture models were fabricated in each anchorage system to compare with the palatal coverage extent of denture base, as a result we got eight models : Hader bar using clips(type 1), cantilevered Hader bar using clips(type 2), Hader bar using clip and ERA attachments(type 3), cantilevered milled-bar using swivel-latchs and frictional pins(type 4). Result: 1. In all experimental models, the highest stress was concentrated on the most distal implant supporting bone on loaded side. 2. In every experimental models with or without palatal coverage of denture base, maximum fringe orders on the distal ipsilateral implant supporting bone in an ascending order is as follows; type 3, type 1, type 4, and type 2. 3. Each implants showed compressive stresses in all experimental models with palatal coverage of denture base, but in the case of those without palatal coverage of denture base, tensile stresses were observed in the distal contralateral implant supporting bone. 4. In all anchorage system without palatal coverage of denture base, higher stresses were concentrated on the most distal implant supporting bone on loaded side. 5. The type of anchorage system affected in load transfer more than palatal coverage extent of the denture base. Conclusion: To the results mentioned above, in the case of patients with unfavorable biomechanical conditions such as not sufficient number of supporting implants, short length of the implant, and poor bone quality, selecting a resilient type attachment or minimizing the distal cantilevered bar is considered to be an appropriate method to prevent overloading on implants by reducing cantilever effect and gaining more support from the distal residual ridge.

• Journal of Periodontal and Implant Science
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• 제30권2호
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• pp.347-360
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• 2000

Bone remodeling results from the combined process of bone resorption and new bone formation which is regulated in part by some of the polypeptide growth factors such as platelet derived growth factor(PDGF), which has been known to be an important local regulator of bone cell activity and participate in normal bone remodeling. This process includes strictly regulated gene expression of several bone matrix proteins such as type I collagen and osteopontin, a 44 kDa phosphorylated glycoprotein, which has important roles in bone formation. The purpose of this study is to evaluate the effecs of PDGF-BB on the mRNA expression of bone matrix protein, type I collagen and osteopontin, in MC3T3- E1 cell culture. Cells were seeded at $5{\times}10^5$ cells in 10 ml of minimum essential medium alpha(${\alpha}-MEM$) containig 10% fetal bovine serum, 10 mM beta glycerophosphate. 0.1, 1, 10 ng/ml PDGF-BB were added to the cells for the day 3, 7, 14, 21, 28 and cultured for 24 hours. Type I collagen cDNA, Hf677, and osteopontin cDNA were used as probes for northern blot analysis. Total cellular RNA was purified at indicated day and northern blot analysis was performed. The results were as follows : Type I collagen mRNA expressions were higher at the day 3 and 7, and lower in the day 14, 21 in the control groups. In the experimental groups, mRNA expressions were increased when 0.1 ng/ml PDGF-BB were added on the day 3, 7, 21, and decreased in dose-dependent manner on the day 14, decreased at all added dose on the day 28. Osteopontin mRNA expressions were highest in the day 21 groups and lowest in the day 14 groups in the control groups. Interesting results were shown in the day 14 and 21 groups. We found that osteopontin mRNA level was increased in dose dependent manner in the day 14 groups, and decreased dose dependent manner in the day 21 groups. In conclusion, PDGF-BB may have various control effects on type I mRNA expression in the growth and differentiation process of MC3T3-E1 cells and may have contrary regulatory effects on osteopontin mRNA expression. For examples, when the baseline level of osteopontin mRNA was low, as in the day 14, PDGF-BB up-regulated osteopontin mRNA expression in dose dependent manner, and when the baseline level was high as in the day 21, PDGF-BB down-regulated dose dependent manner. Thus, it may be useful for clinical application in periodontal regeneration procedure if further study were performed.

• 대한치과보철학회지
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• 제50권2호
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• pp.99-105
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• 2012

연구 목적: 지금까지 성공적인 임플란트 치료를 위해 많은 연구가 진행되어 왔으며, 임플란트 주변 골 흡수 현상에 대한 연구는 매우 관심이 높은 분야 중 하나이다. 이에 본 연구에서는 삼차원 유한요소응력분석을 이용하여 변연골 흡수가 내측연결 임플란트 매식체의 기계적 안정성에 미치는 영향을 간접적으로 확인하고자 하였다. 연구 재료 및 방법: 악골에 식립된 내측연결 형태의 임플란트 매식체에 티타늄 소재의 임플란트 지대주를 지대주 나사로 연결하고 상부에 금합금관을 장착하는 삼차원 유한요소모형을 설계하였다. 0, 1, 2, 3 mm의 변연골 흡수 상태를 적용하고, 교합면 중심에서부터 3 mm 편측에 300 N의 수직 하중을 가하여 임플란트 매식체에 발생하는 최대 주 응력을 계산하였다. 결과: 유한요소분석결과 변연골 흡수에 따른 임플란트 매식체의 최대 주응력 분포는 유사한 양상을 보였으며, 임플란트 매식체 상단에서 가장 높은 응력 집중이 나타났다. 최대 주응력은 처음 1 mm 변연골 흡수를 가정하였을 때 가장 크게 증가하였고, 이후 변연골 흡수가 증가할수록 응력은 증가하였지만 응력 증가의 폭은 감소하는 경향을 보였다. 결론: 이러한 결과로부터 내측연결 임플란트에서 매식체 두께가 얇은 경부의 노출은 변연골 흡수로 인한 응력 증가에 가장 큰 원인임을 알 수 있었으며, 매식체의 변형, 균열 및 파절 등의 기계적 실패를 감소시키기 위해서는 이에 대한 외과적, 보철적 고려가 필요할 것으로 생각된다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권11호
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• pp.1632-1637
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• 2006

We studied the changes in biochemical markers of bone metabolism in growing Thoroughbred horses. Serum osteocalcin (OC), as a marker for bone formation, and carboxy-terminal propeptide of type-I collagen (PICP), as a marker for bone formation, carboxy-terminal telopeptide of type-I collagen (ICTP), as a marker for bone resorption, were determined in nine clinically healthy horses from 3 d to 17 mo of age. The BW and withers height (WH) increased during the study. On the other hand, a rapid reduction in body weight gain (BWG) was observed between 1 mo and 9 mo of age and a rapid reduction in withers height gain was observed between 1 mo and 5 mo of age. The serum markers decreased significantly with increasing age. In particular, dramatic changes in serum markers occurred between 3 d to 1 wk and 5 to 7 mo of age in these horses, which suggests that bone turnover rapidly decreased after birth. On the other hand, the ratio of PICP to ICTP decreased through the experiment. This result suggests that the reduction in bone formation exceeded that of bone resorption. There was a significant correlation between markers and growth parameters, except for the correlation between PICP and BWG on single linear regression analysis. Serum OC and ICTP were affected by the WH in multiple linear regression analysis. These results indicated that the age-related variation in serum biochemical markers of bone metabolism reflected bone growth, but neither BW nor BWG. Therefore, we consider that changes in bone modeling are the major factor affecting the levels of serum biochemical markers by 17 mo of age in horses.

• Journal of Periodontal and Implant Science
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• 제38권3호
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• pp.535-542
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• 2008

Purpose: The aim of this retrospective study is to evaluate survival rate of implant and bone formation, to analyze failure contribution factor. Material and Methods: A total of 52 consecutive patients(35 male, 17 female, mean age 49 years) with 104 osseous defects were treated during the period from October 2004 to June 2007 with a simultaneous or staged GBR approach using non-resorbable or resorbable membranes combined with autogenous bone grafts or xenograft(Bio-Oss, Bio-cera, BBP). Result: A total of 32(30,8%) of 104 GBR-treated sites failed the bone formation and a total of 5(5.6%) of 89 implants were removed. Early exposure of the membrane has significantly affected bone formation(p<0.05). Non-resorbable membrane showed more exposure of the membrane and low success rate of bone formation than resorbable membrane(p<0.05). There were no difference between success rate of bone formation and using autogenous bone or graft materials. There were no statistically significant difference between success rate of bone formation and smoking or using PRP. Mandible showed more success rate of bone formation than maxilla(p<0.05). Conclusion: Early exposure of the membrane, membrane type and maxilla/mandible type have influence on success rate of bone formation during GBR.

• Journal of Periodontal and Implant Science
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• 제50권1호
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• pp.38-47
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• 2020

Purpose: The aim of this study was to investigate the available alveolar bone height between the maxillary molars and the sinus floor according to their anatomical relationship using cone-beam computed tomographic (CBCT) images. Methods: A total of 752 maxillary first (M1) and second molars (M2) on CBCT scans of 188 patients were selected. First, each maxillary molar was categorized as type 1, 2, 3, or 4 according to the relationship of the molar root with the maxillary sinus floor. The frequency distribution of each type was analyzed. Second, the shortest vertical distance (VD) of each molar was measured from the furcation midpoints of the roots to the lowest point of the sinus floor by 2 observers. Intraclass correlation coefficients and the t-test were calculated for the VD measurements. Results: For M1, type 3 was the most frequent, followed by type 2. For M2, type 3 was the most common, followed by type 1. The VD measurements of type 1 were 9.51±3.68 mm and 8.07±2.73 mm for M1 and M2, and those of type 3 were 3.70±1.52 mm and 4.03±1.53 mm for M1 and M2, respectively. The VD measurements of M2 were significantly higher in female patients than in male patients. Conclusions: Type 3 was the most frequent anatomical relationship in the maxillary molars, and showed the lowest alveolar bone height. This information will help clinicians to prevent complications related to the maxillary sinus during maxillary molar treatment and to predict the available bone height for immediate implant planning.

• 대한치과교정학회지
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• 제31권5호
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• pp.499-504
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• 2001

하악골 횡적 성장결핍에 의한 하악 전치부의 총생을 치료하는데 성인의 경우 발치가 종종 요구된다. 그러나 발치에 의한 안모 변화가 바람직하지 않을 때 견인골 신장술을 시행하여 하악 정중부의 확장은 횡적 공간을 확보하여 빠른 교정치료 및 안정성을 확보할 수 있는 방법으로 고려된다. 하악 정중부 견인골 신장술을 시행한 후 tooth-borne type 과 tooth & bone-borne type distractor를 사용하여 latency, distraction, consolidation period를 거쳐 하악 정중부 횡적 확장을 시행하여 전치부 총생을 빠르게 치료할 수 있었으며, 두가지 방법에 의한 치유과정을 비교한 결과 치주적인 요소와 골 형성과정은 유사하였으며, 악관절 부위의 퇴행적 증상변화는 관찰되지 않았다.

• 대한치과보철학회지
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• 제33권3호
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• pp.517-538
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• 1995

Dental implantation is a method restoring missing teeth, especially in the case of severely resorbed edentulous patient. But the direct contact between bone and implant surface, induces stress concentration to the bone and eventually becomes a cause. The purpose of this study was to compare the stress distribution patterns between following two cylindrical implant models. One group has implant apex located in the inferior cortical bone and the other in the cancellous bone. Anterior edentulous mandible was modeled with two dimensional 953,878 nodes, 995,918 elements and compared the deflection and stress distribution under the 70 N,4 load cases for 26 models having variant mandibular height and length. The result were as follows; 1. The stress concentration was more affected by the height of the mandible than implant length. 2. Bicortication mitigates the stress of upper cortical and cancellous bone area at the same height of the mandible 3. Perforation of the inferior mandibular cortex significant stress concentration. 4. Stud type porstheses induced less stress concentration to the cortical and cancellous bone than bar type prostheses. 5. Stress of implant apex for stud type was larger than that of bar type.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권6호
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• pp.337-342
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• 2012

Objectives: Implants connect the internal body to its external structure, and is mainly supported by alveolar bone. Stable osseointegration is therefore required when implants are inserted into bone to retain structural integrity. In this paper, we present an implant with a "wing" design on its area. This type of implant improved stress distribution patterns and promoted changes in bone remodeling. Materials and Methods: Finite element analysis was performed on two types of implants. One implant was designed to have wings on its cervical area, and the other was a general root form type. On each implant, tensile and compressive forces ($30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$) were loaded in the vertical direction. Stress distribution and displacement were subsequently measured. Results: The maximum stresses measured for the compressive forces of the wing-type implant were $21.5979N/m^2$, $25.1974N/m^2$, $29.7971N/m^2$, and $32.3967N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. The maximum stresses measured for the root form type were $23.0442N/m^2$, $26.9950N/m^2$, $30.7257N/m^2$, and $34.5584N/m^2$ when $30N/m^2$, $35N/m^2$, $40N/m^2$, and $45N/m^2$ were loaded, respectively. Thus, the maximum stresses measured for the tensile force of the root form implant were significantly higher (about three times greater) than the wing-type implant. The displacement of each implant showed no significant difference. Modifying the design of cervical implants improves the strength of bone structure surrounding these implants. In this study, we used the wing-type cervical design to reduce both compressive and tensile distribution forces loaded onto the surrounding structures. In future studies, we will optimize implant length and placement to improve results. Conclusion: 1. Changing the cervical design of implants improves stress distribution to the surrounding bone. 2. The wing-type implant yielded better results, in terms of stress distribution, than the former root-type implant.