• Journal of the Korean Arthroscopy Society
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• v.3 no.2
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• pp.91-96
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• 1999

Purpose : The purpose of this study is to compare the clinical and radiologic results of the anterior cruciate ligament(ACL) reconstruction using bone-patellar tendon-bone unit with doubled semitendinosus and gracilis tendons. Materias and Methods : Clinical results of ACL reconstructions which were performed in 47 patients using doubled semitendinosus and gracilis were compared with those performed in 45 patients using bone-patellar tendon-bone autograft. There were no differences in preoperative parameters(age, sex, instability). Average follow-up period were 17 months and 19 months each. Results : There were no significant differences between two groups in functional results (Lysholm knee score), degree of laxity and range of motion at final follow-up. However, the parapatellar complication, especially anterior knee pain after long distance walking or exercise and quadriceps weakness less occurred in hamstring tendon group than in bone-patellar tendon-bone group. Conclusion : Although there were no significant differences in clinical results of ACL reconstruction using bone-patellar tendon-bone autograft and doubled semitendinosus and gacilis, parapateller complications occurred more in the bone-patellar tendon-bone autograft group than in the doubled semitendinosus and gracilis group. It is thought that the careful selection of patient, achivement of skillful technique and active rehabilitation are important to prevent the parapatellar complications.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.95-104
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• 2009

Objective: The purpose of this study was to evaluate the effect of length and shape of cutting flute on mechanical properties of orthodontic mini-implants. Methods: Three types of mini-implants with different flute patterns (Type A with 2.6 mm long flute, Type B with 3.9 mm long and straight flute, Type C with 3.9 mm long and helical flute) were inserted into the biomechanical test blocks (Sawbones Inc., USA) with 2 mm and 4 mm cortical bone thicknesses to test insertion and removal torque. Results: In 4 mm cortical bone thickness, Type C mini-implants showed highest maximum insertion torque, then Type A and Type B in order. Type C also showed shortest total insertion time and highest maximum removal torque, but Type A and B didn't showed statistically significant difference in insertion time and removal torque. In 2 mm cortical bone thickness, there were no significant difference in total insertion time and maximum removal torque in three types of mini-implants, but maximum insertion torque of Type A was higher than two other Types of mini-implants. Conclusions: Consideration about length and shape of cutting flute of mini-implant is also required when the placement site has thick cortical bone.

• 대한족부족관절학회:학술대회논문집
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• 2008.11a
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• pp.13-13
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• 2008

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.250-259
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• 2011

The aim of this study was to suggest a design for an orthodontic miniscrew which may work most favorably in the thin cortical bone of the adolescent. In this study, orthodontic miniscrews with different diameters, lengths, and body types were manufactured and implanted in two artificial bone samples with different cortical bone thickness. Maximum insertion torque, maximum removal torque, and lateral alteration torque were measured. As a result, the bone quality, body type, diameter, and the length all had their effects on the maximum insertion torque, maximum removal torque, and lateral alteration torque. Cortical bone thickness was the most important factor. In initial stability, conical types showed better results than cylindrical types. Increase in the diameter had favorable effects in achieving mechanical stability. Increase in the length did not have as much influence as the other factors did on the initial stability, but there was a statistically significant difference between screws of 6 mm and 8 mm lengths(p<0.05). In conclusion, the conical type screw with a diameter of 1.8 mm is most favorable in the thin cortical bone of the adolescent. In terms of length, the 8 mm screw is expected to perform better than the 6 mm screw.

• 대한치과보철학회:학술대회논문집
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• 1995.12a
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• pp.35-35
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• 1995

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.102-108
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• 2009

Purpose: The bone defects that are associated with shoulder anterior instability may be the causes of failure of arthroscopic surgery. For the treatment of traumatic shoulder instability, we tried to determine the arthroscopic techniques that can be used for the bone defect of the glenoid and the humeral head. The purpose of this study is to assess the surgical techniques for the arthroscopic reconstruction of the shoulder with anterior instability and bone defects. Materials and Methods: We analyzed the articles that have been recently published on anterior shoulder instability and we assessed the arthroscopic surgical techniques. We compared the articles and the methods of arthroscopic surgical techniques for treating bone defects of the anteroinferior glenoid and the posterolateral humeral head, which were considered as the causes of recurrence of shoulder instability. Results: There are the anteroinferior bone defects of the glenoid and Hill-Sachs lesions in the bone defects that appear in patients with anterior shoulder instability. These bone defects are currently the causes of failure of arthroscopic surgery. Conclusion: Open shoulder surgery may be the treatment of the choice for a shoulder with instability and significant bone defects of the glenoid and the humeral head. But efforts are being made to overcome the weaknesses of open surgery by the use of arthroscopy.

• The korean journal of orthodontics
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• v.37 no.1 s.120
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• pp.5-15
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• 2007

Objective: The purpose of this study was to evaluate the mechanical performance of mini-screws during insertion into artificial bone with use of the driving torque tester (Biomaterials Korea, Seoul, Korea), as well as testing of Pull-out Strength (POS). Methods: Experimental bone blocks with different cortical bone thickness were used as specimens. Three modules of commercially available drill-free type mini-screws (Type A; pure cylindrical type, Biomaterials Korea, Seoul, Korea, Type B; partially cylindrical type, Jeil Medical, Seoul, Korea, Type C; combination type of cylindrical and tapered portions, Ortholution, Seoul, Korea), were used. Results: Difference in the cortical bone thickness had little effect on the maximum insertion torque (MIT) in Type A mini-screws. But in Type B and C, MIT increased as the cortical bone thickness Increased. MIT of Type C was highest in all situations, then Type B and Type A in order. Type C showed lower POS than Type A or B in all situations. There were statistically significant correlations between cortical bone thickness and MIT, and POS for each type of the mini-screws. Conclusion: Since different screw designs showed different insertion torques with increases in cortical bone thickness, the best suitable screw design should be selected according to the different cortical thicknesses at the implant sites.

• Journal of Periodontal and Implant Science
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• v.36 no.4
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• pp.913-923
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• 2006

목적 : 최근 발치 후 즉시 임플란트 식립은 널리 사용되는 수술 방식이다. 이 연구의 목적은 임플란트 주위 골결손시 Ca-P으로 표면 처리된 이종골을 사용하여 골재생을 평가하기 위함이다. 재료와 방법 : 두 마리의 개 모델에서 하악 소구치와 제일 대구치를 발치하였다. 발치 6주 후 trephine bur를 이용하여 7.5 mm 지름과 5 mm 깊이를 가진 결손부를 형성하였다. 이 후 이 결손부의 중앙에 3.5 mm 지름과 15mm 길이의 fixture(GS II)를 식립하였다. 결과적으로 임플란트와 주변을 둘러싸고 있는 골 사이에는 2.0 mm정도의 gap이 만들어진다. 준비된 결손부 내로 자기골 또는 $Biocera^{(R)}$를 채웠다. 각각 4주, 8주 후 조직 절편을 제작하였다. 조직학적 평가를 위해 Block biopsy를 시행하였다. 결과 : 두 집단 모두 임상적으로 골이 완전히 채워졌다. 자가골이 이식된 부위(control)의 평균 골-임플란트 접촉(BIC)은 각각 4주째 $28.2{\pm}19%$였고, 8주째 $44.9{\pm}9%$였다. $Biocera^{(R)}$가 이식된 부위(test)의 평균 BIC는 각각 4주째 $34.6{\pm}27%$였고, 8주째 $27.6{\pm}23%$였다. 자가골이 이식된 부위(control)의 평균 골밀도는 각각 4주째 $32.7{\pm}25%$, 8주째 $37.4{\pm}17%$였다. 골-임플란트 접촉(BIC)과 골밀도의 평균 비율(%)은 비슷하였다. 조직학적으로 자가골과 이종골 이식 부위 모두 주변골과 잘 조화를 이루었고 유사한 치유 양상이 관찰되었다. 자가골과 이종골 이식 부위간 유의한 차이는 없었다.(P>0.05) 결론 : 임플란트 주위 2 mm의 골 결손부위에 자가골 또는 이종골로 채운 경우 유사한 결과를 얻었다. 이 결과 임플란트 fixture 주위의 골 결손부 해소를 위해 자가골을 대체할 수 있는 재료로 $Biocera^{(R)}$를 사용할 수 있음을 보여준다.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.128-137
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• 2011

Purpose: Resonance frequency analysis, Periotest, and removal torque (RT) test were known as the methods to assess implant stability. The results of these methods are affected by the bone condition, implant diameter and shape. The purpose of this study is to access the meaning and the correlationship of the resonance frequency analysis, Periotest and RT test in osseointegration simulated acrylic resin when the engaged bone thickness and peri-implant bone defect are changed. Materials and methods: To simulate osseointegration, the fixture was fixed to an aluminum mold with a screw. Acrylic resin powder and liquid were poured into the mold for polymerization. The engaged resin thickness with implant was controlled. Simulated cortical bone thicknesses were 1, 3, 5 and 10 mm. Additional 1, 3 and 5 mm peri-implant bone defects were simulated. Three types of implants were used; 4 mm diameter implants of straight shape, 4 mm diameter implants of tapered shape and 5 mm diameter implants of tapered shape. Five fixtures per each type were tested in respective bone condition. Resonance frequency analysis and Periotest were evaluated in all bone conditions. Peak removal torque was measured at simulated cortical bone thicknesses of 1 and 3 mm. The statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, and Spearman test using a 95% level of confidence. Results: With increasing engaged bone depth, the Implant Stability Quotient (ISQ) values increased and the Periotest values (PTVs) decreased (P<.001, P<.001). With increasing peri-implant bone defect, ISQ values decreased and PTVs increased (P<.001). When the diameter of implant increased, ISQ values increased and Periotest values (PTV) decreased (P<.001). There was a strong correlation between ISQ values and PTVs (r = -0.99, P<.001). Furthermore, the peak removal torque values had weak correlations with both ISQ values and PTVs (r = 0.52, P<.001 ; r = -0.52, P<.001). Conclusion: This study confirmed favorable implant stability with increasing engaged bone depth and implant diameter and decreasing peri-implant bone defect. ISQ values and PTVs showed strong correlation with each other and not with the peak removal torque values.

• Journal of Biomedical Engineering Research
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• v.23 no.6
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• pp.451-458
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• 2002

Osteoporosis is a systemic skeletal disease caused by low bone mass and the decrease of bone density in the microstructure of trabecular bone. Drug therapy(PTH Parathyroid hormone) may increase the trabecular thickness and thus bone strength. Vertebroplasty is a minimally invasive surgery foy the treatment of osteoporotic vertebral compression fracture. This Procedure includes Puncturing vertebrae and filling with Polymethylmethacrylate(PMMA). Although altering recommended monomer-to-Powder ratio affects material properties of bone cement, clinicians commonly alter the mixture ratio to decrease viscosity and increase the working time. The Purposes of this study were to analyze the effect of 4he monomer-to-powder ratio on the mechanical characteristics of trabecular. In this paper, the finite element model of human vertebral trabecualr bone was developed by modified Voronoi diagram, to analyze the relative effect of hormone therapy and vertebroplasty at the treatment of osteoporotic vertebrae. Trabeuclar bone models for vertebroplasty with varied monomer-to-Powder ratio(0.40∼1.07 ㎖/g) were analyzed. Effective modulus and strength of bone cement-treated models were approximately 60% of those of intact models and these are almost twice the values of hormone-treated models. The bone cement models with the ratio of 0.53㎖/g have the maximum modulus and strength. For the ratio of 1.07㎖/g, the modulus and strength were minimum(42% and 49% respectively) but these were greater than those for drug therapy. This study shows that bone cement treatment is more effective than drug therapy. It is found that in vertebroplasty, using a monomer-to-powder ratio different from that recommended by manufacturer nay significantly not only reduce the cement's material Properties but also deteriorate the mechanical characteristics of osteoporotic vertebrae.