• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.321-327
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• 2020

Purpose: The purpose of this study was to measure and compare the strain value exerted on the cervical area using different screw tightening protocols in implant-supported, screw-retained 3-unit prostheses. Materials and methods: Strain gauges were attached to four implants: two external and two internal. Thereafter, two study model were designed each type using acrylic resin. CAD-CAM was used to design hex and nonhex abutments for each group (EH, ENH, IH, and INH group) and Screw-cement-retained prostheses were also designed using a nonprecious base metal. Abutment was fixed with 10 Ncm torque, and the prosthesis was cemented. Screws were fixed with 30 Ncm torque using different three protocols. After 5 min, the strain gauge level was measured, and group analysis was performed (α=.05). Results: External group showed significantly lower strain values than internal group and the EH group showed significantly lower strain values than the ENH group (P<.05). There was no difference in strain value based on the types of screw tightening protocols in same group (P>.05). The IH group exhibited significantly higher strain values than the INH group and the IH group showed a significant difference in strain values based on the types of screw tightening protocols used (P<.05). Conclusion: There was no significant effect on the external type in the implant-supported, screw-retained prostheses. However, strain values were high in the internal type, and the types of screw tightening protocol significantly affected these implants.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.2
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• pp.103-109
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• 2020

Purpose: The purpose of this study was to evaluate the preload maintenance of the retaining screw when using anaerobic sealing agents in implant fixture and abutment components. Specifically, the study examines the effects of anaerobic sealing agents on different types of screws. Materials and methods: External hexagon implants made of titanium and anti-rotational abutments were used. Titanium abutment screws and ebony abutment screws from the same manufacturer were used. The experiment was divided into four groups (n = 10 in each group). In the control group, no sealing agent was used at the implant fixture and abutment screw interface. All abutment screws were tightened according to the manufacturer's recommended torque (30 N.cm). After 24 hours, the removal torque (detorque) of each screw was measured using a digital torque gauge device. The data were analyzed by two-way ANOVA test according to normality distribution satisfaction. Results: Looking at the results for each group, titanium screws and no treatment showed detorque values of 20.3 ± 1.6 N.cm. titanium screws and applied anaerobic sealing agent showed detorque values of 32.4 ± 6.7 N.cm. Ebony screws and no treatment showed detorque values of 20.2 ± 1.5 N.cm. ebony screws and applied anaerobic sealing agent showed detorque values of 30.4 ± 4.5 N.cm. Conclusion: The detorque value was higher in the case of using anaerobic sealing agents in both the titanium screw and ebony screw groups. But there was no difference between the two screws.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.1
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• pp.28-36
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• 2003

Purpose: To determine and to compare the effects of cyclic loading on the fixation strength of different femoral fixation methods in ACL reconstruction. Materials and Methods: Biomechanical test using an Instron(R) machine (Model No.5569. Mass, U.S.A) were carried out to compare the pull out strength of six different femoral fixation techniques after a cyclic loading in 72 Yorkshire pig knees. The graft-bone complex was cyclically loaded between 30N and 150N at 50 mm/min rate for 1000 cycles and maximal tensile testing was performed. A preload of 30N was applied to the graft along the axis of the tunnel 15 minutes. ANOVA and the Duncan multiple comparison test was used for the statistical analysis. Results: The mean maximum tensile strength of femoral fixation before and after the cyclic loading test were 1003.4$\pm$145N and 601.1$\pm$154N in hamstring-LA screw(R) group, 595.5$\pm$104N and 360.7$\pm$56N in hamstring-Bioscrew(R) group, 1431.7$\pm$135N and 710.7$\pm$114N in hamstring-Semifix(R) group, 603.6$\pm$54N and 459.1$\pm$46N in hamstring-Endobutton(R) fixation group, 1067.4$\pm$145 and 601.8$\pm$134N in the BPTB-Titanium interference screw group, and 987.1$\pm$168N and 588.7$\pm$124N in the BPTB-Bioscrew(R) group. And these data illustrated that cyclic loading reduces the maximum tensile strength by 40 $\%$, 39 $\%$, 50 $\%$, 24 $\%$, 44 $\%$, 40 $\%$ respectively. Conclusions: With the results of these experiments it should be emphasized that rehabilitation exercises after anterior cruciate ligament reconstruction should be executed with precaution as the repetitive flexion and extension of the knee would compromise the maximum tensile strength of the graft tendon.

• Journal of the Korean Arthroscopy Society
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• v.6 no.1
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• pp.60-63
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• 2002

Purpose : The purpose of this study was to introduce new femoral fixation technique using a cross-pin and a bioabsorbable interference screw in hamstring ACL reconstruction. Method : Semitendinosus and gracilis were harvested for quadrapled graft. After tibial tunnel had been made, femoral tunnel was made 35 mm in depth. Then the graft passed through the tunnels. Cross-pin was fixed through the drill hole which had been made through upper sleeve of the Rigidfix system. While pulling the graft, bioabsorbable interference screw was fixed through the anteromedial portal. Conclusion : We introduced the new femoral fixation technique using a cross-pin and a bioabsorbable interference screw as a good method with high fixation strength and tight graft-bone contact.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.99-100
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• 2017

많은 연구에서 측면 나사 고정(laminar screw fixation)보다 척추경 나사 고정(pedicle screw fixation)의 생체 역학 강도가 더 나은 것으로 알려져 있다. 그러나 비교적 작은 크기의 척추경(pedicle)과 척수(spinal code), 신경 뿌리 및 척추 동맥에 대한 상해의 위험으로 일반적으로 이 방법은 사용에 제한이 있었다. 최근 3차원 모델링 및 3D 프린팅 기술의 진보는 해부학적인 연구, 특히 척추를 포함한 뼈와 관련된 연구를 용이하게 하고 있으며, 로봇 수술을 위한 다양한 아이디어를 제공하고 있다. 본 연구는 로봇 암(robotic arm)으로 경추 척추경에 나사를 삽입할 때 사용될 수 있는 척추경 나사 삽입을 위한 이상적인 궤적을 계산하는 방법을 제시하였다.

• Journal of the Korean Orthopaedic Association
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• v.56 no.4
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• pp.361-365
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• 2021

Pelvic fractures are high-energy injuries, often accompanied by damage to the adjacent tissues and organs. For patients with pelvic trauma, active treatment is required early in the injury, because mortality can increase if appropriate treatment is not provided. In most cases, however, minimally invasive surgery is considered because extensive surgery cannot be performed due to the patient's condition. Percutaneous fixation of the pubis has been introduced because it can be applied easily to achieve the stability of the anterior part of the pelvis. Although many studies introduced percutaneous fixation of pubic bone fractures, most describe screw fixation for nondisplaced fractures. When treating displaced fractures with percutaneous screw fixation, it is difficult for the guide pin or drill bit to avoid the joint surface. Using a bent guide pin could allow easy insertion of the cannulated screw while avoiding the articular surface.

• Clinics in Shoulder and Elbow
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• v.15 no.2
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• pp.148-153
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• 2012

Various biceps tenodesis techniques being used, make it difficult to compare the result of reports. First, the biceps tenodesis could be classified according to being performed by open incision or by the arthroscopic procedure. Second, it could be classified as a soft tissue and bony tenodesis according to the tissue which the long head of biceps is fixed with. Third, it could be classified as a proximal and distal tenodesis according to the location which the long head of biceps is fixed with. Fourth, it could be classified according to the implant (interference screw, suture anchor, knotless suture anchor). A decision should be suspended until an appropriate strength of tenodesis is revealed.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.1
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• pp.60-66
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• 2015

Screw loosening and screw fracture of abutment is one of most frequent mechanical complications in implant restoration. Fractured fragments in implant restoration like abutment and screw should be completely removed and the procedure needs minimal damage to the fixture of implant. In some cases, it could fail to remove fractured fragments and cause a lot of damage to the fixture of implant. These situations could render implant unusable at the worst. This article describes three different situations and simple techniques for successful removal of fractured fragments without damage of implants. The procedures used are described in this clinical report.

• Clinics in Shoulder and Elbow
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• v.16 no.2
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• pp.94-99
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• 2013

Purpose: The purpose of this study is to evaluate the clinical results of arthroscopic biceps long head suprapectoral tenodesis using an interference screw. Materials and Methods: We reviewed the cases of 30 patients who underwent arthroscopic biceps long head suprapectoral tenodesis using an interference screw between January 2008 and January 2010. The minimum follow up period was one year. Twenty patients had rotator cuff tears. The results were analyzed by VAS, ASES, tenderness in the bicipital groove, fixation failure, and the degree of deformity. Results: VAS, ASES scores showed a statistically significant increase during the final observation in all patients, compared with those before surgery. However, five patients (17%) had anterior shoulder pain and tenderness in the biceps groove, and three patients (10%) had Popeye deformity. Better results were achieved in patients without rotator cuff tear than in patients with rotator cuff tear (p<0.05). Conclusion: Arthroscopic biceps long head tenodesis above the pectoralis major using an interference screw in patients with a pathologic lesion of the proximal biceps tendon showed good results at the last follow up. However, further study for tenderness in the biceps groove in 17% of patients is needed.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.1
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• pp.75-80
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• 2006

Purpose: To evaluate the efficiency of Acutrak screw fixation for radial head fracture (Mason type 2) without considering the safe Bone of radial head. Materials and Methods: Consecutive seven radial head fracture of Mason type II underwent internal fixation with Acutrak screws from May 2001 to February 2003. The mean follow-up period was 1.2years (ranged, $6 months{\sim}2.5 years$). The mean age of patients was 47 years old (ranged, $36{\sim}60years$ old). The cause of injury were fall down -4 cases and traffic accident -3 cases. The results were evaluated by Mayo Clinic results scoring system. Results: Functional Rating Index of Mayo Clinic was excellent- 2 cases and good- 5 cases. There were no nonunion, loosening, heterotopic ossification, infection or degenerative changes. The postoperative range of motion in elbow joint is nearly full for flexion, extension, pronation and supination in this study Conclusion: Consideration of safe zone is not necessary when Acutrak screws are used for radial head fracture. It seems to be a useful method that Acutrak screw fixation for radial head fracture (Mason type II) could achieve good radiologic and clinical results without influencing proximal radio-ulnar joint and has powerful fixation.