• Journal of Trauma and Injury
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• 제35권1호
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• pp.51-55
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• 2022

Pelvic ring injuries have high mortality and morbidity rates, and they are difficult to treat because accompanying injuries to the pelvic organs, genitourinary organs, and neurovascular tissues are common. Genitourinary injuries are common comorbid injuries that have been reported to occur in 5% to 6% of all pelvic ring injuries. However, these injuries usually occur simultaneously with the pelvic ring injury, whereas relatively little research has dealt with genitourinary injuries that occur after treatment of a pelvic ring injury. To the best of our knowledge, only three cases of delayed bladder perforation due to screw loosening after symphyseal plate fixation in anterior pelvic ring injury have been reported worldwide, and no such cases have yet been reported in Korea. Since the authors experienced this very rare complication after pelvic ring surgery, we report this case along with a literature review.

• 대한치과보철학회지
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• 제48권1호
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• pp.61-68
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• 2010

연구 목적: 임플란트 보철물의 유지 나사에 적용되는 전하중은 나사를 조임으로써 임플란트와 지대주 사이에 인장력이 발생하면서 나사가 신장되는 힘을 말한다. 이 연구는 전하중에 영향을 미치는 생역학적 요인들과 나사 풀림에 기여하는 다양한 요인에 대하여 문헌을 고찰하고자 하였다. 연구 재료 및 방법: 1981년부터 2009년까지 발표된 나사 풀림을 다룬 임상연구 중 설정한 기준에 합당한 문헌을 요약하여 나사 풀림의 빈도를 밝혔고 나사의 안정성과 전하중에 관한 생역학을 다룬 문헌을 조사하고 요약하였다. 또한, 본 교실에서 연구한 실험실적 결과도 포함시켰다. 결과 및 결론: 나사 풀림의 정도는 나사에 토크를 가하는 기술이 발달함에 따라 현저히 감소하고 있다. 그 외에도 나사의 재질, 마찰계수를 감소시키기 위한 피복 기술의 발달 및 나사산의 모양 등 전하중에 영향을 줄 수 있는 요인을 고찰하였다. 전하중이 일정 수준 이하로 떨어지게 되면 나사의 움직임이 발생하게 되는데 이는 장기적으로 축적되어 피로파절 및 응착 마모, 소성 변형 등을 유발하게 되므로 주의해야 한다. 최적의 전하중을 주기 위해서는 토크 렌치를 이용하고 환자의 재내원시 다시 토크를 가하는 방법 등이 추천된다.

• The Journal of Advanced Prosthodontics
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• 제1권2호
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• pp.102-106
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• 2009

STATEMENT OF PROBLEM. Screw loosening has been a common complication and still reported frequently. PURPOSE. The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS. Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly mounted in liquid unsaturated poly-esther with dental surveyor. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and weight loss were measured. Mann-Whitney test with SPSS statistical software for Window was applied to analyze the measurement of weight loss. RESULTS. TiN-coated abutment screws of Osstem and 3i showed lesser loss of weight than non-coated those of Osstem and 3i (P < .05, Mann-Whitney test). CONCLUSION. Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability.

• 대한치과보철학회지
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• 제44권4호
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• pp.432-442
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• 2006

Statement of problem: One of common problems associated with dental implant is the loosening of abutment screws that retain the implants. Purpose : This study was performed to investigate the influence of abutment screw length and repeated tightening on screw loosening in dental implant. Material and method: Forty nine Hexplants (13mm length, 4.3mm diameter, Ti grade IV, Warantec. Co. Ltd. Seongnam, Korea) and cementation type abutments(straight abutment) and abutment screws (0.4mm/pitch) were divided into 7 groups, depending on abutment screw length. Each implant and abutment was tightened to 30Ncm by torque controller(MGT50, MARK-10 Inc., USA) and the removal torque values were measured during 10 consecutive closure/opening trials. Results and Conclusion: The results of comparing the removal torque value are as follows : 1. There is no significant difference in the removal torque value between groups in 10 consecutive closure/opening trials (p = 0.97). 2. If the fractured abutment screw is engaged in longer than 2.425 thread length, there is no significant difference in the preload between the fractured abutment screw and the new abutment screw when both are equally tightened to 30 Ncm. 3. The removal torque value in the 1st trial(24.510 Ncm) was lower than that in the 2nd, 3rd, 4th, 5th, 6th, 7th trials and the removal torque value in the 2nd trials(25.551 Ncm) was maximum and was decreased in 1311owing trials. The removal torque value in the 1st trial was significantly lower than that in the 2nd, 3rd, 4th trials and was significantly higher than that in the 8th, 9th, l0th trials(p<0.05). 4. In the 2nd, 3rd, 4th, 5th, 6th, 7th trials, the abutment screw was mainly influenced by settling effect and the higher preload was obtained In the 8th, 9th, l0th trials, the abutment screw was mainly influenced by adhesive wear and the progressively lower preload was obtained.

• The Journal of Advanced Prosthodontics
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• 제9권2호
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• pp.99-103
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• 2017

PURPOSE. The purpose of this study was to achieve more retention and stability and to delay or prevent screw loosening. MATERIALS AND METHODS. Twenty implants (Implantium 3.4 mm, Dentium, Seoul, Korea) were divided into 2 groups (n = 20). In the first group, an adhesive material was applied around the screw of the abutments (test group). In the second group, the screws are soaked in saliva (control group). All the screws were torqued under 30 N/cm, Then, the samples were gone through a cyclic fatigue loading process. After cyclic loading, we detorqued screws and calculated detorque value. RESULTS. In comparison with the control group, all the implant screws in the test group were smeared with the adhesive material, showing significant higher detorque value. CONCLUSION. There are significantly higher detorque values in the group with adhesive. It is recommended to make biocompatible adhesive to reduce screw loosening.

• 대한치과보철학회지
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• 제41권2호
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• pp.128-135
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• 2003

Statement of problem : Implant screw loosening remains a problem in implant prosthodontics. Some abutment screws with treated surfaces were introduced to prevent screw loosening and to increase preload. DLC(Diamond Like Carbon) film has similar properties on hardness, wear resistance, chemical stability, biocompatibility as real diamond materials. Purpose : The purpose of this study was to investigate the effect of lubricant layer on abutment screw and to discriminate more effective method between soft lubricant and hard lubricant to prevent screw loosening. Material and method : In this study, $1{\mu}m$ thickness DLC was used as protective, lubricating layer of titanium screws and 3 times removal torque was measured on the abutment screws to investigate the difference in 10 coated and 10 non-coated abutment screws. Results : The results indicated that the implants with DLC coating group were not more resistant to the applied force in screw loosening. At 32Ncm, the 3 times removal torque in DLC group were $27.75{\pm}2.89,\;25.85{\pm}2.35$ and $26.2{\pm}2.57$. The removal torque in no-coated abutment screws were $27.85{\pm}4.23,\;27.35{\pm}2.81$ and $27.9{\pm}2.31$, respectively. Conclusion : The lubricant layer used in this study was Diamond Like Carbon(DLC) and it have a properties of hard and stable layer. The DLC coating layer was hard enough to prevent distortion of screws in the repeated unscrewing procedure in clinical situation. The reduced friction coefficient in hard DLC layer was not effective to prevent screw loosening.

• 대한치과보철학회지
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• 제44권2호
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• pp.197-206
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• 2006

Statement of problem: One of common problems associated with single teeth dental implant prosthetic is the loosening of screws that retain the implants. Purpose: The maintenance of screw joint stability is considered a function of the preload achieved in the screw when the suggested initial tightening torque is applied. The purpose of this study was to investigate acquired preload after initial clamping torque for estimating screw joint stability. Material and methods: A comparative study on the effect of initial clamping of two types of implant systems with different connections was conducted Three dimensional non-linear finite element analysis is adopted to compare the characteristics of screw preloads and stress distributions between two different types of implant systems composed with abutment, screw, and fixture under the same loading and boundary conditions. Results: 1. When the initial clamping torque of 32Ncm was applied to the implant systems, all types of implants generated the maximum effective stress at the first helix region of screw. 2. Morse taper connection types of implants generate lower stress distributions compared to those by butt joint connection types or implants due to large contact surface between abutment and fixture. 3. The internal types of implant systems with friction grip type implant systems have higher resistance to screw loosening than that of the external types of implant systems since the internal types of implant systems generated larger preload than that generated by the external types for the same tightening moments.

• 대한치과보철학회지
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• 제45권3호
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• pp.329-338
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• 2007

Purpose. The aim of this study is to evaluate the effect of TiN coating of abutment screw on the unscrewing torque. Material and methods. Titanium and Gold-Tite abutment screws were classified into two groups, Group A and C respectively, as control groups. Titanium abutment screws with TiN coatings were also classified into two groups, Group B and D, as experimental ones. Group A and B were tightened to 20 Ncm input torque, and Group C and D were tightened to 32 Ncm torque. Detorque values were measured with digital torque gauge during repeated closing and opening experiment. Results. Abutment screws with TiN coating (Group B and D) showed statistically significant higher mean detorque values than those of Group A and C. Discussion. Physical properties of TiN coating, such as low friction coefficient, high hardness and wear resistance, might contribute to higher detorque values. Conclusion. It is suggested that TiN coating of abutment screw help to reduce the risk of screw loosening and improve the stability of screw joint.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 2003년도 춘계학술대회 및 제1회 한일 공동 학술대회
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• pp.38-38
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• 2003

• 대한치과보철학회지
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• 제43권3호
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• pp.379-392
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• 2005

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection, and in molars. Purpose. The purposes of this study were: (1) to compare the initial abutment screw detorque values of the six different implant-abutment interface designs, (2) to compare the detorque values of the six different implant-abutment interface designs after cyclic loading, (3) to compare the detorque values of regular and wide diameter implants and (4) to compare the initial detorque values with the detorque values after cyclic loading. Material and methods. Six different implant-abutment connection systems were used. The cement retained abutment and titanium screw of each system were assembled and tightened to 32Ncm with digital torque gauge. After 10 minutes, initial detorque values were measured. The custom titanium crown were cemented temporarily and a cyclic sine curve load(20 to 320N, 14Hz) was applied. The detorque values were measured after cyclic loading of one million times by loading machine. One-way ANOVA test, scheffe’s test and Mann-Whitney U test were used. Results. The results were as follows : 1. The initial detorque values of six different implant-abutment connections were not significantly different(p>0.05). 2. The detorque values after one million dynamic cyclic loading were significantly different (p<0.05). 3. The SS-II regular and wide implant both recorded the higher detorque values than other groups after cyclic loading(p<0.05). 4. Of the wide implants, the initial detorque values of Avana Self Tapping Implant, MIS and Tapered Screw Vent, and the detorque values of MIS implant after cyclic loading were higher than their regular counterparts(p<0.05). 5. After cyclic loading, SS-II regular and wide implants showed higher detorque values than before(p<0.05).