• The Journal of Advanced Prosthodontics
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• 제1권2호
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• pp.75-84
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• 2009

STATEMENT OF PROBLEM. A number of studies about the nano-treated surfaces of implants have been conducting along with micro-treated surfaces of implants. PURPOSE. The purpose of this study was to get information for the clinical use of nano-treated surfaces compared with micro-treated surfaces by measuring removal torque and analyzing histological characteristics after the placement of various surface-treated implants on femurs of dogs. MATERIAL AND METHODS. Machined surface implants were used as a control group. 4 nano-treated surface implants and 3 micro-treated surface implants [resorbable blast media surface (RBM), sandblast and acid-etched surface (SAE), anodized RBM surface] were used as experimental groups. Removal torque values of implants were measured respectively and the histological analyses were conducted on both 4weeks and 8weeks after implant surgery. The surfaces of removed implants after measuring removal torque values were observed by scanning electron microscopy (SEM) at 8 weeks. RESULTS. 1. Removal torque values of the nano-treated groups were lower than those of micro-treated groups. 2. Removal torque values were similar in the anodized RBM surface groups. 3. On the histological views, there was much of bone formation at 8 weeks, but there was no difference between 4 and 8 weeks, and between the types of implant surfaces as well. CONCLUSION. it is suggested that implant topography is more effective in removal torque test than surface chemistry. To get better clinical result, further studies should be fulfilled on the combined effect of surface topography and chemistry for the implant surface treatments.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권5호
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• pp.396-405
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• 2001

Osseointegrated implants are used for the fixation of dental prosthesis with good long-term clinical results. In an attempt to improve the quantity and quality of the bone-implant interface, numerous implant modification have been used. Implants surface modifications have been used such as titanium-plasma sprayed, hydroxyapatite-coating, sandblasted, sandblasted and acid-etched, acid-etched. Rough surface implants have greater implant surface area and enhance the bone-implant interface and improve stabilization. The purpose of present study was to evaluate light microscopic and scanning microscopic examinations and removal torque value of newly developed calcium phosphate blast and acid-etched implant in the femur of rabbits. Titanium plasma sprayed(TPS) implant served as controls. After 12 weeks of healing of the femurs of 12 rabitts, the implant-containing segments of femur were removed on bloc and bone block including sections. Histologic examination and histomorphometric and removal torque values comparision were made for two implants. Obtained results are follows: 1. Newly developed calcium phosphate blasted and acid-etched implants were in close contact with bone under light microscopic examinations. 2. New implants showed mean bone-to implant contact 59.8%, whereas TPS implants showed mean bone-to implant contact 54.5% (statistically no difference p<0.05). 3. New implants showed mean bone density 56.7%, whereas TPS implants showed mean bone density 49.2% (statistically difference p<0.05). 4. New implants demonstrated mean removal torque values 40.5Ncm, whereas the mean removal torque values of TPS implants ranged 39.3Ncm. No statistical differences(p<0.05) were observed between two groups of implants nor was there any difference between the two implants at the clinical level.

• 대한치과보철학회지
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• 제44권3호
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• pp.314-324
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• 2006

Statement of problem. Osseointegration is important mechanism of dental implant but it is not easy to evaluate. Indirect measurement is non-invasive and clinically applicable but they need more study about correlation between indirect values and degree of osseointegration. Purpose. The aims of this study were to evaluate the coefficient of correlation between indirect measurement and direct measurement under different healing time, and assessment of effect of initial insertion torque to the implant stability. Material and Methods. 20 rabbits received 3 implants on each side of tibia. Three kinds of implants (machined surface implant, Sandblasted with Large grit and Acid etched implant, Resorbable Blast Media treated implant) were used. During the surgery implant insertion torque were measured with $Osseocare^{TM}$. After the 1, 4, 8, 12 weeks of healing time, animals were sacrificed and stability values (Implant Stability Quotient with $Osstell^{TM}$, removal torque with torque gauge) were measured. Results. The Bone quality of rabbit tibia was classified into 2 groups according to the insertion torque. Resonance frequency analysis (ISQ) and removal torque showed positive correlation until $4^{th}$ week (r=0.555, p=0.040). After $8^{th}$ week (r=0.011, p=0.970) the correlation became weak and it turned negative at $12^{th}$ week (r=-0.074, p=0.801). Insertion torque and ISQ showed changing correlation upon the healing time ($1^{st}$ week: r=0.301, p=0.033, $4^{th}$ week: r=-0.429, p=0.018, $8^{th}$ week: r=0.032, p=0.865, $12^{th}$ week: r=-0.398, p=0.029). Insertion torque and removal torque has positive correlation but it was not statistically significant ($1^{st}$ week: r=0.410, p=0.129, $4^{th}$ week: r=0.156, p=0.578, $8^{th}$ week: r=0.236, p=0.398, $12^{th}$ week: r=0.260, p=0.350). Conclusion. In this study, bone quality may affect the degree of osseointegration positively during healing time and correlation between ISQ and degree of osseointegration can be different according to the healing time and bone quality.

• 대한치과보철학회지
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• 제46권6호
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• pp.628-633
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• 2008

STATEMENT OF PROBLEM: The application of a simple, clinically applicable noninvasive test to assess implant stability are considered highly desirable. So far there is still a controversy about correlation of various tests and implant stability. PURPOSE: In order to assess implant stability, the development of a new method is critical. It's possible to assess implant stability by calculating energy and angular momentum during implant installation. The purpose of this study is to evaluate the correlation of energy and implant stability. MATERIAL AND METHODS: Twenty three implants were installed in two different types of pig bone. Type I bone was retrieved from the distal aspect of the rib, with more cortical bone. Type II bone came from a more proximal region with less cortical components and a higher content of bone marrow and spongeous trabeculae. Insertion torque, removal torque, ISQ values and angular momentum and energy were measured. Pearson Correlation test was done to analyze the relation between RFA, maximum insertion torque, mean insertion torque, bone type, energy and removal torque. RESULTS: Type I bone showed higher removal torque than type II bone. Energy value was significantly correlated with maximum insertion torque and mean insertion torque. RFA values were related with insertion torques but the significance was lower than Energy value. CONCLUSION: Within the limitation of this study energy values were considered clinically predictable method to measure the implant stability.

• 대한치과교정학회지
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• 제36권3호
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• pp.171-177
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• 2006

마이크로 임플랜트는 순티타늄과 티타늄 합금을 사용하고 있다. 순티타늄의 경우 grade가 낮을 수록 생체적합성은 증가하나 기계적 성질이 낮다. 이에 본 연구에서는 순티타늄 grade 2와 grade 4를 재료로 한 마이크로 임플랜트를 각각 토끼의 다리뼈에 식립한 후 2, 8, 12주의 시간경과에 따른 조직학적 소견의 차이와 식립, 제거 시의 최대토크의 측정으로 그 티타늄 종류에 따른 차이를 살펴보았다. 토끼의 경골에 식립한 티타늄의 종류에 따른 식립시 및 시간의 경과에 따른 제거시의 토크를 측정하여 다음과 같은 결론을 얻었다. 첫째, grade 2와 grade 4간의 식립 시 최대 토크의 차이는 없었다. 둘째, 식립 후 2, 8, 12주 후의 제거 시 최대토크 측정에서 전체 마이크로 임플랜트의 그룹간 차이는 없었다. 셋째, 2주에서 8주로 시간이 경과함에 따라 제거 시 최대토크가 유의하게 증가하였으며 8주와 12주간에는 유의한 상관관계가 없었다. 따라서 유지력은 grade 2 티타늄과 비슷하지만 물리적 성질이 더 단단한 grade 4 티타늄을 마이크로 임플랜트 재료로 사용하는 것이 좋은 것으로 생각된다.

• Journal of Yeungnam Medical Science
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• 제36권1호
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• pp.43-49
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• 2019

Background: In the osseointegration of dental implants, the implant surface properties have been reported to be some of the most important critical factors. The effect of implant's surfaces created by resorbable blast media (RBM) followed by laser ablation on bone tissue reactions was examined using the removal torque test and histomorphometric analysis. Methods: Two types of dental implants, RBM-laser implants (experimental group) and RBM implants (control group) (CSM implant system, Daegu, Korea; L=6 mm, diameter=3.75 mm) were placed into the right and left distal femoral metaphysis of 17 adult rabbits. Six weeks after placement, removal torque was measured and histomorphometric analysis was performed. Results: The mean removal torque was $24.0{\pm}10.2Ncm$ and $46.6{\pm}16.4Ncm$ for the control and test specimens, respectively. The experimental RBM-laser implants had significantly higher removal torque values than the control RBM implants (p=0.013). The mean values of total and cortical bone to implant contact (BIC) were respectively $46.3{\pm}10.8%$ and $65.3{\pm}12.5%$ for the experimental group, and $41.9{\pm}18.5%$ and $57.6{\pm}10.6%$ for the control group. The experimental RBM-laser implants showed a higher degree of total and cortical BIC compared with RBM implants, but there was no statistical significance (p=0.482, 0.225). Conclusion: The removal torque and BIC of the test group were higher than those of the control group. In this study, the surface treatment created by RBM treatment followed by laser ablation appears to have a potential in improving bone tissue reactions of dental implants.

• 대한치과보철학회지
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• 제50권3호
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• pp.149-155
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• 2012

연구 목적: 이 논문은 임플란트 고정체가 골융합이 이루어지기전 의원성 동요가 있을 경우 골결합에 어떤 영향을 미치는지를 알아 보고자 한다. 연구 재료 및 방법: 실험에 사용한 임플란트는 직경 3.73 mm, 길이 4 mm의 순수한 타이타늄과 RBM ($MegaGen^{(R)}$: Ca-P) 처리된 임플란트(Grade IV)를 사용하였다. 몸무게 3.5kg 이상의 토끼(Female, New Zealand White)의 한쪽 경골에 2개씩 양쪽 다리에 임플란트를 식립하여 모두 80개의 임플란트가 식립되었다. 비틀림 제거력(Removal torque)의간격에 따라 그룹 I (6주), 그룹 II (4일+6주), 그룹 III (4일+1주+6주), 그룹 IV (1주+6주), 그룹 V (1주+1주+6주), 그룹 VI (2주+6주), 그룹 VII (2주+1주+6주), 그룹 VIII (3주+6주), 그룹 IX (3주+1주+6주), 그룹 X (10주)으로 10개의 그룹으로 나누었다. 본 실험에서 그룹 I과 그룹X가 대조군이며, 비틀림 제거력은 digital torque gauze (Mark-10, USA)를 사용하여 6주와 10주에 측정하였다. 실험군에서는 마지막 비틀림 제거력을 측정하기 전에 의원성 동요를 가하여 한 번 혹은 두 번 비틀림 제거력을 측정하여 그 수치를 기록하였다. 그 후, 대조군을 제외하고 비틀림 제거력을 측정한 임플란트는 가급적 원래의 위치로 돌려 놓고 봉합을 하였다. 모든 실험군은 마지막 비틀림 제거력 측정전까지 6주간의 치유기간을 주었으며, 마지막 비틀림 제거력은 실험군 첫 번째 또는 두 번째 비틀림 제거력값과 비교하여 결과를 분석하였다. 결과: 마지막 비틀림 제거력 측정값에서 그룹X (10주)의 값이 대조군인 그룹 I (6주)의 값보다 높았으나, 통계적으로는 유의하지 않았다. 실험군과 대조군 사이의 통계적으로 유의한 차이를 보이지 않았다(P>.05). 첫 번째 비틀림 제거력 측정치에서, 실험군(4일혹은1주)에서 다른 실험군(2주혹은3주)의 수치보다 낮은 값을 보였다. 치유기간에 따른 각 실험군의 비교에서, 최종 비틀림 제거력 값이 첫 번째 비틀림 제거력 값 보다 현저히 높은 값을 보였다. 결론: 골유착이 형성되기 전 한 번 또는 두 번 의원성으로 동요는, 만약 충분한 치유기간을 가지게 될 경우 임플란트의 골유착에 영향을 주지 않는다.

• 대한치과보철학회지
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• 제52권2호
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• pp.105-112
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• 2014

연구 목적: 이 연구의 목적은 임플란트 식립 초기 수회의 의원성 동요가 최종 골결합에 미치는 영향을 확인하는 것이다. 연구 재료 및 방법: 순수한 티타늄(Grade IV) 으로 직경 3.75 mm, 길이 8 mm의 실험용 임플란트를 제작한 후, 하방 4 mm에 RBM 표면처리($MegaGen^{(R)}$: Ca-P)를 하였다. 임플란트의 하부만 골에 식립되었으며 비침하시켰다. 수술은 3.5 kg이상의 토끼의 좌우 경골의 단층 치밀골에 각각 2개씩 130개를 통상적인 방법으로 식립하였다(Female, New Zealand White). 비틀림 제거 간격에 따라, 다음과 같은 13개의 군으로 나누었다; Group I (1일), Group II (1일 + 2일), Group III (1일 + 2일 + 3일), Group IV (1일 + 2일 + 3일 + 4일), Group V (2일), Group VI (2일 + 4일), Group VII (2일 + 4일 + 6일), Group VIII (2일 + 4일 + 6일 + 8일), Group IX (4일), Group X (4일 + 7일), Group XI (4일 + 7일 + 10일), Group XII (4일 + 7일 + 10일 + 14일), 그리고 대조군. 대조군은 식립 후 8주의 치유기간을 준 후 최종 비틀림 제거력을 측정하였다(Mark-10, USA). 실험군은 각각의 조건에 맞추어 1회에서 4회에 걸쳐 비틀림 제거력을 측정하였다. 비틀림 제거력을 측정한 이후에 대체적으로 임플란트를 측정 전의 위치로 재위치시켰다. 모든 실험군에서 임플란트 식립 후 8주간의 치유기간을 준 다음 최종 비틀림 제거력을 측정하여 대조군, 각 실험군의 1, 2, 3, 4번째 비틀림 제거력과 비교하였다. 결과: 실험군 간에 최종 비틀림 제거력을 비교한 결과에서, XII군을 제외한 실험군의 비틀림 제거력은 대조군과 유의할만한 차이를 보이지는 않았다. 그리고 실험 I군과 II군의 값은 VI, VIII, X, XI, XII군의 값보다 유의하게 높게 나타났다. 그리고 III, IV, V군은 XI, XII군의 값보다 유의하게 높게 나타났다. 각 실험군간 비틀림 제거력 비교에서, 최종 비틀림 제거력은 VIII, X, XI, XII군을 제외한 모든 군에서 높게 나타났다. 결론: 충분한 치유기간이 주어진다면, 토끼에게 임플란트 식립 후 매우 이른 초기에 지대주에 가해지는 약간의 동요는 임플란트 골결합에 영향을 미치지 않았다.

• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.126-132
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• 2014

PURPOSE. This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. MATERIALS AND METHODS. Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (${\alpha}$=0.05). RESULTS. The postload removal torque value was high in the following order with regard to magnitude: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). CONCLUSION. The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate.

• Journal of Korean Dental Science
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• 제11권1호
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• pp.14-20
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• 2018

Purpose: The purpose of this study is to measure and compare the removal torques of different cements applied in attachments of zirconia restorations on titanium (Ti) abutments fitted with retrievable cement-type slot (RCS) on the lingual side for the better retrievablity by use of a slot driver. Materials and Methods: Three types of cements were used in the experiment: two permanent cements in $RelyX^{TM}$ U200 (RU) (3M ESPE) which is a resin cement and $FujiCem^{TM}$ (FC) (GC) which is a resin-modified glass ionomer cement, and a temporary cement in $Freegenol^{TM}$ temporary cement (TC) (GC). Measurements of removal torques were conducted as follows; an attached sample was fixed on the equipment customized for the experiment; a slot driver was connected to a MGT12 (Mark-10 Corp.), a torque measurement instrument; the sample had the driver fitted to its RCS and then was rotated until the it was removed; and finally, the maximum torque value was recorded. Result: As for the removal torque measurement results, the average values were $47.9{\pm}2.6Ncm$ for RU, $43.4{\pm}1.5Ncm$ for FC, and $20.9{\pm}1.0Ncm$ for TC. The statistical analysis using Kruskal-Wallis test yielded the significance probability of P<0.05 (P=0.002), which confirmed the presence of significant differences between the three groups. Conclusion: All three cements exhibit clinically acceptable levels of removal torque when applied to an upper zirconia implant restoration fitted with a lingual slot, with RU and FC, the two permanent cements, having the significantly higher values than that of TC, the temporary cement.