• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.233-249
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• 1999

Primary fixation is one of the most important factor in establishing adequate osseointegration between implant and bone. To evaluate the initial healing response of bone around implants without primary bone contact, this study was designed to create considerable space between implant and bone in 5 mongrel dogs, about 1-year old. After 3 holes of 6.0mm in diameter were prepared at the femur neck of the dogs, commercially pure titanium thread type implants(STERI-$OSS^{(R)}$), 8mm in length and 3.8mm, 5.0mm and 6.0mm in diameter, were inserted. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), and the penetration of upper soft tissue into the gap was inhibited by it. The each implant was positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 were inserted in 2 dogs for mobility test and removal torque test.Fluorescent dyes were injected in order of Doxycycline, Alizarin Red S, and Calcein at intervals of 2 weeks. At 4-, 8-, and 12-week after placement, 3 dogs were sacrificed for histologic observation, and at 8- and 12-week after placement, 2 dogs were sacrificed for mobility test using $Periotest^{(R)}$ (Simens AG, Bensheim, Germany) and torque test using Autograph AGS-1000D $series^{(R)}$(Japan). The result were as follows: 1. The wider the gap between bone and implant was, the less bone maturity was, and the later osseointegration was occurred. Trabecular direction of new bone around implant was changed from parallel to perpendicular to the implant, and the gap was filled with new bone, over time. 2. There was a decreasing tendency over time in the mobility of all implants, but the wider gap between bone and implant was, the smaller decrease of the mobility was. 3. There was a increasing tendency over time in the removal torque gauge of all implants, and the wider gap was, the smaller increase of the removal torque gauge was. The results suggest that osseointegration in case of implant without primary bone contact may be obtained by guided bone regeneration technique with prolonged healing period, but the time of second surgery should be considered carefully.

• Archives of Plastic Surgery
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• 제44권6호
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• pp.516-522
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• 2017

Background Implant-based breast reconstruction is being performed more frequently, and implants are associated with an increased risk of infection. We reviewed the clinical features of cases of implant infection and investigated the risk factors for breast device salvage failure. Methods We retrospectively analyzed 771 patients who underwent implant-based breast reconstruction between January 2010 and December 2016. Age, body mass index, chemotherapy history, radiation exposure, and smoking history were assessed as potential risk factors for postoperative infection. We also evaluated the presence and onset of infection symptoms, wound culture pathogens, and other complications, including seroma, hematoma, and mastectomy skin necrosis. Additionally, we examined the mastectomy type, the use of acellular dermal matrix, the presence of an underlying disease such as hypertension or diabetes, and axillary node dissection. Results The total infection rate was 4.99% (58 of 1,163 cases) and the total salvage rate was 58.6% (34 of 58). The postoperative duration to closed suction drain removal was significantly different between the cellulitis and implant removal groups. Staphylococcus aureus infection was most frequently found, with methicillin resistance in 37.5% of the cases of explantation. Explantation after infection was performed more often in patients who had undergone 2-stage expander/implant reconstruction than in those who had undergone direct-to-implant reconstruction. Conclusions Preventing infection is essential in implant-based breast reconstruction. The high salvage rate argues against early implant removal. However, when infection is due to methicillin-resistant S. aureus and the patient's clinical symptoms do not improve, surgeons should consider implant removal.

• 한국가축번식학회지
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• 제21권4호
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• pp.373-379
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• 1997

This study was carried out to determine the hormone treatment scheme for an efficient superovulation and optimal recovery time for obtaining pronuclear embryos suitable for DNA injection in Korean native goats. For a superovulation, FSH(5.6mg) was given over four days in twice daily injections with (FSH/hCG group) or without(FSH group) hCG(100 IU) co-injection at the time of 7th FSH injection. Estrus cycle was synchronized by norgestomet ear-implantation for 11 days and its removal at the time of 6th FSH injection. Among the treated goats, the percentage of ovulated goats, which were examined at 70 to 76 h following implant removal, was greater in FSH/hCG group than in FSH group (100% vs 36.4%) but there was no significant difference in the mean numbers of ovulation points and fertilization rates between the two groups. To optimize hCG treatment scheme and recovery time, we injected hCG at the time of 7th (FSH/hCGa) or 8th(FSH/hCGb) FSH injection and then examined the developmental stage of the embryos recovered at different times after implant removal. In FSH/hCGa group, significant portions(31 to 44%) were beyond 1-cell stage, which was non-injectable, irrespective of their recovery time. However, in FSH/hCGb group recovered at 70 to 76 h after implant removal, great portions(69%) were fertilized and most of them(96.6%) were injectable 1-cell stage. Considering together the fertilization rate and developmental stage of recovered embryos, it is recommendable to administrate hCG at the time of final 8th FSH injection and collect the embryos at 70 to 76 h after implant removal to obtain injectable embryos as many as possible in Korean native goats.

• 구강회복응용과학지
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• 제31권3호
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• pp.203-211
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• 2015

목적: 완전한 골-임플란트 결합을 가졌던 임플란트가 갑자기 골유착을 잃은 경우의 시간에따른 재골유착을 연구하기 위함이다. 연구 재료 및 방법: 23마리 토끼의 좌우 경골에 각각 2개씩 실험목적으로 제작한 RBM임플란트를 식립 후, 6주 후에 1차로 비틀림 제거력을 측정한 다음, 임플란트를 다시 재위치 침하시키고, 4일, 7일, 11일, 2주, 4주, 6주, 그리고 8주의 재침하시간 경과 후 2차로 비틀림 제거력을 측정하고 시편을 제작하여 조직 형태학적 검사를 하였다. 통계학적 검사를 위해 paired t-test를 시행했고, One-way ANOVA와 Tukey's post-hoc test 통해 그룹간 차이를 비교하여 다음과 같은 결과를 얻었다. 결과: 1차 비틀림 제거력과 비교해봤을 때 2차에서 11일 후에는 증가했으며, 2주 후부터 유의성 있게 증가하였다. 형광조사검사에서, 7일 후부터 골-임플란트 계면 사이에 형광밴드가 나타나는 광물화 현상이 관찰되고, 11일 후부터는 분명한 골 형성이 나타났다. 결론: 토끼에서는 11일 이후가 되면 충분한 재골유착을 얻을 수 있었다.

• 대한두개안면성형외과학회지
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• 제21권1호
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• pp.73-76
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• 2020

Cranial implant removal is recommended if implants become exposed owing to scalp necrosis after cranioplasty. However, it carries the risk of extensive bleeding, and the resultant cranial defects can cause both aesthetic and functional problems. We present a case of a scalp defect exposing a cranial prosthetic implant that was reconstructed with a local flap and salvaged using an indwelling antibiotic irrigation system. A 73-year-old man presented with scalp necrosis after undergoing cranioplasty due to intracranial hemorrhage. The cranial implant was exposed through the scalp defect. Methicillin-resistant Staphylococcus aureus was detected in the culture from the open wound. After debridement of the necrotic tissue and burring of the superficial layer of the implant, a transposition flap was used to cover the defect and an indwelling antibiotic irrigation system was installed. Continuous irrigation with vancomycin was conducted for 5 days, and intravenous vancomycin was continued for 4 weeks. The flap was in good condition at 4 months postoperatively, with no infection. The convex contour of the scalp was well maintained. The patient's neurological status was stable. Exposed cranial implants can be salvaged with continuous antibiotic irrigation as an alternative to implant removal; thus, the risk of bleeding and possible disfigurement may be avoided.

• The Journal of Advanced Prosthodontics
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• 제8권2호
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• pp.131-136
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• 2016

PURPOSE. The aim of this study was to observe stress concentration in the implant, the surrounding bone, and other components under the pull-out force during the crown removal. MATERIALS AND METHODS. Two 3-dimensional models of implant-supported conventional metal ceramic crowns were digitally constructed. One model was designed as a vertically placed implant ($3.7mm{\times}10mm$) with a straight abutment, and the other model was designed as a 30-degree inclined implant ($3.7mm{\times}10mm$) with an angled abutment. A pull-out force of 40 N was applied to the crown. The stress values were calculated within the dental implant, the abutment, the abutment screw, and the surrounding bone. RESULTS. The highest stress concentration was observed at the coronal portion of the straight implant (9.29 MPa). The stress concentrations at the cortical bone were lower than at the implants, and maximum stress concentration in bone structure was 1.73 MPa. At the abutment screws, the stress concentration levels were similiar (3.09 MPa and 3.44 MPa), but the localizations were different. The stress at the angled abutment was higher than the stress at the straight abutment. CONCLUSION. The pull-out force, applied during a crown removal, did not show an evident effect in bone structure. The higher stress concentrations were mostly observed at the implant and the abutment collar. In addition, the abutment screw, which is the weakest part of an implant system, also showed stress concentrations. Implant angulation affected the stress concentration levels and localizations. CLINICAL IMPLICATIONS. These results will help clinicians understand the mechanical behavior of cement-retained implant-supported crowns during crown retrieval.

• 대한치과보철학회지
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• 제32권1호
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• pp.148-169
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• 1994

The concept of biologic attachment of load-bearing implants has developed over the past decades as an alternative to the difficulties associated with long term implantation using mechanical fixation and bone cement. The choice of implant material is also as critical an element as site preparation or insertion procedure. The properties of implants that affect host tissue responses are not limited to chemical composition alone, but also include shape, surface characteristics, site of implantation, and mechanical interaction with host tissues. Initial mechanical interlocking prevents micromotion and may be a prerequisite for direct bone apposition. A hard tightening of screws does not necessarily mean a stronger fixation and final tightening of the fixtures is dependent on the experience of the operator. Removal torque is lower than insertion torque. The purpose of this study was to investigate differences in the removal torques at the bone-implant interface of polished and sandblasted Titanium. This experiment will give insight into important factors that must be considered when interpreting in vivo screwing forces on implants during the connection of the transmucosal abutments. We evaluated the significance of different surface textures by comparison of the withdrawal forces necessary for removal of otherwise identical rough and polished implants of Titanium and also evaluated interfacial response on the light microscopic level to implant surface. And the priority of the area of insertion on osseointegration were evaluated. 9 Titanium implants - among them, 3 were for the developmental - of either a smooth or rough surface finish were inserted in the dog mandible in the right side. 3 months later Kanon Torque Gauge was used to unscrew the implants. The results were as follows : 1. No significant difference was seen in the removal torque due to variation in surface treatment, 23 Ncm for the sandblasted and 23.33 Ncm for the polished surface (p>0.05). 2. Implants in the anterior (25 Ncm) mandible showed better resistance to unscrewing in comparison to ones in the posterior (18 Ncm) region (p<0.05). 3. Developmental fixtures (22 Ncm) had similar pullout strength to the control group (p>0.05).

• 대한치과교정학회지
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• 제41권5호
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• pp.354-360
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• 2011

Objective: To investigate the effects of different pilot-drilling methods on the biomechanical stability of self-tapping mini-implant systems at the time of placement in and removal from artificial bone blocks. Methods: Two types of artificial bone blocks (2-mm and 4-mm, 102-pounds per cubic foot [102-PCF] polyurethane foam layered over 100-mm, 40-PCF polyurethane foam) were custom-fabricated. Eight mini-implants were placed using the conventional motor-driven pilot-drilling method and another 8 mini-implants were placed using a novel manual pilot-drilling method (using a manual drill) within each of the 2-mm and 4-mm layered blocks. The maximum torque values at insertion and removal of the mini-implants were measured, and the total energy was calculated. The data were statistically analyzed using linear regression analysis. Results: The maximum insertion torque was similar regardless of block thickness or pilot-drilling method. Regardless of the pilot-drilling method, the maximum removal torque for the 4-mm block was statistically higher than that for the 2-mm block. For a given block, the total energy at both insertion and removal of the mini-implant for the manual pilot-drilling method were statistically higher than those for the motor-driven pilot-drilling method. Further, the total energies at removal for the 2-mm block was higher than that for the 4-mm block, but the energies at insertion were not influenced by the type of bone blocks. Conclusions: During the insertion and removal of mini-implants in artificial bone blocks, the effect of the manual pilot-drilling method on energy usage was similar to that of the conventional, motor-driven pilot-drilling method.

• 대한치과보철학회지
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• 제57권4호
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• pp.335-341
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• 2019

목적:불산과 염산/ 황산을 두 번 사용하는 임플란트 표면처리 방식은 선반가공한 표면에 비하여 강한 결합력을 보이지만 두 번 산처리하는 방식은 티타늄의 피로도를 야기시켜 미소균열을 야기시킬 수 있으므로, 염산으로 한번 산처리하는 방식이 비슷한 결합력을 가진다면 단순하고 효율적인 산처리 방식이 될 수 있다. 재료 및 방법: 9개의 지름 3.75, 길이 4 mm의 두 번 처리 방식의 임플란트와 같은 크기의 한 번 처리 방식의 임플란트를 토끼의 경골에 심어서, 10일 후에 회전제거력, 거칠기, 젖음각도를 측정하였다. 결과: 두 번 처리 방식과 한 번 처리 방식의 회전제거력은 차이가 없었고 (P = .995). 두 번 처리군의 거칠기는 $0.93{\mu}m$, 한 번 처리는 $0.84{\mu}m$이었다 (P = .170). 평균젖음각은 두 번 처리는 $99^{\circ}$, 한 번 처리는 $98^{\circ}$ 이었다 (P = .829). 각 변수 모두 두 그룹의 차이는 없었다. 결론:산으로 한번 처리하거나 두 번 처리 하거나 두 그룹의 회전제거력, 거칠기, 평균젖음각의 차이는 없었기 때문에 종래의 dual acid treatment보다 한번 처리하여도 유용한 것으로 보여진다.

• The Journal of Advanced Prosthodontics
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• 제6권4호
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• pp.302-308
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• 2014

PURPOSE. The purpose of this study was to compare removal torques and surface topography between laser treated and sandblasted, large-grit, acid-etched (SLA) treated implants. MATERIALS AND METHODS. Laser-treated implants (experimental group) and SLA-treated implants (control group) 8 mm in length and 3.4 mm in diameter were inserted into both sides of the tibiae of 12 rabbits. Surface analysis was accomplished using a field emission scanning electron microscope (FE-SEM; Hitachi S-4800; Japan) under ${\times}25$, ${\times}150$ and ${\times}1,000$ magnification. Surface components were analyzed using energy dispersive spectroscopy (EDS). Rabbits were sacrificed after a 6-week healing period. The removal torque was measured using the MGT-12 digital torque meter (Mark-10 Co., Copiague, NY, USA). RESULTS. In the experimental group, the surface analysis showed uniform porous structures under ${\times}25$, ${\times}150$ and ${\times}1,000$ magnification. Pore sizes in the experimental group were 20-40 mm and consisted of numerous small pores, whereas pore sizes in the control group were 0.5-2.0 mm. EDS analysis showed no significant difference between the two groups. The mean removal torque in the laser-treated and the SLA-treated implant groups were 79.4 Ncm (SD = 20.4; range 34.6-104.3 Ncm) and 52.7 Ncm (SD = 17.2; range 18.7-73.8 Ncm), respectively. The removal torque in the laser-treated surface implant group was significantly higher than that in the control group (P=.004). CONCLUSION. In this study, removal torque values were significantly higher for laser-treated surface implants than for SLA-treated surface implants.