• The Korean Journal of Pain
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• v.32 no.1
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• pp.47-50
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• 2019

Background: It is uncommon for patients who have received a permanent implant to remove the spinal cord stimulator (SCS) after discontinuation of medication in complex regional pain syndrome (CRPS) due to their completely painless state. This study evaluated CRPS patients who successfully removed their SCSs. Methods: This 10-year retrospective study was performed on patients who had received the permanent implantation of an SCS and had removed it 6 months after discontinuation of stimulation, while halting all medications for neuropathic pain. Age, sex, duration of implantation, site and type of CRPS, and their return to work were compared between the removal and non-removal groups. Results: Five (12.5%, M/F = 4/1) of 40 patients (M/F = 33/7) successfully removed the permanent implant. The mean age was younger in the removal group ($27.2{\pm}6.4$ vs. $43.5{\pm}10.7$ years, P < 0.01). The mean duration of implantation in the removal group was $34.4{\pm}18.2$ months. Two of 15 patients (13.3%) and 3 of 25 patients (12%) who had upper and lower extremity pain, respectively, had removed the implant. The implants could be removed in 5 of 27 patients (18.5%) with CRPS type 1 (P < 0.01). All 5 patients (100%) who removed their SCS returned to work, while only 5 of 35 (14.3%) in the non-removal group did (P < 0.01). Conclusions: Even though this study had limited data, younger patients with CRPS type 1 could remove their SCSs within a 5-year period and return to work with complete pain relief.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.396-408
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• 2008

Statement of problem: Within the elastic limit of the screw, the greater the preload, the tighter and more secure the screw joint. However, additional tensile forces can incur plastic deformation of the abutment screw when functional loads are superimposed on preload stresses, and they can elicit the loosening or fracture of the abutment screw. Therefore, it is necessary to find the optimum preload that will maximize fatigue life and simultaneously offer a reasonable degree of protection against loosening. Another critical factor in addition to the applied torque which can affect the amount of preload is the joint connection type between implant and abutment. Purpose: The purpose of this study was to evaluate the influence of tightening torque on the implant-abutment screw joint stability. Material and methods: Respectively, three different amount of tightening torque (20, 30, and 40 Ncm) were applied to implant systems with three different joint connections, one external butt joint and two internal cones. The initial removal torque value and the postload (cyclic loading up to 100,000 cycles) removal torque value of the abutment screw were measured with digital torque gauge. Then rate of the initial and the postload removal torque loss were calculated for the comparison of the effect of tightening torques and joint connection types between implant and abutment on the joint stability. Results and conclusion: 1. Increase in tightening torque value resulted in significant increase in initial and postload removal torque value in all implant systems (P < .05). 2. Initial removal torque loss rates in SS II system were not significantly different when three different tightening torque values were applied (P > .05), however GS II and US II systems exhibited significantly lower loss rates with 40 Ncm torque value than with 20 Ncm (P < .05). 3. In all implant systems, postload removal torque loss rates were lowest when the torque value of 30 Ncm was applied (P < .05). 4. Postload removal torque loss rates tended to increase in order of SS II, GS II and US II system. 5. There was no correlation between initial removal torque value and postload removal torque loss rate (P > .05).

• The Journal of Advanced Prosthodontics
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• v.1 no.2
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• pp.107-112
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• 2009

STATEMENT OF PROBLEM. Macroscopic and especially microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Dental implants with modified surfaces have shown stronger osseointegration than implants which are only turned (machined). Advanced surface modification techniques such as anodic oxidation and Ca-P application have been developed to achieve faster and stronger bonding between the host bone and the implant. PURPOSE. The purpose of this study was to investigate the effect of surface treatment of titanium dental implant on implant stability after insertion using the rabbit tibia model. MATERIAL AND METHODS. Three test groups were prepared: sandblasted, large-grit and acid-etched (SLA) implants, anodic oxidized implants, and anodized implants with Ca-P immersion. The turned implants served as control. Twenty rabbits received 80 implants in the tibia. Resonance frequencies were measured at the time of implant insertion, 2 weeks and 4 weeks of healing. Removal torque values (RTV) were measured 2 and 4 weeks after insertion. RESULTS. The implant stability quotient (ISQ) values of implants for resonance frequency analysis (RFA) increased significantly (P <. 05) during 2 weeks of healing period although there were no significant differences among the test and control groups (P >. 05). The test and control implants also showed significantly higher ISQ values during 4 weeks of healing period (P < .05). No significant differences, however, were found among all the groups. All the groups showed no significant differences in ISQ values between 2 and 4 weeks after implant insertion (P >. 05). The SLA, anodized and Ca-P immersed implants showed higher RTVs at 2 and 4 weeks of healing than the machined one (P < .05). However, there was no significant difference among the experimental groups. CONCLUSION. The surface-modified implants appear to provide superior implant stability to the turned one. Under the limitation of this study, however, we suggest that neither anodic oxidation nor Ca-P immersion techniques have any advantage over the conventional SLA technique with respect to implant stability.

• Journal of Korean Neurosurgical Society
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• v.52 no.4
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• pp.353-358
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• 2012

Objective : The purpose of this study was to determine the efficacy of bone cement-augmented short segment fixation using percutaneous screws for thoracolumbar burst fractures in a background of severe osteoporosis. Methods : Sixteen patients with a single-level thoracolumbar burst fracture (T11-L2) accompanying severe osteoporosis treated from January 2008 to November 2009 were prospectively analyzed. Surgical procedures included postural reduction for 3 days and bone cement augmented percutaneous screw fixation at the fracture level and at adjacent levels without bone fusion. Due to the possibility of implant failure, patients underwent implant removal 12 months after screw fixation. Imaging and clinical findings, including involved vertebral levels, local kyphosis, canal encroachment, and complications were analyzed. Results : Prior to surgery, mean pain score (visual analogue scale) was 8.2 and this decreased to a mean of 2.2 at 12 months after screw fixation. None of the patients complained of pain worsening during the 6 months following implant removal. The percentage of canal compromise at the fractured level improved from a mean of 41.0% to 18.4% at 12 months after surgery. Mean kyphotic angle was improved significantly from $19.8^{\circ}$ before surgery to 7.8 at 12 months after screw fixation. Canal compromise and kyphotic angle improvements were maintained at 6 months after implant removal. No significant neurological deterioration or complications occurred after screw removal in any patient. Conclusion : Bone cement augmented short segment fixation using a percutaneous system can be an alternative to the traditional open technique for the management of selected thoracolumbar burst fractures accompanied by severe osteoporosis.

• The Journal of Advanced Prosthodontics
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• v.5 no.1
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• pp.21-28
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• 2013

PURPOSE. This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS. Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at $30^{\circ}$ to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for $10^5$ cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (${\alpha}$=0.05). RESULTS. Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION. The abutment types did not have a significant influence on short term screw loosening. On the other hand, after $10^5$ cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not.

• The Journal of Advanced Prosthodontics
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• v.10 no.6
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• pp.415-421
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• 2018

PURPOSE. This study investigated the effects of abutment screw lengths on screw loosening and removal torque in external connection implants after oblique cyclic loading. MATERIALS AND METHODS. External connection implants were secured with abutment screws to straight abutments. The abutment-implant assemblies were classified into seven groups based on the abutment screw length, with each group consisting of five assemblies. A cyclic load of 300 N was applied at a $30^{\circ}$ angle to the loading axis until one million cycles were achieved. Removal torque values (RTVs) before and after loading, and RTV differences were evaluated. The measured values were analyzed using repeated measures of analysis of variance with the Student-Newman-Keuls multiple comparisons. RESULTS. All assemblies survived the oblique cyclic loading test without screw loosening. There was a significant decrease in the RTVs throughout the observed abutment screw lengths when the abutment-implant assemblies were loaded repeatedly (P<.001). However, the abutment screw length did not show significant difference on the RTVs before and after the experiment when the abutment screw length ranged from 1.4 to 3.8 mm (P=.647). CONCLUSION. Within the limit of this experiment, our results indicate that the abutment screw length did not significantly affect RTV differences after oblique cyclic loading when a minimum length of 1.4 mm (3.5 threads) was engaged. These findings suggest that short abutment screws may yield stable clinical outcomes comparable to long screws in terms of load resistance.

• 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.

• The Journal of Advanced Prosthodontics
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• v.10 no.1
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• pp.73-78
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• 2018

PURPOSE. The purpose of this study was to analyze the effects of two different implant surface treatments on initial bone connection by comparing the Removal Torque Values (RTQs) at 7 and 10 days after chemically modified, sandblasted, large-grit and acid-etched (modSLA), and Laser-etched (LE) Ti implant placements. MATERIALS AND METHODS. Twenty modSLA and 20 LE implants were installed on the left and right tibias of 20 adult rabbits. RTQs were measured after 7 and 10 days in 10 rabbits each. Scanning electron microscope (SEM) photographs of the two implants were observed by using Quanta FEG 650 from the FEI company (Hillsboro, OR, USA). Analyses of surface elements and components were conducted using energy dispersive spectroscopy (EDS, Horiba, Kyoto, Japan). RESULTS. The mean RTQs were $12.29{\pm}0.830$ and $12.19{\pm}0.713$ Ncm after 7 days (P=.928) and $16.47{\pm}1.324$ and $16.17{\pm}1.165$ Ncm after 10 days (P=.867) for LE and modSLA, respectively, indicating no significant inter-group differences. Pore sizes in the LE were $40{\mu}m$ and consisted of numerous small pores, whereas pore sizes in the modSLA were $5{\mu}m$. In the EDS analysis, Ti, O, and C were the only three elements found in the LE surfaces. Na, Ca, Cl, and K were also observed in modSLA, in addition to Ti, O, and C. CONCLUSION. The implants showed no significant difference in biomechanical bond strength to bone in early-stage osseointegration. LE implant can be considered an excellent surface treatment method in addition to the modSLA implant and can be applied to the early loading of the prosthesis clinically.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.36-41
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• 2024

Background Among breast reconstruction methods, implant-based breast reconstruction has become the mainstream. However, periprosthetic infection is still an unresolved problem. Although published articles have revealed that limited use of antibiotics is sufficient to reduce infection rates, the number of surgeons still preferring elongated usage of antibiotics is not less. The aim of our study is to validate the appropriate duration of antibiotic use to reduce infection rate after implant-based breast reconstruction. Methods A retrospective study reviewed medical record of 235 patients (274 implants for reconstruction) who underwent prepectoral direct to implant breast reconstruction using acellular dermal matrix wrapping technique. Infection rates were analyzed for the patients administered postoperative prophylactic antibiotics until drain removal and those who received only perioperative prophylactic antibiotics for 24 hours. Results Of the 274 implants, 98 who were administered prophylactic antibiotics until drain removal had an infection rate of 3.06% (three implants) and 176 who received prophylactic antibiotics no longer than 24 hours postoperatively had an infection rate of 4.49% (eight implants). A total of 11 patients diagnosed with postoperative infection clinically, 8 were salvaged by antibiotic treatment, and 3 had implant removal and replacement with autologous flap. Postoperative antibiotic prophylaxis duration had no statistically significant effects in the risk of infection (p = 0.549). Conclusion The duration of prophylactic antibiotics after surgery was not related to infection risk. Further study with a large number of patients, randomized control study, and route of antibiotics is needed.

• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.29-32
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• 2009

Purpose: Alloplastic implants, such as $Silastic^{(R)}$, $Supramid^{(R)}$, Porous polyethylene, $Teflon^{(R)}$ have been used to prevent reherniation of orbital tissue and are known to be inert for many years, though complications are infrequently reported many years after their insertion. Complications associated with implants are infrequent, but infection, orbital hemorrhage, implant extrusion, motility restriction, migration of implant causing dacryocystitis, cystic formation have been described. The latter was known as a rare late complication of blow-out fracture repair. Methods: We report the case of a discovery of a intraorbital hemorrhagic cyst which developed after silicon implant insertion. This patient developed diplopia, unilateral proptosis, exophthalmos, vertical dystopia, ectropion 10 years after repair of blow-out fracture. In this case, orbital CT scan revealed intraorbital cyst surrounding the orbital implant. At surgery, a fibrous capsule surrounded the silicon implant and was filled with mucin pools. Results: Proptosis, diplopia, exophthalmos, ectropion, vertical dystopia were resolved after surgical removal of the cyst and implant. Conclusion: This case illustrate that it is important for us to be aware of the complication of cyst formation around the silicon implants.