• Elastomers and Composites
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• v.51 no.4
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• pp.269-274
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• 2016

Two different reactive silicone oligomers, hydroxylpropyl terminated PDMS (PDMS-L) and 1-(2,3-dihydroxy-propoxy)propyl terminated PDMS (PDMS-B), were synthesized through hydrosilylation reaction under Karstedt's catalyst. Using the reactive silicone oligomers, two different silicone-modified gel-coat series were prepared to investigate their thermal and mechanical properties as well as surface characteristics according to reactive silicone oligomer contents. In case of thermal stabilities and mechanical properties, the gel-coat series containing PDMS-B showed higher values than that of the gel-coat series containing the PDMS-L. The contact angle for the gel-coat containing both silicone oligomers/was increased with reactive silicone oligomer contents but there was similar surface tension between PDMS-L and PDMS-B.

• Archives of Plastic Surgery
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• v.42 no.1
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• pp.20-27
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• 2015

Background Hypertrophic scars and keloids are associated with abnormal levels of growth factors. Silicone gel sheets are effective in treating and preventing hypertrophic scars and keloids. There has been no report on the change in growth factors in the scar tissue following the use of silicone gel sheeting for scar prevention. A prospective controlled trial was performed to evaluate whether growth factors are altered by the application of a silicone gel sheet on a fresh surgical scar. Methods Four of seven enrolled patients completed the study. Transforming growth factor (TGF)-${\beta}1$, platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) were investigated immunohistochemically in biopsies taken from five scars at 4 months following surgery. Results In both the epidermis and the dermis, the expression of TGF-${\beta}1$ (P=0.042 and P=0.042) and PDGF (P=0.043 and P=0.042) was significantly lower in the case of silicone gel sheet-treated scars than in the case of untreated scars. The expression of bFGF in the dermis was significantly higher in the case of silicone gel sheet-treated scars than in the case of untreated scars (P=0.042), but in the epidermis, the expression of bFGF showed no significant difference between the groups (P=0.655). Conclusions The levels of TGF-${\beta}1$, PDGF, and bFGF are altered by the silicone gel sheet treatment, which might be one of the mechanisms of action in scar prevention.

• Archives of Plastic Surgery
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• v.33 no.1
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• pp.107-112
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• 2006

If autogenous nail is lost in nail bed injuries, alternative effective nail bed protection material is questionable in postoperative follow up period. The conventional modality with autogenous nail coverage have several disadvantages such as drawback of maintenance, higher chance of loss and complex dressing step (eg. ointment apply for humidification and nail fixation using tape or bandage). So, we have studied the usefulness of adhesive silicone gel sheet for alternative nail bed protection material until the end of nail regeneration. From March 2003 to July 2004, we have experienced 215 traumatic nail bed injuries except fingertip loss. Among these patient, we classified two groups, 30 cases with autogenous nail protection(Group I) and 30 cases with adhesive silicone gel sheet protection(Group II). Mean full nail growth time was 3.6 months in group I and 3.8 months in group II. Mean final nail appearance score(0: poor, 4: excellent) was 3.0 in group I and 3.5 in group II. Adhesive silicone gel sheet protection(Group II) was slightly superior to the autogenous nail protection in final appearance, especially sterile matrix laceration. In conclusion, we believe that adhesive silicone gel sheet application is a simple, acceptable, alternative method for protecting nail bed with loss of autogenous nail. It has a number of advantages compared with autogenous nail such as better humidification, controllable hygiene, less pain, less hospitalization, less frequent visit, less chance of loss, avoiding complex dressing step and more even pressure with adhesiveness, flexibility and durability.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.734-739
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• 2014

Background Rupture is an important complication of breast implants. Before cohesive gel silicone implants, rupture rates of both saline and silicone breast implants were over 10%. Through an analysis of ruptured implants, we can determine the various factors related to ruptured implants. Methods We performed a retrospective review of 72 implants that were removed for implant rupture between 2005 and 2014 at a single institution. The following data were collected: type of implants (saline or silicone), duration of implantation, type of implant shell, degree of capsular contracture, associated symptoms, cause of rupture, diagnostic tools, and management. Results Forty-five Saline implants and 27 silicone implants were used. Rupture was diagnosed at a mean of 5.6 and 12 years after insertion of saline and silicone implants, respectively. There was no association between shell type and risk of rupture. Spontaneous was the most common reason for the rupture. Rupture management was implant change (39 case), microfat graft (2 case), removal only (14 case), and follow-up loss (17 case). Conclusions Saline implants have a shorter average duration of rupture, but diagnosis is easier and safer, leading to fewer complications. Previous-generation silicone implants required frequent follow-up observation, and it is recommended that they be changed to a cohesive gel implant before hidden rupture occurs.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.703-706
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• 2011

Purpose: Augmentation mammoplasty by cohesive silicone gel implant is becoming more popular nowadays. Many types of complications have been reported, such as hematoma, seroma, infection, capsular contracture and etc. But there were no report of deep vein thrombosis(DVT) after augmentation mammoplasty in Korea. The authors experienced one case of DVT after augmentation mammoplasty using a cohesive silicone gel implant. Methods: A 38-year-old woman with breast cancer underwent reconstruction by tissue expander and augmentation mammoplasty by cohesive silicone gel implant, and exchange of expander to cohesive silicone gel implant. The operation was finished without any complicating event. On 4th day after the operation, the patient complained of intermittent right lower leg pain. By doppler ultrasonography, the patient was diagnosed with acute venous thrombosis of the popliteal vein, posterior tibial vein and peroneal vein. Results: Intravenous heparinization and oral warfarin were started immediately and elastic compression stocking was applied. Intravenous heparinization was continued until INR (blood coagulation unit) reached to target levels. The patient was discharged on 11th day of operation with oral warfarin. Other complication has not been reported after 10 weeks of operation. Conclusion: To our knowledge, this is the first report of DVT after silicone implant based breast augmentation.

• Journal of Biomedical Engineering Research
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• v.33 no.2
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• pp.89-97
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• 2012

The purpose of this study is to develop the guideline of the physicochemical and mechanical properties evaluation for silicone gel filled breast implants. First of all, the use and development status for silicone gel filled breast implants were investigated, and then, standard and criteria about performance evaluation established by the international organizations such as ASTM, FDA guidance and ISO were examined. To evaluate the mechanical properties, data research and testing for breaking strength, elongation, tensile set, joint intensity, silicone gel cohesion, weight loss from heating, static rupture resistance, impact resistance test, fatigue test, and gel bleed were performed. On the other hand, to evaluate the physicochemical properties, volatile matter, extent of cross linking, heavy metals, and extractable were analyzed. In this study, results for general function, mechanical properties and physicochemical properties were examined and reviewed for the accordance with international standard, and objective and standardized guideline was provided.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.700-705
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• 2006

Purpose: For hypertrophic scars and keloids no universally effective treatment modality exists. Surgical revision, intralesional steroid injection, silicone gel sheeting, pressure, laser, and others have been used with variable success, but many treatments are associated with high recurrence rates. Although optimal treatment remains undefined, successful treatment can be obtained through a combined therapeutic approach. Methods: We used three therapeutic modalities in combination, which are intralesional injection of triamcinolone acetonide, silicone gel sheeting, and 585 nm flashlamp-pumped pulsed dye laser. Fifty-eight cases of hypertrophic or keloid scar were treated by combined therapeutic regimen for mean period of 18 months. The changes of thickness, color, and pliability of scars were evaluated with clinical photographs by grading scale. Results: As summing the grades and categorizing the result into three group, we obtained 28% good, 67% fair, and 5% poor results. There was a desirable improvement of scars with insignificant adverse effects. Conclusion: Combination of intralesional steroid injection, silicone gel sheeting, and pulsed dye laser can lead to successful treatment of hypertrophic scar and keloid.

• Archives of Plastic Surgery
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• v.35 no.6
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• pp.659-662
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• 2008

Purpose: Silicone gel sheet(SGS) is used for preventing and treating keloid or hypertrophic scars. Because the product is weak in tear strength and adherence, it requires several replacements, which requires high cost. As a solution for this problem, we developed a new silicone gel sheet, named as Scar Clinic, and confirmed its physical properties. Methods: Tensile strength, elongation rate, adhesiveness, and water vapor transmission rate were experimentally compared between the most commonly used SGS product and the Scar Clinic. Results: The newly developed SGS showed better results compared to the existed SGS in regards to tensile strength, elongation rate, adhesiveness, and water vapor transmission rate. Conclusion: The Scar Clinic showed higher durability and flexibility. It will be a useful product for treating scars clinically.

• Transactions on Electrical and Electronic Materials
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• v.11 no.4
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• pp.178-181
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• 2010

An automotive IC voltage regulator which consists of one-chip based on a metal-oxide semiconductor field effect transistor (MOSFET) is investigated experimentally with three types of packaging. The closed type is filled with thermal silicone gel and covered with a plastic lid on the MOSFET. The half-closed type is covered with a plastic case but without thermal silicone gel on the MOSFET. Opened type is no lid without thermal silicone gel. In order to simulate the high temperature condition in engine bay, the operating circuit of the MOSFET is constructed and the surrounding temperature is maintained at $100^{\circ}C$. In the overshoot the maximum was mainly found at the half-closed packaging and the magnitude is dependent on the packaging type and the surrounding temperature. Also the impressed current decreased exponentially during the MOSFET operation.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.256-258
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• 2010

Purpose: Predicting the change in breast size for a specific patient's need is a challenging problem in breast augmentation. We intended to investigate the postaugmentation degree of breast size according to the size of cohesive silicone gel implant. Methods: To predict post-augmentation breast size, we measured 100 patients' pre-and postoperative 3 month's bust circumference. All patients were performed by total subfascial breast augmentation with moderate profile cohesive silicone gel implant through areolar omega (transareolar-perinipple) incision. Results: According to this study, each additional one pair of 100 mL in implant size yielded an approximate 1.5 cm increase in bust circumference (p=0.006). Conclusion: From this result, we conclude that each additional one pair of 100 mL in implant volume yielded about 1.5 cm increase in bust circumference. Although this result may not be applied to every patient, we believe that it yields a practical chart that can help to predict the amount of increase in breast size with the use of cohesive silicone gel implant of a specific size preoperatively.