There are some attempts to improve the survival of venous island flap, such as delay procedure and pharmacological agents. This study includes prefabrication of vein which could enhance the survival of the venous island flap. The venous island flap was created by a branch of the central vein in rabbit auricle. At 1.5 cm away from the distal margin of the designed flap, the central vein was dissected and transferred under the random part of the future venous flap for 1 week. The survival of prefabricated venous flap was compared with unprefabricated flap 1 week after the flap elevation. The vasculature in the flap were also visualized by microfil cast. The results were as follows: 1. The prefabrication improved the survival of the venous flap significantly. 2. The transferred veins in the prefabricated flap were well visualized 1 week after the flap elevation. In conclusion, it is inferred that the prefabrication enhance the survival of the venous island flap.
Silicone Elastomers ; Veins

PURPOSE: The aim of the study was to evaluate the effect of 3 silicone primers and 3 surface characterization of acrylic resin surface on bond strength between silicone elastomer and acrylic resin. MATERIALS AND METHODS: 96 Cosmesil silicones bonded to heat-curing acrylic resin were fabricated with the dimension of 75 x 10 x 3 mm. The 3 primers used in this study were G611 platinum primer, A-330 Gold platinum primer, and cyanoacrylates resin. Specimens without primer were used as control. The 3 types of surface characterization done were retentive holes with 1.5 mm in diameter and 0.5 mm deep, retentive beads of 0.6 mm diameter and the third type which was plain without any characterization. The specimens were then checked for bond strength by subjecting them to 180degrees peel test on a universal testing machine. The obtained results were then subjected to statistical analysis using 2-way ANOVA and Scheffe multiple post hoc procedures. The statistical significance was set at 5% level of significance. RESULTS: The maximum bond strength was seen for samples in which A-330G primer was used followed by G611 primer. The control group showed the minimum bond strength. Surface characterization of retentive holes increased the bond strength considerably as compared to retentive beads and samples without any surface characterization. CONCLUSION: Within the limitations of the study, A-330G primer was more compatible with Cosmesil M511 silicone and has better bonding of Cosmesil to acrylic resin. Retentive holes made on acrylic surface increased the bond strength considerably than those without any surface characterization.
Collodion ; Cyanoacrylates ; Platinum ; Silicone Elastomers

PURPOSE: This study evaluated the effect of loss of interproximal papilla, creating an undercut, on the accuracy of impression materials. MATERIALS AND METHODS: Two addition type silicone impression materials (Extrude(R) Wash, Imprint(TM) II Quick Step Light Body) and one alginate impression material (Cavex Impressional) were used to make impressions of a maxillary master model simulating clinical conditions with or without interproximal papilla. Stone was poured in the impressions and working casts were fabricated. A total of 6 groups with 6 working casts in each group were scanned using 3-dimensional optical scanner. The accuracy of the impressions was assessed by measuring the dimensional changes (DeltaI (%)) of 6 distances on working casts compared to a master model with a 3-dimensional digitizing and inspection software. The data were analyzed by two-way ANOVA (P<.05). RESULTS: Three of 6 distances showed statistically significant differences among the impression materials. Only 1 of 6 distances in alginate impression showed a statistically significant difference between casts with and without interproximal papilla (P=.047). CONCLUSION: The presence of undercut due to loss of interproximal papilla did not significantly influence the dimensional accuracy of addition type silicone and alginate impression materials.
Alginates ; Dental Impression Materials ; Silicone Elastomers

A line is drawn from the nasal tip to the most anterior point of the lower lip. The distance from soft tissue pogonion to the ideal soft tissue pogonion is the amount of correction. Alloplastic augmentation does not correct the soft tissue in a 1:1 ratio. In the case of a patient having normal soft tissue(8~11 mm), the ratio of the soft tissue correction is 1:0.66. In the case of a patient having a soft tissue deficiency(less than 7mm), the ratio of the soft tissue correction is 1:0.8. In the case of a patient having a soft tissue excess(more than 12mm), the ratio of the soft tissue correction is 1:0.5. The length of the implant is required to be more lateral to the mental foramen by 1~1.5 cm for restoration of the prejowl sulcus. The posterior surface of the implant must be carved to shape precisely to the bony surface. I usually make several vertical etchings and 20~30 holes in the implant. The vertical etchings help expand the implant to securely fit the mandibular contour. Fenestrated silastic implants can be further stabilized with fibrous tissue ingrowth and future reconstruction if bony erosion occurs.
Chin ; Dimethylpolysiloxanes ; Humans ; Lip ; Silicone Elastomers

PURPOSE: To evaluate the effect of combined immunosuppressive treatment with FK 506-cyclophosphamide on surgical angiogenesis in non-vascularized bone xenografts. MATERIALS AND METHODS: Twenty-seven hamster-to-rat non-vascularized bone xenografts were performed. For surgical angiogenesis, recipient origin saphenous arteriovenous bundles were implanted into the medullary canals of graft bones. Immunosuppression with FK 506-cyclophosphamide was performed in group 1, not in group 2, control group. At postoperative 4 weeks, microangiography with microfil was conducted. Decalcified bones were cleared and the area of newly formed capillary, capillary density, were quantitatively evaluated using Scion image program. Bone specimens stained with hematoxylin-eosin were evaluated histologically also. RESULTS: There was no significant difference of capillary densities between immunosuppressed group and non-immunosuppressed control group (0.37+/-0.03/0.39+/-0.02, P=0.58). On histological examination, both groups showed neoangiogenesis into the medullary canals and endosteal bones. CONCLUSION: FK 506-cyclophosphamide immunosuppression did not suppress the angiogenesis in non-vascularized bone xenografts, FK 506-cyclophosphamide combination of immunosuppression will be useful even in the condition of surgical angiogenesis.
Capillaries ; Heterografts ; Immunosuppression ; Silicone Elastomers ; Transplants

PURPOSE: To evaluate the effect of combined immunosuppressive treatment with FK 506-cyclophosphamide on surgical angiogenesis in non-vascularized bone xenografts. MATERIALS AND METHODS: Twenty-seven hamster-to-rat non-vascularized bone xenografts were performed. For surgical angiogenesis, recipient origin saphenous arteriovenous bundles were implanted into the medullary canals of graft bones. Immunosuppression with FK 506-cyclophosphamide was performed in group 1, not in group 2, control group. At postoperative 4 weeks, microangiography with microfil was conducted. Decalcified bones were cleared and the area of newly formed capillary, capillary density, were quantitatively evaluated using Scion image program. Bone specimens stained with hematoxylin-eosin were evaluated histologically also. RESULTS: There was no significant difference of capillary densities between immunosuppressed group and non-immunosuppressed control group (0.37+/-0.03/0.39+/-0.02, P=0.58). On histological examination, both groups showed neoangiogenesis into the medullary canals and endosteal bones. CONCLUSION: FK 506-cyclophosphamide immunosuppression did not suppress the angiogenesis in non-vascularized bone xenografts, FK 506-cyclophosphamide combination of immunosuppression will be useful even in the condition of surgical angiogenesis.
Capillaries ; Heterografts ; Immunosuppression ; Silicone Elastomers ; Transplants

This paper reviews and analyzes the modifications of silicone rubber, containing nanometer material tilling, plasma surface modification, surface grafting, mixture with bioactive substrates and bionic coating. At last, the author shows the prospect for the future development of silicone rubber modification.
Equipment and Supplies ; Humans ; Silicone Elastomers ; chemistry

For many years permanent soft denture liners has been widely used in dental practice directly or indirectly because of its function in absorbing and distributing the impact force. However, it reveals problems such as lack of permanency and decreased bond strength in long term use. The purpose of this study is to measure the bond strength and failure between denture base resin and several permanent liners. Lucitone 199 was used as denture base resin with soft acrylic liners (Triad, Tokuso Rebase) and silicone elastomers (Tokuyama, Ufi Gel C) bonded to measure the tensile strength before and after thermocycling. The thermocycling was done in 2000 cycles at 5degrees C, 26degrees C and 55degrees C and the measured tensile strength values before and after thermocycling were compared. The mode of failure was investigated in the separated specimens. The results are as follows. 1. As to tensile strength, the strongest material is Tokuso Rebase followed by Triad, Tokuyama, Ufi Gel C in before thermocycling and the order of Triad, Tokuso Rebase, Tokuyama, Ufi Gel C in after thermocycling state. There was significant difference between the values of Triad, Tokuso Rebase and Tokuyama, Ufi Gel C(p<0.05). 2. As to degree of displacement, Ufi Gel C showed most displacement with or without thermocycling treatment and also the difference was significant with the other materials(p<0.05). 3. As to comparisons before and after thermocycling, Tokuso Rebase and Tokuyama showed significant difference in bond strength, whereas Triad and Tokuso Rebase showed significant difference in the degree of displacement(p<0.05). 4. In debonded specimens, Triad and Ufi Gel C showed adhesion failure and Tokuyama showed cohesion failure. Both failures were observed in Tokuso Rebase with adhesion failure up to 70%. The results of this study showed that degree of bond strength between permanent soft denture liner and denture base resin were variable. There was a significant difference between soft acrylics and silicone elastomers with regard to bond strength. Further research in improving bond strength of widely used silicone elastomers and in developing the method of measuring bond strength between denture base resin and the lining materials is needed.
Denture Bases* ; Denture Liners* ; Dentures* ; Silicone Elastomers ; Tensile Strength

No abstract available.
Animals ; Dogs* ; Facial Bones* ; Periosteum* ; Silicone Elastomers* ; Transplants*

The silicone rubber implants are widely used in plastic surgery because of various advantages; however, calcification in surface of implant(as a chemical resistance) may transform or destroy the high molecular biomaterial when it stays too long within the human body. The purpose of this study is to determine the relationship between calcification and the histological disparities of the tissues surrounding the area adjoining the silicone nasal implant by examining the regional characteristics of calcium deposits in the silicone nasal implant via elemental analyses using EDX(energy-dispersive X-ray analysis) and ultrastructural analyses using SEM(scanning electron microscopy). The subjects of the study were 19 silicone nasal implants removed by revision rhinoplasty, all displaying calcification. According to the tissue characters, the implant surface was divided into 4 zones with the rhinion as the basis. For each zone, elemental and ultrastructural analyses were performed. Elemental analysis revealed that the calcium deposits consisted of Ca and P only. There were no statistically significant disparities among the ratios between Ca and P according to the zones. Ultrastructural analysis showed acellular mineral-like deposits coalesced to create amorphous deposits in all zones; however, in zones 1 and 3(more pressurized zones by periosteum or nasal bone), additional flaky cylinder-shaped calcium deposits were detected. Thus, it seems that the histological disparities in the surrounding tissues do not affect the components and their proportions in the calcification process. However, it can be inferred that the physical environment due to the histological disparities in the surrounding tissues affects the ultrastructures of calcium deposits.
Calcium ; Human Body ; Periosteum ; Rhinoplasty ; Silicone Elastomers ; Surgery, Plastic