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

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

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

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

The purpose of this study was to evaluate the difference in the surface roughness after polishing and to evaluate the difference in color stability after immersion in a dye solution among four types of composite resin materials. Four light-polymerized composite resins (Shade A2) with different sized filler content (a nanofilled, a hybrid, a microfilled, a flowble) were used. Average surface roughness (Ra) was measured with a surface roughness tester (Surftest Formtracer) before and after polishing with aluminum oxide abrasive discs (Super-Snap). Color of specimens before and after staining with 2% methylene blue solution were measured using spectrophotometer (CM-3700d) with SCI geometries. The results of Ra and DeltaE were analyzed by one-way analysis of variance (ANOVA), a Scheffe multiple comparison test and Student t-test (p = 0.05). After polishing, Ra values were decreased regardless of type of composite resins. In surface roughness after polishing and color stability after staining, nanofilled composite resin was not different with other composite resins except flowable resins.
Aluminum Oxide ; Composite Resins* ; Humans ; Immersion ; Methylene Blue ; Silicone Elastomers

PURPOSE: Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS: Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment , and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of +37degrees C. Color measurements were made with a spectrophotometer and registered according to the CIELAB L*a*b* color model system. The changes in L*, a* and b* values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS: The UV exposure resulted in visually noticeable and statistically significant color changes in the L*, a* and b* values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the a* and b* values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION: The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.
Aging ; Darkness ; Humidity ; Incubators ; Maxillofacial Prosthesis ; Silicone Elastomers ; Skin

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